Phase II Trial of Definitive Therapy for Osseous Oligometastases in Breast Cancer

PURPOSE/OBJECTIVE(S)

Phase II data for consolidative local therapy for oligometastatic disease demonstrated improved outcomes for various malignancies. However, a randomized phase II study of oligometastatic breast cancer patients testing predominantly ablative dose radiotherapy (RT) did not demonstrate progression-free survival (PFS) benefit. We conducted a single-arm phase II trial evaluating local therapy as part of the multidisciplinary management of breast cancer patients with limited bone metastases.

MATERIALS/METHODS

Patients with synchronous (n = 15) and metachronous (n = 15) oligometastatic breast cancer involving ≤3 osseous sites were enrolled from July 2009 to April 2016 and treated to a total of 44 bone metastases. The trial closed early due to slow accrual. Following ≤9 months of systemic therapy, local therapy entailed surgery (n = 3) or RT delivered via conventional fractionation (≥60 Gy, n = 36) or stereotactic technique (27 Gy/3 fractions for spine mets, n = 6). When indicated, RT to the primary was delivered concurrently (n = 15). The primary endpoint was to determine PFS. Secondary endpoints were overall survival (OS), local control (LC) and toxicity. Outcomes were evaluated with Kaplan-Meier and univariate Cox proportional hazards analyses.

RESULTS

Of the 30 patients included in the trial, 23 (77%) had ER+ or PR+/HER2- disease, 4 (13%) had Her2+ disease, and 3 (10%) were triple negative. Median age was 53, and 20 patients (67%) presented with 1 distant metastasis. A total of 21 patients (70%) experienced disease progression at a median 20.5 months (IQR: 8.2-41.2), including 5 local failures among 44 treated bone metastases (11%). At a median follow-up of 76.7 mon (IQR: 45.4-108.8), the median PFS was 37.8 mon, with 2- and 5-year rates (95% CI) of 60% (45-80%) and 32% (19-55%), respectively. The 2- and 5-year OS rates were 93% (85-100%) and 64% (48-85%), respectively, and the 2- and 5-year LC rates were 91% (80-100%) and 71% (51-98%). For patients who achieved LC, median PFS was 47.7 months (IQR 12.2-73.0). Twenty-one patients (70%) received cytotoxic chemotherapy with or without endocrine therapy for newly diagnosed oligometastatic disease. Nine patients (30%) were still alive with no evidence of disease (NED) at a median 96.9 mon (range: 47.7-158.6). PFS was worse among triple negative patients (p = 0.03), with no difference based on synchronous vs non-synchronous presentation (p = 0.10), receipt of cytotoxic chemotherapy prior to definitive therapy (p = 0.08) or Her2+ status (p = 0.21). There were no Grade ≥3 adverse events.

CONCLUSION

Definitive, predominantly conventionally fractionated local therapy was associated with long-term NED status for 30% of patients with oligometastatic breast cancer involving osseous sites, with minimal treatment-associated toxicity. Developing randomized trials for breast cancer subsets may warrant consideration of standard fractionation regimen data and the need for strategies to identify patients who may benefit from definitive local therapy.

Prospective Clinical Trial of Premastectomy Radiotherapy Followed by Immediate Breast Reconstruction for Operable Breast Cancer

PURPOSE/OBJECTIVE(S)

Radiation delivered prior to mastectomy and autologous breast reconstruction may avoid the adverse effects of radiation on autologous donor tissue while providing the psychologic benefit of immediate reconstruction. We aimed to study the feasibility of premastectomy radiation therapy (PreMRT).

MATERIALS/METHODS

A total of 50 women enrolled in a prospective trial of preoperative radiation to the breast and regional nodes followed by mastectomy with axillary evaluation and immediate breast reconstruction. The trial was embedded in a randomized trial of hypofractionated versus conventionally fractionated regional nodal irradiation (NCT02912312). Eligible women enrolled from 2018-22, had cT0-T3 N0-3 breast cancer, and a pre-operative recommendation for radiation. The primary outcome was frequency of complete free flap loss. Mastectomy skin flap necrosis was assessed by validated SKIN grading score. The Satisfaction with Breast Cosmetic Outcomes Scales evaluated patient satisfaction with cosmetic result. Descriptive statistics and 95% exact confidence intervals were calculated.

RESULTS

One patient withdrew prior to any treatment and one elected not to have breast reconstruction. Median age of the 48 women completing PreMRT and reconstruction was 48 [range 31-72]. Most had ER-positive HER2-negative (77%), cT3 (54%) or cT2 (38%), cN1 (79%) disease and received 50 Gy in 25 fractions (n = 24) or 40.05 Gy in 15 fractions (n = 23). Four received 10-16 Gy internal mammary or infraclavicular boost. 35% VMAT, 48% matched photon-electron, and 17% partially-wide-tangent technique. Median time to surgery was 23 days [14-85]. Skin reaction delayed surgery for one patient. Most had skin-sparing mastectomy (92%) and axillary lymph node dissection (67%). 12 surgeons performed the reconstructions: 35 deep inferior epigastric perforators; 4 profunda artery perforator; 2 muscle-sparing transverse rectus abdominis myocutaneous; 1 latissimus dorsi (LD); 2 LD/implant; 2 LD/tissue expander (TE); and 2 subpectoral (SP) TE. There were no complete flap losses. Two patients (4.4%, 95% CI 0.5%-14.8%) with free flaps had partial flap loss with revision surgery. Both patients with SP TEs had infections and unplanned reoperation. The protocol was subsequently amended to not allow SP TE reconstruction. Eight patients had skin flap necrosis: 5 partial and 3 full thickness necrosis; only 1 required operative debridement. Seven had pathologic complete response. At six months 19/31 (61%) reported being "quite a bit" or "very much" satisfied with how they looked in the mirror clothed. There are no recurrences with a median follow up of 33 months [5-119].

CONCLUSION

Radiation treatment of the breast and lymph node basins prior to mastectomy with immediate autologous reconstruction is feasible. There were no autologous flap loses and complication rates are similar to reconstruction after radiation series. This promising strategy reduces time to autologous reconstruction and merits further prospective study.

Addition of Metastasis-Directed Therapy to Standard of Care Systemic Therapy for Oligometastatic Breast Cancer (EXTEND): A Multicenter, Randomized Phase II Trial

PURPOSE/OBJECTIVE(S)

Prior retrospective and prospective evidence have suggested a potential survival benefit of adding metastasis-directed therapy (MDT) to standard of care systemic therapy for oligometastatic breast cancer. This has led to the increased utilization of MDT in this setting despite the lack of randomized evidence to support this approach. Furthermore, the recent presentation of NRG-BR002 has questioned the value of MDT. Thus, we evaluated whether the addition of MDT to systemic therapy improves PFS in oligometastatic breast cancer.

MATERIALS/METHODS

EXTEND (NCT03599765) is a phase II randomized basket trial for multiple solid tumors testing whether the addition of MDT improves PFS. The primary endpoint was pre-specified to be independently assessed and reported for the breast basket when a minimum of 6 months of follow-up had been reached. Patients with ≤5 metastases were randomized to standard of care systemic therapy with or without MDT. The choice of systemic therapy was at the discretion of the treating medical oncologist. Number of metastatic lesions and prior lines of systemic therapy for metastatic disease were used as stratification variables pre-randomization. The primary endpoint was progression-free survival (PFS) defined as time to randomization to date of clinical or radiographic progression or death. The study was designed to have 80% power to detect an improvement in median PFS from 18 to 36 months, with a type I error of 0.1.

RESULTS

Between September 2018 to July 2022, 43 patients were randomized. 22 patients were assigned to the MDT arm, and 21 patients to the no MDT arm. Three patients were not evaluable. The MDT arm patients were older vs the no-MDT arm patients (median 61.5 years vs 48 years, p = 0.01). Otherwise, the arms were well-balanced. Overall, 8 patients had triple negative disease (18.6%), and 12 patients (30%) had de novo metastatic disease. Of those patients with de novo presentation randomized to MDT, all except one had the primary tumor treated with surgery and radiation. At a median follow-up of 19.4 months, 20 events were observed. Among the 40 evaluable patients, there were 5 deaths (3 in the MDT arm and 2 in the no MDT arm). There was no difference in PFS between the MDT and no MDT arms (median 15.6 v 24.9 months, p = 0.66). Similarly, there was no difference in the secondary endpoint of time to new metastatic lesion appearance between the MDT and no MDT arms (median 15.6 months vs not reached, p = 0.09). Two grade 3 toxicities were observed in the MDT arm, and 1 in the no MDT arm. Further analysis of correlative translational biomarkers, including immune markers and ctDNA, are ongoing.

CONCLUSION

The addition of MDT to standard of care systemic therapy did not improve PFS or time to new metastatic lesion in patients with oligometastatic breast cancer. This data coupled with the recently presented NRG-BR002 results, suggests there is no benefit to MDT in an otherwise unselected oligometastatic breast cancer population.

Subacute Cutaneous Toxicity with Single-Fraction Electron FLASH RT in Yorkshire Swine

PURPOSE/OBJECTIVE(S)

Information regarding acute/subacute skin toxicity of electron FLASH radiation therapy (RT) is limited. We evaluated short-term safety of electron FLASH for human trials by investigating subacute toxicity compared to conventional dose-rate RT (CONV) in the Yorkshire pig, an animal model known to closely approximate human skin and routinely used for toxicity studies.

MATERIALS/METHODS

Two healthy 50 kg pigs underwent CT imaging for RT treatment planning with field visualization via BBs and tattoos on each dorsolateral flank. Each target received a single fraction of 20, 25 or 30 Gy with FLASH and CONV on opposing sides delivered using a dedicated mobile linear accelerator. FLASH dose rates ranged from 164-245 Gy/sec (12 pulses delivered over 0.122 sec) while the CONV dose rate was set at 0.18 Gy/sec. Doses were verified using thermo- and optically stimulated luminescent dosimeters, and Gafchromic films. We obtained baseline and weekly images up to 98 days post-RT (D98) for blinded toxicity grading by 3 expert radiation oncologists using the modified RTOG radiation dermatitis (RD) scale. We measured erythema and pigmentation indices on those timepoints using a handheld spectrophotometer. We also obtained punch biopsies of targets and non-irradiated controls on D10 and D30 for RNA sequencing and two 6-marker multiplex immunofluorescence analyses of inflammation, immune response, and fibrosis. FLASH and CONV data were compared using repeated measures ANOVA and transcriptomic analyses using DESeq2.

RESULTS

All RT targets developed peak median grade 4 (ulceration, hemorrhage, or necrosis) RD by D84 regardless of FLASH or CONV delivery. However, FLASH targets developed peak RD later than CONV targets after 20 Gy (D84 vs D63), 25 Gy (D84 vs D49) and 30 Gy (D63 vs D42). FLASH induced qualitatively lower mean pigmentation and erythema indices than CONV for all 3 doses. Similarly, peak mean pigmentation indices occurred later with FLASH vs CONV for 20 Gy (D84 vs D63), 25 Gy (D84 vs D49) and 30 Gy (D77 vs D63). However, peak mean erythema indices occurred on the same day for FLASH and CONV (D63 for 20 Gy and D42 for 25 and 30 Gy). Transcriptomic analyses revealed significantly upregulated signals for wound healing (including TGF-beta, cell adhesion and extracellular matrix receptor interaction) and leukocyte infiltration with 20 Gy CONV mostly by D10, while FLASH upregulated those pathways only after 25 or 30 Gy, or by D30, or never at all. Preliminary immunofluorescence data showed FLASH may induce less T cell infiltrate and TGF-beta-expressing macrophages than CONV.

CONCLUSION

Single-fraction electron FLASH resulted in delayed onsets of both subacute cutaneous toxicity and wound healing with leukocytic infiltration signaling than dose-matched CONV based on both subjective and objective metrics of skin injury. Our findings suggest further investigations of optimal dose of electron FLASH for safe clinical translation is warranted, and we have a dose-finding study currently underway.

Inflammatory breast cancer defined: proposed common diagnostic criteria to guide treatment and research

Purpose

Inflammatory breast cancer is a deadly and aggressive type of breast cancer. A key challenge relates to the need for a more detailed, formal, objective definition of IBC, the lack of which compromises clinical care, hampers the conduct of clinical trials, and hinders the search for IBC-specific biomarkers and treatments because of the heterogeneity of patients considered to have IBC.

Methods

Susan G. Komen, the Inflammatory Breast Cancer Research Foundation, and the Milburn Foundation convened patient advocates, clinicians, and researchers to review the state of IBC and to propose initiatives to advance the field. After literature review of the defining clinical, pathologic, and imaging characteristics of IBC, the experts developed a novel quantitative scoring system for diagnosis.

Results

The experts identified through consensus several “defining characteristics” of IBC, including factors related to timing of onset and specific symptoms. These reflect common pathophysiologic changes, sometimes detectable on biopsy in the form of dermal lymphovascular tumor emboli and often reflected in imaging findings. Based on the importance and extent of these characteristics, the experts developed a scoring scale that yields a continuous score from 0 to 48 and proposed cut-points for categorization that can be tested in subsequent validation studies.

Conclusion

To move beyond subjective ‘clinical diagnosis’ of IBC, we propose a quantitative scoring system to define IBC, based on clinical, pathologic, and imaging features. This system is intended to predict outcome and biology, guide treatment decisions and inclusion in clinical trials, and increase diagnostic accuracy to aid basic research; future validation studies are necessary to evaluate its performance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06434-x.

Evaluation of overall survival and barriers to surgery for patients with breast cancer treated without surgery: a National Cancer Database analysis

Surgery remains the foundation of curative therapy for non-metastatic breast cancer, but many patients do not undergo surgery. Evidence is limited regarding this population. We sought to assess factors associated with lack of surgery and overall survival (OS) in patients not receiving breast cancer surgery. Retrospective cohort study of patients in the US National Cancer Database treated in 2004-2016. The dataset comprised 2,696,734 patients; excluding patients with unknown surgical status or stage IV, cT0, cTx, or pIS, metastatic or recurrent disease resulted in 1,192,294 patients for analysis. Chi-square and Wilcoxon rank-sum tests were used to assess differences between groups. OS was analyzed using the Kaplan-Meier method with a Cox proportional hazards model performed to assess associated factors. In total 50,626 (4.3%) did not undergo surgery. Black race, age >50 years, lower income, uninsured or public insurance, and lower education were more prevalent in the non-surgical cohort; this group was also more likely to have more comorbidities, higher disease stage, and more aggressive disease biology. Only 3,689 non-surgical patients (7.3%) received radiation therapy (RT). Median OS time for the non-surgical patients was 58 months (3-year and 5-year OS rates 63% and 49%). Median OS times were longer for patients who received chemotherapy (80 vs 50 (no-chemo) months) and RT (85 vs 56 (no-RT) months). On multivariate analysis, age, race, income, insurance status, comorbidity score, disease stage, tumor subtype, treatment facility type and location, and receipt of RT were associated with OS. On subgroup analysis, receipt of chemotherapy improved OS for patients with triple negative (HR 0.66, 95% CI 0.59-0.75, P < 0.001) and HER2+ (HR 0.74, 95% CI 0.65-0.84, P < 0.001) subgroups while RT improved OS for ER+ (HR 0.72, 95% CI 0.64-0.82, P < 0.001) and favorable-disease (ER+, early-stage, age >60) (HR 0.61, 95% CI 0.45-0.83, P = 0.002) subgroups. Approximately 4% of women with breast cancer do not undergo surgery, particularly those with more aggressive disease and lower socioeconomic status. Despite its benefits, RT was underutilized. This study provides a benchmark of survival outcomes for patients who do not undergo surgery and highlights a potential role for use of RT.

Abstract P2-01-03: Lipocalin 2 promotes inflammatory breast cancer tumorigenesis and skin invasion

Background: Inflammatory breast cancer (IBC) is the most lethal form of primary breast cancer and accounts for a significant 10 % of breast cancer deaths in the USA owing to its aggressive proliferation and metastasis, and a lack of effective therapeutic options. Unraveling the underlying mechanisms of growth and metastasis of this aggressive disease could lead to effective therapeutic strategies for an improved outcome in IBC patients. We recently generated in vitro and in vivo IBC models for brain metastasis studies [Debeb et al. JNCI, 2016] and observed an upregulation of Lipocalin 2 (LCN2), a small, secreted iron-trafficking protein which plays a significant role in immune and inflammatory responses and the promotion of malignant progression. The purpose of this study was to investigate the function of LCN2 in IBC tumorigenesis and metastasis.

Methods: Stable knockdown (KD) of LCN2 in IBC cell lines was achieved with lentiviral vectors. Proteomic and gene expression profiling were performed using RPPA and Affymetrix Clariom D microarray. For in vivo studies, control and LCN2 KD IBC cells were transplanted into the cleared mammary fat pad of SCID/Beige mice. Tumor-skin involvement was assessed visually during primary tumor growth and tumor excision. LCN2 gene expression levels in clinical samples were analyzed from the IBC Consortium as well as public data sets. LCN2 serum levels in IBC patients were measured using ELISA and were correlated with clinicopathological variables and outcome data.

Results: LCN2 gene expression is higher in IBC versus non-IBC patients (p=0.00036), independently of the molecular subtypes, and higher in more aggressive (TNBC and HER2+) than hormone receptor-positive subtypes (p&lt;0.00001). LCN2 expression in patient tissues is correlated with reduced overall survival (p&lt;0.00001) and metastasis-free survival (p=0.04) in non-IBC; however, LCN2 was not associated with overall survival in IBC patient serum samples. LCN2 expression was also significantly higher in IBC cell lines, in their culture media, and in brain metastasis sublines compared to non-IBC cell lines (p=0.004). In IBC cell lines, LCN2 KD reduced proliferation, colony formation, migration, and cancer stem cell properties. In vivo silencing of LCN2 in SUM149 cells inhibited primary tumor growth (p=0.001)and resulted in a well-differentiated tumor histology. Additionally, SUM149 LCN2 KD significantly reduced skin invasion/recurrence (LCN2 control vs LCN2 KD: 88 % vs 25 %, p=0.01) suggesting LCN2 is a mediator of tumorigenesis. Analysis of proteomics data showed changes in major signaling pathways including PI3K-Akt signaling and EGF/EGFR signaling pathways. Mechanistically, LCN2 depletion in SUM149 abrogated EGF-induced EGFR phosphorylation and ERK activation.

Conclusions: Our findings suggest that LCN2 may drive IBC tumor progression and skin invasion/recurrence potentially via the EGFR signaling pathway.Future studies will determine the role of LCN2 in metastasis and pinpoint the detailed mechanisms of LCN2-mediated IBC tumorigenesis and recurrence.

Citation Format: Villodre ES, Larson R, Hu X, Stecklein SR, Gomez K, Finetti P, Krishnamurthy S, Ivan C, Su X, Ueno NT, Van Laere S, Bertucci F, Tripathy D, Vivas-Mejía P, A Woodward W, Debeb BG. Lipocalin 2 promotes inflammatory breast cancer tumorigenesis and skin invasion [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-01-03.

Abstract P5-05-04: Myc as a poor prognostic marker for ER+ inflammatory breast cancer (IBC): Quantitative estrogen receptor (ER) expression analysis and gene expression analysis in ER+ IBC vs non-IBC

Background

Estrogen receptor-positive (ER+) primary inflammatory breast cancer (IBC) has a poorer prognosis than ER+ primary non-IBC. Our objective was to determine the association between ER positivity and survival outcome in order to elucidate the biological reason that ER+ IBC is more aggressive than non-IBC.

Methods

We retrospectively determined the relationship between ER expression by immunohistochemistry staining and neoadjuvant chemotherapy response as well as survival outcome for 189 patients with ER+ and HER2-negative (HER2-) IBC and 896 case-matched patients with stage III non-IBC seen at MD Anderson Cancer Center between January 1989 and April 2015. We performed gene expression (GE) analysis for 39 patients with ER+/HER2- IBC and 40 patients with non-IBC to detect genes that are specifically overexpressed in IBC. Logistic regression and Cox proportional hazards model were used to determine the predictive and prognostic value of percentages of cells positive for ER and progesterone receptor (PR) among the patients with ER+/HER2- IBC and non-IBC. Recursive partitioning analysis (RPA) was used to determine the optimal cutoff points for ER% and progesterone receptor (PR) % that maximized differences in survival. The identified cutoff points were tested in an external cohort of 192 ER+/HER2- IBC patients from Institut Paoli-Calmettes in France.

Results

The median values for ER% for IBC and non-IBC were 85 (range, 1-100) and 90 (range, 1-100), respectively. The logistic regression model demonstrated a lack of a relationship of ER% with pathological complete response rate to neoadjuvant chemotherapy both in IBC (P=0.29) and non-IBC (P=0.14). Expression of ER was significantly associated with distant disease-free survival (DDFS); hazard ratio (HR), 0.56 [95% CI, 0.37-0.83] per 50% increase in ER%; P&lt;0.05). Also, ER% was significantly associated with overall survival (OS) (HR, 0.40 [95% CI, 0.25-0.63] per 50% increase in ER%; P&lt;0.05). RPA showed that 91.5% and 9.0% were the optimal cutoff points for ER% and PR%, respectively, for DDFS and overall survival in IBC patients. However, the cutoff points could not be validated in the French external cohort. In the GE study, 84 genes were detected as significantly distinguishing ER+ IBC from non-IBC. Among the top 15 canonical pathways shown by IPA, the ERK/MAPK signaling pathway, PDGF pathway, insulin receptor signaling pathway, and IL-7 signaling pathway were associated with the ER signaling pathway. MYC upregulation was observed in three of these four pathways. Indeed, ER+/HER- IBC had significantly higher MYC amplification compared to those with non-IBC (P&lt;0.05) and higher MYC level was associated with poor relapse free survival for IBC (HR, 1.85 [95% CI, 1.05-2.70], P&lt;0.05).

Conclusions

Increased ER positivity was significantly associated with improved survival in ER+/HER- IBC patients. ER+/HER- IBC had several activated pathways with MYC upregulation compared to non-IBC. MYC upregulation was associated with a poor survival outcome for ER+/HER- IBC. The results indicate that MYC is a key gene for understanding the aggressive biological behavior of ER+/HER- IBC.

Citation Format: Iwase T, Harano K, Masuda H, Kida K, Espinosa Fernandez JR, Hess KR, Wang Y, Woodward WA, Layman RM, Dirix L, Van Laere SJ, Bertucci F, Ueno NT. Myc as a poor prognostic marker for ER+ inflammatory breast cancer (IBC): Quantitative estrogen receptor (ER) expression analysis and gene expression analysis in ER+ IBC vs non-IBC [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-05-04.

Abstract OT1-02-01: A phase II study of anti-PD-1 (MK-3475) therapy in patients with metastatic inflammatory breast cancer (MIBC) or non-IBC triple negative breast cancer (non-IBC TNBC) who have achieved clinical response or stable disease to prior chemotherapy

Primary Objective: To assess the efficacy of MK-3475 as a single agent in patients with MIBC and non-IBC TNBC. The primary endpoint is disease control rate at the end of 4 months after receiving the treatment. We will also investigate the association between biomarkers in the peripheral blood and tumor tissue, safety and efficacy.

Background: The extensive invasion of lymphatic vessels by tumor emboli in patients with IBC suggests that the host immune surveillance system is suboptimal or that the tumor cells have decreased immunogenicity through immune editing to avoid detection by the host. In the immune-competent host, tumor cells must overcome both innate and adaptive immunologic defenses of the host. The PD-1 receptor-ligand interaction is a major pathway hijacked by tumors to suppress immune control. MK-3475 is a potent and highly selective humanized mAb designed to block the interaction between PD-1 and its ligands, PD-L1 and PD-L2. MK-3475 strongly enhances T lymphocyte immune responses in cultured blood cells from healthy human donors, cancer patients, and primates. Mouse anti-PD-1, as a monotherapy, demonstrated efficacy in several syngeneic mouse tumor models. To date, no specific targeted therapeutic options exist for the treatment of MIBC and TNBC. After patients achieving a clinical response to systemic therapy, the maintenance of disease control is not guaranteed. Further, our recent publication suggests that IBC has immune dysfunction. Chemotherapies can debulk the disease volume but cannot be used for maintenance due to their toxicities. Using an anti PD-1 monoclonal antibody is a promising approach for this patient population.

Study Design and Treatment Plan: This is a single arm phase II study. Up to 35 patients with HER2 negative MIBC or metastatic TN-IBC (MTNBC) who have achieved clinical response or stable disease after receiving any prior systemic therapy for metastatic/recurrent disease, and meet all other criteria will be eligible. Patients will receive MK-3475 200 mg IV every 3 weeks for up to 2 years.

Statistical Considerations: The trial will be conducted using Simon's optimal two-stage design and the rate of disease control will be estimated accordingly. It is assumed that the MK-3475 single agent will have a disease control rate of 30%. A disease control rate of 10% or lower will be considered treatment failure and the regimen will be rejected under this circumstance.

Status of the study:

Activation Date: June 2015. 13 patients have been enrolled. Enrollment continues.

Sponsor: Merck Sharp & Dohme Corp.

State of Texas appropriation for rare and aggressive breast cancer research.

Citation Format: Willey JS, Parker CA, Valero V, Lim B, Reuben JM, Krishnamurthy S, Gong Y, Scoggins ME, Dryden MJ, Liu DD, Woodward WA, Ueno NT. A phase II study of anti-PD-1 (MK-3475) therapy in patients with metastatic inflammatory breast cancer (MIBC) or non-IBC triple negative breast cancer (non-IBC TNBC) who have achieved clinical response or stable disease to prior chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-02-01.

Abstract P2-02-04: Circulating protein biomarker profile for inflammatory breast cancer using a multiplexed proximity extension assay

Background: Expression of cancer related genes and proteins in clinical specimens are the mainstay of personalized targeted therapy; however, a diagnostic signature for inflammatory breast cancer (IBC) remains elusive. In this study, we employed a blood-based, non-invasive, sensitive technology to map biomarkers in patients with IBC at the protein level. Proximity Extension Assay consists of a harmonious blending of immunoassay and PCR to amplify protein expression signal, thereby enabling multiplexing with small sample input (1 μl). Other multi-platform assays require a large amount of clinical material, multi-step sample processing and complicated data analysis.

Materials and methods: Serum samples (n= 159) from patients with primary IBC (IBC, n= 30), metastatic IBC (MIBC, n= 54), locally advanced breast cancer (LABC, n= 24) and metastatic breast cancer (MBC, n= 27) were prospectively collected from subjects prior to starting a new therapy (treatment naive) or a new line of therapy between 2009 and 2012. Sera from 24 healthy normal donors (HD) were included in the analysis for comparison. The samples were analyzed using two panels: Proseek Multiplex Oncology II and Proseek Multiplex Inflammation I (Olink Proteomics, Uppsala, Sweden) for simultaneous detection of 92 human protein biomarkers in each panel. In the assay, each protein biomarker is detected by a matched pair of antibodies coupled to unique DNA-tags. Upon binding to the proteins, the correctly hybridized DNA-tags form an amplicon that can be measured by PCR.For initial analysis, sample populations were compared using the Mann-Whitney-U test.

Results: In comparison with HD sera, sera of breast cancer patients had 41 proteins from the oncology panel and 28 from the inflammation panel that were significantly higher, whereas 5 from the inflammation panel were significantly lower. From the inflammation panel, 11 proteins (PD-L1, IL-2, IL-7, IL-18, uPA, CCL4, CCL23, CXCL9, CXCL10, CXCL11 and TNF-alpha) showed significant differential expression between IBC and non-IBC derived samples (irrespective of metastatic status); for each marker, levels were higher in IBC than in non-IBC. In contrast, 9 proteins from the oncology panel (CRNN, CTSV, ERBB4, FR-gamma, ITGAV, MIA, PODXL, SCF and SEZ6L) were differentially expressed; however, each of these proteins was higher in non-IBC than in IBC. Among the aforementioned proteins, CCL4, IL-2, IL-7, PD-L1, TNF-alpha, uPA, CRNN, CTSV, FR-gamma, ITGAV, MIA, SCF and SEZ6L did not differentiate cancer and HD, but were uniquely characteristic of the IBC vs non-IBC comparison.

Conclusion: These preliminary data suggest that it is possible to distinguish between cancer patients and healthy normal donors, and also to delineate between IBC and non-IBC patients based on expression of serum proteins. Validation of this serum protein signature is planned in a larger patient cohort.

Citation Format: Cohen EN, Jayachandran G, Gao H, Tin S, Alvarez RH, Valero V, Lim B, Woodward WA, Ueno NT, Reuben JM. Circulating protein biomarker profile for inflammatory breast cancer using a multiplexed proximity extension assay [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-04.

Abstract OT3-06-04: A randomized phase II study of neoadjuvant panitumumab /carboplatin/paclitaxel (PaCT) versus carboplatin/paclitaxel (CT) followed by adriamycin and cyclophosphamide (AC) for newly diagnosed primary triple-negative inflammatory breast cancer (TNIBC)

Primary Objective: To determine pathological complete response (pCR) rate in patients with primary TNIBC treated with PaCT in comparison with CT, followed by AC. To explore if the pCR rate correlates with reduced nodal expression status; and with arginine methylation status of epidermal growth factor receptor (EGFR). We will identify molecular biomarkers predictive of the pCR rate by analysis of multiplexed immunohistochemical (IHC) staining, identify molecular biomarkers predictive of the pCR rate by genomic and proteomic analysis, and determine whether the inhibition of the EGFR pathway down regulates the COX-2 pathway and mesenchymal marker.

Background: EGFR is overexpressed in triple negative breast cancer (TNBC) and inflammatory breast cancer (IBC). Therefore, EGFR targeted therapy may have a promising role in TNBC and IBC. A study showed that EGFR-targeted therapy may enhance the initial chemosensitivity of TNBC cells. Panitumumab blocks epidermal growth factor ligands and transforming growth factor EGFá (TGFá) binding to EGFR, inhibits tumor growth, and elicits both tumor regression and eradication of established tumors in murine xenograft tumor models. Panitumumab, a fully humanized anti-EGFR antibody, has been shown to be active in a breast cancer preclinical model using human breast cancer cell line MDA-MB-468, which has been shown to overexpress EGFR by both IHC and fluorescence in situ hybridization (FISH). Furthermore, EGFR tyrosine kinase inhibitors such as erlotinib have antitumor activity against human IBC cell lines. Thus, EGFR targeted therapy may have a promising role in TNBC and IBC.

Study Design: In this open label randomized phase II trial, up to 72 patients with primary IBC, have no HER2 overexpression, and have &lt;10% expression of ER and PgR, who also meet other criteria will be randomized to PaCT arm - receiving panitumumab single agent in window study and 4 cycles PaCT, or CT arm - receiving 4 cycles of CT. All patients will receive 4 cycles of AC before surgery.

Statistical Considerations: A sample size of 36 patients per arm will achieve 84% power to detect a difference of 0.24 in pCR rate between 0.2 in the CT arm and 0.44 in the PaCT arm with a type I error rate of 10% using one-sided Z test. Based on historical data, we expect that the pCR rate of a PaCT regimen to achieve 24% additional efficacy compared with the CT regimen.

Status of the study:

Activation date: Oct. 2016. So far 6 patients have been enrolled. Enrollment continues.

Sponsor: Amgen.

State of Texas appropriation for rare and aggressive breast cancer research.

NIH grant 1R01CA205043-01A1

Citation Format: Willey JS, Parker CA, Lim B, Valero V, Le-Petross HT, Krishnamurthy S, Woodward WA, Lucci A, Wood AL, Sun H, Babiera GV, Song J, Shen Y, Valero V, Wang X, Ueno NT. A randomized phase II study of neoadjuvant panitumumab /carboplatin/paclitaxel (PaCT) versus carboplatin/paclitaxel (CT) followed by adriamycin and cyclophosphamide (AC) for newly diagnosed primary triple-negative inflammatory breast cancer (TNIBC) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-06-04.

Abstract OT1-01-05: A phase II study using talimogene laherparepvec as a single agent for inflammatory breast cancer or non-inflammatory breast cancer patients with inoperable local recurrence

Objective: The primary purpose of the study is to determine the local and systemic antitumor efficacy of talimogene laherparepvec in locally recurrent breast cancer patients with or without distant metastases, as evidenced by improved overall response rates. This will be the first study to use biopsy of distant disease to demonstrate whether systemic immune modulation has antitumor efficacy in breast cancer patients.

BACKGROUND: Patients with locally recurrent breast disease frequently undergo multimodal treatment at the first occurrence of breast cancer, and because local treatment modalities such as surgical intervention and radiation are difficult to add, they subsequently receive systemic therapy. Talimogene laherparepvec (T-VEC) was developed to eliminate solid tumors and has since been considered as a potential treatment option for body surface tumors. In addition to T-VECinjected area, this agent is capable of modifying the immune response with the potential of inhibiting distant metastases. Hence, locally recurrent breast disease could benefit from T-VECregardless of concomitant distant metastases, and may offer a new local treatment option.

Study Design and Treatment Plan: This is a single agent phase II study. Patients with breast cancer who have recurrence of chest wall disease with or without distant metastasis, have at least 1 injectable lesion ≥5 mm in longest diameter or multiple injectable lesions that in aggregate have a longest diameter of ≥ 5 mm, and meet inclusion and exclusion criteria will be eligible to participate in the study. Patient will receive T-VEC via intra-tumoral injection every 2 weeks after the first initial injection (3 weeks).

STATISTICAL METHODS:

Up to 35 patients will be enrolled in the study. The trial will be conducted using a two-stage design and the overall response rate will be estimated accordingly. It is assumed that the talimogene laherparepvec single agent will have a response rate of 20%. A response rate of 5% or lower will be considered treatment failure and the regimen will be rejected under this circumstance.

Status of the study:

Activation Date: Aug 2016. 6 patients have been treated. Enrollment continues.

Sponsor: Amgen

State of Texas appropriation for rare and aggressive breast cancer research.

Citation Format: Willey JS, Marx AN, Lim B, Ibrahim NK, Valero V, Mittendorf EA, Reuben JM, Le-Petross HT, Whitman GJ, Krishnamurthy S, Woodward WA, Lucci A, Liu DD, Shen Y, Ueno NT. A phase II study using talimogene laherparepvec as a single agent for inflammatory breast cancer or non-inflammatory breast cancer patients with inoperable local recurrence [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-01-05.

Abstract OT1-02-05: A single arm phase II study of adjuvant anti-PD1 (pembrolizumab) in combination with hormonal therapy in patients with hormone receptor (HR)-positive localized inflammatory breast cancer (IBC) who did not achieve a pathological complete response (pCR) to neoadjuvant chemotherapy

Background: The pCR rate to conventional chemotherapy in hormone receptor positive IBC has historically been low (7.4% for HR+ HER2-, and 30% for HR+ HER2+), and despite the use of adjuvant endocrine therapy, the recurrence rate is still as high as 40%. To date, no targeted agent is proven to improve the efficacy of adjuvant endocrine therapy within the IBC population to improve this poor disease free survival (DFS). One plausible reason for the poor efficacy of endocrine therapy is a suppressed immune system, which allows tumor cells to avoid detection despite expression of potential immunogenic surface antigens.

Trial Design: This is a single arm trial that will enroll stage III HR+ IBC patients who have completed neoadjuvant therapy but had residual disease at mastectomy. Enrollment should be before or within 2 months of beginning endocrine therapy. Monitoring of DFS will be done with radiological imaging every 3 cycles (starting at cycle 4) as clinically indicated, per standard of care. Pembrolizumab is given on day 1 of each 21 day cycle for up to 2 years if the disease is controlled, and hormonal therapy will be administered per standard of care.

Eligibility Criteria: Clinical stage 3 IBC ER+/PR+ and HER2 negative patients who completed neoadjuvant chemotherapy and surgery with evidence of residual cancer in the breast or lymph nodes, but be clinically disease-free with good performance status at the start of study. Patients also must have adequate hematologic and organ function, and have recovered from the acute effects from prior treatments.

Specific Aims: The primary objective is to determine the disease free survival (DFS) at 2 years of patients with adjuvant therapy using Pembrolizumab in combination with standard adjuvant hormonal therapy. The secondary objective is to determine the safety and toxicity profile of this combination.

Statistical Methods: With a sample size of 37 patients, assuming that 80% are alive (20% increase from historical data) and disease-free at 2 years, and all patients are followed for &gt;2 years after enrollment with no dropout, a 95% confidence interval around the 2-year estimate of DFS will be generated. DFS will then be compared with the historical control rate of 60% by year 2 using a one-sided exponential MLE test.

Accrual: To date we have enrolled 3 patients since activation in January 2017, and the target enrollment is 37 patients.

Contact information: For more information or to refer a patient, please contact study coordinator, Angela Alexander - aalexand@mdanderson.org

Citation Format: Alexander A, Willey J, Sun H, Parker CA, Marx AN, Wood AL, Reddy SM, Reuben JM, Bassett RL, Le-Petross HT, Krishnamurthy S, Gong Y, Woodward WA, Valero V, Ueno NT, Lim B. A single arm phase II study of adjuvant anti-PD1 (pembrolizumab) in combination with hormonal therapy in patients with hormone receptor (HR)-positive localized inflammatory breast cancer (IBC) who did not achieve a pathological complete response (pCR) to neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-02-05.

Abstract P3-07-04: EphA2: An emerging target in triple-negative breast cancer

Purpose: Breast tumors classified as 'triple negative' (TNBC) lack defining markers ER/PR/HER2 and do not have clinically-approved targeted therapy. This heterogeneous classification of breast cancers, while immediately responsive to standard chemotherapy, commonly develop resistance and have a poor five-year survival rate. As such, the identification of new therapeutic targets are warranted. As part of our drug discovery platform, we have identified EphA2, as a synthetic-lethal gene that enhances the therapeutic action of FDA-approved, anti-inflammatory compounds. Thus we sought to ascertain the relevance of EphA2-targeted therapy in TNBC, through the evaluation of the marker in preclinical and clinical specimens.

Methods: Sixty-one human and murine breast cancer cell lines or patient-derived xenografts were collated. Protein lysates were created from cells in vitro or from respective tumors established from cells implanted into NSG mice. Forty-nine tumors established (minimum 500mm3) and were surgically removed, fixed in formalin and paraffin embedded. A TMA was constructed with tumor specimens represented twice on the array and reflected all molecular subtypes including; ER-positive (n=5), PR-positive (n=3), HER2-positive (n=9) and TNBC (n=31). Immunostaining for EphA2 was performed with the rabbit monoclonal antibody EphA2 (D4A2) XP (Cell Signaling, #6997) using manufacturer's instructions. Immunostaining was evaluated using the H-score method (score between 0-300), with positive staining for EphA2 reflecting a score of 100 or greater. Analysis of breast cancer lysates by western blot was analyzed by absolute and relative quantitation methods; gene expression data was assessed through Oncomine or using the BreastMark algorithm (http://glados.ucd.ie/BreastMark/). This algorithm integrates gene expression and survival data from 26 datasets on 12 different microarray platforms corresponding to ˜17,000 genes in up to 4,738 samples.

Results: In an integrated gene expression platform (BreastMark), we observed that elevated EphA2 expression was associated with poor prognosis in a cohort of TNBC patient tumor samples. Western blot analysis of EphA2 protein on breast cancer cell lines, identified a greater percentage of TNBC cells expressing EphA2 compared to non-TNBC cell lines. EphA2 immunostaining was observed in the majority of tumor tissues. When present on cancer cells, EphA2 localized to the cell surface; while displaying ubiquitous localization within stromal populations. Cell surface expression of EphA2 on cancer cells was largely restricted to TNBC tumors (11/31 tumors, 35.5%) compared to other molecular subtypes (1/13 non-TNBC tumors, 7.7%; p = 0.0294). Expression of EphA2 in stromal cell populations was similar between groups (TNBC = 22/31, non-TNBC = 11/13; p = 0.1711).

Conclusions: Our analysis determined that EphA2 was specifically expressed on cancer cells derived from tumors with a 'triple-negative' molecular subtype. Collectively our data suggests that EphA2 is an emerging target in TNBC and that therapies directed against EphA2 may provide a significant benefit for a majority of patients that express this marker.

Citation Format: Eckhardt BL, Torres AM, Woodward WA, Krishnamurthy S, Meric-Bernstam F, Ueno NT. EphA2: An emerging target in triple-negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-07-04.

Abstract PD6-06: Understanding the complexity of macrophage and mesenchymal stem cell interactions to improve treatment outcome for IBC patients

Cells within the tumor microenvironment, including but not limited to macrophages and mesenchymal stem cells (MSCs), can promote the phenotype and aggressiveness of inflammatory breast cancer (IBC). For example, co-injection of MSCs with SUM149 IBC cells significantly increased the clinical features of IBC such as skin invasion and metastasis. Our preliminary work showed that MSCs can be educated by co-culture with M1 polarized (anti-tumor) or M2 polarized (pro-tumor) mouse Raw macrophages. Such education of MSCs by M2 Raw macrophages leads to increased IL6 secretion by MSCs, relative to M1-educated or uneducated MSCs. M2-educated MSCs also have increased migration toward IBC cell lines SUM149 and IBC3, effects that can be blocked by an anti-IL6 antibody. Co-culture with M2-educated MSCs also enhances migration and mammosphere formation of IBC cells. Radiation response of IBC cells upon interactions with cells from the tumor microenvironment was also analyzed. Preliminary work shows that co-culture of IBC cells (SUM149 and KPL4) with M2-polarized human THP1 macrophages, prior to ionizing radiation, mediates radiation resistance of IBC cells, and this effect can be decreased by either adding HDL lipoproteins during co-culture period or by STAT6 inhibitors that block IL4/IL13-mediated phosphorylation of STAT6 and M2-polarization in THP1 macrophages. MSCs can also be polarized into either a MSC1 phenotype or a MSC2 phenotype by exposure to toll-like receptor (TLR) ligands TLR4 or TLR3, respectively. Indoleamine-pyrrole 2,3-dioxygenase (IDO) expression in MSCs is a marker of MSC2 polarization that is induced after exposure with TLR3 ligand (PolyIC) relative to MSC1 (TLR4 stimulated; LPS-treated) or parental MSCs. Similar to macrophage polarization, while MSC1 mediates anti-tumor effects, MSC2 are immunosuppressive and thus contribute to tumor growth. Preliminary work also shows that co-culture of IBC cells with MSC2 mediates radioresistance and this can be decreased as well by exposure to HDL during co-culture period prior to radiation. HDL protective effects, in part, can be explained by decreased expression of TLR3-induced IDO mRNA levels in MSC2. In the present work, we extended the above mentioned observations regarding the crosstalk between mouse Raw macrophages and MSCs by analyzing the effect of co-culture of human THP1 macrophages (parental designated as M0, M1- or M2-polarized) with MSCs on the IDO mRNA expression in MSCs, a marker of MSC2 polarization. Surprisingly, co-culture of M1-polarized THP1 with MSCs resulted in a robust increased expression of IDO mRNA in MSC relative to parental MSC (uneducated) or MSCs co-cultured with M2-THP1. Further studies are needed to determine the effects of increased IDO expression in MSC, upon M1-THP1 co-culture, on the aggressive behavior of IBC cells and whether this could be altered with IDO inhibitors. Our results suggest that there could be inter-species differences between mouse and human macrophages on the education of human MSCs. Based on our findings we propose testing a combination of STAT6 inhibitors that reverse M2-polarization of macrophages and IDO inhibitors that can decrease MSC2 phenotype mediated by TLR3 exposure and/or M1-THP1 education.

Citation Format: Rahal OM, Wolfe AR, Mandal PK, Larson R, Tin S, Reuben JM, McMurray JS, Woodward WA. Understanding the complexity of macrophage and mesenchymal stem cell interactions to improve treatment outcome for IBC patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-06.

Abstract P2-11-12: Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy

Purpose/Objective(s):

To prospectively compare late toxicity after accelerated partial breast irradiation (APBI) with 3D-conformal external beam radiotherapy (3D-CRT) or single-entry multi-lumen intracavitary brachytherapy.

Patients/Methods:

Two hundred eighty-one patients with pTis or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled on a multi-institution observational protocol from 12/2008 – 8/2014. Patients were enrolled and treated at primary, satellite, and affiliated academic institutions. APBI was delivered using 3D-CRT or with a Contura®, MammoSite®, or SAVI® brachytherapy catheter. 3D-CRT patients were treated to 34.0 Gy (7%) or 38.5 Gy (93%) at 3.4-3.85 Gy/fx BID and brachytherapy patients were treated to 34.0 Gy at 3.4 Gy/fx BID. Per protocol, patients were clinically evaluated at 2, 6, 12, 18, and 24 months and then annually. At each clinical evaluation the radiation oncologist scored cosmetic outcome (excellent/good/fair/poor according to the Harvard Cosmesis Scale), toxicity (seroma/infection/fat necrosis/pain/telangiectasia/radiation dermatitis/hyperpigmentation/hypopigmentation/fibrosis/induration/edema/other according to CTCAE v3.0) and recurrence status.

Results:

The median age was 61 years. Of 281 patients, 211 (75%) had invasive breast cancer and 70 (25%) had in situ disease. Among patients with invasive disease, 90% were HR+/HER2-, and among patients with in situ disease, 83% were HR+. APBI was delivered with 3D-CRT in 29 (10%) patients and with single-entry multi-lumen intracavitary brachytherapy in 252 (90%) patients. Among the brachytherapy patients, APBI was delivered with the SAVI®, Contura®, and MammoSite® devices in 176 (70%), 56 (22%), and 20 (8%) patients, respectively. With a median follow-up of 49 months, rates of Grade 1 (G1) and Grade 2-3 (G2-3) toxicity are:

 3D-CRTBrachytherapy   G1G2-3G1G2-3G1G2-3 N (%)N (%)N (%)N (%)  Fibrosis13 (46%)1 (4%)176 (72%)6 (2%)p=0.008p=0.54Fat Necrosis0 (0%)0 (0%)0 (0%)4 (2%)p=1.00p=1.00Telangiectasia6 (21%)1 (4%)44 (18%)5 (2%)p=0.61p=0.48Seroma2 (7%)1 (4%)135 (55%)12 (5%)p&lt;0.0001p=1.00

Mean skin dose of the maximally-irradiated 0.1 cc (D0.1cc) of skin was significantly higher in patients who developed telangiectasia (103.4% ± 16.1% compared to 96.5% ± 18.6% of prescription dose, p=0.007) and fibrosis (100.1% ± 15.5% compared to 92.8% ± 23.0% of prescription dose, p=0.02). Crude rates of fair or poor cosmetic outcome at 2-4 and 4-6 years were 6.9% and 14.8%, respectively, for 3D-CRT and 14.8% and 21.3%, respectively, for brachytherapy (p&gt;0.05 at both timepoints). Five-year recurrence-free survival was 96.3% with 3D-CRT and 96.1% for brachytherapy (p&gt;0.05).

Conclusion:

APBI with single-entry multi-lumen intracavitary brachytherapy is associated with increased rates of grade 1 fibrosis and seroma than APBI with 3D-CRT. Higher mean skin D0.1cc is associated with increased risk of telangiectasia and fibrosis. Despite increased low-grade fibrosis, there is no significant difference in radiation oncologist-reported fair or poor cosmetic outcome out to six years, or rate of five-year ipsilateral breast recurrence.

Citation Format: Stecklein SR, Babiera GV, Bedrosian I, Shaitelman SF, Ballo MT, Tereffe W, Arzu IY, Perkins GH, Strom EA, Reed VK, Dvorak T, Smith BD, Woodward WA, Hoffman KE, Schlembach PJ, Chronowski GM, Shah SJ, Kirsner SM, Nelson CL, Guerra W, Dibaj SS, Bloom ES. Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-12.

In vitro and in vivo effect of flutamide on steroid hormone secretion in canine and human inflammatory breast cancer cell lines

The aim was to study the effects of flutamide on cell proliferation, in vivo tumour growth and steroid production in canine and human IBC cell lines. IPC-366 and SUM149 cell cultures were exposed to flutamide concentrations for 72 hours. Additionally, IPC-366 and SUM149 xenotransplanted mice were treated subcutaneously with flutamide 3 times a week for 2 weeks. Steroid hormones determination in culture media, serum and tumour homogenates (pregnenolone, progesterone, androstenedione, testosterone, dihydrotestosterone, 17β-oestradiol and oestrone sulphate) were assayed by EIA. in vitro cell proliferation percentages showed a decrease in all flutamide dosages in IPC-366 and SUM149. in vivo flutamide reduced tumour size by 55% to 65%, and metastasis rates decreased. In treated groups, androgen levels in culture media, serum and tumour homogenates were increased as oestrogen levels decreased. These results suggest that flutamide treatment inhibits cell proliferation and promotes tumour reduction by increasing androgen levels and also support future therapy approaches.

Abstract P1-07-14: Rates of immune infiltration in patients with triple-negative breast cancers by molecular subtype and in patients with inflammatory and non-inflammatory breast cancers

Background

In patients with triple-negative breast cancer (TNBC), tumor-infiltrating lymphocytes (TILs) have been reported to be associated with improved survival. Lehmann et al. identified 6 molecular subtypes of TNBC [basal-like (BL) 1, BL2, mesenchymal (M), mesenchymal stem like (MSL), immunomodulatory (IM), and luminal androgen receptor (LAR)], and we previously reported that TNBC subtype is a predictor of pathologic complete response (pCR). Recently, the IM gene expression signature has been shown to be indicative of the presence of TILs and has been incorporated into TNBC subtyping as a modifier of the other groups rather than a separate subtype. However, the association between TNBC subtype and the presence of TILs is not known. We hypothesized that the BL2 and LAR subtypes, which have low pCR rates, have low rates of immune infiltration. Inflammatory breast cancer (IBC) is an aggressive cancer that is frequently triple-negative. The association between IBC and the presence of TILs also is not known. In this study, we analyzed the association between TNBC molecular subtype and the IM signature and determined whether the IM signature differed between patients with IBC and non-IBC.

Methods

We retrospectively analyzed 88 patients with TNBC from the World IBC Consortium dataset for whom IBC status was known (IBC, n=39; non-IBC, n=49) and tumor gene expression data were available. TNBC specimens were classified using the TNBCtype algorithm (Insight Genetics, Inc., TN, USA), which uses a 101-gene signature. For each tumor, the TNBCtype algorithm reports the TNBC molecular subtype (BL1, BL2, M, MSL, or LAR) and the IM status, which is described as positive (IM+) or negative (IM-). Recently, Fisher's exact test was used to analyze differences in subtype distribution between the IM+ and IM- tumors.

Results

The subtype distribution differed significantly between the IM+ and IM- tumors

IM signature in TNBC subtypesSubtypeTotal (n=88)IM+ (n=32)IM- (n=56)BL13015 (50)15 (50)BL2202 (100)M808 (100)MSL3113 (42)18 (58)LAR121 (8)11 (92)Not determined53 (60)2 (40) (p=0.0087). The majority of IM+ cases occurred in the BL1 and MSL subtypes. No IM+ cases were observed in the BL2 or M subtypes, and only 1 was observed in the LAR subtype. IM+ cases occurred at roughly the same frequency in patients with IBC (33%) and non-IBC (37%, p=0.73).

Conclusions

TNBC molecular subtypes differ in their degree of immune infiltration, and most IM+ TNBCs are of the BL1 and MSL subtypes. Our finding that the proportion of IM+ cases was not different between IBC and non-IBC indicates that TILs are recruited to the tumor microenvironment similarly in IBC and non-IBC tumors. Further, Pietenpol et al recently showed that the MSL signature represents normal stromal cells rather than tumor cells by performing laser-capture microdissection of TNBC specimen. Validation studies are needed to corroborate and further expand upon our findings.

Citation Format: Harano K, Wang Y, Lim B, Seitz RS, Morris SW, Bailey DB, Hout DR, Skelton RL, Ring BZ, Masuda H, Rao AUK, Woodward WA, Reuben JM, Ueno NT. Rates of immune infiltration in patients with triple-negative breast cancers by molecular subtype and in patients with inflammatory and non-inflammatory breast cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-07-14.

Abstract P3-05-07: Flutamide reduced tumor progression and altered steroid hormone secretion in human and canine inflammatory breast cancer cell lines

Background: Inflammatory breast carcinoma (IBC) is a special type of breast cancer with a poor survival rate and accounts for 6% of diagnosed breast cancers. The role of androgens on breast cancer is on rise in research, trying to propose anti-androgen therapeutic strategies. The aim of this study was to determine the effects in vivo and in vitro of flutamide (anti-androgen drug) on cell proliferation, tumor progression and steroid production in two cancer IBC triple negative cell lines (SUM-149 and IPC-366, human and canine, respectively). Material and Methods: IPC-366 was cultured in Dulbecco's modified Eagle medium nutrient mixture F-12 Ham (DMEM/F12) and SUM149 was maintained in Ham's F-12 media. Flutamide concentrations added to the culture media were: 5 µm, 10 µm, and 15 µm for 72 hours. Additionally, IPC-366 and SUM149 xenotrasplanted mice were used for in vivo assays with the same flutamide concentrations administrated subcutaneously. Steroid hormones determination in culture media and tumor homogenates (pregnenolone (P5), progesterone (P4), dihydroepiandrostenedione (DHEA), androstenedione (A4), testosterone (T), dihydritestosterone (DHT), 17β-estradiol (E2) and estrone sulphate (SO4E1)) were assayed by EIA previously validated. Immunohistochemical (IHC) analysis of the steroidogenic enzymes CYP11A1, 3β-HSD, CYP19A1, 17β-HSD and 5α-reductase were assayed. Results: Percentage of cell proliferation showed a decrease in all treatments in IPC-366 and SUM149. In vivo tumor progression was reduced in around 65% in IPC-366 and SUM149 xenotrasplanted mice. Regarding hormonal secretion assayed in pellets and homogenates. in treated groups there was an increased in steroid secretion as showed the high levels found in P5, P4 and A4. T and DHT concentrations were higher in treated groups, in contrast to E2 levels that decreased. 17β-HSD and 5α-reductase by IHC showed a high expression in treated groups. Conclusion: IPC-366 and SUM149 treated with flutamide reduced the proliferation of neoplastic cells, reduced tumor progression in xenotrasplanted mice and altered steroid hormone secretion by increasing T production and decreasing in E2 levels. These results open a future approach for IBC and triple negative breast cancer.

Citation Format: Caceres S, Pena L, Silvan G, Illera MJ, Monsalve B, Woodward WA, Reuben J, Illera JC. Flutamide reduced tumor progression and altered steroid hormone secretion in human and canine inflammatory breast cancer cell lines [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-05-07.

Abstract P1-01-19: Circulating tumor cells in triple-negative breast cancer patients express prostate related genes and show different genetic profiles in US and German patient cohorts

Background: Triple negative breast cancer (TNBC) is known for its aggressive behavior and poor prognosis since treatment options are limited. Specific biomarkers are urgently needed to treat patients (pts) accordingly. In this regard, circulating tumor cells (CTCs) are discussed to be an ideal surrogate marker for individualized treatment options. Using a multi-marker gene panel for the characterization of CTCs, we recently demonstrated that CTCs in TNBC pts and non-TNBC pts showed different genetic profiles including the expression of the androgen receptor (AR). We here compared CTCs of TNBC pts in two different national Institutions in the US (mainly Afro-American women) and Germany (Caucasian women) to identify potentially ethnical differences and to further explore AR expression related similarities of prostate cancer to TNBC.

Methods: 2x5 ml blood of TNBC pts before therapy (n=18 from the Dep. of Gynecol. and Obstetrics, Essen, GER; n=31 from the MDA Cancer Center Houston, US) were analyzed for CTCs applying positive immunomagnetic selection targeting EpCAM, EGFR and HER2 using the AdnaTest EMT-2/Stem Cell Select (QIAGEN Hannover GmbH, Germany). Subsequently, cDNA was pre-amplified for specific genes using TaqMan PreAmp Master Mix according to in house designed assays. Establishment of a 19 gene qPCR panel was performed for the markers PI3K, AKT2, ERCC1, AURKA, HER2, HER3, EGFR, ALK, AR, BRCA1, c-KIT, c-MET, KRT5, mTOR, NOTCH1, PARP1, SRC1, CD45 (leucocyte control) and GAPDH (housekeeping gene) as well as an internal reference. The cutoff was calculated, taking the false positive rate in healthy donors into account, and defined as Ct (cutoff) - Ct (sample) - [Ct (CD45cutoff) – Ct (CD45sample)]. Using the AdnaPanel Prostate Cancer (QIAGEN Hannover GmbH, Germany), cDNA obtained from a subset of 14 pts was further analyzed for the expression profile of AR, prostate specific antigen (PSA) as well as prostate specific membrane antigen (PSMA).

Results: The overall CTC-positivity rate (at least one of the markers expressed) was comparable between both sites (GER: 78%; US: 65%). Similar overexpression frequencies were found for AKT2, AR, AURKA, c-KIT, NOTCH1 and SRC at both sites. However, ALK, BRCA1, HER3 and KRT5 were predominantly found in CTCs of German pts while these genes were not or only weakly expressed in CTCs of the US group. In contrast, c-MET, ERCC1, HER2 and PARP were mainly expressed in CTCs of the US group and rarely in the German group. Interestingly, EGFR was not detected in both groups. Analyzing the overexpression of prostate related genes in a subgroup of 14 TNBC pts resulted in the expression of AR in 21%, PSA in 14%, and PSMA in 36% of cases, respectively.

Conclusion: Although we observed similar gene expression profiles in both patient cohorts, clear differences in some gene expression frequencies were detected at both sites. Whether these findings can be related to ethnic differences will be subject of further investigations. Furthermore, we were able to demonstrate that prostate related genes were frequently detectable which so far have not been discussed in the context of breast cancer.

Citation Format: Kasimir-Bauer S, Gao H, Bittner A-K, Plappert L, Feniuk N, Ueno NT, Cohen L, Valero V, Woodward WA, Alvarez RH, Hoffmann O, Kimmig R, Reuben JM. Circulating tumor cells in triple-negative breast cancer patients express prostate related genes and show different genetic profiles in US and German patient cohorts [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-01-19.

Circulating Tumor Cells (CTC) Are Associated with Defects in Adaptive Immunity in Patients with Inflammatory Breast Cancer

Background: Circulating tumor cells (CTCs) play a crucial role in tumor dissemination and are prognostic in primary and metastatic breast cancer. Peripheral blood (PB) immune cells contribute to an unfavorable microenvironment for CTC survival. This study aimed to correlate CTCs with the PB T-cell immunophenotypes and functions of patients with inflammatory breast cancer (IBC).

Methods: This study included 65 IBC patients treated at the MD Anderson Cancer Center. PB was obtained from patients prior to starting a new line of chemotherapy for CTCs enumeration by CellSearch^®, and T cell phenotype and function by flow cytometry; the results were correlated with CTCs and clinical outcome.

Results: At least 1 CTC (≥1) or ≥5 CTCs was detected in 61.5% or 32.3% of patients, respectively. CTC count did not correlate with total lymphocytes; however, patients with ≥1 CTC or ≥5 CTCs had lower percentages (%) of CD3+ and CD4+ T cells compared with patients with no CTCs or <5 CTCs, respectively. Patients with ≥1 CTC had a lower percentage of T-cell receptor (TCR)-activated CD8+ T cells synthesizing TNF-α and IFN-γ and a higher percentage of T-regulatory lymphocytes compared to patients without CTCs. In multivariate analysis, tumor grade and % CD3+ T-cells were associated with ≥1 CTC, whereas ≥5 CTC was associated with tumor grade, stage, % CD3+ and % CD4+ T cells, and % TCR-activated CD8 T-cells synthesizing IL-17.

Conclusions: IBC patients with CTCs in PB had abnormalities in adaptive immunity that could potentially impact tumor cell dissemination and initiation of the metastatic cascade.

Abstract P4-04-18: High serum miR-19a levels correlated with favorable prognosis in patients with metastatic HER2+ breast cancer and might result from effective antibody-dependent cell-mediated cytotoxicity (ADCC) induced by trastuzumab and Th1-mediated antitumor immune response

Introduction

HER2 amplification is found in up to 20% of breast cancer and is associated with poor survival. To date, no predictive biomarker has been validated for clinical practice in patients with HER2+ breast cancer. Type 1 T helper lymphocytes (Th1) are required to activate antitumor cytotoxic T lymphocytes (CTL) necessary for tumor clearance. Particularly, IFN-γ secreted by Th1 cells is necessary for the development of CTL-mediated antitumor response. Trastuzumab can induce antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by natural killer (NK) cells. In turn, trastuzumab-activated NK cells can trigger Th1 cells by driving their differentiation and maturation. Furthermore, NK-mediated ADCC can increase tumor cell membrane permeability through pore formation induced by perforin secreted by NK cells.

We found that: 1) high serum miR-19a levels in patients with metastatic HER2+ breast cancer were predictive of favorable prognosis; 2) Th1 cells expressed and secreted high miR-19a levels; 3) and breast cancer tissue expressed higher miR-19a levels than normal adjacent tissue. Therefore, the high serum miR-19a levels in patients with good prognosis may derive from tumor cells killed by NK-mediated ADCC and secretion from Th1 cells. MiR-19a may represent a marker of effective anti-tumor immune response.

Results

HER2+ metastatic breast cancer patients with high serum miR-19a levels (n=27) had longer PFS (7.9 vs. 4.1 months; p=0.003) and OS (median not reached vs. 13.1 months; p&lt;0.0001) than patients with low serum miR-19a levels (n=24). Locally advanced breast cancer tissue (n=35) expressed higher levels of miR-19a than normal adjacent tissue (n=10) (p=0.048). KPL-4 cells (HER2-amplified) expressed higher miR-19a levels than SKBR3 cells (HER2-amplified) (p=0.010) and MCF-7 cells (non-HER2-amplified, used as control) (p&lt;0.0001). In in vitro ADCC assay, trastuzumab induced an increased tumor cell killing by NK cells and consequent miR-19a release into the supernatants of MCF-7 (p=0.004; p=0.0005), SKBR3 (p=0.001; p&lt;0.0001) and KPL-4 (p=0.0005; p&lt;0.0001), respectively. Th1 cells expressed (p&lt;0.0001) and secreted (p=0.0002) higher miR-19a levels than Th2 cells (Th1 antagonist). Patients with favorable prognosis had higher levels of IFN-γ-secreting Th1 cells (p=0.049) in the peripheral blood than patients with worse prognosis.

Conclusion

High serum miR-19a levels in patients with metastatic HER2+ breast cancer may result from an increased ability of trastuzumab to induce an effective NK-mediated ADCC and activation of Th1-mediated immune response. This may explain the different clinical outcome between patients with high and low serum miR-19a levels. Our results suggest that miR-19a may potentially represent a novel serum biomarker to evaluate trastuzumab response and Th1-mediated anti-tumor immunity in patients with metastatic HER2+ breast cancer.

Citation Format: Anfossi S, Huo L, Woodward WA, Ueno NT, Valero V, Calin GA, Reuben JM. High serum miR-19a levels correlated with favorable prognosis in patients with metastatic HER2+ breast cancer and might result from effective antibody-dependent cell-mediated cytotoxicity (ADCC) induced by trastuzumab and Th1-mediated antitumor immune response. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-04-18.

Abstract OT3-03-04: NRG-BR002: A phase IIR/III trial of standard of care therapy with or without stereotactic body radiotherapy (SBRT) &/or surgical ablation for newly oligometastatic breast cancer

Background:

The current standard of care for metastatic breast cancer patients (pts) is to deliver palliative chemotherapy, biologic &/or hormonal therapy when appropriate, with radiation &/or surgery reserved for the management of symptomatic or non-responsive (mets). For selected pts with limited metastatic (met) disease, mets-directed ablative therapy, with either surgical resection or high dose conformal radiotherapy (in addition to standard systemic therapies) to lung, liver, CNS adrenal, & multiple organs has been shown to result in long-term disease control numerically superior to systemic therapy alone. NRG-BR002 is a randomized Phase II trial to evaluate stereotactic body radiotherapy (SBRT) &/or surgical resection (SR) of all met sites in newly oligometastatic breast cancer in addition to standard systemic therapy.

Trial Design & Eligibility

For the Ph IIR, eligible breast cancer pts who have received up to 6 months of first line systemic therapy without progression will be randomized to receive either standard systemic therapy with mets directed therapy as needed ( control arm) versus ablative therapy of all met sites with either body SBRT &/or surgical resection (SR) ( per the treating physician discretion) to determine if there is an improvement median progression free survival (PFS). If this aim is met the trial continues as a Ph III to evaluate if SBRT/SR improves 5 year overall survival. Secondary aims include local control in the met site, new distant met rate, & technical quality. The primary translational endpoint tests whether &lt; 5 CTCs (per 7.5ml of blood) is an independent prognostic (outcome) marker for improved PFS & OS in oligometastatic breast cancer.

Women with pathologically confirmed met breast cancer to &lt; /= 2 sites, with up to 6 months of standard first line systemic therapy & the primary site disease is controlled. CNS mets are ineligible. ER/PR & HER-2 neu are required on either the primary or met site. Site radiation credentialing & a facility questionnaire are required. Randomization is to standard systemic therapy with local radiotherapy/ surgery for palliation when necessary vs ablative therapy of all mets with SBRT &/or SR.

Statistics:

For the Ph IIR portion to detect a signal for improved median PFS from 10.5 months to 19 months with 95% power & accounting for ineligible/lost pts, 146 pts will be required. For the Ph III, an additional 246, for a total of 402 pts will be required to definitively determine if ablative therapy improves 5-year overall survival from 28% to 42.5% (HR=0.67), with 85% power & a 1-sided type I error of 0.025. For the translational research, the number of pts accrued in the Ph IIR & Ph III portions will provide sufficient power ≥ 91% to detect whether &lt; 5 CTC's is a prognostic marker for improved PFS & OS.

Present Accrual & Target Accrual

NRG BR002 activated 12/24/2014 with a target accrual of 146 pts for the Ph II component & 256 additional for the Ph III.

Contact Information:

Protocol: CTSU member web site https://www.ctsu.org. Enrollment: OPEN at https://open.ctsu.org.

Support:

Supported by NRG Oncology grants U10CA180868 & U10CA180822 from the National Cancer Institute (NCI).

Citation Format: Chmura SJ, Winter KA, Salama JK, Woodward WA, Borges VF, Al-Hallaq H, Matuszak M, Jaskowiak NT, Milano MT, Bandos H, White JR. NRG-BR002: A phase IIR/III trial of standard of care therapy with or without stereotactic body radiotherapy (SBRT) &/or surgical ablation for newly oligometastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-03-04.

Long-term treatment efficacy in primary inflammatory breast cancer by hormonal receptor- and HER2-defined subtypes

BACKGROUND

Subtypes defined by hormonal receptor (HR) and HER2 status have not been well studied in inflammatory breast cancer (IBC). We characterized clinical parameters and long-term outcomes, and compared pathological complete response (pCR) rates by HR/HER2 subtype in a large IBC patient population. We also compared disease-free survival (DFS) and overall survival (OS) between IBC patients who received targeted therapies (anti-hormonal, anti-HER2) and those who did not.

PATIENTS AND METHODS

We retrospectively reviewed the records of patients diagnosed with IBC and treated at MD Anderson Cancer Center from January 1989 to January 2011. Of those, 527 patients had received neoadjuvant chemotherapy and had available information on estrogen receptor (ER), progesterone receptor (PR), and HER2 status. HR status was considered positive if either ER or PR status was positive. Using the Kaplan-Meier method, we estimated median DFS and OS durations from the time of definitive surgery. Using the Cox proportional hazards regression model, we determined the effect of prognostic factors on DFS and OS. Results were compared by subtype.

RESULTS

The overall pCR rate in stage III IBC was 15.2%, with the HR-positive/HER2-negative subtype showing the lowest rate (7.5%) and the HR-negative/HER2-positive subtype, the highest (30.6%). The HR-negative, HER2-negative subtype (triple-negative breast cancer, TNBC) had the worst survival rate. HR-positive disease, irrespective of HER2 status, had poor prognosis that did not differ from that of the HR-negative/HER2-positive subtype with regard to OS or DFS. Achieving pCR, no evidence of vascular invasion, non-TNBC, adjuvant hormonal therapy, and radiotherapy were associated with longer DFS and OS.

CONCLUSIONS

Hormone receptor and HER2 molecular subtypes had limited predictive and prognostic power in our IBC population. All molecular subtypes of IBC had a poor prognosis. HR-positive status did not necessarily confer a good prognosis. For all IBC subtypes, novel, specific treatment strategies are needed in the neoadjuvant and adjuvant settings.

Abstract ES07-2: Inflammatory breast cancer: Diagnosis, treatment and biology

Inflammatory breast cancer (IBC) is a relatively rare variant of breast cancer accounting for a disproportionate amount of breast cancer mortality. It is histopathologically similar to non-IBC but presents with a very distinct clinical picture: rapid onset of breast redness and swelling often without an obvious lump. Misdiagnosis and delay in diagnosis are common. Although the breast appears “inflamed” obvious inflammatory infiltrates are not detectable in most tissues. Three presentations will focus on the diagnostic challenges, determinants, epidemiology, management and biology of inflammatory breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr ES07-2.

Abstract P6-12-02: Survival differences between patients with metastatic inflammatory and non-inflammatory breast cancer

Background: Very little is known about the survival of patients with inflammatory breast cancer (IBC) and distant metastasis. Furthermore, the American Joint Committee on Cancer classification of breast cancer does not recognize metastatic IBC as a distinct entity within stage IV. We hypothesized that the survival of patients with IBC and distant metastasis is worse than the survival of patients with stage-matched non-IBC.

Patients and Methods: We retrospectively reviewed 5314 consecutive patients with stage III or IV breast cancer (IBC or non-IBC) who were treated at our institution between 1986 and 2012. A total of 1079 patients presented with IBC (stage III: 861; stage IV: 218) and 4235 non-IBC (stage III: 2781; stage IV: 1454). We compared the time to distant metastasis from initial diagnosis, distant metastasis–free survival (DMFS), and overall survival (OS) in stage-matched patients with IBC or non-IBC.

Results: The median follow-up periods were 3.3 years for patients with stage III disease (range, 0-32.2 years) and 1.8 years for patients with stage IV disease (range, 0-19.9 years). The total number of recorded events (metastasis/death) was 1657 for stage III, while the numbers of deaths for stage III and IV were 1337 and 973, respectively. In patients with stage III, the time to distant metastasis was shorter in IBC than in non-IBC (median 1.3 vs. 1.7 years, P &lt; .001). DMFS and OS were shorter in patients with stage III IBC than in those with stage III non-IBC (2.5 vs. 6.9 years, P &lt; .001; and 4.7 vs. 8.9 years, P &lt; .001; respectively). However, there was no significant difference in OS after development of distant metastasis between stage III IBC and non-IBC (median for both 1.3 years, P = .83). In multivariate analysis, the diagnosis of IBC remained significantly associated with mortality after adjusting for potential confounders. De novo stage IV IBC presented more frequently with multiple sites of metastasis than de novo stage IV non-IBC (P = .02). In patients with de novo stage IV disease, OS was shorter in IBC than in non-IBC (2.3 vs. 3.4 years, P = .004). In the multicovariate Cox model, while ethnicity, tumor grade, hormone receptor status and HER2 status, site of metastasis, number of sites of metastasis, and definitive breast surgery by 1 year were all significant factors in OS for stage IV breast cancer, the diagnosis of IBC conferred a hazard ratio of 1.33 (95% confidence interval: 1.05 - 1.69) in multivariate analysis.

Conclusion: Our findings suggest that IBC patients with metastasis at diagnosis have worse outcomes than stage-matched non-IBC patients. IBC patients presenting with de novo stage IV disease should be considered as a separate subcategory of stage IV in the tumor-node-metastasis classification because their clinical course and prognosis are different from those of patients with stage IV non-IBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-02.

Abstract P6-12-04: Risk factors for inflammatory breast cancer

Background: The 5-year survival rates for inflammatory breast cancer (IBC) are significantly lower than non-IBC, highlighting the importance of cancer prevention in IBC. We investigated the risk factors for IBC subtypes based on estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2neu) status to determine distinct etiological pathways. The Morgan Welch Inflammatory Breast Cancer Research Program and Clinic at University of Texas MD Anderson Cancer Center (UTMDACC) treats the largest number of IBC patients in a single center. The center maintains a prospective, comprehensive epidemiology registry, through which we were able to conduct the largest single center case-control study on IBC. Methods: We identified 246 patients diagnosed with IBC using strict consensus criteria and 397 cancer free patients seen at the UTMDACC Dan L. Duncan Cancer prevention clinic. We used logistic regression to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations between breast cancer reproductive and lifestyle risk factors and IBC tumor subtypes. The tumor subtypes of IBC patients were classified as ER-positive (ER+/PR+/Her2neu-), Her2neu-positive (Her2neu+) and triple negative (ER-/PR-/Her2neu-). Results: In age-adjusted univariate analysis, body mass index (BMI), history of smoking, number of children, age at first pregnancy, breastfeeding, menopausal status, and first degree family history of breast cancer were statistically significant associated with risk of IBC (p&lt;0.05). In multivariable analysis of IBC tumor subtypes, compared to cancer free controls, patients with triple negative (OR = 3.73, 95% CI = 1.52 – 9.13) and Her2neu-positive (OR = 19.27, CI = 4.14 – 89.62) tumors were significantly more likely to have ≥ 2 vs 0-1 children. Patients with triple negative (OR = 0.19, 95% CI = 0.09 – 0.45) and ER-positive (OR = 0.42, CI = 0.19 – 0.88) tumors were significantly less likely to have a history of breastfeeding. Patients with ER-positive (OR = 5.02, CI = 2.29 – 10.99) tumors were also significantly more likely to have a history of smoking. Patients with triple negative (OR = 6.07, CI = 2.62 – 17.07), ER-positive (OR = 7.22, CI = 2.94 – 17.78) and Her2neu-positive (OR = 12.81, CI = 4.59 – 35.78) were more likely to be overweight or obese (BMI ≥ 25kg/m2). Conclusion: The associations identified suggest that overweight or obese status is an important modifiable risk factor for all IBC subtypes. Triple negative IBC share similar risk factors as non-IBC triple negative tumors with increasing number of children and lack of breastfeeding associated with increased risk. Interestingly lack of breastfeeding was also associated with ER-positive IBC tumors, and Her2neu-positive IBC tumors were associated with increasing number of children; two associations that have not been previously reported. Impact: These results highlight the importance of evaluating epidemiologic risk factors of IBC, which could lead to the identification of subtype specific prevention strategies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-04.

Abstract P5-14-08: Prospective phase II study of concurrent capecitabine and radiation demonstrates futility in triple negative chemo-resistant breast cancer

Background: Capecitabine is an established radiosensitizer in rectal and other cancers. We conducted a prospective single arm phase II study to examine the response rate of gross chemo-refractory breast cancer treated with concurrent capecitabine and radiotherapy.

Methods: Patients who had inoperable or marginally operable gross disease in the breast and/or lymph node(s) after chemotherapy or gross disease on the chest wall or in the regional lymphatics after mastectomy were eligible. Patients 1-9 received capecitabine 825 mg/m2 BID daily beginning on the first day of radiotherapy. Excess grade 3 toxicity (%) was observed; the protocol was amended and subsequent patients received drug only on radiation treatment days. Radiation dose was at the discretion of the treating physician (50Gy-72 Gy, with no more than 2.5 Gy/fraction). Response was assessed by a single physician using paired radiation planning CTs (pretreatment and on-treatment after 45 Gy). Clinical correlation to all other available imaging was also made. Kaplan-Meier curves were used to estimate overall survival (OS) and local recurrence-free survival (LRFS). Circulating tumor cells (CTCs) in blood were examined in consenting patients.

Results: The trial was stopped early after an unplanned interim analysis prompted by slow accrual suggested futility independent of response. From 2009-2012, 32 patients were accrued; 26 completed protocol specific treatment (17 post-mastectomy radiation with gross nodes, 4 pre-op, 5 aggressive palliation) and are included in this analysis. Median follow up was 7.3 months (interquartile range 6.7 – 17.4). Nineteen patients (73%) had a partial or complete response. Fourteen patients (53.9%) experienced at least one grade 3 non-dermatitis toxicity including 7/9 treated with continuous dosing. Four inoperable patients were treated with pre-op radiation therapy and 3 converted to operable. None achieved a pCR or near pCR. One-year actuarial OS was 52%. There was no difference in OS comparing among PMRT vs. preoperative or palliative RT (P = 0.90). One-year actuarial local recurrence free survival among PMRT patients was 38%. Ten patients had triple negative (TN) receptor status. There was no difference in radiation response by receptor status (P = 0.56); however, treatment was deemed subjectively futile (i.e., converted to operable but death secondary to new widespread M1 disease immediately post-op) in 9 of the 10 patients with TN disease versus 6 of the 16 patients with non-TN disease (P = 0.014). Median OS and 1-yr actuarial OS, among non-TN vs. TN patients were not reached vs. 6.1 months and 77% vs. 10% (P &lt; 0.001), respectively. Eight/fifteen patients tested were positive for CTCs. CTCs did not correlate to receptor status, futility of RT or OS.

Conclusions: Capecitabine can be safely administered as a daily concurrent chemoradiation regimen with weekend holidays. However, in this small, prospective and selected cohort, concurrent chemoradiation with capecitabine was futile among patients with TN breast cancer. Alternative strategies are urgently needed in TN patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-08.

Abstract P1-06-07: Immune-induced epithelial to mesenchymal transition in inflammatory breast cancer induces unique increases in E-cadherin, adhesion and migration through TNF-a, IL-6 and TGF-b

BACKGROUND AND RATIONALE

Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer and patients frequently present with metastases at the time of their diagnosis. Although a robust IBC-specific molecular signature remains elusive, the disease is frequently characterized by persistent expression of the adhesion molecule, E-cadherin. This is highly counterintuitive as epithelial to mesenchymal transition (EMT), frequently associated with metastasis, results in decreased E-cadherin expression and highly aggressive cancers frequently express low levels of E-cadherin.

We hypothesized that persistent inflammation, mediated by immune activation, increases the plasticity of IBC cells, inducing EMT and allowing the re-acquisition of epithelia characteristics once removed from the inflammatory foci. In support of this hypothesis, previous in vitro work showed that soluble factors from activated immune cells induce EMT-related transcripts in both IBC and non-IBC cell lines. However, uniquely in 3 of 4 IBC cell lines but none of the non-IBC cell lines, this program included an increase of E-cadherin expression.

RESULTS

We used real-time cell analysis (RTCA) from Acea Biosciences (San Diego, CA) to probe the effect of immune conditioned media, produced by stimulating healthy donor peripheral blood mononuclear cells through the T-cell receptor or through toll-like receptor-4, on SUM149 inflammatory breast cancer cells. Consistent with the increased expression of E-cadherin, we observed rapid and strong increases in cellular adhesion as measured by the RCTA cell-index following culture with immune inflammatory factors. However, using the CIM chip, the same cells also showed strong increases in invasion and migration.

To determine the inflammatory factors involved in this process, we screened the immune conditioned media using a Luminex array (Millipore, Billerica, MA). TGF-b, TNF-α, and IL-6, previously shown to induce EMT, were all found at elevated levels. In 5 culture supernatants of healthy donor PBMC activated for 48h with anti-CD3 antibody, TGF-β had a modest 1.6-fold increase; TNF-α had an average 101-fold increase; while IL-6 had an average 347-fold increase. When added to cultures of SUM149 cells, these factors recapitulated the EMT gene expression signature in SUM149 including the increase in E-cadherin expression. Furthermore, the addition of neutralizing antibodies against TNF-α, TGF-β, and IL-6 to immune conditioned media prior to exposure to SUM149 cells resulted in less EMT.

CONCLUSIONS

Inflammatory factors may induce both the migratory ability and the characteristic persistent E-cadherin expression of IBC cells. This is mediated in part by TNF-α, TGF-β, and IL-6. However, the molecular basis for this unique IBC response requires further study hindering the development of optimal therapies. Ongoing studies at MD Anderson are exploring both the tumor and stromal components of inflammatory breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-07.

Gene expression profiles of inflammatory breast cancer: correlation with response to neoadjuvant chemotherapy and metastasis-free survival

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive disease. To date, no molecular feature reliably predicts either the response to chemotherapy (CT) or the survival. Using DNA microarrays, we searched for multigene predictors.

PATIENTS AND METHODS

The World IBC Consortium generated whole-genome expression profiles of 137 IBC and 252 non-IBC (nIBC) samples. We searched for transcriptional profiles associated with pathological complete response (pCR) to neoadjuvant anthracycline-based CT and distant metastasis-free survival (DMFS) in respective subsets of 87 and 106 informative IBC samples. Correlations were investigated with predictive and prognostic gene expression signatures published in nIBC (nIBC-GES). Supervised analyses tested genes and activation signatures of 19 biological pathways and 234 transcription factors.

RESULTS

Three of five tested prognostic nIBC-GES and the two tested predictive nIBC-GES discriminated between IBC with and without pCR, as well as two interferon activation signatures. We identified a 107-gene signature enriched for immunity-related genes that distinguished between responders and nonresponders in IBC. Its robustness was demonstrated by external validation in three independent sets including two IBC sets and one nIBC set, with independent significant predictive value in IBC and nIBC validation sets in multivariate analysis. We found no robust signature associated with DMFS in patients with IBC, and neither of the tested prognostic GES, nor the molecular subtypes were informative, whereas they were in our nIBC series (220 stage I-III informative samples).

CONCLUSION

Despite the relatively small sample size, we show that response to neoadjuvant CT in IBC is, as in nIBC, associated with immunity-related processes, suggesting that similar mechanisms responsible for pCR exist. Analysis of a larger IBC series is warranted regarding the correlation of gene expression profiles and DMFS.

Accelerated partial-breast irradiation using intensity-modulated proton radiotherapy: do uncertainties outweigh potential benefits?

OBJECTIVE

Passive scattering proton beam (PSPB) radiotherapy for accelerated partial-breast irradiation (APBI) provides superior dosimetry for APBI three-dimensional conformal photon radiotherapy (3DCRT). Here we examine the potential incremental benefit of intensity-modulated proton radiotherapy (IMPT) for APBI and compare its dosimetry with PSPB and 3DCRT.

METHODS

Two theoretical IMPT plans, TANGENT_PAIR and TANGENT_ENFACE, were created for 11 patients previously treated with 3DCRT APBI and were compared with PSPB and 3DCRT plans for the same CT data sets. The impact of range, motion and set-up uncertainties as well as scanned spot mismatching between fields of IMPT plans was evaluated.

RESULTS

IMPT plans for APBI were significantly better regarding breast skin sparing (p<0.005) and other normal tissue sparing than 3DCRT plans (p<0.01) with comparable target coverage (p=ns). IMPT plans were statistically better than PSPB plans regarding breast skin (p<0.002) and non-target breast (p<0.007) in higher dose regions but worse or comparable in lower dose regions. IMPT plans using TANGENT_ENFACE were superior to that using TANGENT_PAIR in terms of target coverage (p<0.003) and normal tissue sparing (p<0.05) in low-dose regions. IMPT uncertainties were demonstrated for multiple causes. Qualitative comparison of dose-volume histogram confidence intervals for IMPT suggests that numeric gains may be offset by IMPT uncertainties.

CONCLUSION

Using current clinical dosimetry, PSPB provides excellent dosimetry compared with 3DCRT with fewer uncertainties compared with IMPT.

ADVANCES IN KNOWLEDGE

As currently delivered in the clinic, PSPB planning for APBI provides as good or better dosimetry than IMPT with less uncertainty.

Clinical relevance of cancer stem cells in bone marrow of early breast cancer patients

BACKGROUND

Cancer stem cells (CSCs) are epithelial tumor cells that express CD44(+)CD24(-/lo). CSCs can be further divided into those that have aldehyde dehydrogenase (ALDH) activity (Aldefluor(+)) and those that do not. We hypothesized that if CSCs are responsible for tumor dissemination, their presence in bone marrow (BM) would be prognostic in early stages of breast cancer (EBC) patients.

PATIENTS AND METHODS

BM aspirates were collected at the time of surgery from 108 patients with EBC. BM was analyzed for CSCs and ALDH activity by flow cytometry. Overall survival and disease-free survival (DFS) were calculated from the date of diagnosis and analyzed with Kaplan-Meier survival plots. Cox multivariate proportional hazards model was also carried out.

RESULTS

Patients with CSCs in BM had a hazard ratio (HR) of 8.8 for DFS (P = 0.002); patients with Aldefluor(+) CSCs had a HR of 5.9 (P = 0.052) for DFS. All deceased patients (n = 7) had CSCs in BM. In multivariate analysis, the presence of CSCs in BM was a prognostic factor of DFS (HR = 15.8, P = 0.017).

CONCLUSIONS

The presence of BM metastasis is correlated with CSCs and these CSCs irrespective of ALDH activity are an independent adverse prognostic factor in EBC patients.

Pathologic complete response to neoadjuvant chemotherapy with trastuzumab predicts for improved survival in women with HER2-overexpressing breast cancer

BACKGROUND

We sought to determine the prognostic value of pathologic response to neoadjuvant chemotherapy with concurrent trastuzumab.

PATIENTS AND METHODS

Two hundred and twenty-nine women with HER2/neu (HER2)-overexpressing breast cancer were treated with neoadjuvant chemotherapy plus trastuzumab between 2001 and 2008. Patients were grouped based on pathologic complete response (pCR, n = 114) or less than pCR (<pCR, n = 115); as well as by pathologic stage. Locoregional recurrence-free (LRFS), distant metastasis-free (DMFS), recurrence-free (RFS), and overall survival (OS) rates were compared.

RESULTS

The median follow-up was 63 (range 53-77) months. There was no difference in clinical stage between patients with pCR or <pCR. Compared with patients achieving <pCR, those with the pCR had higher 5-year rates of LRFS (100% versus 95%, P = 0.011), DMFS (96% versus 80%, P < 0.001), RFS (96% versus 79%, P < 0.001), and OS (95% versus 84%, P = 0.006). Improvements in RFS and OS were seen with decreasing post-treatment stage. Failure to achieve a pCR was the strongest independent predictor of recurrence (hazard ratio [HR] = 4.09, 95% confidence interval [CI]: 1.67-10.04, P = 0.002) and death (HR = 4.15, 95% CI: 1.39-12.38, P = 0.011).

CONCLUSIONS

pCR and lower pathologic stage after neoadjuvant chemotherapy with trastuzumab are the strongest predictors of recurrence and survival and are surrogates of the long-term outcome in patients with HER2-overexpressing disease.

Abstract P3-10-01: Epidemiological risk factors and normal breast tissue markers in inflammatory breast cancer

Background: Inflammatory breast cancer (IBC) is a rare form of aggressive breast cancer with no existing identifiers for screening or prevention strategies. Women with triple-negative (TNBC, ER–, PR–, Her2–) non-inflammatory breast cancer are less likely to breastfeed, and we have shown in adjacent normal breast tissue that this tissue has more foci of stem cells compared to non-TNBC cancers. A disproportionately higher percentage of women with IBC have TNBC relative to women with non-IBC. We hypothesized that adjacent normal tissue in TNBC IBC vs. TN non-IBC may also display unique biological features based on epidemiologic characteristics.

Methods: We examined epidemiologic factors by breast cancer receptor subtype in 144 patients diagnosed with IBC in 1991–2011 at MD Anderson Cancer Center. Breast cancer risk factors including parity and breastfeeding were compared between patients with TN and non-TN IBC with chi-square or Wilcoxon rank sum tests. Normal adjacent tissues were stained for stem cell markers CD44+CD49f+CD133/2+ and macrophage marker CD68.

Results: The mean age at diagnosis was 52.3 years (range = 23–80) and 83% of patients were non-Hispanic white, 80% were overweight or obese (BMI &gt;25), and 36% were TN IBC. Patients with TN IBC had significantly lower frequency of breastfeeding compared with non-TN IBC, 28% vs. 55%, (p = 0.01). No differences were found in the frequency of other breast cancer risk factors. All 8 IBC adjacent tissue samples showed a distinct spatial distribution of stem cell staining, not limited to the triple negative patients. Compared with 0/60 non-IBC cases, 0/8 triple negative non-IBC, (p = 0.001 Pearson chi-square). Given the high BMI among IBC patients, we further examined normal tissues for the presence of CD68+ cells distributed individually or as clusters exhibiting a “crown-like” pattern (multiple CD 68+ macrophages found around dead adipocytes), and found that 7 of the 8 IBC adjacent tissues were CD68+. Benign biopsies collected from 2 patients at 10 years before diagnosis displayed similar staining, including both stem cell and CD68 staining. Compared with 12/60 non-IBC adjacent tissues were positive for CD68, with 1/8 TN non-IBC, (p = 0.001 Pearson chi-square).

Conclusion: We describe for the first time a stem-cell staining pattern unique to IBC present in all IBC tissues examined, including pre-cancer biopsies. Tissue samples from additional patients will be examined to further explore the relationship between stem cells and CD68 positivity with IBC subtypes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-10-01.

Abstract PD03-08: Statin use and improved outcome in primary inflammatory breast cancer: retrospective cohort study

Background Inflammatory breast cancer (IBC) is the most aggressive type of breast cancer. HMG-CoA reductase inhibitors (statins) are cholesterol reducing agents with pleiotropic effects, including antitumorigenic and anti-inflammatory properties. We hypothesized that statins reduce the metastatic potential in primary IBC.

Methods We retrospectively reviewed 724 patients diagnosed with and treated for primary IBC at The University of Texas MD Anderson Cancer Center between Jan. 12, 1995 and Jan. 27, 2011. Patients with records indicating statin use at the time of IBC diagnosis on the electronic medical record were compared with those without. We further compared outcomes stratified by statin type (hydrophilic [H] versus lipophilic [L]). We used the Kaplan-Meier method to estimate the median disease-free survival (DFS) after surgery, overall survival (OS), and disease specific survival (DSS), followed by Cox proportional hazards regression model to test statistical significance of several potential prognostic factors.

Results For primary IBC patients who had information on their statin use status at IBC diagnosis, the median DFS time were 4.88 years, 2.47 years and 1.76 years (P= 0.04); the median OS time 5.05 years, 3.79 years and 4.32 years (P= 0.35); and the median DSS time 5.10 years, 3.79 years and 4.52 years (P= 0.37), for patients who took “ H”, “L” and no statin, respectively. In multivariable Cox model stratified by radiation therapy, ER/PR status and HER2 status, statin “H” use was associated with significantly improved DFS compared to no statin use (HR=0.49; 95% CI: 0.28–0.84; p&lt;0.01), adjusted for lymphatic/vascular invasion. Although there is a trend that patients who used statin “H” had a longer time to death compared to patients who did not take statin, it did not reach statistical significance for OS (HR=0.80; 95% CI: 0.43–1.49; p=0.49) and DSS (HR=0.85; 95% CI: 0.46–1.57, p=0.59) after adjustment for lymphatic/vascular invasion, nuclear grade and surgery status within one year.

Conclusions Hydrophilic statin use was associated with improved DFS. There was a trend for reduced HR in OS and DSS among primary IBC patient who used hydrophilic statins. A prospective randomized study to evaluate the potential survival benefits of statins in primary IBC population is warranted.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD03-08.

Abstract P5-03-05: Histone deacetylase (HDAC)-inhibitor mediated reprogramming drives cancer cells to the pentose phosphate metabolic pathway

Recent studies have shown that energy metabolism in human pluripotent cells contrasts sharply with energy metabolism in differentiated cell types. Specifically, it has been shown that nuclear reprogramming from somatic cells to induced pluripotent stem cells is associated with a switch from oxidative to glycolytic metabolism. Whether a metabolic switch also occurs in reprogrammed/dedifferentiated breast cancer cells is unknown. Moreover, the function of the metabolic state in stemness is poorly understood and no data are available on whether breast cancer stem cells (CSCs) are metabolically different from committed cancer cells. Herein we demonstrated that HDAC inhibitors reprogram committed single aldefluor negative breast cancer cells into aldefluor positive cells (10.3 ± 2.8 vs 21.3 ±3.7% untreated vs treated P &lt;0.05, representing an average of 5 single cell derived clones) and promoted tumor initiation from non-initiating committed cells (p = 0.004). Further, induced stem-like cells were resistant to taxol and salinomycin, a drug previously described to target CSCs. These reprogrammed cancer cells have enhanced activity of the pentose phosphate pathway (PPP) with upregulation of G6PD expression and activity and higher levels of NADPH and ROS. Hypothesizing that CSCs may favor the PPP in order to survive and self renew, we used G6PD inhibitors, 6-AN and Imatinib, to target mammosphere formation and aldefluor activity in HDAC inhibition induced stem-like cells. Not only was there a significant decrease in mammospheres from reprogrammed cells, the aldefluor activity was totally blocked at a concentration that does not affect proliferation. This work demonstrates that HDAC inhibition mediated cancer cell dedifferentiation promotes metabolic reprogramming and highlights an FDA approved drug that targets metabolism in stem cell plasticity. Further functional endpoint studies are underway to validate these findings.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-05.

Abstract P5-04-06: Soluble factors from activated immune cells induce epithelial mesenchymal transition in inflammatory breast cancer cells

Rationale: Inflammatory breast cancer (IBC) is the most insidious form of locally advanced disease. Emerging evidence suggests that host factors in the microenviromement may interact with underlying IBC genetics to promote the aggressive nature of the tumor. An integral part of the metastatic process involves epithelial to mesenchymal transition (EMT) where primary breast cancer cells gain motility and stem cell features that allow distant seeding. Interestingly, the IBC consortium microarray data found no clear evidence for EMT in IBC tumor tissues. However, it is unknown if soluble factors secreted by activated immune cells mediate EMT in the IBC microenvironment that may account for the absence of EMT in studies of the tumor cells themselves. Therefore, we tested whether the conditioned media of activated immune cells were capable of inducing EMT in IBC cells.

Methods: Conditioned media (CM) were generated using healthy donor peripheral blood mononuclear cells that were activated with anti-CD3 antibody immobilized to plastic and soluble anti-CD28 antibody to activate T cells through the T-cell receptor (TCR) or left unstimulated for 48 hours. Thereafter, CM from each of the cultures was harvested and filtered. Next, 48-hour pre-seeded SUM149 IBC cells were grown in culture medium consisting of 25% CM and 75% IBC culture medium for an additional 2 days. Unconditioned media and TGF-β were used as negative and positive controls, respectively for EMT. Following treatment with CM, RNA was extracted from the target cells and analyzed for the presence of EMT-related transcription factors (EMT-TF) and markers of epithelial and mesenchymal states by TaqMan® qRT-PCR. Subsequently, a panel of 24 genes was tested on 4 IBC cell lines (SUM149, SUM190, KPL4 and IBC-3) and 5 non-IBC cell lines (MCF-10a, MCF-7, MDA-231, and MDA-453) treated with immune-activated CM using the Fluidigm® Dynamic Array integrated fluidic circuit (“chip”) gene expression platform which allows for the simultaneous quantification of 2,304 data points using TaqMan® assays. Formalin-fixed, paraffin embedded blocks were prepared from trypsinized cells for immunohistochemical (IHC) staining to detect E-cadherin and vimentin expression.

Results: SUM149 cells cultured in the presence of TCR-activated CM for two days showed upregulation in EMT-TFs (SNAIL1, ZEB1, and TG2), vimentin and fibronectin by qRT-PCR. IHC staining showed increases in both vimentin and E-cadherin expression after 48-hour exposure to anti-TCR CM. Fluidigm® gene expression analysis of multiple cell lines exposed to anti-TCR CM showed that E-cadherin expression was unchanged or slightly decreased in non-IBC cell lines, whereas 3 of 4 IBC cell lines showed an increase in E-cadherin.

Discussion: These data suggest that soluble factors secreted by activated immune cells are capable of inducing EMT in IBC cells and may mediate the persistent E-cadherin expression observed in IBC. Such processes may contribute to the highly aggressive nature of the disease; however, an immune competent in vivo model is warranted to fully understand the implications of these findings.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-04-06.

Abstract P3-10-05: Response to neoadjuvant systemic therapy (NST) in inflammatory breast cancer (IBC) according to estrogen receptor (ER) and HER2 expression

Background: Inflammatory breast cancer (IBC) is the most aggressive form breast cancer. NST, followed by local therapy (surgery and radiation therapy), is considered the current standard therapy for IBC. Among noninflammatory breast cancers, sensitivity to NST differs based on ER and HER2 status. However, whether the sensitivity to NST also differs in primary IBC based on ER status or other prognostic factors has not been studied in a large cohort.

Methods: We retrospectively reviewed 1078 patients (pts) newly diagnosed with IBC from April 1989 to January 2011. Of these, 838 pts met our inclusion criterion of stage III disease at diagnosis, and 713 of these pts had received NST and surgery. Among this population, 545 pts had information available on both ER and HER2 status. We compared pathological complete response (pCR) rates (defined as no evidence of invasive disease in the breast and ipsilateral axillary limph nodes) and clinical characteristics between ER and HER2-status subgroups and analyzed their clinical outcome. We used the Kaplan-Meier method to estimate the median recurrence-free survival (RFS) after surgery and overall survival (OS), and the Cox proportional hazards regression model to test the statistical significance of potential prognostic factors in each group.

Results: Overall 177 pts had ER+HER2− tumors; 75, ER+HER2+; 134, ER-HER2+; and 159, ER-HER2−. NST consisted of anthracycline-based [A] alone, a taxane [T] alone or with A+T; HER2 targeting therapies (H) were administered to 117 patients with HER2-positive breast cancer after 1998. Overall pCR rate was 14.7%. pCR rates are shown by marker subtype and NST received in the table below. pCR rate, nuclear grade, vascular invasion, clinical response to NST, adjuvant treatment, radiation therapy, and adjuvant hormonal therapy differed significantly among subgroups.

The median RFS and OS for all patients was 19.2 and 33.2 months, respectively. In multivariate analysis, BMI, ER status, lymphatic invasion, radiation therapy, and pCR rate were associated with RFS, and ER status, vascular invasion, radiation therapy, and pCR rate were associated with OS. Except in the ER+HER2− group, pCR was associated with better prognosis compared to non-pCR. Adjuvant hormonal therapy improved RFS both in ER+HER2+ and ER+HER2− groups, but did not improve OS in the ER+HER2+ group. Among 209 patients with HER2+ IBC, 134 received HER2 targeting therapies in neoadjuvant or adjuvant chemotherapy, and had a trend to improvement in RFS compared to chemotherapy alone (p = 0.082). The ER-HER2− group showed poorest outcome compared to other subgroups (P &lt; 0.001).

Conclusions: Sensitivity to NST differs depending on the ER and HER2 status in IBC pts. pCR rates based on these subgroups appear to be low. There is a need more effective treatments in the neoadjuvant and adjuvant therapies for all subgroups of IBC.

Abstract P5-03-10: HIF-1alpha knockout radiosensitizes select Inflammatory Breast Cancer cells through reduction of stem-like cancer cells

Independent of the tumor stroma, HIF-1α regulates tumor cell metabolism, cell proliferation and DNA repair pathways, which may produce conflicting responses to radiation, promoting either radioresistance or radiosensitization. Recently, HIF-1α was shown to increase tumor initiating cells (TICs) activity in normoxic tumor cells derived from the MMTV-PyMT trasngenic mouse model of luminal-like breast cancer. While TICs have been reported to be relatively radio-resistant, the role of HIF-1α in mediating the radation response in breast cancer TICs remains unknown. Herein, we examined radiosenstitivity of TICs derived from either PyMT HIF-1α knock out (KO) tumor cells or human breast cancer cell lines transduced with a HIF-1α dominant negative (DN) construct. Consistent prior results that loss of HIF-1 activity reduces TIC frequency, down-regulation of HIF-1 activity through the HIF DN construct reduced mammosphere formation in SUM-159, SUM-149 and MCF-7 cells (by 5.0-, 2.0-, and 2.0-fold respectively). Moreover, β-catenin expression was down-regulated in SUM-149 and SUM-159 cells transfected with the HIF-1α DN construct. Moreover, SUM-149 cells expressing the HIF-1α DN construct exhibited delayed tumor growth in vivo (p = 0.05). Standard clonogenic assays demonstrated that PyMT HIF-1α KO cells and SUM-149 cells expressing the HIF-1α DN construct were more sensitive to radiation therapy (SF6 of PyMT, HIF-1α:Control, 0.016:0.087), but that the PyMT KO and SUM-149 mammospheres that persisted after radiation were completely radioresistant (SF6 of PyMT, HIF-1 α: Control, 0.48:0.44). In contrast, MCF-7 cells were not radiosensitized in either standard or mammosphere assays. Interestingly, in HIF-1α DN MCF-7 cells, molecular features of IBC were observed, such as the increased expression of E-Cadherin and loss of Wisp3. But, Notch1 protein expression was unchanged between HIF-1α DN MCF7 or SUM149 cells. Moreover, concurrent radiation in the presence of a gamma secretase inhibitor or with a p53-MDM2 inhibitor nutlin failed to radiosensitize HIF KO mammosphere clonogens. We conclude that downregulation of HIF-1 activity selectively radiosensitizes IBC clonogenic cells but fails to radiosensitize the residual mammospheres. These data suggest that the known HIF-1α mediated mechanisms that favor radiosensitivity, such as the promotion of glycolysis and proliferation under stress, may predominate in mammospheres, which ultimately leads to radioresistance in residual mammospheres after HIF inhibition.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-10.

Abstract P2-03-01: Identification of cancer stem cells (CD44+CD24−/lo) in bone marrow as a prognostic factor in early breast cancer patients

Background: Cancer stem cells (CSCs) in bone marrow (BM) are epithelial tumor cells that express CD44+CD24−/lo. CSCs can be further divided into those that have ALDH activity (Aldefluor+) and those that do not. We hypothesized that if CSCs are responsible for tumor dissemination, their presence in BM would be prognostic in early stages of breast cancer (EBC) patients. Therefore, using multiparameter flow cytometry (FACS), we assessed epithelial cells for expression of CD44+CD24−/low and Aldefluor in BM of EBC patients and correlated these findings with circulating tumor cells (CTC), disseminated tumor cells (DTC) and clinical outcome.

Methods: This is a prospective laboratory study (Protocol 04–0657) conducted in the Departments of Surgical Oncology and Hematopathology, at The University of Texas MD Anderson Cancer Center in Houston, TX, USA, and was approved by the institutional review board. BM aspirates were collected at the time of surgery from 108 patients with EBC. BM was analyzed for CSCs and ALDH activity by FACS analysis. Ten cytospin slides of the bone marrow mononuclear cells were prepared from each BM aspirate and reacted with a cocktail of antibodies, including AE1/AE3, CAM5.2, MNF116, CK8 and CK18, to identify epithelial cells (DTC) by immunohistochemistry (IHC). In addition, the CellSearch system (Veridex, Raritan, NJ) was used to enumerate CTCs in each of 3 tubes of 7.5 mL of peripheral blood per patient. Overall survival (OS) and disease-free survival (DFS) were calculated from the date of diagnosis and analyzed with Kaplan-Meier survival plots. Cox multivariate proportional hazards model was also performed.

Results: Of the 103 evaluable patients, 45 patients received neoadjuvant chemotherapy, 35 adjuvant chemotherapy and 23 no chemotherapy. The median follow-up was 40 months (range 7–66 months). Patients with CSCs in BM had a hazard ratio (HR) of 8.8 for DFS (p = 0.002); patients with Aldefluor+ CSCs had a HR of 5.9 (p = 0.052) for DFS. Seven patients have expired and all of them had CSCs in BM. Moreover, we evaluated the presence of DTCs by FACS (CD326+CD45−) in 104 patients. Sixty-one (75%) of patients had positive BM samples for DTC (CD326+CD45- BM cells ≥ 0.53%). No association was shown between DTC in BM as determined by FACS and CTCs in PB. In a multivariate model, after adjusting for age (&lt; 45 years old), clinical T stage, N stage, ER, PR, HER2 status, and nuclear grading, the presence of CSCs was found to be an independent predictor of DFS (HR = 15.8, P = 0.017) as was the presence of CTCs (HR = 13.9, P = 0.007). In this subset of patients, the presence of Aldefluor+ CSCs and DTCs was not found to be predictive of DFS in the multivariate model including the same factors as listed above.

Conclusions: Our data indicate that the presence of BM metastasis is correlated to CSCs, and CSCs irrespective of ALDH activity are independent adverse prognostic factors in EBC patients. Moreover, the presence of CTCs was a strong independent predictor of DFS.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-03-01.

P1-04-03: The Effect of Survivin Downregulation on Radiosensitization of Breast Cancer Cell Lines Grown under Adherent and Stem Cell Promoting Culture Conditions

Survivin, the smallest member of the inhibitor of apoptosis protein (IAP) family, is a bifunctional protein that has been implicated in both control of cell division and inhibition of apoptosis. Survivin has been shown to be involved in radiation resistance of various cancer types and its expression is increased by sublethal doses of irradiation in both differentiated and cancer stem cell (CSC) population. However, it is unknown whether suppression of survivin radiosensitizes the CSC population or diminishes its self renewal ability. Herein, we cloned the survivin dominant-negative mutant lacking a phosphorylation site (T34A) (Mesri et al., 2001 JCI) into the lentiviral LeGo vectors and assessed mammosphere formation and radiosensitization in MCF7, SUM149 and SUM159 cell lines grown under adherent or stem cell promoting conditions. We found an induction of survivin by western blotting in the dominant negative mutant (T34A)-transfected cell lines. Moreover, we observed a higher than two-fold increase in the Sub-G1 population as well as an increased Caspase 3 activity in the T34A-transfected SUM149 and SUM159 cells compared to control cells indicating an anti-apoptotic function of survivin. We also found that T34A-transfected cells showed a 1.5 to 2-fold decrease in the number of mammospheres compared to the control-transfected cells. Furthermore, T34A-transfected cells showed radiosensitization in adherent cells from SUM149 and SUM159 cells but no effect was observed in MCF7 cells. However, no radiosensitization was observed in stem cell promoting culture conditions with increasing doses of radiation in all tested cell lines. This indicates that the widely used standard clonogenic assays do not optimally select anti-CSC agents and that targeted therapies should be specifically tested for their activity against the CSC population. Further functional endpoint studies will be conducted to validate the in vitro findings.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-04-03.

P4-20-04: Cytokine Synthesis by Activated Dendritic Cells in Relation to Disease Progression in Inflammatory Breast Cancer (IBC)

Background: Deficiencies in innate and adaptive immune responses by plasmacytoid dendritic cells (pDC) and myeloid DC (mDC) have been linked to poor clinical outcome in breast cancer (BC) (Treilleux, Clin Cancer Res, 2004, PMID 15569976). pDC produce IFN-a and pro-inflammatory cytokines that regulate innate and adaptive immunity in breast cancer. mDC present in blood and secondary lymphoid organs secrete IL-12 and induce inflammatory cytokine production by T cells. Therefore, we studied DC activity in the peripheral blood and assessed their function with clinical outcome in breast cancer patients.

Methods: We recruited 115 BC patients [25 with locally advanced non-IBC (LABC), 25 with IBC, 21 with metastatic breast cancer (MBC), and 44 with metastatic IBC (mIBC)] and 31 healthy donors (HD) for this study. Peripheral blood pDC and mDC were activated through toll-like receptor (TLR)-7 to assess IFN-α and IL-10 production whereas mDC were activated through TLR-8 to assess production of IL-12 and TNF-α by multi-parameter flow cytometry. Associations between cytokine production by TLR-activated pDC and mDC with progression free survival (PFS) and overall survival (OS) of patients were analyzed by Kaplan Meier Test.

Results: The median follow-up (FU) of 113 evaluable patients was 14.1 months with a median time to progression of 10.5 months; 54 patients had stable disease (SD) and 59 had progression of disease (PD). Metastasis, previous treatments, and IBC contributed to shorter PFS and OS. Compared to HD, BC patients had significantly fewer total DC (p=0.008), mDC (p=0.008), and pDC (p=0.003) per μL. In general, the number of TLR-7-activated pDC per μL that produced IFN-a(p=0.023) or IL-10 (p=0.027) and the number of TLR-8-activated mDC per μL that produced IL-12 (p&lt;0.001) or TNF-α (p=0,008) were significantly lower in BC patients than in HD. However, patients with DC that produced these cytokines above the median levels of HD had shorter PFS or OS. In IBC patients, higher numbers of TLR-8-activated mDC that produced TNF-α (p=0.025) or IL-12 (p=0.003) predicted shorter OS. In mIBC patients, a higher number of TLR-7-activated pDC producing IFN-α (p=0.024) or IL-10 (p=0.034) predicted shorter PFS.

Conclusion: BC patients had significantly fewer pDC and mDC in peripheral blood than HD. IBC patients with above average numbers of TLR-activated DC capable of producing proinflammatory cytokines had a significantly shorter PFS or OS. Disease progression in IBC is related to an increased number of activated dendritic cells producing inflammatory cytokines.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-20-04.

P2-02-01: A Novel Inflammatory Breast Cancer-Specific Oncogene, Tazarotene-Induced Gene 1, Promotes Tumorigenicity and Invasiveness through the Receptor Tyrosine Kinase Axl

Background: Inflammatory breast cancer (IBC) is the most lethal and aggressive form of breast cancer and is highly metastatic. The prognosis of patients with IBC is poor, and effective standard therapies for IBC are limited because the molecular mechanisms underlying the pathogenesis of IBC remain unknown. We recently found that tazarotene-induced gene 1 (TIG1) expression is significantly higher in IBC cell lines than in non-IBC cell lines. In both IBC and non-IBC data sets, estrogen receptor-negative/HER2−negative samples had significantly higher expression of TIG1 than did other clinical subtypes (estrogen receptor-positive/HER2−negative and HER2−positive). Therefore, we hypothesized that TIG1 plays an important role in the malignant process of IBC. In these studies, we determined the biological function of TIG1 in IBC cells and elucidated the molecular mechanism by which TIG1 regulates the invasiveness of IBC cells.

Methods: TIG1 expression in SUM149 and KPL-4 IBC cells was stably knocked down, and the effects of this knockdown on in vitro cell proliferation, migration, and invasion were analyzed. The effects of restoring TIG1 expression on TIG1-silencing IBC cells were also examined. To determine the tumorigenic activity of TIG1 in vivo, TIG1 stable-knockdown SUM149 cells and control shRNA-transfected cells were implanted into the mammary fat pads of athymic nude mice, and tumor growth was monitored. The receptor tyrosine kinase Axl, a potential functional partner of TIG1, was identified using DNA microarray analysis. The interaction between TIG1 and Axl in IBC cells was examined using immunoprecipitation and confocal microscopy assays. The signaling pathway in IBC cells in which TIG1 participates was also investigated.

Results: Knockdown of TIG1 expression in IBC cells reduced their proliferation, migration, and invasion in vitro. Also, silencing of TIG1 dramatically inhibited IBC tumor growth in a xenograft model. Moreover, restoring TIG1 expression rescued the proliferation, motility, and invasiveness of TIG1-silenced IBC cells. Most importantly, we identified Axl as a functional partner of TIG1 by showing that TIG1 interacted with and stabilized Axl in IBC cells. TIG1 regulated the invasiveness of IBC cells through mediation of the Axl signaling pathway. In SUM149 cells, TIG1 depletion decreased Axl expression, which led to downregulation of expression of matrix metalloproteinase-9, a molecule required for Axl-mediated invasion, and inactivation of nuclear factor-kB, ultimately leading to decreased invasiveness of IBC cells.

Conclusion: Our results identified TIG1 as an oncogenic gene that contributes to the tumorigenic and metastatic properties of IBC. Our data also linked TIG1 with the key tumorigenic gene Axl in IBC cells. Further studies designed to establish TIG1 as a therapeutic target in the treatment of patients with IBC are under way.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-02-01.

P4-20-03: T-Cell Cytokine Production Related to Progression of Breast Cancer Patients

Background: Impaired immunosurveillance and immune dysregulation contribute to the pathogenesis and progression of breast cancer (BC). Upon activation, T cells synthesize inflammatory cytokines such as TNF-α that can promote or inhibit tumor growth. We therefore investigated T-cell cytokine syntheses as a predictor of disease progression.

Methods: We recruited 115 BC patients [25 with locally advanced breast cancer (LABC), 21 with metastatic breast cancer (MBC), 25 with non-metastatic inflammatory breast cancer (IBC), and 44 with metastatic IBC (mIBC)] and 31 healthy donors (HD) for this ongoing study. The tumor phenotype consisted of 69 hormone receptor (HR) positive (including 26 patients with HER2 positive disease), 16 HR negative but HER2+, 30 triple negative BC (TNBC). To evaluate T cell function, peripheral blood mononuclear cells from patients and HD were stimulated overnight with immobilized anti-CD3 and soluble anti-CD28 antibodies and assessed for the percentage of T cells that synthesized cytokines by multi-parameter flow cytometry. The associations of T cell cytokine production profile with patient progression free survival (PFS) were analyzed by Kaplan Meier Test.

Results: The median follow-up (FU) of 113 evaluable patients was 14.1 months with a median time to relapse of 10.5 months; 54 patients had stable disease (SD) and 59 patients had progression of disease (PD). In the entire cohort, on univariate analysis, metastasis, IBC, stage, and previous treatment predicted for worse PFS (p&lt; 0.05). In non-metastatic patients (LABC+IBC), absolute count of anti-CD3 activated CD8+ T cells producing IL-17 was significantly higher in the SD patients compared with patient with PD (p=0.038), but it did not predict PFS (p=0.073). Similarly in metastatic patients, anti-CD3 activated CD4+ T cells producing TNF-α were significantly higher in patients with SD (p=0.025) and was predictive of longer PFS (p=0.033). Considering all patients with IBC (IBC + mIBC), although patients with PD had significantly fewer (percent and absolute number) anti-CD3 activated T cells capable of producing cytokines, this immune impairment was mostly related to metastasis and previous treatment. However, the percentage of anti-CD3 activated CD8+ T cells producing TNF-α was an independent positive prognostic indicator of PFS (p=0.002).

Conclusion: Higher than average cytokine syntheses by anti-CD3 activated T cells are significantly associated with longer PFS. These data are consistent with the hypothesis that an adaptive immune response can control disease progression.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-20-03.

Identifying factors that impact survival among women with inflammatory breast cancer

BACKGROUND

The objective of this retrospective study was to determine factors impacting survival among women with inflammatory breast cancer (IBC).

METHODS

The Surveillance, Epidemiology and End Results Registry (SEER) was searched to identify women with stage III/IV IBC diagnosed between 2004 and 2007. IBC was identified within SEER as T4d disease as defined by the sixth edition of the American Joint Committee on Cancer. The Kaplan-Meier product-limit method was used to describe inflammatory breast cancer-specific survival (IBCS). Cox models were fitted to assess the multivariable relationship of various patient and tumor characteristics and IBCS.

RESULTS

Two thousand three hundred and eighty-four women with stage IIIB/C and IV IBC were identified. Two-year IBCS among women with stage IIIB, IIIC and IV disease was 81%, 67% and 42%, respectively (P < 0.0001). In the multivariable model, patients with stage IIIB disease and those with stage IIIC disease had a 63% [hazard ratio (HR) 0.373, 95% confidence interval (CI) 0.296-0.470, P < 0.001] and 31% (HR 0.691, 95% CI 0.512-0.933, P = 0.016) decreased risk of death from IBC, respectively, compared with women with stage IV disease. Other factors significantly associated with decreased risk of death from IBC included low-grade tumors, being of white/other race, undergoing surgery, receiving radiation therapy and hormone receptor-positive disease. Among women with stage IV disease, those who underwent surgery of their primary had a 51% decreased risk of death compared with those who did not undergo surgery (HR = 0.489, 95% CI 0.339-0.704, P < 0.0001).

CONCLUSIONS

Although IBC is an aggressive subtype of locally advanced breast cancer, it is heterogeneous with various factors affecting survival. Furthermore, our results indicate that a subgroup of women with stage IV IBC may benefit from aggressive combined modality management.

Abstract PD02-07: Impact of Mesenchymal Stem Cells on Radiation Therapy Response

Background: Radiation increases engraftment of human bone-marrow derived mesenchymal stem cells (MSC) in tumors and this effect is augmented following repeated doses of radiation. We have recently demonstrated that MSC increase formation of mammospheres, which are enriched with radiation resistant tumor-initiating cells. Thus, we hypothesized that MSC may impact radiation therapy response through enhanced survival of tumor-initiating cells.

Materials & Methods: To evaluate the impact of MSC on radiation response we performed in vitro clonogenic survival assays using 2D and 3D clonogenic assays. Colony (2D) and sphere (3D) formation was quantified following irradiation of different cell lines (breast, lung, head and neck and cervix) at 2, 4 and 6 Gy in the presence of MSC conditioned media. In vivo, MSC were co-injected subcutaneously at increasing percentages with 4T1 murine breast cancer cells in BALB/c mice. The effects of MSC on radiation response were evaluated by examination of tumor size and weight following tumor irradiation at 2 and 5 Gy. Results: In vitro 2D clonogenic cell survival assays demonstrated that MSC conditioned media increased survival of breast (MDA231), lung (H460), head and neck (HN5), and cervical (SiHa) cancer cells following irradiation with 2 and 4 Gy as compared to control fibroblast conditioned media. Moreover, MSC conditioned media increased the number of HMLE (breast normal ephitelial cells) and SUM149 (breast cancer cells) mammospheres formed (55 vs 195and 263 vs 1054, respectively) and increased clonogenic survival of mammospheres after 2, 4 and 6 Gy compared to serum-free media. In vivo, irradiation with 5 Gy reduced murine breast 4T1tumors weight by 75% as compared to control untreated tumors. However, tumors co-injected with MSC did not significantly respond to 5 Gy. Discussion: MSC increase tumor resistance to radiation therapy in vivo and in vitro in 2D and 3D cultures. This effect is mediated at least in part by paracrine factors secreted by MSC. Our results here described suggest that MSC secrete factors which activate survival pathways on cancer cells exposed to sub-lethal radiation doses.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD02-07.

International expert panel on inflammatory breast cancer: consensus statement for standardized diagnosis and treatment

BACKGROUND

Inflammatory breast cancer (IBC) represents the most aggressive presentation of breast cancer. Women diagnosed with IBC typically have a poorer prognosis compared with those diagnosed with non-IBC tumors. Recommendations and guidelines published to date on the diagnosis, management, and follow-up of women with breast cancer have focused primarily on non-IBC tumors. Establishing a minimum standard for clinical diagnosis and treatment of IBC is needed.

METHODS

Recognizing IBC to be a distinct entity, a group of international experts met in December 2008 at the First International Conference on Inflammatory Breast Cancer to develop guidelines for the management of IBC.

RESULTS

The panel of leading IBC experts formed a consensus on the minimum requirements to accurately diagnose IBC, supported by pathological confirmation. In addition, the panel emphasized a multimodality approach of systemic chemotherapy, surgery, and radiation therapy.

CONCLUSIONS

The goal of these guidelines, based on an expert consensus after careful review of published data, is to help the clinical diagnosis of this rare disease and to standardize management of IBC among treating physicians in both the academic and community settings.