Clinical outcomes after 1 versus 2-3 lines of neoadjuvant therapy in stage III inflammatory breast cancer

PURPOSE

Many stage III inflammatory breast cancer (IBC) patients experience a sufficient response to first-line (1L) neoadjuvant chemotherapy (NAC) to allow surgery, while some require additional NAC. We evaluated the pathologic complete response (pCR), breast cancer-free survival (BCFS) and overall survival (OS) among patients requiring 1 vs. 2-3 lines (L) of NAC prior to surgery.

METHODS

Stage III IBC patients from 2 institutions who received 1L or 2-3L of NAC prior to surgery were identified. Hormone receptor and HER2 status, grade, and pCR were evaluated. BCFS and OS were evaluated by the Kaplan-Meier method. Multivariable Cox models were utilized to estimate the hazard ratio (HR).

RESULTS

808 eligible patients (1997-2020) were identified (median age 51 years, median follow-up 69 months). 733 (91%) had 1L and 75 (9%) had 2-3L of NAC. Grade III, triple-negative and HER2-positive disease were more prevalent in 2-3L patients. 178 (24%) 1L and 14 (19%) 2-3L patients had pCR. 376 1L patients and 41 2-3L patients had recurrences. The 5-year BCFS was worse for the 2-3L group (33 vs. 46%, HR = 1.37; 95% CI 0.99-1.91). However, in 192 patients with a pCR, BCFS was similar (76 vs. 83% in 1L vs. 2-3L, respectively). There were 308 deaths (276 among 1L and 32 among 2-3L patients). The 5-year OS in 1L vs. 2-3L was 60 vs. 53% (HR = 1.32, 95% CI 0.91-1.93).

CONCLUSIONS

Among stage III IBC patients, pCR rates were similar, irrespective of the NAC lines number, and BCFS and OS were comparable with pCR after 1L and 2-3L.

Premastectomy Radiotherapy and Immediate Breast Reconstruction: A Randomized Clinical Trial

Importance

Premastectomy radiotherapy (PreMRT) is a new treatment sequence to avoid the adverse effects of radiotherapy on the final breast reconstruction while achieving the benefits of immediate breast reconstruction (IMBR).

Objective

To evaluate outcomes among patients who received PreMRT and regional nodal irradiation (RNI) followed by mastectomy and IMBR.

Design, Setting, and Participants

This was a phase 2 single-center randomized clinical trial conducted between August 3, 2018, and August 2, 2022, evaluating the feasibility and safety of PreMRT and RNI (including internal mammary lymph nodes). Patients with cT0-T3, N0-N3b breast cancer and a recommendation for radiotherapy were eligible.

Intervention

This trial evaluated outcomes after PreMRT followed by mastectomy and IMBR. Patients were randomized to receive either hypofractionated (40.05 Gy/15 fractions) or conventionally fractionated (50 Gy/25 fractions) RNI.

Main Outcome and Measures

The primary outcome was reconstructive failure, defined as complete autologous flap loss. Demographic, treatment, and outcomes data were collected, and associations between multiple variables and outcomes were evaluated. Analysis was performed on an intent-to-treat basis.

Results

Fifty patients were enrolled. Among 49 evaluable patients, the median age was 48 years (range, 31-72 years), and 46 patients (94%) received neoadjuvant systemic therapy. Twenty-five patients received 50 Gy in 25 fractions to the breast and 45 Gy in 25 fractions to regional nodes, and 24 patients received 40.05 Gy in 15 fractions to the breast and 37.5 Gy in 15 fractions to regional nodes, including internal mammary lymph nodes. Forty-eight patients underwent mastectomy with IMBR, at a median of 23 days (IQR, 20-28.5 days) after radiotherapy. Forty-one patients had microvascular autologous flap reconstruction, 5 underwent latissimus dorsi pedicled flap reconstruction, and 2 had tissue expander placement. There were no complete autologous flap losses, and 1 patient underwent tissue expander explantation. Eight of 48 patients (17%) had mastectomy skin flap necrosis of the treated breast, of whom 1 underwent reoperation. During follow-up (median, 29.7 months [range, 10.1-65.2 months]), there were no locoregional recurrences or distant metastasis.

Conclusions and Relevance

This randomized clinical trial found PreMRT and RNI followed by mastectomy and microvascular autologous flap IMBR to be feasible and safe. Based on these results, a larger randomized clinical trial of hypofractionated vs conventionally fractionated PreMRT has been started (NCT05774678).

Trial Registration

ClinicalTrials.gov Identifier: NCT02912312.

Patient Interest in Exploring Nonsurgical Treatment Approaches for Early-Stage Breast Cancer: A Qualitative Study

PURPOSE

Advances in radiation therapy have enabled the ability to deliver ablative treatments, but there has been limited application of these treatments to early-stage breast cancers with a goal of omitting surgery. The purpose of this study was to explore patient interest in pursuing nonsurgical treatment approaches for their early-stage breast cancer.

METHODS AND MATERIALS

We conducted a qualitative study involving interviews with 21 patients with early-stage breast cancer who were eligible for participation in a phase 2 clinical trial offering omission of definitive surgery. Interviews were transcribed and an inductive, thematic analysis was performed by 3 independent reviewers to generate themes and subthemes.

RESULTS

Data analysis revealed the following factors that affected patient willingness and desire to explore nonsurgical treatment options: (1) perceptions and feelings about their cancer; (2) current quality of life and the level of support available in their daily life; (3) external conversations focusing on family members' and friends' experiences with cancer and/or cancer treatments; (4) personal health care experiences, including their current breast cancer diagnosis; (5) perceptions and feelings about their physicians; (6) conversations with their physicians about their treatment options; and (7) self-identified desire to direct care decisions. Specifically, patients verbalized fearing surgery and surgical recovery; wanting to preserve their breast(s); the prior negative surgical experiences of friends, family, and themselves; a desire to receive treatment per the latest research; wanting to match the level of treatment with the severity of their cancer; and other comorbidities as reasons for wanting to explore omitting surgery.

CONCLUSIONS

Our findings demonstrate an unmet need directed by patient interest to explore nonsurgical options for early-stage, biologically favorable breast cancer. These results may shape conversations around shared decision-making and clinical trial design, and result in more personalized treatment options for women with early-stage breast cancer.

Neoadjuvant radioimmunotherapy synergy in triple-negative breast cancer: Is microenvironment-guided patient selection on the horizon?

Neoadjuvant chemotherapy plus immunotherapy for triple-negative breast cancer (TNBC) is associated with improved but incomplete response. In this issue of Cancer Cell, Shiao et al. characterize longitudinal biopsies from a window of opportunity study with single-cell RNA sequencing (scRNA-seq) and spatial proteomic profiling and elucidate synergy between radiotherapy (RT) and pembrolizumab.

Inflammatory Breast Cancer: Understanding the Patient Experience

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive, locally advanced cancer with a 5-year survival rate of approximately 40%. Although patients with IBC likely experience significant and variable symptom burden from diagnosis through survivorship, the description of the symptom burden in this population is limited.

OBJECTIVES

The purpose of this study was to describe the experience of patients with IBC and define the content domain for a patient-reported outcome measure of IBC symptom burden.

METHODS

Twenty patients with IBC described their experience in single qualitative interviews. Content analysis was used to define the symptom burden content domain. Relevance ratings by a panel of experts reduced the number of items for a preliminary patient-reported outcome symptom burden measure.

RESULTS

The mean (SD) participant age was 52.8 (12.0) years; 50.0% had distant metastatic disease, and 85.0% were currently receiving treatment. Content analysis revealed 45 symptoms, with 20 symptoms reported by greater than or equal to 20% of participants. All participants described localized disease-related symptoms. Treatment-related symptoms varied among participants based on the modalities received.

CONCLUSION

Patients with IBC experience symptom burden that is distinct from the symptom burden experienced by patients with non-IBC.

IMPLICATIONS FOR PRACTICE

Differentiating the disease-related symptoms of IBC may assist clinicians in making timely and accurate diagnoses for IBC. A disease- and treatment-specific measure of the symptom burden of IBC should be incorporated in clinical practice to allow for regular assessment and evaluation of symptom burden and implementation of evidence-based interventions for symptom management.

Association Between Symptom Burden and Early Lymphatic Abnormalities After Regional Nodal Irradiation for Breast Cancer

PURPOSE

Dermal backflow visualized on near-infrared fluorescence lymphatic imaging (NIRF-LI) signals preclinical lymphedema that precedes the development of volumetrically defined lymphedema. We sought to evaluate whether dermal backflow correlates with patient-reported lymphedema outcomes (PRLO) surveys in breast cancer patients treated with regional nodal irradiation (RNI).

METHODS AND MATERIALS

Patients with breast cancer planned for axillary dissection and RNI prospectively underwent perometry, NIRF-LI, and PRLOs (the Lymphedema Symptom Intensity and Distress Survey [LSIDS] and QuickDASH) at baseline, after surgery, and at 6, 12, and 18 months after radiation. Clinical lymphedema was defined as an arm volume increase ≥5% over baseline. Trends over time were assessed using analysis of variance testing. The association between survey responses and both dermal backflow and lymphedema was assessed using a linear mixed-effects model.

RESULTS

Sixty participants completed at least 2 sets of measurements and surveys and were eligible for analysis. Fifty-four percent of patients had cT3-T4 disease, 53% cN3 disease, and 75% had a body mass index >25. Dermal backflow and clinical lymphedema increased from 10% to 85% and from 0% to 40%, respectively, from baseline to 18 months. In the adjusted model, soft tissue sensation, neurologic sensation, and functional LSIDS subscale scores were associated with presence of dermal backflow (all P < .05). Both dermal backflow and lymphedema were associated with QuickDASH score (P < .05).

CONCLUSIONS

In this high-risk cohort, we found highly prevalent early signs of lymphedema, with increased symptom burden from baseline. Presence of dermal backflow correlated with PRLO measures, highlighting a potential NIRF-LI use to identify patients for early intervention trials after RNI.

Influence of Macrophages on Vascular Invasion of Inflammatory Breast Cancer Emboli Measured Using an In Vitro Microfluidic Multi-Cellular Platform

Inflammatory breast cancer (IBC) is an aggressive disease with a poor prognosis and a lack of effective treatments. It is widely established that understanding the interactions between tumor-associated macrophages (TAMs) and the tumor microenvironment is essential for identifying distinct targeting markers that help with prognosis and subsequent development of effective treatments. In this study, we present a 3D in vitro microfluidic IBC platform consisting of THP1 M0, M1, or M2 macrophages, IBC cells, and endothelial cells. The platform comprises a collagen matrix that includes an endothelialized vessel, creating a physiologically relevant environment for cellular interactions. Through the utilization of this platform, it was discovered that the inclusion of tumor-associated macrophages (TAMs) led to an increase in the formation of new blood vessel sprouts and enhanced permeability of the endothelium, regardless of the macrophage phenotype. Interestingly, the platforms containing THP-1 M1 or M2 macrophages exhibited significantly greater porosity in the collagen extracellular matrix (ECM) compared to the platforms containing THP-1 M0 and the MDA-IBC3 cells alone. Cytokine analysis revealed that IL-8 and MMP9 showed selective increases when macrophages were cultured in the platforms. Notably, intravasation of tumor cells into the vessels was observed exclusively in the platform containing MDA-IBC3 and M0 macrophages.

High-fat diet, but not duration of lactation, increases mammary gland lymphatic vessel function and subsequent growth of inflammatory breast cancer cells

Inflammatory breast cancer (IBC) presents as rapid-onset swelling and breast skin changes caused by tumor emboli in the breast and breast skin lymphatics. IBC has been linked with obesity and duration of breastfeeding, but how these factors affect IBC tumor progression is not clear. We modeled the simultaneous effects of diet and weaning in mice on in vivo lymphatic function; on IBC tumor growth; and on aspects of the mammary gland microenvironment before and after IBC (SUM149) xenograft inoculation. We hypothesized that weaning status and diet would have synergistic effects on lymphatic function and the breast microenvironment to enhance IBC tumor growth. Changes in lymphatic structure and function were characterized with in vivo near-infrared fluorescence (NIRF) imaging. Mice were fed either a high-fat diet (HFD; 60 kcal%) or a normal/low-fat diet (LFD; 10 kcal%), bred twice, and subjected to either normal-duration nursing (NW) or forced weaning (FW). SUM149 IBC tumors were implanted at 14 months; images were obtained before and after implantation. Multiparous mice fed HFD showed increased pre-tumor lymphatic pulsing in both the FW and NW groups relative to mice fed LFD. HFD promoted tumor growth independent of weaning time (P = 0.04). Pre-tumor lymphatic pulsing was associated with tumor volume at 8 weeks (P = 0.02) and was significantly correlated with expression of the lymphatic tracking ligand CCL21 (P = 0.05, Table 1). HFD significantly increased the numbers of monocyte-derived IBA1+, CD163+, and CD11c+ cells (P < 0.0001, P < 0.0001, P = 0.0005) in the contralateral, non-tumor-bearing mammary gland. Numbers of lymphangiogenic podoplanin+/IBA1+ macrophages were increased in the ducts of HFD and FW mice (all P < 0.003). HFD in nulliparous mice had a similar increase in lymphatic pulsing at 14 weeks (P = 0.006), indicating that this functional change was independent of parity. We conclude that HFD induced increases in mammary gland lymphatic function, assessed as pulsing rate before tumor initiation, and correlated with inflammation in the mammary gland and increased SUM149 tumor growth. The relationship between diet, lymphatic pulsing, and tumor growth warrants further investigation.

Low Rates of Local-Regional Recurrence Among Inflammatory Breast Cancer Patients After Contemporary Trimodal Therapy

BACKGROUND

Inflammatory breast cancer (IBC) represents a rare (2-3 %) but aggressive subset of breast cancer with a historically reported 5-year overall survival rate of 50 % and a 3-year local-regional recurrence (LRR) rate of 20 %. This study aimed to evaluate long-term LRR in a contemporary cohort of non-metastatic IBC patients undergoing trimodal therapy at a single institution and identify factors associated with local and distant failure.

METHODS

The study identified 262 patients with non-metastatic IBC who received trimodal therapy (neoadjuvant chemotherapy, modified radical mastectomy, adjuvant radiation) from an institutional prospective database (2007-2019). Long-term outcomes of local-regional and distant metastasis were reported. Survival outcomes were analyzed using the Cox proportional hazards regression model.

RESULTS

The median age at diagnosis was 52 years, and the median follow-up period was 5.1 years. In this cohort, 82 (31.3 %) patients achieved a pathologic complete response (pCR) in the breast and axilla. Local-regional recurrence was observed in 18 (6.9 %) patients (11 isolated to the chest wall, 4 isolated to regional nodes, and 3 involving chest wall and ipsilateral axillary nodes). Distant metastasis was observed in 92 (35.1 %) patients. During the follow-up period, 90 deaths occurred. In the multivariate analysis, pCR was associated with improved disease-free survival (hazard ratio [HR], 0.26; 95 % confidence interval [CI], 0.13-0.51; p = 0.001) and overall survival (HR, 0.31; 95 % CI, 0.15-0.65; p = 002).

CONCLUSIONS

During a median follow-up period longer than 5 years, the local-regional relapse rate for the IBC patients treated with contemporary trimodal therapy was 6.9%, similar to that for the non-IBC patients. After chemotherapy, surgical resection with modified radical mastectomy to negative margins and postmastectomy radiation therapy resulted in excellent long-term local-regional control.

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.

Standardized Definitions for Efficacy End Points in Neoadjuvant Breast Cancer Clinical Trials: NeoSTEEP

PURPOSE

The Standardized Definitions for Efficacy End Points (STEEP) criteria, established in 2007 and updated in 2021 (STEEP 2.0), provide standardized definitions of adjuvant breast cancer (BC) end points. STEEP 2.0 identified a need to separately address end points for neoadjuvant clinical trials. The multidisciplinary NeoSTEEP working group of experts was convened to critically evaluate and align neoadjuvant BC trial end points.

METHODS

The NeoSTEEP working group concentrated on neoadjuvant systemic therapy end points in clinical trials with efficacy outcomes-both pathologic and time-to-event survival end points-particularly for registrational intent. Special considerations for subtypes and therapeutic approaches, imaging, nodal staging at surgery, bilateral and multifocal diseases, correlative tissue collection, and US Food and Drug Administration regulatory considerations were contemplated.

RESULTS

The working group recommends a preferred definition of pathologic complete response (pCR) as the absence of residual invasive cancer in the complete resected breast specimen and all sampled regional lymph nodes (ypT0/Tis ypN0 per AJCC staging). Residual cancer burden should be a secondary end point to facilitate future assessment of its utility. Alternative end points are needed for hormone receptor-positive disease. Time-to-event survival end point definitions should pay particular attention to the measurement starting point. Trials should include end points originating at random assignment (event-free survival and overall survival) to capture presurgery progression and deaths as events. Secondary end points adapted from STEEP 2.0, which are defined from starting at curative-intent surgery, may also be appropriate. Specification and standardization of biopsy protocols, imaging, and pathologic nodal evaluation are also crucial.

CONCLUSION

End points in addition to pCR should be selected on the basis of clinical and biologic aspects of the tumor and the therapeutic agent investigated. Consistent prespecified definitions and interventions are paramount for clinically meaningful trial results and cross-trial comparison.

Radiotherapy Use and Incidence of Locoregional Recurrence in Patients With Favorable-Risk, Node-Positive Breast Cancer Enrolled in the SWOG S1007 Trial

Importance

Little is known about regional nodal irradiation (RNI) practice patterns or rates of locoregional recurrence (LRR) with and without RNI in patients with limited nodal disease and favorable biology treated with modern surgical and systemic therapy, including approaches that de-escalate those latter treatments.

Objective

To investigate how often patients with low-recurrence score breast cancer with 1 to 3 nodes involved receive RNI, incidence and predictors of LRR, and associations between locoregional therapy and disease-free survival.

Design, Setting, and Participants

In this secondary analysis of the SWOG S1007 trial, patients with hormone receptor-positive, ERBB2-negative breast cancer, and a Oncotype DX 21-gene Breast Recurrence Score assay result of no more than 25, were randomized to endocrine therapy alone vs chemotherapy then endocrine therapy. Prospectively collected radiotherapy information was collected from 4871 patients treated in diverse settings. Data were analyzed June 2022 to April 2023.

Exposure

Receipt of RNI (targeting at least the supraclavicular region).

Main Outcome(s) and Measure(s)

Cumulative incidence of LRR was calculated by locoregional treatment received. Analyses were assessed for associations between invasive disease-free survival (IDFS) and locoregional therapy, adjusted for menopausal status, treatment group, recurrence score, tumor size, nodes involved, and axillary surgery. Radiotherapy information was recorded in the first year after randomization, so survival analyses were landmarked as starting at 1 year among those still at risk.

Results

Of 4871 female patients (median [range] age, 57 [18-87] years) with radiotherapy forms, 3947 (81.0%) reported radiotherapy receipt. Of 3852 patients who received radiotherapy and had complete information on targets, 2274 (59.0%) received RNI. With a median follow-up of 6.1 years, the cumulative incidence of LRR by 5 years was 0.85% among patients who received breast-conserving surgery and radiotherapy with RNI; 0.55% after breast-conserving surgery with radiotherapy without RNI; 0.11% after mastectomy with postmastectomy radiotherapy; and 1.7% after mastectomy without radiotherapy. Similarly low LRR was observed within the group assigned to endocrine therapy without chemotherapy. The rate of IDFS did not differ by RNI receipt (premenopausal: hazard ratio [HR], 1.03; 95% CI, 0.74-1.43; P = .87; postmenopausal: HR, 0.85; 95% CI, 0.68-1.07; P = .16).

Conclusions and Relevance

In this secondary analysis of a clinical trial, RNI use was divided in the setting of biologically favorable N1 disease, and rates of LRR were low even in patients who did not receive RNI. Disease-free survival was not associated with RNI receipt; omission of chemotherapy among patients similar to those enrolled in the S1007 trial is not an independent indication for use of RNI.

Differential Gene Expression of fresh tissue and patient-derived explants' matricellular proteins augment inflammatory breast cancer metastasis: the possible role of IL-6 and MCP-1

BACKGROUND

Matricellular proteins comprising matrisome and adhesome are responsible for structure integrity and interactions between cells in the tumour microenvironment of breast cancer. Changes in the gene expression of matrisome and adhesome augment metastasis. Since inflammatory breast cancer (IBC) is characterized by high metastatic behaviour. Herein, we compared the gene expression profile of matrisome and adhesome in non-IBC and IBC in fresh tissue and ex vivo patient-derived explants (PDEs) and we also compared the secretory inflammatory mediators of PDEs in non-IBC and IBC to identify secretory cytokines participate in cross-talk between cells via interactions with matrisome and adhisome.

METHODS

Fifty patients (31 non-IBC and 19 IBC) were enrolled in the present study. To test their validation in clinical studies, PDEs were cultured as an ex vivo model. Gene expression and cytokine array were used to identify candidate genes and cytokines contributing to metastasis in the examined fresh tissues and PDEs. Bioinformatics analysis was applied on identified differentially expressed genes using GeneMANIA and Metascape gene annotation and analysis resource to identify pathways involved in IBC metastasis.

RESULTS

Normal and cancer fresh tissues and PDEs of IBC were characterized by overexpression of CDH1 and MMP14 and downregulation of CTNNA1 and TIMP1 compared with non-IBC. The secretome of IBC cancer PDEs is characterized by significantly high expression of interleukin 6 and monocyte chemoattractant protein-1 (CCL2) compared with non-IBC.

CONCLUSION

Genes expressed by adhisome and matrisome play a significant role in IBC metastasis and should be considered novel target therapy.

Prospective, early longitudinal assessment of lymphedema-related quality of life among patients with locally advanced breast cancer: The foundation for building a patient-centered screening program

BACKGROUND

We examined how breast cancer-related lymphedema (BCRL) affects health-related quality of life (HRQOL), productivity, and compliance with therapeutic interventions to guide structuring BCRL screening programs.

METHODS

We prospectively followed consecutive breast cancer patients who underwent axillary lymph node dissection (ALND) with arm volume screening and measures assessing patient-reported health-related quality of life (HRQOL) and perceptions of BCRL care. Comparisons by BCRL status were made with Mann-Whitney U, Chi-square, Fisher's exact, or t tests. Trends over time from ALND were assessed with linear mixed-effects models.

RESULTS

With a median follow-up of 8 months in 247 patients, 46% self-reported ever having BCRL, a proportion that increased over time. About 73% reported fear of BCRL, which was stable over time. Further in time from ALND, patients were more likely to report that BCRL screening reduced fear. Patient-reported BCRL was associated with higher soft tissue sensation intensity, biobehavioral, and resource concerns, absenteeism, and work/activity impairment. Objectively measured BCRL had fewer associations with outcomes. Most patients reported performing prevention exercises, but compliance decreased over time; patient-reported BCRL was not associated with exercise frequency. Fear of BCRL was positively associated with performing prevention exercises and using compressive garments.

CONCLUSIONS

Both incidence and fear of BCRL were high after ALND for breast cancer. Fear was associated with improved therapeutic compliance, but compliance decreased over time. Patient-reported BCRL was more strongly associated with worse HRQOL and productivity than was objective BCRL. Screening programs must support patients' psychological needs and aim to sustain long-term compliance with recommended interventions.

Prediction of breast cancer-related lymphedema by dermal backflow detected with near-infrared fluorescence lymphatic imaging

PURPOSE

Mild breast cancer-related lymphedema (BCRL) is clinically diagnosed as a 5%-10% increase in arm volume, typically measured no earlier than 3-6 months after locoregional treatment. Early BCRL treatment is associated with better outcomes, yet amid increasing evidence that lymphedema exists in a latent form, treatment is typically delayed until arm swelling is obvious. In this study, we investigated whether near-infrared fluorescence lymphatic imaging (NIRF-LI) surveillance could characterize early onset of peripheral lymphatic dysfunction as a predictor of BCRL.

METHODS

In a prospective, longitudinal cohort/observational study (NCT02949726), subjects with locally advanced breast cancer who received axillary lymph node dissection and regional nodal radiotherapy (RT) were followed serially, between 2016 and 2021, before surgery, 4-8 weeks after surgery, and 6, 12, and 18 months after RT. Arm volume was measured by perometry, and lymphatic (dys) function was assessed by NIRF-LI.

RESULTS

By 18 months after RT, 30 of 42 study subjects (71%) developed mild-moderate BCRL (i.e., ≥ 5% arm swelling relative to baseline), all manifested by "dermal backflow" of lymph into lymphatic capillaries or interstitial spaces. Dermal backflow had an 83% positive predictive value and 86% negative predictive value for BCRL, with a sensitivity of 97%, specificity of 50%, accuracy of 83%, positive likelihood ratio of 1.93, negative likelihood ratio of 0.07, and odds ratio of 29.00. Dermal backflow appeared on average 8.3 months, but up to 23 months, before the onset of mild BCRL.

CONCLUSION

BCRL can be predicted by dermal backflow, which often appears months before arm swelling, enabling early treatment before the onset of edema and irreversible tissue changes.

Lymphedema in Inflammatory Breast Cancer Patients Following Trimodal Treatment

BACKGROUND

Breast cancer-related lymphedema (BCRL) is a debilitating sequela of breast cancer treatment and is becoming a greater concern in light of improved long-term survival. Inflammatory breast cancer (IBC) is a rare and aggressive malignancy for which systemic therapy, surgery, and radiotherapy remain the standard of care, thereby making IBC patients highly susceptible to developing BCRL. This study evaluated BCRL in IBC following trimodal therapy.

METHODS

IBC patients treated from 2016 to 2019 were identified from an institutional database. Patients were excluded if they presented with recurrent disease, underwent bilateral axillary surgery, did not complete trimodal therapy, or were lost to follow-up. Demographic, clinicopathologic factors, oncologic outcomes, and perometer measurements were recorded. BCRL was defined by clinician diagnosis and/or objective perometer measurements when available. Time to development of BCRL and treatment received were captured.

RESULTS

Eighty-three patients were included. Median follow-up was 33 months. The incidence of BCRL was 50.6% (n = 42). Mean time to BCRL from surgery was 13 (range 2-24) months. Demographic and clinicopathologic features were similar between patients with and without BCRL with exception of higher proportion receiving delayed reconstruction in the BCRL group (38.1% vs. 14.6%, p = 0.03). Forty patients (95.2%) underwent BCRL treatment, which included physical therapy (n = 39), compression (n = 38), therapeutic lymphovenous bypass (n = 13), and/or vascularized lymph node transfer (n = 12).

CONCLUSIONS

IBC patients are at high-risk for BCRL after treatment, impacting 51% of patients in this cohort. Strategies to reduce or prevent BCRL and improve real-time diagnosis should be implemented to better direct early management in this patient population.

Long-term Oncologic Outcomes in Patients with Inflammatory Breast Cancer with Supraclavicular Nodal Involvement

BACKGROUND

Inflammatory breast cancer (IBC) is a rare and aggressive subtype of breast cancer characterized by rapid progression and early metastasis, often with advanced nodal locations, including the supraclavicular (SCV) nodal basin. Previously considered M1 disease, ipsilateral clinical supraclavicular node involvement (N3c) disease is now considered locally advanced disease and warrants treatment with intent to cure. The objective of this study was to evaluate the long-term outcomes of patients with IBC and N3c disease.

PATIENTS AND METHODS

This study was conducted using a prospectively collected database of all patients with IBC treated at a dedicated cancer center from 2007 to 2019. Surgical patients with SCV nodal involvement and complete follow-up were identified. Our primary outcome was 5-year overall survival (OS). Multivariate Cox proportional hazards models were used to determine predictors for survival. Event-free survival (EFS) and OS were calculated using the Kaplan-Meier method.

RESULTS

There were 70 patients who met inclusion criteria. All patients underwent comprehensive trimodality therapy. The majority of patients had complete (66.2%) radiologic response in the SCV nodal basins following neoadjuvant therapy. Six patients (8.6%) had a locoregional recurrence, with two (2.9%) occurring in the supraclavicular fossa. The 5-year OS was 60.2% [95% confidence interval (CI) 47.7-72.7%]. Increasing age (hazard ratio 2.7; p = 0.03) and triple-negative subtype (hazard ratio 4.9; p = 0.03) were associated with poor OS. The 5-year EFS was 56.1% (95% CI 40.9-68.8%). The presence of more than ten positive axillary nodes on final surgical pathology (hazard ratio 5.5; p = 0.01) predicted poor EFS.

CONCLUSIONS

With comprehensive trimodality therapy and multidisciplinary team approach, patients with IBC with supraclavicular nodal involvement experience excellent locoregional control and favorable survival.

Inflammatory Breast Cancer: The Cytokinome of Post-Mastectomy Wound Fluid Augments Proliferation, Invasion, and Stem Cell Markers

Inflammatory breast cancer (IBC) is an aggressive phenotype with a high recurrence and low survival rate. Approximately 90% of local breast cancer recurrences occur adjacent to the same quadrant as the initial cancer, implying that tumor recurrence may be caused by residual cancer cells and/or quiescent cancer stem cells (CSCs) in the tumor. We hypothesized that wound fluid (WF) collected after modified radical mastectomy (MRM) may activate cancer cells and CSCs, promoting epithelial mesenchymal transition (EMT) and invasion. Therefore, we characterized the cytokinome of WF drained from post-MRM cavities of non-IBC and IBC patients. The WF of IBC patients showed a significantly higher expression of various cytokines than in non-IBC patients. In vitro cell culture models of non-IBC and IBC cell lines were grown in media conditioned with and/without WF for 48 h. Afterwards, we assessed cell viability, the expression of CSCs and EMT-specific genes, and tumor invasion. Genes associated with CSCs properties and EMT markers were regulated in cells seeded in media conditioned by WF. IBC-WF exhibited a greater potential for inducing IBC cell invasion than non-IBC cells. The present study demonstrates the role of the post-surgical tumor cavity in IBC recurrence and metastasis.

A multi-institutional prediction model to estimate the risk of recurrence and mortality after mastectomy for T1-2N1 breast cancer

Background

Post‐mastectomy radiation therapy (PMRT) in women with pathologic stage T1‐2N1M0 breast cancer is controversial.

Methods

Data from five North American institutions including women undergoing mastectomy without neoadjuvant therapy with pT1‐2N1M0 breast cancer treated from 2006 to 2015 were pooled for analysis. Competing‐risks regression was performed to identify factors associated with locoregional recurrence (LRR), distant metastasis (DM), overall recurrence (OR), and breast cancer mortality (BCM).

Results

A total of 3532 patients were included for analysis with a median follow‐up time among survivors of 6.8 years (interquartile range [IQR], 4.5–9.5 years). The 2154 (61%) patients who received PMRT had significantly more adverse risk factors than those patients not receiving PMRT: younger age, larger tumors, more positive lymph nodes, lymphovascular invasion, extracapsular extension, and positive margins (p < .05 for all). On competing risk regression analysis, receipt of PMRT was significantly associated with a decreased risk of LRR (hazard ratio [HR], 0.21; 95% confidence interval [CI], 0.14–0.31; p < .001) and OR (HR, 0.76; 95% CI, 0.62–0.94; p = .011). Model performance metrics for each end point showed good discrimination and calibration. An online prediction model to estimate predicted risks for each outcome based on individual patient and tumor characteristics was created from the model.

Conclusions

In a large multi‐institutional cohort of patients, PMRT for T1‐2N1 breast cancer was associated with a significant reduction in locoregional and overall recurrence after accounting for known prognostic factors. An online calculator was developed to aid in personalized decision‐making regarding PMRT in this population.

In a large multi‐institutional cohort of patients, post‐mastectomy radiation therapy (PMRT) for T1‐2N1 breast cancer was associated with a significant reduction in locoregional and overall recurrence after accounting for known prognostic factors. An online calculator was developed to aid in personalized decision‐making regarding PMRT in this population.

Patient interest in exploring nonsurgical treatment approaches for early-stage breast cancer: A qualitative study

578

Background: Advances in radiotherapy allow the ability to deliver ablative treatments without compromising outcomes, but there has been limited application of these treatments to early-stage breast cancers. The purpose of this study was to explore patients’ interest in pursuing nonsurgical treatment approaches for their early-stage breast cancer. Methods: Investigators conducted a qualitative descriptive study involving semi-structured interviews with 21 early-stage breast cancer patients eligible for participation in a phase 2 trial offering omission of surgery. Interviews were transcribed, and three independent reviewers performed an inductive, thematic analysis to generate themes and subthemes. Results: Data analysis revealed the following factors that impacted patients’ willingness and desire to explore nonsurgical treatment options: Perceptions and feelings about their cancer; Current quality of life and the level of support available in their daily life; External conversations focusing on family members’ and friends’ experiences with cancer and/or cancer treatments; Personal healthcare experiences, including with their current breast cancer diagnosis; Perceptions and feelings about their physicians; Conversations with their physicians about their treatment options; and Self-identified desire to direct care decisions. Specifically, patients described fearing surgery and surgical recovery and wanting to avoid negative surgery-related events previously experienced by friends, family, and themselves. Participants also expressed a desire to preserve their breast(s), receive treatment per the latest research, match the level of treatment with the severity of their cancer, and avoid other comorbidities as reasons for omitting surgery. Patient reasons for pursuing surgery included the desire to remove their cancer immediately, prior positive experiences of friends, family, and themselves with surgery, lack of concern about preserving their breast(s), and prior negative experiences of friends, family, and themselves with radiation. Conclusions: The results of this study highlight that there is patient interest in nonsurgical options for biologically favorable early stage breast cancers. A key factor hindering patient education and awareness of nonsurgical options is how the physician frames the discussion and presents treatment options. In addition, patients’ self-identity and the prior experiences of friends, family, and self with cancer treatment and surgery in general appear to be key factors in their decision-making. The findings from this study demonstrate an unmet need to explore nonsurgical options for early-stage breast cancer. Study results can help shape conversations around shared decision making and clinical trial design and result in more personalized treatment options for women with early-stage breast cancer.

NRG-BR002: A phase IIR/III trial of standard of care systemic therapy with or without stereotactic body radiotherapy (SBRT) and/or surgical resection (SR) for newly oligometastatic breast cancer (NCT02364557)

1007

Background: Prospective and retrospective studies of patients (pts) with oligometastatic (OM) disease have supported that metastases (mets) directed treatment (MDT) with SBRT or SR in addition to standard of care systemic therapy (SOC ST) can improve progression-free (PFS) and overall survival (OS) compared with SOC ST alone. However, randomized evidence in oligometastatic breast cancer (OMBC) are lacking. NRG-BR002, a randomized Phase IIR/III trial, sought to determine the efficacy of SOC ST + MDT (SBRT or SR) as first line treatment of OMBC. Methods: OMBC pts with ≤ 4 extracranial mets on standard imaging with controlled primary disease were eligible if on first line SOC ST for ≤ 12 months without progression. Pts were randomized (1:1) to ARM 1 – SOC ST (mainly chemotherapy, endocrine therapy, anti-HER2) or ARM 2 – SOC ST with MDT of all mets. Stratification included mets number (1 vs > 1), ER/PR and Her2 status, and chemotherapy use. Phase IIR targeted sample size was 128 total/116 eligible pts, for 92% power and 1-sided significance level = 0.15 to determine if adding MDT shows a signal for improved PFS (hazard ratio [HR] = 0.55, corresponding to median PFS (mPFS) from 10.5 to 19 months), in order to continue to the full phase III trial for OS. PFS and OS were estimated by Kaplan-Meier and arms compared with log-rank. Results: 125 of the 129 pts randomized were eligible (ARM 1 = 65, ARM 2 = 60). Key characteristics included median age 54, 79% ER+ or PR+/HER2-, 13% HER2+, 8% triple negative. 60% had 1 metastasis and 20% presented synchronously with primary disease. Following randomization, systemic therapy was delivered to 95% in ARM 1 and 93% in ARM 2; ablation: SBRT 93%, SR 2%, and 5% none. The median follow-up was 30 mo. The mPFS (70% CI) in ARM 1 was 23 mo (18, 29) and 19.5 mo (17, 36) in ARM 2; 24 and 36-mo PFS (70% CI) for ARM 1 were 45.7% (38.9, 52.5) and 32.8% (26.0, 39.5) compared with 46.8 (39.2, 54.3) and 38.1 (29.7, 46.6) in ARM 2; HR (70% CI): 0.92 (0.71, 1.17); and 1-sided log-rank p = 0.36. As PFS did not show signal, OS reporting is included: median OS was not reached in either arm; 36-mo OS (95% CI) in ARM 1 71.8% (58.9, 84.7) and ARM 2 68.9% (55.1, 82.6; 2-sided log-rank p = 0.54). Analysis of first failure showed new mets outside index area (Arm 1) /RT field (Arm 2) developed similarly in both arms at 40%. There were fewer new mets inside treated/index area for Arm 2 6.7% vs ARM 1 29.2%, respectively. There were no grade 5 treatment-related adverse events (AEs), 1 grade 4 AE in ARM 1, and 9.7% and 5.3% grade 3 AEs in ARMS 1 and 2, respectively. Circulating tumor cell counts (0 vs ≥1) at baseline were similar in both arms and were not prognostic HR (95% CI): 1.04 (0.54, 2.02). Conclusions: The addition of MDT to SOC ST did not show signal for improved PFS, nor OS difference in patients with OMBC. The trial will not proceed to the Phase III component. Clinical trial information: NCT02364557.

NDRG1 in Aggressive Breast Cancer Progression and Brain Metastasis

BACKGROUND

N-Myc downstream regulated gene 1 (NDRG1) suppresses metastasis in many human malignancies, including breast cancer, yet has been associated with worse survival in patients with inflammatory breast cancer. The role of NDRG1 in the pathobiology of aggressive breast cancers remains elusive.

METHODS

To study the role of NDRG1 in tumor growth and brain metastasis in vivo, we transplanted cells into cleared mammary fat pads or injected them in tail veins of SCID/Beige mice (n = 7-10 per group). NDRG1 protein expression in patient breast tumors (n = 216) was assessed by immunohistochemical staining. Kaplan-Meier method with 2-sided log-rank test was used to analyze the associations between NDRG1 and time-to-event outcomes. A multivariable Cox regression model was used to determine independent prognostic factors. All statistical tests were 2-sided.

RESULTS

We generated new sublines that exhibited a distinct propensity to metastasize to the brain. NDRG1-high-expressing cells produced more prevalent brain metastases (100% vs 44.4% for NDRG1-low sublines, P = .01, Fisher's exact test), greater tumor burden, and reduced survival in mice. In aggressive breast cancer cell lines, silencing NDRG1 led to reduced migration, invasion, and tumor-initiating cell subpopulations. In xenograft models, depleting NDRG1 inhibited primary tumor growth and brain metastasis. In patient breast tumors, NDRG1 was associated with aggressiveness: NDRG1-high expression was also associated with shorter overall survival (hazard ratio [HR] = 2.27, 95% confidence interval [95% CI] = 1.20 to 4.29, P = .009) and breast cancer-specific survival (HR = 2.19, 95% CI = 1.07 to 4.48, P = .03). Multivariable analysis showed NDRG1 to be an independent predictor of overall survival (HR = 2.17, 95% CI = 1.10 to 4.30, P = .03) and breast cancer-specific survival rates (HR = 2.27, 95% CI = 1.05 to 4.92, P = .04).

CONCLUSIONS

We demonstrated that NDRG1 drives tumor progression and brain metastasis in aggressive breast cancers and that NDRG1-high expression correlates with worse clinical outcomes, suggesting that NDRG1 may serve as a therapeutic target and prognostic biomarker in aggressive breast cancers.

Locoregional Management and Prognostic Factors in Breast Cancer Patients with Ipsilateral Internal Mammary and Axillary Lymph Node Involvement

PURPOSE

Breast cancer patients with ipislateral axillary and internal mammary (IM) lymph node involvement (cN3b) often forego IM node resection. Therefore, radiation is important for curative therapy. However, prognosis is not well-described in the era of modern systemic therapy and limited data exist to guide optimal locoregional treatment recommendations.

METHODS

We retrospectively reviewed 117 patients with non-metastatic cN3b breast cancer treated at our institution between 2014-2019. Staging included ultrasound evaluation of all regional nodal basins. All patients received neoadjuvant chemotherapy (NAC), resection of the breast primary and axillary nodal dissection, followed by adjuvant radiation to the breast/chest wall and regional nodes. Institutional guidelines recommend a 10 Gy boost to radiographically resolved nodes, and 16 Gy boost to unresolved nodes. Overall survival (OS), recurrence (RFS), locoregional (LRRFS), internal mammary (IMRFS), and distant metastasis free survival (DMFS) were evaluated with Kaplan Meier analysis. A multivariable model for RFS was constructed.

RESULTS

Median follow-up for 117 patients was 3.82 years. Median age at diagnosis was 46 years and 56 (48%) patients were receptor group ER+/HER2-. Mastectomy was performed in 96 (82%) of patients, 38 (32%) had biopsy confirmed IMC involvement, and 8 (7%) had IM node dissection. The median initial radiation dose was 50 Gy (range, 50-55) and IMC boost 10 Gy (range, 0-16). The 5-year OS, IMRFS, LRRFS, DMFS, and RFS were 74%, 98%, 89%, 68% and 67% respectively. On multivariable analysis, a clinical complete response (CR) of the IM nodes or pathologic ypN0 status had improved 5-year RFS with HR 0.24 (p=0.006) and HR 0.27 (p=0.05), respectively. Extranodal extension or lymphovascular invasion were associated with worse 5-year RFS with HR 4.13 (p=0.001) and HR 2.25 (p=0.04), respectively.

CONCLUSION

Multimodality therapy provides excellent locoregional control of 89% at 5 years for cN3b breast cancer patients. Adjuvant radiation yields a 5-year IMRFS of 98%. Clinical and pathologic response of IM nodes are independently prognostic for RFS.

Adoption of Ultrahypofractionated Radiation Therapy in Patients With Breast Cancer

Introduction

The first high-quality clinical trial to support ultrahypofractionated whole-breast irradiation (ultra-HF-WBI) for invasive early-stage breast cancer (ESBC) was published in April 2020, coinciding with the beginning of the COVID-19 pandemic. We analyzed adoption of ultra-HF-WBI for ductal carcinoma in situ (DCIS) and ESBC at our institution after primary trial publication.

Methods and Materials

We evaluated radiation fractionation prescriptions for all patients with DCIS or ESBC treated with WBI from March 2020 to May 2021 at our main campus and regional campuses. Demographic and clinical characteristics were extracted from the electronic medical record. Treating physician characteristics were collected from licensure data. Hierarchical logistic regression models identified factors correlated with adoption of ultra-HF-WBI (26 Gy in 5 daily factions [UK-FAST-FORWARD] or 28.5 Gy in 5 weekly fractions [UK-FAST]).

Results

Of 665 included patients, the median age was 61.5 years, and 478 patients (71.9%) had invasive, hormone-receptor-positive breast cancer. Twenty-one physicians treated the included patients. In total, 249 patients (37.4%) received ultra-HF-WBI, increasing from 4.3% (2 of 46) in March-April 2020 to a high of 45.5% (45 of 99) in July-August 2020 (P < .001). Patient factors associated with increased use of ultra-HF-WBI included older age (≥50 years old), low-grade WBI without inclusion of the low axilla, no radiation boost, and farther travel distance (P < .03). Physician variation accounted for 21.7% of variance in the outcome, with rate of use of ultra-HF-WBI by the treating physicians ranging from 0% to 75.6%. No measured physician characteristics were associated with use of ultra-HF-WBI.

Conclusions

Adoption of ultra-HF-WBI at our institution increased substantially after the publication of randomized evidence supporting its use. Ultra-HF-WBI was preferentially used in patients with lower risk disease, suggesting careful selection for this new approach while long-term data are maturing. Substantial physician-level variation may reflect a lack of consensus on the evidentiary standards required to change practice.

Abstract P5-08-13: NDRG1 expression is an independent prognostic factor in inflammatory breast cancer

Background: Inflammatory breast cancer (IBC) is a rare and highly aggressive form of breast cancer. Patients with IBC still have worse clinical outcomes compared to patients with non-IBC (40% versus 63% for 5 years overall survival, respectively) despite advances in breast cancer treatment. IBC remains a poorly characterized disease lacking specific therapeutic targets and prognostic biomarkers. Our group demonstrated that N-myc downstream regulated gene 1 (NDRG1) is crucial in promoting tumorigenesis and brain metastasis in mouse models of IBC. Our hypothesis is that NDRG1 is a prognostic marker associated with poor outcome in IBC patients. Methods: 64 IBC patients in a tissue microarray were evaluated by immunohistochemical staining with anti-NDRG1 primary antibody and NDRG1 levels were quantified. Using the median value, 32 patients were grouped as NDRG1-low (≤ median), and 32 as NDRG1-high (&gt;median). Survival data were compared by Kaplan–Meier curves and log-rank test. Results: The average age of patients was 50 years. Sixty-two percent of patients had estrogen receptor (ER)-negative tumors, 83% were stage III, 80% high grade, and 67% of these patients received adjuvant radiation. The median follow-up time for the patients studied was 11.7 years, and the median overall survival (OS) time was 3.7 years. On univariate analysis, NDRG1 expression, tumor grade, disease stage, ER status, and adjuvant radiation therapy were associated with OS and disease specific survival (DSS). Patients with NDRG1-low tumors experienced better actuarial 10-year OS (p=0.0129) and DSS (p=0.0074), and showed significant higher 10-year OS and DSS rates than patients with NDRG1-high(OS, 45% vs. 19%, p=0.0278; DSS, 52% vs. 22%, p=0.0139). The median OS and DSS times were shorter for NDRG1-high patients (OS, 2.5 years; DSS, 3.1 years) than for NDRG1-low patients (OS, 5.9 years; DSS, 10.7 years). Multivariable analysis, NDRG1 was an independent predictor of OS (hazard ratio [HR]=2.449, p=0.0274) and DSS (HR=2.727, p=0.0039). ER status, disease stage and adjuvant radiation were also independent predictor for both OS and DSS. Furthermore, we observed that NDRG1-high expressing ER-negative tumors exhibit worse outcome in IBC patients (OS, p=0.0003; DSS, p=0.0003). NDRG1-high expression correlated with worse outcome in patients that received adjuvant radiation treatment (OS, p=0.0088; DSS, p=0.0093), and those with stage III (OS, p=0.0450; DSS, p=0.0239). Conclusions: Our findings demonstrated that NDRG1 is positively correlated with aggressive tumor characteristics in IBC and that it is an independent prognostic factor for OS and DSS in IBC patients, suggesting that targeting NDRG1 may provide a novel therapeutic strategy to improve outcomes for patients with IBC. Our data further suggests that NDRG1 warrants further investigation in radiation response.

Citation Format: Emilly Schlee Villodre, Yun Gong, Xiaoding Hu, Lei Huo, Esther C Yoon, Naoto T Ueno, Wendy A Woodward, Debu Tripathy, Juhee Song, Bisrat G Debeb. NDRG1 expression is an independent prognostic factor in inflammatory breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-08-13.

Abstract P1-24-06: Risk factor modeled microenvironment effects lymphatics activity and IBC invasiveness and progression

Background. Lymphovascular invasion (LVI) and breast tumor emboli within dermal and breast lymphatic vessels are prognostic for metastatic spread and poor outcomes, and are abundant in Inflammatory breast cancer (IBC). IBC is an aggressive breast cancer that presents suddenly with breast swelling and redness due to tumor emboli in lymphatics. Lack of breast-feeding and obesity are IBC risk factors. We sought to demonstrate the combinatorial effects of a high-fat diet and nursing on lymphatic function and compare these to IBC tumor induced changes in lymphatic function. We hypothesize that risk factors for aggressive breast cancer may alter lymphatic function in the normal gland prior to tumor initiation. Methods. Following two rounds of pregnancy in 20 multiparous SCID Beige immunocompromised mice, half of the mice were force weaned while half nursed pups. Prior to forced weaning, half of each of these groups were fed a high fat diet (HFD: 60 Kcal %, N = 10) while the other half received a low-fat diet (LFD: 10 Kcal %, N = 10). Consecutive dynamic near-infrared fluorescence (NIRF) lymphatic imaging was performed at 6-7 months (covid interruption) and 14 months after initiating the diet by injecting a near-IR fluorophore into the mammary fatpad and recording lymphatic pulsing over 8 minutes using V++. Matlab and ImageJ were used to quantify pulsing rates on the ventral lymphatics in each animal. Fatpads were subsequently inoculated with SUM149 IBC cells and imaging was repeated 16 months post diet initiation. Lymphatic imaging over time by HFD vs LFD was further studied in nulliparous animals. Tissues were collected for further analyses. ResultsData analysis prior to tumor injection, demonstrated lymphatic pulsing (pulses/4 minutes) increased over time in HFD force weaned (HFFW) and HFD nursing (HFN) animals only (65.5 vs 72.6, P=0.059; 60.1 vs 76.6, P=0.0099, respectively). Comparing HFFW and HFN to matched LFD groups (LFFW and LFN), at 14 weeks HFD was associated with increased pumping after forced weaning (62.3 vs. 72.6, P=0.074), and nursing (62.5 vs 76.6, P=0.0023). There was an increase in pulsing after tumor initiation (16 months after initiation of diet) in all groups (80.1, 84.1, 83.2, 82.4, P &gt; 0.05 all comparisons to initial timepoint). In a separate experiment examining HFD (N=5) vs LFD (N=5) in nulliparous mice, lymphatic contractile activity increased in all animals over. time, average ventral lymphatic contractile frequency for LFD and HFD at week 8,11 and 14 weeks after diet initiation were 5, 8.64, 15.9 pumps/4 mins vs 11.8, 18.5, 28.2 pumps/4 mins, (P = 0.01, 0.05, and 0.0005 respectively). ConclusionsHFD increased lymphatic pulsing rate over time to a significantly greater extent than LFD continuing over 14 months independent of reproductive and nursing status. Tumor initiation prompted further increased pulsing rates beyond that observed after HFD across all groups. The magnitude of the effect of HFD on lymphatic pulsing approached the rate after tumor initiation, while reproductive variables did not impact lymphatic pulsing. Further studies are warranted to demonstrate the relationship if any between lymphatic pumping pre-initiation and LVI after tumor initiation and examine the role of intervention on reducing LVI.

Citation Format: Wintana Balema, Janelle Morton, Richard Larson, Fred C Velasquez, Eva Sevick-Muraca, Wendy A Woodward. Risk factor modeled microenvironment effects lymphatics activity and IBC invasiveness and progression [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-24-06.

Outcomes After Breast Radiation Therapy in a Diverse Patient Cohort With a Germline BRCA1/2 Mutation

PURPOSE

BRCA1/2 pathogenic variant (PV) mutations confer radiation sensitivity preclinically, but there are limited data regarding breast cancer outcomes after radiation therapy (RT) among patients with documented BRCA1/2 PV mutations versus no PV mutations.

METHODS AND MATERIALS

This retrospective cohort study included women with clinical stage I-III breast cancer who received definitive surgery and RT and underwent BRCA1/2 genetic evaluation at the The University of Texas MD Anderson Cancer Center. Rates of locoregional recurrence (LRR), disease-specific death (DSD), toxicities, and second cancers were compared by BRCA1/2 PV status.

RESULTS

Of the 2213 women who underwent BRCA1/2 testing, 63% self-reported their race as White, 13.6% as Black/African American, 17.6% as Hispanic, and 5.8% as Asian/American Indian/Alaska Native; 124 had BRCA1 and 100 had BRCA2 mutations; and 1394 (63%) received regional nodal RT. The median follow-up time for all patients was 7.4 years (95% confidence interval [CI], 7.1-7.7 years). No differences were found between the groups with and without BRCA1/2 PV mutations in 10-year cumulative incidences of LRR (with mutations: 11.6% [95% CI, 7.0%-17.6%]; without mutations: 6.6% [95% CI, 5.3%-8.0%]; P = .466) and DSD (with mutations: 12.3% [95% CI, 8.0%-17.7%]; without mutations: 13.8% [95% CI, 12.0%-15.8%]; P = .716). On multivariable analysis, BRCA1/2 status was not associated with LRR or DSD, but Black/African American patients (P = .036) and Asians/American Indians/Alaska Native patients (P = .002) were at higher risk of LRR compared with White patients, and Black/African American patients were at higher risk of DSD versus White patients (P = .004). No in-field, nonbreast second cancers were observed in the BRCA1/2 PV group. Rates of acute and late grade ≥3 radiation-related toxicity in the BCRA1/2 PV group were 5.4% (n = 12) and 0.4% (n = 1), respectively.

CONCLUSIONS

Oncologic outcomes in a diverse cohort of patients with breast cancer who had a germline BRCA1/2 PV mutation and were treated with RT were similar to those of patients with no mutation, supporting the use of RT according to standard indications in patients with a germline BRCA1/2 PV mutation.

Breast Radiation Therapy-Related Treatment Outcomes in Patients With or Without Germline Mutations on Multigene Panel Testing

PURPOSE

Multigene panel testing has increased the detection of germline mutations in patients with breast cancer. The implications of using radiation therapy (RT) to treat patients with pathogenic variant (PV) mutations are not well understood and have been studied mostly in women with only BRCA1 or BRCA2 PVs. We analyzed oncologic outcomes and toxicity after adjuvant RT in a contemporary, diverse cohort of patients with breast cancer who underwent genetic panel testing.

METHODS AND MATERIALS

We retrospectively reviewed the records of 286 women with clinical stage I-III breast cancer diagnosed from 1995 to 2017 who underwent surgery, breast or chest wall RT with or without regional nodal irradiation, multigene panel testing, and evaluation at a large cancer center's genetic screening program. We evaluated rates of overall survival, locoregional recurrence, disease-specific death, and radiation-related toxicities in 3 groups: BRCA1/2 PV carriers, non-BRCA1/2 PV carriers, and patients without PV mutations.

RESULTS

PVs were detected in 25.2% of the cohort (12.6% BRCA1/2 and 12.6% non-BRCA1/2). The most commonly detected non-BRCA1/2 mutated genes were ATM, CHEK2, PALB2, CDH1, TP53, and PTEN. The median follow-up time for the entire cohort was 4.4 years (95% confidence interval, 3.8-4.9 years). No differences were found in overall survival, locoregional recurrence, or disease-specific death between groups (P > .1 for all). Acute and late toxicities were comparable across groups.

CONCLUSION

Oncologic and toxicity outcomes after RT in women with PV germline mutations detected by multigene pane testing are similar to those in patients without detectable mutations, supporting the use of adjuvant RT as a standard of care when indicated.

Trends in Sentinel Lymph Node Biopsies in Patients With Inflammatory Breast Cancer in the US

IMPORTANCE

The standard of care for inflammatory breast cancer (IBC) is neoadjuvant chemotherapy, total mastectomy with axillary lymph node dissection (ALND), and postmastectomy radiation therapy. Existing studies suggest that sentinel lymph node biopsy (SLNB) may not be reliable in IBC. The use and frequency of SLNB in women with IBC is not well characterized.

OBJECTIVE

To determine the frequency and temporal trend of SLNB in patients with IBC.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used the National Cancer Database, a nationwide hospital-based cancer registry, and included women who were diagnosed with nonmetastatic IBC and underwent axillary surgery from 2012 to 2017. Data were analyzed from January 2021 to May 2021.

EXPOSURES

Any SLNB, including SLNB alone and SLNB followed by ALND, and ALND alone.

MAIN OUTCOMES AND MEASURES

Scatterplot fit with a linear regression model were used to evaluate the yearly increase of any SLNB use. Multivariable logistic regression models to evaluate the association of study variables with the outcome of any SLNB.

RESULTS

This study included a total of 1096 women (mean [SD] age, 56.1 [12.9] years) who were 18 years or older with nonmetastatic IBC diagnosed between 2012 and 2017. Of the 186 of 1096 women (17%) who received any SLNB, 137 (73.7%) were White individuals; and of the 910 of 1096 women (83%) who received an ALND only, 676 (74.3%) were White individuals. Among women undergoing any SLNB, 119 of 186 (64%) did not undergo a completion ALND. There was a statistically significant increasing trend in the use of SLNB from 2012 to 2017 (22 of 205 patients [11%] vs 32 of 148 patients [22%]; P = .004). In multivariable analysis, the use of SLNB was associated with diagnosis year (2017 vs 2012; odds ratio [OR], 2.26; 95% CI, 1.26-4.20), clinical nodal status (cN3 vs 0; OR, 0.39; 95% CI, 0.22-0.67), and receipt of reconstructive surgery (OR, 1.80; 95% CI, 1.09-2.96).

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that there is frequent and increasing use of SLNB in patients with IBC that is not evidence-based or supported by current treatment guidelines.

Why diagnosing inflammatory breast cancer is hard and how to overcome the challenges: a narrative review

OBJECTIVE

The purpose of this narrative review is to summarize the contributors to misdiagnosis or delayed diagnosis of inflammatory breast cancer (IBC) and strategies for expedient diagnosis.

BACKGROUND

Patients with IBC often report the disease as initially being misdiagnosed, most commonly as mastitis.

METHODS

We reviewed the literature on this challenging diagnosis by using sequential PubMed search criteria including IBC breast symptoms, IBC diagnosis, and IBC imaging modalities to augment the authors' knowledge of IBC. Other references were added from the manuscripts identified in the PubMed searches and from manuscript reviewers.

CONCLUSIONS

Several factors contribute to the delayed diagnosis of IBC. One important factor is that IBC is uncommon, and many generalists may not be aware of it in the differential diagnosis of breast skin symptoms. Several features of IBC contribute to the low sensitivity of mammography for its detection, and so the diagnosis is based on clinical factors and is thereby subjective. The presentation can be highly varied; classic textbook images that do not capture the range of presenting signs and symptoms across skin tones may contribute to missed diagnoses in patients with atypical presentations. In fact, the staging system of the American Joint Committee on Cancer, which requires erythema of the breast skin for diagnosis, may exclude patients with obvious global breast skin findings that are not explicitly red. We present an adapted algorithm for working up the undiagnosed inflammatory breast to ensure the timely and accurate diagnosis of IBC. We assert that frank, non-erythematous global skin signs in an enlarged breast with diffuse breast malignancy are sufficient to diagnose IBC if the timing of these signs and findings on biopsy are consistent. We further provide images of atypical IBC identified by global breast skin signs, including peau d'orange, consistent with IBC in the absence of frank erythema.

How should radiation be done for inflammatory breast cancer patients?-a narrative review of modern literature

OBJECTIVE

This review highlights the considerations of the radiation oncologist when managing patients with inflammatory breast cancer (IBC) as well as the radiation oncologist's role as a member of the multi-disciplinary team.

BACKGROUND

IBC makes up only 1-4% of all breast cancer diagnoses but incidence is increasing. IBC is diagnosed based on a constellation of clinical features, including the rapid onset of breast erythema and edema (peau d'orange) of one-third or more of the skin of the breast and with a palpable border to the edema. Most published IBC local-regional control rates are consistently lower than those observed in non-IBC, which the highlights the need for deliberate treatment techniques to maximize clinical outcomes.

METHODS

For this narrative review, we discuss the principles of radiation target delineation and dose escalation; highlight new findings in the local-regional management of IBC; provide a critical evaluation of the recent literature evaluating local-regional treatment of IBC; and offer a brief introduction to possible future directions regarding the optimal treatment and management of IBC based on our institutional experience.

CONCLUSIONS

IBC is an aggressive type of breast cancer that warrants multi-disciplinary care from breast surgical, medical, and radiation oncology. Several strategies exist to enhance the effect of radiation therapy (RT) on local-regional control, including hyperfractionation, use of bolus, increased total RT dose, and radiosensitizers, which are currently being tested in randomized trials. With an individualized patient approach, local-regional control rates are improving for IBC.

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.

Lipocalin 2 promotes inflammatory breast cancer tumorigenesis and skin invasion

Inflammatory breast cancer (IBC) is an aggressive form of primary breast cancer characterized by rapid onset and high risk of metastasis and poor clinical outcomes. The biological basis for the aggressiveness of IBC is still not well understood and no IBC-specific targeted therapies exist. In this study, we report that lipocalin 2 (LCN2), a small secreted glycoprotein belonging to the lipocalin superfamily, is expressed at significantly higher levels in IBC vs non-IBC tumors, independently of molecular subtype. LCN2 levels were also significantly higher in IBC cell lines and in their culture media than in non-IBC cell lines. High expression was associated with poor-prognosis features and shorter overall survival in IBC patients. Depletion of LCN2 in IBC cell lines reduced colony formation, migration, and cancer stem cell populations in vitro and inhibited tumor growth, skin invasion, and brain metastasis in mouse models of IBC. Analysis of our proteomics data showed reduced expression of proteins involved in cell cycle and DNA repair in LCN2-silenced IBC cells. Our findings support that LCN2 promotes IBC tumor aggressiveness and offer a new potential therapeutic target for IBC.

Association of statin use with clinical outcomes in patients with triple-negative breast cancer

BACKGROUND

Previous studies have examined the association of statin therapy and breast cancer outcomes with mixed results. The objective of this study was to investigate the clinical effects of incident statin use among individuals with triple-negative breast cancer (TNBC).

METHODS

Data from the Surveillance, Epidemiology, and End Results-Medicare and Texas Cancer Registry-Medicare databases were used, and women aged ≥66 years who had stage I, II, and III breast cancer were identified. Multivariable Cox proportional hazards regression models were used to examine the association of new statin use in the 12 months after a breast cancer diagnosis with overall survival (OS) and breast cancer-specific survival (BCSS).

RESULTS

When examining incident statin use, defined as the initiation of statin therapy in the 12 months after breast cancer diagnosis, a significant association was observed between statin use and improved BCSS (standardized hazard ratio, 0.42; 95% confidence interval [CI], 0.20-0.88; P = .022) and OS (hazard ratio, 0.70; 95% CI, 0.50-0.99; P = .046) among patients with TNBC (n = 1534). No association was observed with BCSS (standardized hazard ratio, 0.99; 95% CI, 0.71-1.39; P = .97) or OS (hazard ratio, 1.04; 95% CI, 0.92-1.17; P = .55) among those without TNBC (n = 15,979). The results were consistent when examining statin exposure as a time-varying variable.

CONCLUSIONS

Among women with I, II, and III TNBC, initiation of statin therapy in the 12 months after breast cancer diagnosis was associated with an OS and BCSS benefit. Statins may have a role in select patients with breast cancer, and further investigation is warranted.

Inflammatory breast cancer appearance at presentation is associated with overall survival

Background

Inflammatory breast cancer (IBC) is a clinical diagnosis. Here, we examined the association of a “classic” triad of clinical signs, swollen involved breast, nipple change, and diffuse skin change, with overall survival (OS).

Method

Breast medical photographs from patients enrolled on a prospective IBC registry were scored by two independent reviewers as classic (triad above), not classic, and difficult to assign. Chi‐squared test, Fisher's exact test, and Wilcoxon rank‐sum test were used to assess differences between patient groups. Kaplan–Meier estimates and the log‐rank test and Cox proportional hazard regression were used to assess the OS.

Results

We analyzed 245 IBC patients with median age 54 (range 26–81), M0 versus M1 status (157 and 88 patients, respectively). The classic triad was significantly associated with smoking, post‐menopausal status, and metastatic disease at presentation (p = 0.002, 0.013, and 0.035, respectively). Ten‐year actuarial OS for not classic and difficult to assign were not significantly different and were grouped for further analyses. Ten‐year OS was 29.7% among patients with the classic sign triad versus 57.2% for non‐classic (p < 0.0001). The multivariate Cox regression model adjusting for clinical staging (p < 0.0001) and TNBC status (<0.0001) demonstrated classic presentation score significantly associated with poorer OS time (HR 2.6, 95% CI 1.7–3.9, p < 0.0001).

Conclusions

A triad of classic IBC signs independently predicted OS in patients diagnosed with IBC. Further work is warranted to understand the biology related to clinical signs and further extend the understanding of physical examination findings in IBC.

Inflammatory Breast Cancer at the Extremes of Age

BACKGROUND

Inflammatory breast cancer (IBC) is a rare breast malignancy with poor outcomes compared with non-IBC. Age-related differences in tumor biology, treatment, and clinical outcomes have been described in non-IBC. This study evaluated age-related differences in IBC.

METHODS

From an institutional prospective database, patients with an IBC diagnosed from 2010 to 2019 were identified. Age was categorized as 40 years or younger, 41 to 64 years, and 65 years or older. Demographics, clinicopathologic features, and treatment received were compared. Recurrence and survival outcomes were analyzed using the log-rank test and the Cox proportional hazards model.

RESULTS

Of 523 IBC patients, 113 (21.6%) were age 40 years or younger, and 72 (13.8%) were age 65 years or older. The groups did not differ statistically by race/ethnicity, N stage, clinical stage, or tumor subtype. The younger patients included a higher proportion of Hispanic and Asian patients, triple-negative breast cancer (TNBC), and clinical N2/N3. Trimodality therapy was received by 92% of the stage 3 patients, with no difference in pathologic complete response (pCR) by age (23.3% vs 28.6%; p = 0.46). During a median follow-up period of 40 months, 17% of the patients experienced locoregional recurrence and 42.8% had distant metastasis. No difference in 3-year recurrence-free survival (57.9% vs 42.6% vs 54%; p = 0.42, log rank) or overall survival (OS) (75.6% vs 77.1% vs 64.4%; p = 0.31, log rank) by age was observed, and no difference in OS by age in de novo stage 4 disease was observed. In the multivariate analysis, worse OS was associated with TNBC (hazard ratio [HR], 1.99, 95% confidence interval [CI], 1.31-3.05) and no pCR (HR, 4.45; 95% CI, 2.16-9.18).

CONCLUSION

No significant differences were observed in demographics, treatment patterns, or clinical outcomes for IBC patients age 40 years or younger compared with those age 65 years or older treated by a specialized multidisciplinary team. These findings do not support age-related treatment de-escalation in IBC.

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.

Contralateral Axillary Metastasis in Patients with Inflammatory Breast Cancer

BACKGROUND

Nearly one-third of patients with inflammatory breast cancer (IBC) present with de novo stage IV disease. There are limited data on frequency and clinical outcomes of contralateral axillary metastasis (CAM) in IBC with no consensus diagnostic and treatment guidelines.

PATIENTS AND METHODS

Frequency of synchronous CAM was calculated in unilateral IBC patients at a single center (10/2004-6/2019). Clinicopathologic variables, diagnostic evaluation, treatment received, and overall survival (OS) were assessed and compared.

RESULTS

Of 588 unilateral IBC patients, 49 (8.3%) had synchronous CAM. Of these, 32 (65.3%) also presented with metastatic disease at another distant site. CAM was not associated with age, tumor laterality, breast cancer subtype, grade, or cN stage (p > 0.05). The sensitivity/specificity to detect CAM was as follows: mammography (18.2%/99.2%), ultrasound (92.3%/95.5%), PET (90.1/99.1%), and MRI (76.0%/98.6%). Following systemic therapy, 22 patients had contralateral axillary surgery, and 18 received adjuvant contralateral nodal radiation. On multivariable analysis including tumor receptor subtypes, patients with stage IV-isolated CAM has statistically similar survival to stage III patients (HR 1.37, 95% CI 0.70-2.69, p = 0.36). Patients with Stage IV non-CAM (HR 2.18, 95% CI 1.66-2.85, p < 0.001) and stage IV-CAM plus other distant metastasis (HR 2.57, 95% CI 1.59-4.16, p < 0.001) had higher risk of death (reference: stage III disease).

CONCLUSIONS

CAM in IBC was diagnosed in 8.3% of patients at presentation and was best identified by ultrasound and PET. We recommend routine contralateral axillary ultrasound as part of staging for all IBC patients. Diagnosis of CAM is a key first step toward much-needed prospective clinical trials evaluating management and outcomes of CAM in IBC.