LGR5+ Intestinal Stem Cells Display Sex-Dependent Radiosensitivity

Tissue radiosensitivity plays a critical role in the overall outcome of radiation therapy. Identifying characteristics that predict how a patient may respond to radiotherapy enables clinicians to maximize the therapeutic window. Limited clinical data have suggested a difference in male and female radiotherapy outcomes. Radiotherapy for gastrointestinal malignancy is still a challenge due to intestinal sensitivity to radiation toxicity. In this manuscript, we demonstrated sex-specific differences in intestinal epithelial radiosensitivity. In a mouse model of abdominal irradiation, we observed a significant increase in oxidative stress and injury in males compared to females. Lgr5+ve intestinal stem cells from male mice showed higher sensitivity to radiation-induced toxicity. However, sex-specific differences in intestinal radiosensitivity were not dependent on sex hormones, as we demonstrated similar sex-specific radiosensitivity differences in pre-pubescent mice. In an ex vivo study, we found that patient-derived intestinal organoid (PID) from males showed higher sensitivity to radiation compared to females as evident from loss of budding crypts, organoid size, and membrane integrity. Transcriptomic analysis of human Lgr5+ intestinal stem cells suggested radiation-induced upregulation of mitochondrial oxidative metabolism in males compared to females, a possible mechanism for radiosensitivity differences.

ctDNA and residual cancer burden are prognostic in triple-negative breast cancer patients with residual disease

Triple-negative breast cancer (TNBC) patients with residual disease (RD) after neoadjuvant systemic therapy (NAST) are at high risk for recurrence. Biomarkers to risk-stratify patients with RD could help individualize adjuvant therapy and inform future adjuvant therapy trials. We aim to investigate the impact of circulating tumor DNA (ctDNA) status and residual cancer burden (RCB) class on outcomes in TNBC patients with RD. We analyze end-of-treatment ctDNA status in 80 TNBC patients with residual disease who are enrolled in a prospective multisite registry. Among 80 patients, 33% are ctDNA positive (ctDNA+) and RCB class distribution is RCB-I = 26%, RCB-II = 49%, RCB-III = 18% and 7% unknown. ctDNA status is associated with RCB status, with 14%, 31%, and 57% of patients within RCB-I, -II, and -III classes demonstrating ctDNA+ status (P = 0.028). ctDNA+ status is associated with inferior 3-year EFS (48% vs. 82%, P < 0.001) and OS (50% vs. 86%, P = 0.002). ctDNA+ status predicts inferior 3-year EFS among RCB-II patients (65% vs. 87%, P = 0.044) and shows a trend for inferior EFS among RCB-III patients (13% vs. 40%, P = 0.081). On multivariate analysis accounting for T stage and nodal status, RCB class and ctDNA status independently predict EFS (HR = 5.16, P = 0.016 for RCB class; HR = 3.71, P = 0.020 for ctDNA status). End-of-treatment ctDNA is detectable in one-third of TNBC patients with residual disease after NAST. ctDNA status and RCB are independently prognostic in this setting.

EGFR as a potent CAR T target in triple negative breast cancer brain metastases

PURPOSE

There is currently no curative treatment for patients diagnosed with triple-negative breast cancer brain metastases (TNBC-BM). CAR T cells hold potential for curative treatment given they retain the cytolytic activity of a T cell combined with the specificity of an antibody. In this proposal we evaluated the potential of EGFR re-directed CAR T cells as a therapeutic treatment against TNBC cells in vitro and in vivo.

METHODS

We leveraged a TNBC-BM tissue microarray and a large panel of TNBC cell lines and identified elevated epidermal growth factor receptor (EGFR) expression. Next, we designed a second-generation anti-EGFR CAR T construct incorporating a clinically relevant mAb806 tumor specific single-chain variable fragment (scFv) and intracellular 4-1BB costimulatory domain and CD3ζ using a lentivirus system and evaluated in vitro and in vivo anti-tumor activity.

RESULTS

We demonstrate EGFR is enriched in TNBC-BM patient tissue after neurosurgical resection, with six of 13 brain metastases demonstrating both membranous and cytoplasmic EGFR. Eleven of 13 TNBC cell lines have EGFR surface expression ≥ 85% by flow cytometry. EGFR806 CAR T treated mice effectively eradicated TNBC-BM and enhanced mouse survival (log rank p < 0.004).

CONCLUSION

Our results demonstrates anti-tumor activity of EGFR806 CAR T cells against TNBC cells in vitro and in vivo. Given EGFR806 CAR T cells are currently undergoing clinical trials in primary brain tumor patients without obvious toxicity, our results are immediately actionable against the TNBC-BM patient population.

Impact of low versus negative estrogen/progesterone receptor status on clinico-pathologic characteristics and survival outcomes in HER2-negative breast cancer

Triple-negative breast cancer (TNBC) is classically defined by estrogen receptor (ER) and progesterone receptor (PR) immunohistochemistry expression <1% and absence of HER2 amplification/overexpression. HER2-negative breast cancer with low ER/PR expression (1–10%) has a gene expression profile similar to TNBC; however, real-world treatment patterns, chemotherapy response, endocrine therapy benefit, and survival outcomes for the Low-ER group are not well known. 516 patients with stage I-III HER2-negative breast cancer and ER/PR expression ≤10% who were enrolled in a multisite prospective registry between 2011 and 2019 were categorized on the basis of ER/PR expression. TNBC (ER and PR < 1%) and Low-ER (ER and/or PR 1–10%) groups comprised 87.4% (n = 451) and 12.6% (n = 65) of patients, respectively. Demographic, clinical, and treatment characteristics, including prevalence of germline BRCA1/2 mutation, racial and ethnic distribution, and chemotherapy use were not different between TNBC and Low-ER groups. No difference was observed in recurrence-free survival (RFS) and overall survival (OS) between TNBC and Low-ER groups (3-year RFS 82.5% versus 82.4%, respectively, p = 0.728; 3-year OS 88.0% versus 83.4%, respectively, p = 0.632). Among 358 patients receiving neoadjuvant chemotherapy, rates of pathologic complete response were similar for TNBC and Low-ER groups (49.2% vs 51.3%, respectively, p = 0.808). The HER2-negative Low-ER group is often excluded from TNBC clinical trials assessing novel treatments (immunotherapy and antibody-drug conjugates), thus limiting efficacy data for newer effective therapies in this group. Given that HER2-negative Low-ER disease displays clinical characteristics and outcomes similar to TNBC, inclusion of this group in TNBC clinical trials is encouraged.

Human Peripheral Blood Mononucleocyte Derived Myeloid Committed Progenitor Cells Mitigate H-ARS by Exosomal Paracrine Signal

Radiation-induced loss of the hematopoietic stem cell progenitor population compromises bone marrow regeneration and development of mature blood cells. Failure to rescue bone marrow functions results in fatal consequences from hematopoietic injury, systemic infections, and sepsis. So far, bone marrow transplant is the only effective option, which partially minimizes radiation-induced hematopoietic toxicities. However, a bone marrow transplant will require HLA matching, which will not be feasible in large casualty settings such as a nuclear accident or an act of terrorism. In this study we demonstrated that human peripheral blood mononuclear cell-derived myeloid committed progenitor cells can mitigate radiation-induced bone marrow toxicity and improve survival in mice. These cells can rescue the recipient's hematopoietic stem cells from radiation toxicity even when administered up to 24 h after radiation exposure and can be subjected to allogenic transplant without GVHD development. Transplanted cells deliver sEVs enriched with regenerative and immune-modulatory paracrine signals to mitigate radiation-induced hematopoietic toxicity. This provides a natural polypharmacy solution against a complex injury process. In summary, myeloid committed progenitor cells can be prepared from blood cells as an off-the-shelf alternative to invasive bone marrow harvesting and can be administered in an allogenic setting to mitigate hematopoietic acute radiation syndrome.

Lessons Learned from the Impact of COVID-19 on NCI-sponsored Cancer Prevention Clinical Trials: Moving Toward Participant-centric Study Designs

The COVID-19 pandemic overloaded health care systems around the globe and brought travel restrictions and other mandates. These effects critically impacted cancer care and conduct of clinical trials, and required medical and research communities to incorporate changes and novel flexible workflows within clinical trials and regulations to improve efficiency. We report the impact of the pandemic on cancer prevention clinical trials managed by the Division of Cancer Prevention within the NCI, focusing on participant-centric, study staff-centric and regulatory elements. Learning lessons from this challenging period, the cancer prevention community has the opportunity to incorporate many of these necessitated novel approaches to future design of clinical trials, to streamline and improve clinical trial efficiency and impact.

Abstract P1-09-03: Omega-3 polyunsaturated fatty acid supplementation shifts the gut and breast microbiome to influence inflammation

Obesity increases the risk of postmenopausal breast cancer. Obesity also influences the gut microbiome. The gut microbiome represents the totality of microorganisms living within the body and can influence the development of many different types of diseases, including breast cancer. Obesity is associated with an increase in the Firmicute-to-Bacteriodetes bacterial phyla ratio in the gut microbiome promoting dysbiosis and inflammation. We previously demonstrated that diet and obesity shift both the gut and breast tissue microbiome using a non-human primate model. To investigate the impact of omega-3 PUFA supplementation on the gut and breast microbiome, we used a combination of a preclinical murine model and human fecal samples collected from overweight and obese postmenopausal women enrolled in a weight loss clinical trial supplemented with placebo or high dose omega-3 PUFA (clinicaltrials.gov identifier: NCT02101970). Female C57BL/6 mice fed a Western (0.2% kcal from omega-3 PUFA) or a Western +omega-3 PUFA diet (1.3% kcal omega-3 PUFA) for 16 weeks demonstrate differences in intestinal permeability as measured by circulating plasma LPS, in vivo FITC-dextran permeability assay, and intestinal tight junction protein ZO-1 gene expression. Elevated LPS bioavailability associated with metabolic endotoxemia has been associated with breast cancer risk. Omega-3 PUFA supplementation shifts the gut and mammary gland (MG) microbiome. 16S sequencing of DNA isolated from matched fecal and MG samples demonstrate that omega-3 PUFA supplementation independently regulated both microbiomes. Moreover, omega-3 PUFA supplementation in a Western diet reduced Firmicute-to-Bacteriodetes ratio in the murine MG tissue. Obese and overweight postmenopausal women (n=46) were enrolled in a weight loss clinical trial (combination of calorie restriction and exercise) and were administered a placebo or 3.25 g/day combined eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids omega-3 PUFA supplements for 6 months. Bacterial sequencing of DNA isolated from fecal collections at baseline and after 6 months of intervention shows significant decrease in Firmicutes-to-Bacteriodetes ratio regardless of intervention group. However, when clustering subjects by relative weight loss and intervention (&lt;10% weight loss on placebo; &lt;10% weight loss on omega-3; &gt;10% weight loss on placebo, or &gt;10% weight loss on omega-3), women in the &lt;10% weight loss on omega-3 PUFA group displayed significant reduction in the Firmicutes-to-Bacteriodetes ratio from baseline that was not observed in the &lt;10% weight loss on placebo group. These data suggest that women who did not achieve substantial weight loss but were supplemented with omega-3 PUFA, show an improved gut microbiome for potential enhancement of health outcomes. Taken together, these data demonstrate that increasing omega-3 PUFA intake to approximately 2% of total daily calories can shift the gut and mammary gland microbiome to a pattern associated with improved intestinal permeability parameters and less chronic inflammation, which in turn is associated with reduced risk of postmenopausal breast cancer.

Citation Format: Katherine L. Cook, Adam S Wilson, David R Soto-Pantoja, Bruce F. Kimler, Shahid Umar, Carol J. Fabian. Omega-3 polyunsaturated fatty acid supplementation shifts the gut and breast microbiome to influence inflammation [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 P1-09-03.

Abstract P2-01-05: Impact of post-treatment ctDNA and residual cancer burden (RCB) on outcomes in patients with triple-negative breast cancer (TNBC) and residual disease

Introduction: Residual disease (RD) after neoadjuvant chemotherapy (NACT) is associated with high risk of recurrence in TNBC. RCB classification is prognostic in patients with RD. Recent studies show that post-NACT circulating cell-free tumor DNA (ctDNA) also provides prognostic information in patients with RD. Most TNBC patients with RD receive adjuvant therapy after surgery (chemotherapy and/or radiation), thus ctDNA status at completion of all adjuvant therapy (end of treatment, EOT) may be a better indicator of long-term prognosis. Furthermore, the impact of EOT ctDNA status on prognosis in context of RCB is of interest. Utilizing data from a prospective registry, the objective of this study was to investigate the impact of EOT ctDNA status and RCB class on outcomes in TNBC patients with RD. We hypothesized that RCB and EOT ctDNA status may provide complementary prognostic information. Methods: Study population included TNBC patients with RD post-NACT and available EOT plasma samples who were enrolled in an IRB-approved multisite prospective registry between 2011 and 2018. EOT samples were collected after completion (1-6 months) of all curative treatment (local and systemic). ctDNA was isolated and subjected to next generation sequencing (QIAseq 275-gene Human Comprehensive Cancer Panel on an Illumina NextSeq 550). Samples demonstrating pathogenic/likely pathogenic variant(s) with 3-40% allelic frequencies were considered ctDNA positive. Variants with allelic frequencies ≥40% were included in ctDNA positive status only if not present in ClinVar8/dbSNP9 as a known germline variant. The impact of EOT ctDNA status and RCB on event-free survival (EFS) and overall survival (OS) were estimated according to the Kaplan-Meier method and compared among groups by log-rank test, followed by Cox regression analysis. Results: For 47 TNBC patients with RD and available EOT plasma sample, the median age was 47 years, and 43% had node-positive disease at diagnosis. RCB class distribution was as follows: RCB I=28%, RCB II=49%, RCB III=15%, RCB unknown=8%. 45% of patients received adjuvant chemotherapy (59% with RCB II-III received adjuvant chemotherapy), and 68% received adjuvant radiation. EOT ctDNA was positive in 34% (16/47) of patients and was associated with higher T stage (p=0.012), TNM stage (p=0.033) and trend toward higher RCB class (p=0.078). ctDNA positivity rates in RCB I, II and III classes were 23%, 30% and 71%, respectively. Among all patients, 3-year EFS and OS were 71% and 73%, respectively. Table 1 provides 3-year EFS and OS by ctDNA status in all patients and by RCB class. ctDNA positive status was associated with inferior EFS and OS. Conclusion: EOT ctDNA positivity was noted in one-third of TNBC patients with residual disease and was highly prognostic, with almost half of patients with ctDNA positivity suffering an EFS event by 3 years. Patients with RCB III had very poor outcome (3-year EFS ≤20%) regardless of ctDNA status. However, in RCB classes I/II, ctDNA provided further prognostic utility, as ctDNA negative patients with RCB I/II had excellent outcomes (3-year EFS &gt;90%). These findings should be confirmed in other studies and provide insights into the role of ctDNA for patient stratification/selection in residual disease adjuvant therapy intensification trials for TNBC.

3-year EFS3-year OSAll patients: ctDNA positive vs ctDNA negative56% vs 78%, HR 3.02 (95% CI: 1.01-9.01), p=0.03856% vs 82%, HR 3.05 (95% CI: 1.02-9.13), p=0.037RCB I/II: ctDNA positive vs ctDNA negative73% vs 92%, HR 4.38, p=0.07873% vs 92%, HR 3.03, p=0.159RCB III: ctDNA positive vs ctDNA negative0% vs 20%, HR 1.67, p=0.5610% vs 20%, HR 1.30, p=0.765

Citation Format: Priyanka Sharma, Shane R Stecklein, Bruce F Kimler, Rachel Yoder, Kelsey Schwensen, Joshua M Staley, Qamar J Khan, Anne P O'Dea, Lauren E Nye, Manana Elia, Jaimie Heldstab, Trisha Home, Stephen Hyter, Kamilla Isakova, Harsh B Pathak, Andrew K Godwin. Impact of post-treatment ctDNA and residual cancer burden (RCB) on outcomes in patients with triple-negative breast cancer (TNBC) and residual disease [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 P2-01-05.

Abstract P4-10-03: Immunogenicity of SARS-CoV-2 vaccination in subjects on active treatment for breast cancer

Background: Infection with SARS-CoV-2 has led to a global pandemic and has significantly impacted the care of cancer patients. Breast cancer patients receiving active systemic therapy need protection against COVID19 but the efficacy of vaccines in this population is unknown. Although specific biomarkers associated with protection from SARS-CoV-2 infection have yet to be identified, measurement of serum antibody activity is generally accepted as a surrogate of in vivo humoral response to vaccine. This study evaluates the efficiency and durability of binding antibodies to SARS-CoV-2 spike (S) protein in response to COVID19 vaccine in breast cancer patients receiving systemic treatment. Methods: Breast cancer patients, who were unvaccinated, partially or fully vaccinated with Pfizer-BioNTech BNT162b2 (PF), Moderna mRNA-1273 (Mod) or Johnson & Johnson AD26.COV2.S (J&J) were enrolled in this prospective longitudinal study. Eligible patients were on systemic treatment with cytotoxic chemotherapy, chemotherapy plus a checkpoint inhibitor (CPI), CPI alone or a CDK 4/6 inhibitor. Longitudinal blood samples are being collected at baseline, prior to vaccination in unvaccinated patients (T0), 2 weeks after the first vaccine dose and before the second dose for the mRNA vaccines (T1), 1 month (T2), 3 months (T3), 6 months (T4) and 12 month post vaccination. For J&J, there was no T1 timepoint. Roche Elecsys® Anti-SARS-CoV-2 S receptor binding domain (RBD) antibody immunoassay was used to measure antibody titers (range 0.4 to 250 U/mL). Cut points of &lt;0.8 U/mL = negative, ≥0.8 U/mL = seropositive, were based on validated product specifications. Results: Of the 84 breast cancer patients enrolled, 9 had documented COVID infection at baseline and were excluded from analysis. Mean age was 58 years; 99% were female, 85% were Caucasian, 49% had early stage disease and 51% had metastatic breast cancer. 67% were receiving cytotoxic chemotherapy, 20% a CKD 4/6 inhibitor, 13% a CPI with or without chemotherapy. 61.2% were vaccinated with PF, 34.3% with Mod and 4.5% with J&J vaccines. Seropositivity rate for the entire group was 10% at T0, 78% at T1, 98% at T2 and 100% at T3. Seropositivity rates of all cohorts at different timepoints are shown in the table. Mean titers for all patients were 12.6 U/mL at T0, 102.3 U/mL at T1, 204.4 U/mL at T2 and 214.6 U/mL at T3 timepoints. Similar incremental increase in antibody levels was observed in all cohorts (Table). Conclusions: 78% of the patients with breast cancer on active systemic treatment were seropositive after the first dose of COVID19 vaccine and 98% after the second dose. The antibody response was maintained at 3 months, with 100% seropositivity rate. 6-month antibody response will be available at the time of presentation. Durability of antibody response at 6 and 12 months will help determine the timing of additional vaccine booster doses in this population. Importantly, this study has found that active treatment with chemotherapy, immunotherapy or CDK4/6 inhibitor therapy does not impact antibody response to SARS-CoV-2 vaccination in patients with breast cancer. Table: Seropositivity rate and mean Anti-S protein antibody levels by cohort at each time point. T0= baseline, T1=after first vaccine dose (mRNA vaccines), T2= 4 weeks after 2 doses of mRNA vaccine or after single dose of J&J vaccine, T3=3 months after the first dose of vaccine.

N% Seropositive (&gt;0.8 U/mL)Mean Antibody Levels (U/mL)T0T1T2T3T0T1T2T3All subjects7510789810012.6102.3204.4214.6Chemotherapy50577961003.3105.6200.0250CDK 4/6 inhibitors15257510010013.786.8234.7205.8CPI + Chemotherapy82583100NA*62.8121.4177.5NA*CPI therapy20100100NA*0.46.82250NA*CPI=Checkpoint Inhibitors; *Timepoint for longitudinal samples not reached

Citation Format: Cory Bivona, Kevin Li, Priyanka Sharma, Jianghua He, Grace Martin, Andrew K Godwin, Anthony Rooney, Stephen Williamson, Gary Doolittle, Weijing Sun, Bruce F Kimler, Anne P O'Dea, Lauren E Nye, Joseph P McGuirk, Ziyan Pessetto, Lisa Haney, Nicole Balmaceda, Laura Mitchell, Karissa Finke, Maggie Nelson, Dinesh Pal Mudaranthakam, Natalie Streeter, Stephanie Lafaver, Jaimie Heldstab, Qamar J Khan. Immunogenicity of SARS-CoV-2 vaccination in subjects on active treatment for 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 P4-10-03.

Abstract P1-10-04: AGR2, an estrogen response gene associated with tamoxifen resistance, is modulated by acolbifene in premenopausal women at high risk for development of breast cancer

Anterior Gradient 2 is an estrogen early response gene (AGR2) and protein (AGR-2). High expression is associated with endoplasmic reticulum stress and endocrine therapy resistance. Developmentally, AGR2 is associated with estrogen-mediated epithelial proliferation and lobuloalveolar development. In the adult, AGR2 is upregulated by inflammatory and metabolic stress signaling from NFKB, HSP90, IGFR-1, and FOXA1, in addition to estrogen bound to its receptor. The Selective Estrogen Receptor Modulator (SERM) Full dose tamoxifen has been reported to upregulate AGR2 in breast cancer but Selective Estrogen Receptor Down Regulators (SERDs) and aromatase inhibitors do not. AGR-2 is also a secreted protein, with increased tumor levels associated with metastases and decreased disease-free survival in tamoxifen-treated patients. We assessed AGR2 expression in reserved benign breast tissue from baseline and off-study specimens acquired by random periareolar fine needle aspiration (RPFNA) of premenopausal women at high risk for development of breast cancer who had participated in an early phase prevention trial of the SERM acolbifene (20 mg daily for 6 months). This pilot had demonstrated reduced Ki-67 and down-regulation of several estrogen response genes (Fabian et al. Ca Prev Res 2015). Methods Total RNA was extracted from aliquots of frozen benign breast tissue using TRIzol LS (Life Technologies) and purified using RNeasy MinElute Cleanup Kit (Qiagen). RNA was amplified using MessageAmpII aRNA amplification kit (Life Technologies) and reverse transcribed to cDNA using SMARTScribe Reverse Transcriptase (Takara Bio USA, Inc.) and random nonamer primers. Real-time quantitative PCR (qPCR) was performed using hydrolysis probes with baseline and postintervention specimens assessed together. PCR reactions were run on an Applied Biosystems Prism 7000 Sequence Detection System. The cycle threshold mean value for each transcript (from duplicate assays per specimen) was normalized using three reference transcripts, plus two epithelial cell transcripts. Relative levels of each transcript were calculated using the ΔΔCt method. The ratio (postintervention: baseline) of final values indicated upregulation (value &gt; 1) or downregulation (value &lt; 1). Results There were 17 available paired specimens for analysis for AGR2 gene expression which was downregulated in 13 with nine by more than a 50% reduction; for the four cases of up-regulation, three were increased by more than two-fold (p=0.076, Wilcoxon signed ranks test). Several estrogen response genes (TFF1, PGR, and the ratio of ESR1:ESR2) exhibited significant down-regulation (p≤0.007). Further, there was no evidence of linear correlation (p&gt;0.28; Spearman’s rho) between change in AGR2 and any of these other estrogen response genes. Lastly, when an Estrogen Response Gene Index (ERGI) was constructed using the average log2(fold change) for TFF1, PGR, and the ratio of ESR1:ESR2, down regulation was observed in 16 of the 17 paired specimens with only one increase. ERGI and AGR2 change indicate favorable modulation by acolbifene and appear to provide independent information. Conclusions These results suggest that change in expression of benign breast AGR2 might be a useful addition to change in expression of other classic estrogen response genes in evaluating the potential of novel SERMs such as acolbifene compared to standard SERMs like tamoxifen in early phase prevention trials.

Citation Format: Carol J. Fabian, Teresa A. Phillips, Bruce F. Kimler. AGR2, an estrogen response gene associated with tamoxifen resistance, is modulated by acolbifene in premenopausal women at high risk for development of 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 P1-10-04.

Abstract P2-10-02: Random periareolar fine-needle aspiration (RPFNA) cell number, prior precancerous breast disease and subsequent uptake of a prevention intervention predict short-term breast cancer risk

Introduction: In 2000 we published initial observations from a high-risk cohort of 480 women that cytologic evidence of hyperplasia with atypia in benign breast tissue obtained by random periareolar fine-needle aspiration (RPFNA) was associated with a five-fold increased risk of developing DCIS or invasive breast cancer at a median follow-up of 45 months [Fabian, JNCI 2000]. Few women in the initial cohort had any exposure to prevention agents, as NSABP-P1 was not reported until 1998. We began a new high-risk cohort in 2002 as the tissue processing changed from a filter technique to Thin PrepTM. The superior nuclear detail permitted assessment of cytologic atypia in the absence of high cellularity. Women in the second cohort were told that RPFNA atypia was a risk factor for developing breast cancer and in addition to standard prevention options were offered participation in clinical trials, if applicable. The purpose of this subsequent analysis was to determine if the predictive value of RPFNA atypia was maintained with change in tissue processing and availability of prevention options. Methods: A total of 1,135 high-risk women, eligible on the basis of family history, BRCA1/2 mutation status, prior biopsy indicating LCIS or atypical hyperplasia (AH), prior contralateral breast cancer and/or high mammographic breast density, underwent baseline RPFNA and were enrolled in our second cohort between 2002 and 2015. As in the earlier study published in 2000, if women had 2 aspirations without an intervening intervention within 21 months the worse result was utilized as baseline. In addition to cytomorphology, breast tissue was also categorized by cellularity of the aspirate (10-100, 100-1000, 1000-5000, and &gt;5000 cells per cytology slide). The primary aspirator (CJF) and cytopathologist (CMZ) were the same for both cohorts. Women were censored at the time of prophylactic mastectomy, development of other site cancer, or death. Kaplan-Meier hazard plots and Cox-regression analysis were used to analyze time to development of DCIS or invasive breast cancer and effect of joint variables, respectively. Results: At a median follow-up of 86 months, 79 cases of DCIS or invasive breast cancer had been diagnosed. By univariate analysis, RPFNA atypia at entry was not predictive of subsequent breast cancer (p=0.58; log-rank test). However, breast cancer risk was increased by a prior breast biopsy with LCIS or AH (HR 2.6, 95% CI 1.6-2.4, p&lt;0.001) or by high RPFNA cellularity, defined as &gt;5000 epithelial cells per RPFNA cytomorphology slide (HR 2.1, 95% CI 1.3-3.5, p=0.0034). Thirty-six percent of women subsequently chose to undergo a prevention intervention, including a standard drug, enrollment in a prevention clinical trial of 6-12 months duration, or a prophylactic bilateral salpingo-oophorectomy (BSO) prior to age 45. Prevention interventions were more prevalent in women with RPFNA atypia (49% vs 30%, p&lt;0.001). Not only was uptake of a prevention intervention associated with reduced breast cancer risk on univariate analysis (p=0.043), it was retained on multivariate analysis. The final Cox Regression risk model included prior breast biopsy with LCIS or AH (HR 2.4, 95% CI 1.5-3.9; p&lt;0.001), high RPFNA cellularity (HR 2.2, 95% CI 1.3-3.7; p=0.003) and prevention intervention (HR 0.54, 95% CI 0.33-0.89; p=0.015). Conclusions: In a second large cohort of high-risk women for whom RPFNA acquired cells were processed to slides via ThinPrep™, high RPFNA cellularity (&gt;5000 epithelial cells/slide) but not cytologic atypia predicted short-term breast cancer risk. However, women with atypia were significantly more likely than women without atypia to participate in a prevention intervention, which in turn was associated with reduced breast cancer risk

Citation Format: Whitney L Hensing, Carol J Fabian, Carola M Zalles, Priyanka Sharma, Amy L Kreutzjans, Kandy R Powers, Lynn Chollet-Hilton, Bruce F Kimler. Random periareolar fine-needle aspiration (RPFNA) cell number, prior precancerous breast disease and subsequent uptake of a prevention intervention predict short-term breast cancer risk [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 P2-10-02.

Abstract P2-11-17: Feasibility of microbiome analysis from random periareolar fine needle aspiration in premenopausal women at increased risk for breast cancer

Background: Nearly 10% of breast cancers (BC) are diagnosed in premenopausal woman under age 45 and of childbearing potential. Women considering future childbearing are typically excluded from BC prevention trials and are ineligible for standard of care chemoprevention. More biomarkers are needed to support BC prevention trials in this young cohort. Women of childbearing potential are encouraged to supplement diet with minimum of 300mg of EPA + DHA omega-3 fatty acids (FA) per day. EPA and DHA are thought to have a favorable effect on the gut microbiome implicated in cancer development. Few studies have characterized the breast microbiome by core biopsy or surgical sample but to our knowledge no studies have explored the feasibility of breast microbiome collection using the less invasive technique Random Periareolar Fine Needle Aspiration (RPFNA). In a pilot study, we demonstrated feasibility of recruiting premenopausal women considering future pregnancy to a BC prevention trial with a 6-month intervention of omega-3 FA supplementation (19-A-1921-SABCS). RPFNA was used to collect breast tissue for biomarker analysis, which is a mildly invasive technique used for repeated sample collection in BC prevention trials. Objectives: 1) To determine the feasibility of characterizing breast microbiome from specimens collected by RPFNA in premenopausal woman at high risk for BC, 2) To identify changes in the breast and stool microbiome with omega-3 FA supplementation in this population. Methods: Ten women between the ages of 21 and 40 who were considering future pregnancy and at high risk for BC were enrolled to a pilot study and took Omega-3-Acid Ethyl Ester (total of 750mg DHA and 930mg EPA) daily for 6 months. Tissue collection with RPFNA of breast as well as blood, urine and stool were completed at baseline and off-study visit. RPFNA samples from the first 2 passes at each site of breast (4 sites total) were collected for microbiome and placed in a 2mL tube with 0.5 – 1cc of PBS and flash frozen and stored at -80C. DNA was isolated from RPFNA samples using QIAamp DNA Mini Kit (51304). Microbiome profiling analysis was performed by Veracet using 16S V4 rRNA gene sequencing on the Illumina MiSeq platform. Wilcoxon signed rank test was used to compare paired samples. Results: Of the 10 women enrolled, median age was 33 years (range 22-37). 90% (9 of 10) returned for off-study visit. Of the 9 women who completed the off-study visit, 2 elected to not undergo off-study RPFNA. There were 16 total stool samples and 17 total RPFNA samples for microbiome evaluation. There were 6 paired (baseline and off-study) stool and 7 paired RPFNA samples. Mean DNA concentration from RPFNA samples was 10.36ng/µl (range 0.62 – 74.10). From all samples, 52.1% of operational taxonomic units (OTUs) were classified at the genus level. Breast samples were sequenced to a depth of mean 27,767 reads (range 5,745 – 125,445) and stool to a depth of mean 119,296 reads (range 72,979 – 188,867). The alpha diversity metric of OTU richness was 1069 (breast) and 438 (stool). Shannon diversity was 4.51 (breast) and 3.89 (stool). Mean OTU richness for baseline and off-study RPFNA samples were 1098 and 1028 respectively (V = 25, p value = 0.076). Mean OTU richness for baseline and off-study stool samples were 440 and 437 respectively (V = 15, p value = 0.40). Conclusion: We demonstrated feasibility of analyzing breast microbiome from an RPFNA specimen. Additional investigation with modifications to technique and/or sample population is. needed to achieve adequate sequencing depth for characterization of breast microbiome. Lower depth of sequencing in breast samples is thought to reflect differences in microbial DNA quantity. We were unable to assess change in microbiome composition in breast or stool samples with omega-3 fatty acid supplementation due to small sample size.

Citation Format: Lauren E Nye, Jennifer R Klemp, Kandy R Powers, Anne P O'Dea, Amy L Kreutzjans, Trina Metheny, Teresa A Phillips, Susan E Carlson, Bruce F Kimler, Carol J Fabian. Feasibility of microbiome analysis from random periareolar fine needle aspiration in premenopausal women at increased risk for 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 P2-11-17.

Rapid Escalation of High-Volume Exercise during Caloric Restriction; Change in Visceral Adipose Tissue and Adipocytokines in Obese Sedentary Breast Cancer Survivors

Simple Summary

Aerobic exercise reduces risk for developing breast cancer or for breast cancer recurrence. In obese women exercise can significantly augment the effects of caloric restriction on visceral fat, reducing metabolic abnormalities and cancer. Women who are older, obese, and sedentary, especially those who have been treated for breast cancer, find it difficult to initiate and achieve the minimum or optimum levels of exercise. In a two-part pilot we found that by providing older, obese, sedentary breast cancer survivors 12 weeks of twice weekly personal training sessions, they could safely increase exercise to ≥200 min/week by 9 weeks during caloric restriction. At 24 weeks, high levels of exercise were still observed with continued behavioral support and study-provided exercise facility. Substantial improvement in visceral fat and breast cancer risk biomarkers were observed with this affordable intervention that is readily exportable to the community.

Abstract

Aerobic exercise reduces risk for breast cancer and recurrence and promotes visceral adipose tissue (VAT) loss in obesity. However, few breast cancer survivors achieve recommended levels of moderate to vigorous physical activity (MVPA) without supervision. In a two-cohort study, feasibility of 12 weeks of partially supervised exercise was started concomitantly with caloric restriction and effects on body composition and systemic risk biomarkers were explored. In total, 22 obese postmenopausal sedentary women (including 18 breast cancer survivors) with median age of 60 and BMI of 37 kg/m² were enrolled. Using personal trainers twice weekly at area YMCAs, MVPA was escalated to ≥200 min/week over 9 weeks. For cohort 2, maintenance of effect was assessed when study provided trainer services were stopped but monitoring, group counseling sessions, and access to the exercise facility were continued. Median post-escalation MVPA was 219 min/week with median 12-week mass and VAT loss of 8 and 19%. MVPA was associated with VAT loss which was associated with improved adiponectin:leptin ratio. In total, 9/11 of cohort-2 women continued the behavioral intervention for another 12 weeks without trainers. High MVPA continued with median 24-week mass and VAT loss of 12 and 29%. This intervention should be further studied in obese sedentary women.

Clinical and Biomarker Results from Phase I/II Study of PI3K Inhibitor Alpelisib plus Nab-paclitaxel in HER2-Negative Metastatic Breast Cancer

PURPOSE

PIK3CA mutations are common in breast cancer and promote tumor progression and treatment resistance. We conducted a phase I/II trial of alpelisib (α-specific PI3K inhibitor) plus nab-paclitaxel in patients with HER2-negative metastatic breast cancer (MBC).

PATIENTS AND METHODS

Eligible patients had HER2-negative MBC with any number of prior chemotherapies. Phase I was 3+3 dose-escalation design with three dose levels of alpelisib (250, 300, and 350 mg) daily plus nab-paclitaxel 100 mg/m2 administered on days 1, 8, and 15 every 28 days. Phase II was according to Simon's two-stage design. PIK3CA mutations in tumor/circulating tumor DNA (ctDNA) were assessed. Primary endpoints were recommended phase II dose (RP2D) and objective response rate (ORR). Additional endpoints included safety, pharmacokinetics, progression-free survival (PFS), and association of PIK3CA mutation with outcomes.

RESULTS

A total of 43 patients were enrolled (phase I, n = 13 and phase II, n = 30). A total of 84% had visceral disease and 84% had prior taxane. No dose-limiting toxicities occurred in phase I. RP2D was alpelisib 350 mg daily plus nab-paclitaxel 100 mg/m2 on days 1, 8, and 15. Hyperglycemia (grade 3, 26% and grade 4, 0%), neutropenia (grade 3, 23% and grade 4, 7%), diarrhea (grade 3, 5% and grade 4, 0%), and rash (grade 3, 7% and grade 4, 0%) were the most common adverse events. Among 42 evaluable patients, ORR was 59% (complete response, 7% and partial response, 52%), 21% of whom had response lasting >12 months; median PFS was 8.7 months. A total of 40% of patients demonstrated tumor and/or ctDNA PIK3CA mutation; patients with tumor/ctDNA mutation demonstrated better PFS compared with those without mutation (11.9 vs. 7.5 months; HR, 0.44; P = 0.027). Patients with normal metabolic status had longer PFS compared with prediabetic/diabetic patients (12 vs. 7.5 months; P = 0.014). No pharmacokinetics interactions were detected.

CONCLUSIONS

The alpelisib plus nab-paclitaxel combination was well tolerated and shows encouraging efficacy, especially in patients with PIK3CA-mutated tumor/ctDNA. The impact of metabolic status on response to this combination merits further investigation.

Change in Blood and Benign Breast Biomarkers in Women Undergoing a Weight-Loss Intervention Randomized to High-Dose ω-3 Fatty Acids versus Placebo

The inflammation-resolving and insulin-sensitizing properties of eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids have potential to augment effects of weight loss on breast cancer risk. In a feasibility study, 46 peri/postmenopausal women at increased risk for breast cancer with a body mass index (BMI) of 28 kg/m² or greater were randomized to 3.25 g/day combined EPA and DHA (ω-3-FA) or placebo concomitantly with initiation of a weight-loss intervention. Forty-five women started the intervention. Study discontinuation for women randomized to ω-3-FA and initiating the weight-loss intervention was 9% at 6 months and thus satisfied our main endpoint, which was feasibility. Between baseline and 6 months significant change (P < 0.05) was observed in 12 of 25 serum metabolic markers associated with breast cancer risk for women randomized to ω-3-FA, but only four for those randomized to placebo. Weight loss (median of 10% for trial initiators and 12% for the 42 completing 6 months) had a significant impact on biomarker modulation. Median loss was similar for placebo (-11%) and ω-3-FA (-13%). No significant change between ω-3-FA and placebo was observed for individual biomarkers, likely due to sample size and effect of weight loss. Women randomized to ω-3-FA exhibiting more than 10% weight loss at 6 months showed greatest biomarker improvement including 6- and 12-month serum adiponectin, insulin, omentin, and C-reactive protein (CRP), and 12-month tissue adiponectin. Given the importance of a favorable adipokine profile in countering the prooncogenic effects of obesity, further evaluation of high-dose ω-3-FA during a weight-loss intervention in obese high-risk women should be considered. PREVENTION RELEVANCE: This study examines biomarkers of response that may be modulated by omega-3 fatty acids when combined with a weight-loss intervention. While focused on obese, postmenopausal women at high risk for development of breast cancer, the findings are applicable to other cancers studied in clinical prevention trials.

Abstract 2567: Duavee® improves metabolic health without increasing cancer risk: findings from a preclinical model of obesity and postmenopausal breast cancer

Introduction: Many women at high risk for breast cancer will not take standard selective estrogen receptor modulators (SERMs) for cancer prevention due to concern of side effects, especially vasomotor symptoms. Duavee®, a tissue selective complex of the SERM bazedoxifene (BZA; 20mg) + conjugated estrogen (CE; 0.45mg), is FDA approved for relief of hot-flashes. Preclinical and early phase human studies suggest Duavee® has potential for breast cancer prevention, with favorable change in mammographic fibroglandular volume and proliferation. Given the &gt;40% incidence of obesity in postmenopausal women, and that obesity increases breast cancer risk, the current study was aimed at identifying the effects of obesity on response to Duavee® in a rodent model of obesity and postmenopausal breast cancer.

Methods: This study used our well-characterized rat model of diet-induced obesity and postmenopausal ER-positive breast cancer. Rats were injected with N-methylnitrosourea (MNU, 50 mg/kg) at 7 weeks of age to induce mammary tumors and fed a high fat diet (HF; 46% kcal fat) to promote obesity. Lean and obese rat were selected based on % body fat at 16 weeks. Tumors were monitored by manual palpation weekly and measured using digital calipers. Tumor-bearing rats were ovariectomized (OVX) when a tumor reached 0.7cm3. Rats were then maintained on ad libitum HF diet or HF diet plus a daily oral dose of Duavee® (3mg BZA+ 0.07mg CE/kg body weight) for 8 weeks. Body composition was analyzed biweekly (qMR) and fat pads weighed at study end to determine regional fat distribution.

Results: Like menopause in women, OVX induces weight gain in this model. Duavee® significantly blunted the OVX-induced weight gain in both lean (-65%, p&lt;0.001) and obese (-88%, p&lt;0.001) rats compared to controls. Similarly, Duavee®-treated rats gained less body fat after OVX vs controls (-50% lean; -97% obese, p&lt;0.001). Duavee® administration was associated with reduction in glucose in obese rats after 2 weeks and in lean and obese rats after 8 weeks (-11% vs controls, p=0.03). The effects of Duavee® on regional fat deposition varied by adiposity. Obese Duavee®-treated rats had significantly lower pericardial fat (-17%, p&lt;0.05) and tended to have lower mammary fat (-19%, p=0.08); lean rats had less gonadal fat (-20%, p&lt;0.05), while deposition in this region was not altered by Duavee® in obese rats. At 8 weeks there was no evidence that Duavee® promoted tumor development or growth in lean or obese OVX rats.

Conclusions: These data suggest that Duavee® may provide beneficial effects on body composition and metabolism in obese OVX animals without promotion of tumor growth. Further analyses will include study of direct effects of Duavee® on tumors, the tumor microenvironment, and systemic markers of insulin resistance and mammary cancer risk in our rat model of pre-and postmenopausal obesity and breast cancer.

Citation Format: Karen A. Corleto, Tara N. Mahmood, Danilo Landrock, Stephen D. Hursting, Carol J. Fabian, Bruce F. Kimler, Erin D. Giles. Duavee® improves metabolic health without increasing cancer risk: findings from a preclinical model of obesity and postmenopausal breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2567.

Romidepsin (HDACi) plus cisplatin and nivolumab triplet combination in patients with metastatic triple negative breast cancer (mTNBC)

1076

Background: Histone deacetylase inhibitors (HDACi) upregulate genes involved in antigen presentation machinery and increase expression of natural killer group 2, member D ligands (NKG2DL), thus resulting in enhanced tumor cell recognition and response to PD-1/CTLA-4 blockade. Cisplatin and HDACi combination synergistically induces cytotoxicity, apoptosis, and DNA damage. This phase I-II trial investigated combination of romidepsin (HDACi) plus cisplatin and nivolumab (PD-1 inhibitor) in mTNBC. Patients and Methods: Eligible patients had mTNBC with any number of prior chemotherapies. Phase I was 3+3 dose-escalation design with three dose levels of romidepsin (8, 10, 12mg/m2, D2, 9) plus cisplatin 75mg/m2 D 1 every 21 days. Phase II treatment included romidepsin plus cisplatin plus nivolumab 360mg every 21 days and was designed according to Simon’s two stage minimax design. Primary endpoints were recommended phase 2 dose (RP2D) and objective response rate (ORR). Additional endpoints included safety, PFS, and pharmacokinetics. Results: 51 patients were enrolled (N=13 phase I, N=38 phase II) between 2015-2020. 69% had received ≥1 prior metastatic chemotherapy, 47% had prior platinum, 53% had liver metastasis, 12% had BRCA1/2 mutation, and 11% had PD-L1 positive disease. There were no dose limiting toxicities in phase I. The RP2D was romidepsin 12mg/m2 D2,9 + cisplatin 75mg/m2 D1 + nivolumab 360mg D1 every 21 days. Thrombocytopenia (G3:27%, G4:0%), neutropenia (G3:25%, G4:0%), anemia (G3:22%, G4:0%), nausea (G3:22%, G4:0%), and vomiting (G3:20%, G4:0%) were the most common grade 3/4 adverse events. 21% of patients had immune AEs (G3-4:8%). Among 34 evaluable phase II patients, ORR was 44% (Table), median PFS was 4.4 months, and 1-year PFS was 23%. Median OS was 10.3 months and 1-year OS was 43%. No pharmacokinetic interactions were detected with co-administration of romidepsin-cisplatin-nivolumab. Conclusions: The triplet combination of romidepsin plus cisplatin and nivolumab was well tolerated and shows encouraging efficacy in pretreated mTNBC, including in patients with PD-L1 negative disease and in those with liver metastasis. Correlative biomarker work is ongoing. This combination warrants further evaluation in larger studies. Clinical trial information: NCT02393794 .[Table: see text]

Abstract PS6-04: Impact of low versus negative estrogen/progesterone receptor status on clinico-pathologic characteristics and survival outcomes in HER2 negative breast cancer

Background: Triple negative breast cancer is defined by lack of expression of ER/PR (immunohistochemistry expression &lt;1%) and absence of HER2 gene amplification. However, data regarding endocrine therapy benefit in patients with low levels (1-10%) of ER/PR expression are lacking. Furthermore, gene expression studies show tremendous similarities between HER2 negative tumors with low and negative ER/PR status. Accordingly, the 2020 ASCO/CAP guideline designates that ER expression of 1-10% be reported as a distinct “ER low positive” category. Utilizing data from a prospective registry, the aim of this study was to determine the impact of low versus negative ER/PR status on clinico-pathologic characteristics and survival outcomes in patients with HER2 negative breast cancers. Methods: 516 subjects with stage I-III HER2 negative breast cancer and ER/PR IHC ≤10% were enrolled in an IRB-approved multisite prospective registry between 2011 and 2019. Demographic, clinical, pathologic, and treatment information was collected, and patients were followed for recurrence and survival. Patients were categorized according to ER/PR expression into two groups: TNBC (ER and PR &lt;1%) and Low-ER (ER and/or PR 1-10%). Recurrence free survival (RFS) and overall survival (OS) were estimated according to the Kaplan-Meier method and compared among groups by log-rank test, followed by Cox regression analysis. Results: TNBC and Low-ER groups comprised 451/516 (87.4%) and 65/516 (12.6%) patients, respectively. Demographic, clinical, pathologic, and treatment characteristics of the two groups are described in Table 1. Median follow-up was 39 months. Three-year RFS was 82% for both TNBC and Low-ER groups (p=0.70). Three-year OS was 88% and 83% for TNBC and Low-ER groups, respectively (p=0.63). Twenty percent of patients in the Low-ER group received adjuvant endocrine therapy, and endocrine therapy use did not impact outcomes in the Low-ER group (RFS: p=0.32; OS: p=0.88). On multivariate analysis, T stage, nodal status, and age significantly impacted RFS (T stage 3/4 vs 1/2, HR=2.7, p&lt;0.001; nodal status positive vs negative, HR=2.4, p&lt;0.001; age above vs below median, HR=1.8, p=0.006) and OS (T stage 3/4 vs 1/2, HR=3.6, p&lt;0.001; nodal status positive vs negative, HR=2.8, p&lt;0.001; age above vs below median, HR=1.026, p=0.01). For patients who received neoadjuvant chemotherapy, achievement of pathological complete response (pCR) was associated with superior RFS (3-year RFS of 95% and 67% in those with and without pCR, respectively, HR=0.18, p&lt;0.001). Conclusions: Patients with TNBC and Low-ER HER2 negative breast cancer present with similar clinico-pathologic characteristics, including prevalence of germline BRCA1/2 mutation. Prognosis and rate of pCR (with neo-adjuvant chemotherapy) in patients with Low-ER HER2 negative breast cancer is similar to those with TNBC. The role and efficacy of adjuvant endocrine therapy in patients with Low-ER breast cancer is unclear. These findings support consideration for inclusion of patients with Low-ER disease along with TNBC for future clinical trial eligibility and planning.

Table 1. Demographic, clinical, pathologic, and treatment characteristicsCharacteristics - N (%)All N=516TNBC (ER & PR &lt;1%) n=451Low-ER (ER or PR 1-10%) n=65pAge at diagnosis, years - median (range)53 (23-97)54 (23-97)51 (28-76)0.61RaceWhite386 (75%)335 (74%)51 (79%)0.69Black101 (20%)89 (20%)12 (19%)Asian8 (2%)8 (2%)0 (0%)Menopausal statusPre214 (42%)181 (41%)33 (51%)0.25Post295 (58%)263 (59%)32 (49%)Histological gradeI2 (0.4%)2 (0.4%)0 (0%)0.82II86 (17%)76 (17%)10 (15%)III428 (83%)373 (83%)55 (85%)T stageT1-2446 (87%)388 (87%)58 (89%)0.56T3-467 (13%)60 (13%)7 (11%)N statusPositive177 (34%)158 (35%)19 (29%)0.36Negative339 (66%)293 (65%)46 (71%)TNM stageI179 (35%)150 (33%)29 (44%)0.10II263 (51%)232 (52%)31 (48%)III74 (14%)69 (15%)5 (8%)Germline BRCA1/2 mutationYes70 (14%)64 (14%)6 (9%)0.53No357 (69%)309 (69%)48 (74%)Unknown89 (17%)78 (17%)11 (17%)ChemotherapyNeoadjuvant357 (69%)318 (71%)39 (60%)0.23Adjuvant147 (29%)123 (27%)24 (37%)None12 (2%)10 (2%)2 (3%)Surgery typeMastectomy308 (60%)275 (61%)33 (51%)0.10Lumpectomy205 (40%)173 (39%)32 (49%)Adjuvant endocrine therapyYes20 (4%)7 (2%)13 (20%)&lt;0.001No496 (96%)444 (98%)52 (80%)pCR (in patients with neoadjuvant chemotherapy, n=357)176 (49%)157 (49%)19 (49%)0.94

Citation Format: Rachel Yoder, Bruce F Kimler, Joshua M Staley, Kelsey Schwensen, Yen Y Wang, Karissa Finke, Anne O'Dea, Lauren Nye, Manana Elia, Gregory Crane, Richard McKittrick, Robert Pluenneke, Sheshadri Madhusudhana, Larry Beck, Roberto Rodriguez, Anuj Shrestha, Larry Corum, Mark Marsico, Andrew K Godwin, Qamar Khan, Priyanka Sharma. Impact of low versus negative estrogen/progesterone receptor status on clinico-pathologic characteristics and survival outcomes in HER2 negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-04.

Abstract PD11-02: Randomized trial of 12 months of omega-3 fatty acids vs placebo during a weight loss intervention in post-menopausal women at increased risk for breast cancer

Objectives: The primary objective was to determine tolerability of ω-3 fatty acids (2150 mg of eicosapentaenoic acid (EPA) and 1050 docosahexaenoic acid (DHA) ethyl esters) vs placebo in women in undergoing a behavioral weight loss intervention (6 months loss and 6 months maintenance). Secondary objectives were to explore potential differences in modulation of blood and benign breast tissue risk biomarkers, satiety and quality of life indices, and weight loss. Results: 46 peri and postmenopausal women were randomized and 42 completed the 6 months of the weight loss intervention and were biomarker evaluable (22 placebo and 20 ω-3 FA). Median baseline BMI in the 42 evaluable women was 31 kg/m2 with a median 6-month relative weight loss of 11% and relative fat mass loss of 20% (DXA). Median 12-month relative mass loss was 10% in the 35 women completing 12 months of the intervention. ω-3 fatty acids increased the ratio of (EPA+DHA): arachidonic acid 2.6-fold (median, range 1.8 - 3.8) vs no change for placebo. There was no difference by randomization group in relative weight or fat mass loss at 6 or 12 months, grade 2 and 3 adverse events, early discontinuation, satiety or other quality of life measures. More serum biomarkers exhibited significant within-group improvement at 6 and 12 months for evaluable women randomized to ω-3 FA than to placebo. At 6 months, significant change (P&lt;0.05) was observed for adiponectin, leptin, adiponectin:leptin ratio, insulin, lipocalin-2, resistin, PAI-1, HGF, CRP, SHBG, and bioavailable testosterone in women randomized to ω-3 FA but only for leptin, adiponectin: leptin ratio and SHBG in those randomized to placebo. At 6 months, the 21 women who lost &gt;10% weight (median 15%) showed significant within-group improvement in adiponectin, leptin, adiponectin:leptin ratio, insulin, lipocalin-2, resistin, PAI-1, HGF, CRP, SHBG, bioavailable estradiol and bioavailable testosterone. For women with &lt;10% weight loss (median 6%) there was significant within-group improvement only for leptin, the adiponectin: leptin ratio, and SHBG. Little change was observed for inflammatory cytokines IL-6, TNF-alpha, MCP-1 or FABP4, or FGF-21 with ω-3 FA or &gt;10% weight loss. Given the dramatic effect of weight loss on biomarkers, we examined within-group and between-group change from baseline to 6 and 12 months for the four subgroups (10-11 women in each) defined by ω-3 FA or placebo and &lt; or &gt; 10% weight loss at 6 months. The subgroup of &gt;10% loss + ω-3 FA had the greatest within-group change in the proportion of significantly modulated biomarkers at 6 months. &gt;10% loss + ω-3 FA was the only subgroup with a significant within-group increase in adiponectin at both 6 and 12 months and achievement of a beneficial ratio of adiponectin (ug/ml) to leptin (ng/ml) of &gt; 1.0 in 100% of participants. There was a significant between-group effect for adiponectin for &gt;10% loss + ω-3 FA vs each of the other groups. Biomarkers were assessed in tissue acquired by random periareolar fine needle aspiration (RPFNA). There were no significant differences in change in cytomorphology or Ki-67 between women randomized to ω-3 FA or placebo but there were significant within-group increases in benign breast adiponectin (pg/ug protein) at 12 months (p=0.014) for women randomized to ω-3 FA. Conclusions: EPA + DHA ethyl esters (3150 mg/day), added to a behavioral weight loss program in overweight women at increased risk for breast cancer, is well-tolerated and may further improve risk biomarker modulation. The increase in adiponectin when ω-3 FA is added to weight loss is of particular interest given that adiponectin opposes the oncogenic effect of leptin and is associated with improved insulin sensitivity and reduced mTOR signaling. Further study is warranted with enough subjects to detect between-group differences.

Citation Format: Carol J Fabian, Christie A Befort, Debra K Sullivan, Susan E Carlson, Jennifer L Nydegger, Amy L Kreutzjans, Kandy R Powers, Teresa A. Phillips, Trina Metheny, Carola M Zalles, Erin D Giles, Stephen D Hursting, Bruce F Kimler. Randomized trial of 12 months of omega-3 fatty acids vs placebo during a weight loss intervention in post-menopausal women at increased risk for breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD11-02.

Randomized Phase II Trial of Anthracycline-free and Anthracycline-containing Neoadjuvant Carboplatin Chemotherapy Regimens in Stage I-III Triple-negative Breast Cancer (NeoSTOP)

PURPOSE

Addition of carboplatin (Cb) to anthracycline chemotherapy improves pathologic complete response (pCR), and carboplatin plus taxane regimens also yield encouraging pCR rates in triple-negative breast cancer (TNBC). Aim of the NeoSTOP multisite randomized phase II trial was to assess efficacy of anthracycline-free and anthracycline-containing neoadjuvant carboplatin regimens.

PATIENTS AND METHODS

Patients aged ≥18 years with stage I-III TNBC were randomized (1:1) to receive either paclitaxel (P) weekly × 12 plus carboplatin AUC6 every 21 days × 4 followed by doxorubicin/cyclophosphamide (AC) every 14 days × 4 (CbP → AC, arm A), or carboplatin AUC6 + docetaxel (D) every 21 days × 6 (CbD, arm B). Stromal tumor-infiltrating lymphocytes (sTIL) were assessed. Primary endpoint was pCR in breast and axilla. Other endpoints included residual cancer burden (RCB), toxicity, cost, and event-free (EFS) and overall survival (OS).

RESULTS

One hundred patients were randomized; arm A (n = 48) or arm B (n = 52). pCR was 54% [95% confidence interval (CI), 40%-69%] in arm A and 54% (95% CI, 40%-68%) in arm B. RCB 0+I rate was 67% in both arms. Median sTIL density was numerically higher in those with pCR compared with those with residual disease (20% vs. 5%; P = 0.25). At median follow-up of 38 months, EFS and OS were similar in the two arms. Grade 3/4 adverse events were more common in arm A compared with arm B, with the most notable differences in neutropenia (60% vs. 8%; P < 0.001) and febrile neutropenia (19% vs. 0%; P < 0.001). There was one treatment-related death (arm A) due to acute leukemia. Mean treatment cost was lower for arm B compared with arm A (P = 0.02).

CONCLUSIONS

The two-drug CbD regimen yielded pCR, RCB 0+I, and survival rates similar to the four-drug regimen of CbP → AC, but with a more favorable toxicity profile and lower treatment-associated cost.

Abstract 1120: Randomized clinical trial of a flaxseed lignan in pre-menopausal women at high risk for development of breast cancer

Breast cancer prevention strategies for young pre-menopausal women must have minimal side effects and accommodate potential future child-bearing. Based on epidemiologic evidence and informed by a single-arm pilot study, we conducted a multi-institutional, placebo-controlled Phase IIB trial of the lignan secoisolariciresinol diglycoside (SDG) found in high concentrations in flaxseed. Benign breast tissue was acquired by random periareolar fine needle aspiration (RPFNA) from pre-menopausal women at increased risk for breast cancer during the follicular phase as estimated by dates. Those with cytologic hyperplasia and ≥2% positive cells by Ki-67 immunocytochemistry were eligible for randomization 2:1 to daily Brevail® (50 mg SDG) or placebo. After 12 months, RPFNA and blood for hormone assays were repeated. The primary endpoint was difference in change in Ki-67 between the randomization groups. A planned accrual of 230 was to provide an 80% power of detecting a 2.5% reduction in Ki-67 for the SDG group vs no reduction in the placebo group. Accrual was slower than anticipated and the study was closed with 180 enrollees at five sites. 152 (51 placebo, 101 SDG) sets of paired specimens were evaluable for the primary endpoint. Baseline Ki-67 was a median of 4.1% (range, 2.0 - 26.8%), with no difference between arms (Mann-Whitney nonparametric test, p=0.34). Both arms showed a decrease in percent Ki-67 over time (Wilcoxon signed rank test; p=0.034 for placebo, p=0.001 for SDG). Although Ki-67 reduction was greater in the SDG arm (median of -1.8% vs -1.2%), there was no statistically significant difference between the two arms (Mann-Whitney, p=0.72). Since luteal phase progesterone affects proliferation, we excluded 35 women that by serum progesterone levels could not be confirmed to be in the same phase of the menstrual cycle at baseline and off-study. Analyzing the remaining 117 for Ki-67 (42 placebo, 75 SDG), there was no significant change for the placebo arm (Wilcoxon, p=0.14) but the significant change in the SDG arm persisted (p=0.002). As an exploratory analysis, assessment of gene expression was performed by RT-qPCR on 77 pairs of non-bloody RPFNA specimens. 22 had significant ERα gene expression changes (defined &lt;0.5 or &gt;2.0 fold changes). There was no significant change over time for the placebo group (7/10 increases, Wilcoxon, p=0.16), but there was significant change for the SDG group (10/12 decreases, p=0.027). There was also a significant difference between the groups (Mann-Whitney, p=0.018). While the primary trial result is null, there is supportive evidence SDG may favorably affect cell proliferation and estrogen signaling in premenopausal women at high risk for development of breast cancer. Supported by Susan G. Komen Promise Grant KG101039. Study agent (Brevail®, placebo) provided by Lignan Research Inc. (later Barlean's Oils) which was otherwise not involved in the design, conduct, or analysis of the study.

Citation Format: Carol J. Fabian, Seema A. Khan, Judy E. Garber, William C. Dooley, Lisa D. Yee, Carola M. Zalles, Trina Metheny, Teresa A. Phillips, Jinxiang Hu, Brian K. Petroff, Stephen D. Hursting, Bruce F. Kimler. Randomized clinical trial of a flaxseed lignan in pre-menopausal women at high risk for development of breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1120.

Randomized Phase IIB Trial of the Lignan Secoisolariciresinol Diglucoside in Premenopausal Women at Increased Risk for Development of Breast Cancer

We conducted a multiinstitutional, placebo-controlled phase IIB trial of the lignan secoisolariciresinol diglucoside (SDG) found in flaxseed. Benign breast tissue was acquired by random periareolar fine needle aspiration (RPFNA) from premenopausal women at increased risk for breast cancer. Those with hyperplasia and ≥2% Ki-67 positive cells were eligible for randomization 2:1 to 50 mg SDG/day (Brevail) versus placebo for 12 months with repeat bio-specimen acquisition. The primary endpoint was difference in change in Ki-67 between randomization groups. A total of 180 women were randomized, with 152 ultimately evaluable for the primary endpoint. Median baseline Ki-67 was 4.1% with no difference between arms. Median Ki-67 change was -1.8% in the SDG arm (P = 0.001) and -1.2% for placebo (P = 0.034); with no significant difference between arms. As menstrual cycle phase affects proliferation, secondary analysis was performed for 117 women who by progesterone levels were in the same phase of the menstrual cycle at baseline and off-study tissue sampling. The significant Ki-67 decrease persisted for SDG (median = -2.2%; P = 0.002) but not placebo (median = -1.0%). qRT-PCR was performed on 77 pairs of tissue specimens. Twenty-two had significant ERα gene expression changes (<0.5 or >2.0) with 7 of 10 increases in placebo and 10 of 12 decreases for SDG (P = 0.028), and a difference between arms (P = 0.017). Adverse event incidence was similar in both groups, with no evidence that 50 mg/day SDG is harmful. Although the proliferation biomarker analysis showed no difference between the treatment group and the placebo, the trial demonstrated use of SDG is tolerable and safe.

Effects of Weight Loss and Weight Regain on Circulating Biomarkers in Overweight/Obese Breast Cancer Survivors Enrolled in a Weight Loss Trial in the Rural Midwest

BACKGROUND

Obesity is associated with worse breast cancer prognosis, however little is known about the level of weight loss required to improve pathway biomarkers. The effects of weight regain on biomarkers are also largely unknown.

METHODS

Overweight/obese breast cancer survivors enrolled in an 18-month behavioral weight loss trial provided weight and serum biomarkers [leptin, adiponectin, insulin, plasminogen activator inhibitor-1 (PAI-1), IL-6, TNFα, and hepatocyte growth factor HGF] at baseline, 6, and 18 months (n = 138). Change in biomarkers over time and by weight loss thresholds were examined.

RESULTS

Mean weight loss at 6 months was 13.3 ± 5.0 kg; from 6 to 18 months, mean regain was 4.0 ± 5.2 kg. Favorable biomarker modulations were observed at 6 months for leptin, adiponectin, insulin, PAI-1, IL-6, and HGF (P < 0.006 to P < 0.0001). These changes remained significant overall at 18 months despite attenuation in some. Women who lost <10% of baseline weight showed significantly smaller modulation effects for leptin (P < 0.0001), adiponectin:leptin (A/L) ratio (P < 0.0001), PAI-1 (P < 0.001), and insulin (P = 0.003) compared with women who lost >10%. Women who lost >10% observed a significant increase in adiponectin (P < 0.0001), and these women continued to show improved adiponectin from 6 to 18 months despite weight regain. Physical activity contributed additional effects on biomarker change for leptin, A/L ratio, and PAI-1.

CONCLUSIONS

These findings are consistent with a clinical target of 10% weight.

IMPACT

Sustained increases in adiponectin likely confer benefits for breast cancer prognosis even with weight regain.

Abstract PD3-06: Biomarker modulation by bazedoxifene and conjugated estrogen (Duavee®) in women at high risk for development of breast cancer

Agents which both reduce risk for development of breast cancer and relieve vasomotor symptoms are likely to have good uptake and adherence. We conducted a pilot study with 6 months of the tissue selective estrogen complex bazedoxifene (20 mg) and conjugated estrogen (0.45 mg) (Duavee®) to assess feasibility and effects on biomarkers. Risk biomarkers for postmenopausal breast cancer included fully automated mammographic volumetric density (Volpara®), benign breast tissue Ki-67, and serum levels of progesterone, IGF-1 and IGFBP3, bioavailable estradiol and testosterone. Exploratory biomarkers included selected estrogen and progesterone responsive gene expression in benign breast tissue. 28 peri- and post-menopausal women at increased risk for breast cancer were enrolled; 13 in Cohort A with baseline Ki-67 &lt; 1% and 15 in Cohort B with baseline Ki-67 of 1-4%. All completed the study with &gt; 85% drug adherence. An improvement in median hot flash score from 15 at baseline to 0 at 6 months, and menopause specific quality of life total, vasomotor and sexual domain scores were also observed (p&lt; 0.001). Significant changes in risk biomarkers, uncorrected for multiple comparisons, were a decrease in mammographic fibroglandular volume (p=0.043); decreases in serum progesterone, bioavailable testosterone, and IGF-1 (p&lt;0.01); and for women from Cohort B, a reduction in Ki-67 (p=0.017) despite an increase in serum bioavailable estradiol. Unsupervised cluster analysis of RT-qPCR results indicated two clusters with differences in change in early estrogen response genes including ERS1, TFF1, GREB1a, PGR and AREG. The 10 women in one cluster tended to have increased expression of two or more of early estrogen response genes, but not increased expression of CCND1 (cyclin D1) or genes downstream of activated progesterone receptor such as STAT5a, PdK4, and STK. A trend towards decrease in several genes with predominant stromal expression implicated in breast cancer development including FASN, LEP, CXCL12, SDF1a and B, and CYP19A1 was observed. The 17 women in cluster 2 by contrast exhibited predominately decreased expression of early estrogen response genes. Given the favorable effects on vasomotor symptoms and risk biomarkers, a placebo-controlled Phase IIB trial is warranted.

This study was supported in part by grants from the Breast Cancer Research Foundation (BCRF-16-049, BCRF-17-049, BCRF-18-049); and an NIH Clinical and Translational Science Award grant (UL1 TR000001, formerly UL1RR033179) awarded to the University of Kansas Medical Center, and an internal clinical pilot grant program of the KUMC Research Institute.

Citation Format: Carol J Fabian, Lauren Nye, Teresa A Phillips, Onalisa Winblad, Carola M Zalles, Christy R Hagan, Merit L Goodman, Byron J Gajewski, Devin C Koestler, Prabhakar Chalise, Bruce F Kimler. Biomarker modulation by bazedoxifene and conjugated estrogen (Duavee®) in women at high risk for development of breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD3-06.

Abstract P1-14-01: Feasibility study of moderate dose omega 3 fatty acid supplementation in premenopausal women at high risk for breast cancer considering future pregnancy

Background: 11% of women developing breast cancer are pre-menopausal women of childbearing potential under the age of 45. Pregnancy and breast feeding provide long term protection for breast cancer when they occur at an early age. The reasons for protection are poorly understood but likely involve both changes in the immune microenvironment and ductal and lobular epithelial differentiation. This pilot study is addressing a potential prevention strategy in a population otherwise excluded from breast cancer prevention trials and not eligible for standard of care chemoprevention.

Methods: Eligible individuals included pre-menopausal women ages 21-40 that were considering future pregnancy and are at high risk for breast cancer based on family history, prior precancerous biopsy, or 5-year Gail model risk estimate of ≥ 1.7% or 10-year Tyrer-Cuzick risk of 2x population risk as listed in the model. Participants were enrolled and baseline tissue collection included random periareolar fine-needle aspiration (RPFNA) of breast, as well as collection of blood, urine and stool. Women were asked to take two capsules of Omega-3-Acid Ethyl Esters daily (a total of 750 mg DHA and 930 mg EPA) for six months. Post-intervention visit included repeat tissue collection. If women were pregnant at time of post-intervention visit, RPFNA was not done. Baseline and post-intervention DHA Food Frequency Questionnaire (FFQ) and the BCPT Questionnaire were administered. The intervention length was shortened for some participants due to the study ending.

Objectives: 1) To determine feasibility of a breast cancer prevention intervention study in this cohort of pre-menopausal women at high risk for breast cancer and considering future pregnancy, 2) measure compliance with the omega-3 fatty acid supplement in this population, 3) identify novel biomarkers modulated by moderate dose omega-3 fatty acids in this population.

Results: Ten women were successfully enrolled at an average rate of 1.5/month from a single center high risk breast clinic. Of the ten women enrolled, median age was 33 years (range 22-37, ±5.04 stdev), 70% married, 80% Non-Hispanic White, 10% of Ashkenazi Jewish descent and 40% reported having a genetic mutation. Feasibility was achieved with 80% (8 out of 10) of participants returning for post-intervention visit. Reasons given for discontinuation of study were (n=1) side effect from supplement (bloating) and (n=1) scheduling conflicts. Of the eight women who completed the off study visit, two chose not to undergo the off study RPFNA due to discomfort with initial procedure or time commitment. Self-reported pill count showed an average of three missed pills/month. Grade 1 related adverse events reported included odor, nausea and flatulence. Post-intervention, more participants reported diarrhea, vaginal discharge and bleeding, weight gain, general aches and dizziness on BCPT items compared to baseline. Change in benign breast tissue biomarkers will be reported including breast tissue cytomorphology, Ki67, fatty acid analysis and selected gene expression.

Conclusion: It is feasible to recruit premenopausal women considering future pregnancy to a breast cancer prevention trial with a minimally invasive sampling procedure. Results from this trial will inform a larger randomized prevention trial.

Citation Format: Lauren E Nye, Jennifer R Klemp, Kandy R Powers, Anne P O'Dea, Kendra A Cruz, Amy L Kreutzjans, Trina Metheny, Teresa A Phillips, Susan E Carlson, Bruce F Kimler, Carol J Fabian. Feasibility study of moderate dose omega 3 fatty acid supplementation in premenopausal women at high risk for breast cancer considering future pregnancy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-14-01.

Differential sensitivity of inbred mouse strains to ovarian damage in response to low-dose total body irradiation†

Radiation induces ovarian damage and accelerates reproductive aging. Inbred mouse strains exhibit differential sensitivity to lethality induced by total body irradiation (TBI), with the BALB/cAnNCrl (BALB/c) strain being more sensitive than the 129S2/SvPasCrl (129) strain. However, whether TBI-induced ovarian damage follows a similar pattern of strain sensitivity is unknown. To examine this possibility, female BALB/c and 129 mice were exposed to a single dose of 1 Gy (cesium-137 γ) TBI at 5 weeks of age, and ovarian tissue was harvested for histological and gene expression analyses 2 weeks post exposure. Sham-treated mice served as controls. 1 Gy radiation nearly eradicated the primordial follicles and dramatically decreased the primary follicles in both strains. In contrast, larger growing follicles were less affected in the 129 relative to BALB/c strain. Although this TBI paradigm did not induce detectable ovarian fibrosis in either of the strains, we did observe strain-dependent changes in osteopontin (Spp1) expression, a gene involved in wound healing, inflammation, and fibrosis. Ovaries from BALB/c mice exhibited higher baseline Spp1 expression that underwent a significant decrease in response to radiation relative to ovaries from the 129 strain. A correspondingly greater change in the ovarian matrix, as evidenced by reduced ovarian hyaluronan content, was also observed following TBI in BALB/c mice relative to 129 mice. These early changes in the ovary may predispose BALB/c mice to more pronounced late effects of TBI. Taken together, our results demonstrate that aspects of ovarian damage mirror other organ systems with respect to overall strain-dependent radiation sensitivity.

Effect of Bazedoxifene and Conjugated Estrogen (Duavee) on Breast Cancer Risk Biomarkers in High-Risk Women: A Pilot Study

Interventions that relieve vasomotor symptoms while reducing risk for breast cancer would likely improve uptake of chemoprevention for perimenopausal and postmenopausal women. We conducted a pilot study with 6 months of the tissue selective estrogen complex bazedoxifene (20 mg) and conjugated estrogen (0.45 mg; Duavee) to assess feasibility and effects on risk biomarkers for postmenopausal breast cancer. Risk biomarkers included fully automated mammographic volumetric density (Volpara), benign breast tissue Ki-67 (MIB-1 immunochemistry), and serum levels of progesterone, IGF-1, and IGFBP3, bioavailable estradiol and testosterone. Twenty-eight perimenopausal and postmenopausal women at increased risk for breast cancer were enrolled: 13 in cohort A with baseline Ki-67 < 1% and 15 in cohort B with baseline Ki-67 of 1% to 4%. All completed the study with > 85% drug adherence. Significant changes in biomarkers, uncorrected for multiple comparisons, were a decrease in mammographic fibroglandular volume (P = 0.043); decreases in serum progesterone, bioavailable testosterone, and IGF-1 (P < 0.01), an increase in serum bioavailable estradiol (P < 0.001), and for women from cohort B a reduction in Ki-67 (P = 0.017). An improvement in median hot flash score from 15 at baseline to 0 at 6 months, and menopause-specific quality-of-life total, vasomotor, and sexual domain scores were also observed (P < 0.001). Given the favorable effects on risk biomarkers and patient reported outcomes, a placebo-controlled phase IIB trial is warranted.

Abstract 2425: Moderate to vigorous physical activity reduces visceral adipose tissue in obese breast cancer survivors undergoing a weight loss intervention

Background: Body composition, adipose distribution, and fitness are likely superior to BMI alone in predicting outcomes in obese breast cancer survivors. Visceral adipose tissue (VAT) is thought to be disproportionately responsible for the metabolic and inflammatory changes linking obesity and breast cancer recurrence.

Purpose: Feasibility of achievement of high volume moderate-to-vigorous physical activity (MVPA) and its effect on body composition including VAT and other risk biomarkers in older sedentary, obese breast cancer survivors participating in a behavioral weight loss intervention.

Methods: Modest caloric restriction (350-500 kcal per day) was combined with a study provided YMCA membership and twice weekly personal trainer sessions. MVPA (40-80% of heart rate reserve in older women) was assessed by Garmin Vivoactive smart watches linked to GarminConnect. Total activity was escalated from 100 minutes week 1 to a total of 300 minutes per week by week 9 with a goal of &gt; 200 min/wk as MVPA. Women were evaluated pre- and post-intervention for peak oxygen consumption (VO2peak), body composition by dual energy x-ray absorptiometry (GE Lunar iDXA), and serum levels of adipokines, cytokines, and hormones.

Results: 18 breast cancer survivors were enrolled and completed the 3 months of the behavioral weight loss intervention which included the YMCA membership and twice weekly personal trainer. Median age was 60, 11 had received prior chemotherapy, and 13 were currently taking aromatase inhibitors. Median (and range) baseline anthropomorphic values were BMI 37 (31-43) kg/m2, total mass 95 (76-125) kg, total fat 46 (34-66) kg, and VAT 1.7 (1.0-3.0) kg. All but one had a baseline VAT &gt; 1.17 kg, consistent with elevated risk of metabolic syndrome. 17/18 achieved at least 150 min/wk of MVPA, with a median of 176 (range 55-291) min/wk for weeks 9-12. Fitness measured as VO2peak increased from 18.9 (13.7-25.3) to 21.1 (17.1-31.4) ml/kg/min (p=0.0003; Wilcoxon signed rank test). At 3 months, significant reductions were observed for total mass (median 7%), fat mass (median 13%), and VAT (median 20%, range 1-41%)(p&lt;0.0003); as well as serum leptin, insulin, and leptin: adiponectin ratio (p&lt;0.01). A strong correlation was observed between week 9-12 MVPA and leptin: adiponectin ratio (p=0.001) with more modest correlations between week 9-12 MVPA and VAT loss (p=0.043), and leptin: adiponectin ratio and VAT loss (p=0.013).

Conclusion: High volume moderate-to-vigorous physical activity can be achieved by older, sedentary, obese breast cancer survivors; and this translates to favorable modulation of body composition including VAT measures and serum risk biomarkers.

Citation Format: Carol J. Fabian, Jennifer R. Klemp, Jeffrey M. Burns, Eric D. Vidoni, Lauren Nye, Christie A. Befort, Jill M. Hamilton-Reeves, Debra K. Sullivan, Teresa A. Phillips, Stephen D. Hursting, Bruce F. Kimler. Moderate to vigorous physical activity reduces visceral adipose tissue in obese breast cancer survivors undergoing a weight loss intervention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2425.

Results of randomized phase II trial of neoadjuvant carboplatin plus docetaxel or carboplatin plus paclitaxel followed by AC in stage I-III triple-negative breast cancer (NCT02413320)

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Background: Addition of neoadjuvant carboplatin (Cb) to paclitaxel (T) followed by doxorubicin + cyclophosphamide (AC) improves pathologic complete response (pCR) rate compared to T/AC in TNBC. An anthracycline-free regimen of Cb plus docetaxel (D) also yields high pCR rates in TNBC, and patients achieving pCR with this regimen demonstrate excellent 3-year outcomes without adjuvant anthracycline. This study was designed to compare the efficacy of neoadjuvant regimens CbT→AC and CbD in TNBC. Methods: In this multicenter study, eligible patients with stage I–III TNBC were randomized (1:1) to either paclitaxel 80 mg/m2 every week X 12 + carboplatin (AUC 6) every 3 weeks X 4, followed by doxorubicin 60 mg/m2 + cyclophosphamide 600 mg/m2 every 2 weeks X 4 (CbT→AC, Arm A), or to carboplatin (AUC 6) + docetaxel (75 mg/m2) every 21 days X 6 cycles (CbD, Arm B). The primary endpoint was pCR (no evidence of invasive tumor in the breast and axilla). The two regimens were compared for differences in pCR, residual cancer burden (RCB), treatment delivery, and toxicity. Results: Between 2015 and 2018, 100 patients were randomized; 48 to Arm A and 52 to Arm B. Median age was 52 years, median tumor size was 2.7 cm, 30% were lymph node-positive and 17% carried a BRCA1/2 mutation. Baseline demographic and tumor characteristics were balanced between two arms. pCR was 55% (95%CI: 41%-59%) in Arm A and 52% (95%CI: 39%-65%) in Arm B, p =0.84. RCB 0+1 rate was 67% in both arms. Grade 3/4 adverse events were more common in Arm A compared to Arm B (73% vs 21%, p < 0.0001), with most notable differences in rates of G3/4 neutropenia (Arm A = 60%, Arm B = 8%, p = 0.0001), febrile neutropenia (Arm A = 18%, Arm B = 0%, p = 0.0001), and G3/4 anemia (Arm A = 46%, Arm B = 4%, p = 0.0001). 81% of Arm A patients completed all 4 doses of AC and 4 doses of Cb, and 71% completed > 9 doses of T. 90% of Arm B patients completed all 6 doses of CbD (p = 0.034). Conclusions: The non-anthracycline platinum regimen of CbD yields pCR and RCB 0+1 rates similar to 4-drug regimen of CbTàAC, but with a more favorable toxicity profile and higher treatment completion rate. The CbD regimen should be further explored as a way to de-escalate therapy in TNBC. Clinical trial information: NCT02413320.

Fixed dose, dose-dense capecitabine in metastatic breast cancer

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Background: Capecitabine (C) is the only oral chemotherapy agent for metastatic breast cancer (MBC), and compared to IV agents, can be continued indefinitely if toxicities can be managed. The optimal dose and schedule of C are not known. FDA approved dose of 2500 mg/m2 daily is associated with median PFS (progression free survival) of 4-5 months and dose reduction and discontinuation rates from toxicity of 35% and 16% respectively. According to Norton-Simon mathematical model of tumor growth in which dosing schedules are determined based on efficacy, a 7 day on and 7 days off (7-7) schedule of C was predicted as optimal. We report efficacy and toxicity of fixed dose C (1500 mg BID) on a 7-7 schedule in MBC. Methods: Retrospective chart review of patients with MBC treated at our institution between June 2013 and December 2018 and received fixed dose C (1500 mg BID) on a 7-7 dosing schedule were included. Results: 39 patients with MBC were identified; 14 (35%) had de novo MBC and 25 (62.5%) had recurrent disease. 31 (77.5%) had ER+ disease, 6 (15%) were HER2+, and8 (20.5%) had triple negative breast cancer (TNBC). 10 (25%) had received no prior chemotherapy, 15 (37.5%) had received 1 line of chemotherapy, and 14 (35%) had received ≥2 lines of chemotherapy. Median PFS was 13 months. PFS was 17 months in ER+ patients and 8 months in patients with TNBC. Palmar plantar erythrodysesthesia (PPE) was the most frequent toxicity with 11 (27.5%) having mild PPE, 2 (5%) with moderate PPE, and 5 (12.5%) with severe PPE. Mild diarrhea was experienced by 14 (35%) and one patient experienced severe diarrhea. One patient experienced grade 3 neutropenia. No patients discontinued C due to toxicity. 11 (27.5%) required a dose reduction. Conclusions: Fixed dose capecitabine (1500 mg oral BID) on a 7 day on and 7 day off schedule is associated with encouraging PFS and has limited toxicity and a low rate of dose reduction and therapy discontinuation. Randomized trial comparing this dose and schedule of capecitabine to standard dose and schedule of capecitabine is ongoing.

Circulating adipose stromal cells as a response biomarker in phase II energy balance trials of obese breast cancer survivors and high-risk women

PURPOSE

Circulating adipose stromal cells (CASC) are thought to be increased in obesity and facilitate angiogenesis, and tumor metastases.

METHODS

CASC were identified from buffy coat peripheral blood mononuclear cells (PBMCs) by flow cytometry as CD34^brightCD31^- CD45^- and CASC frequency was compared to adiposity measures in 33 women at increased risk for breast cancer. Feasibility of CASC as a response biomarker for a diet and exercise intervention in ten breast cancer survivors was then explored.

RESULTS

For 33 high-risk women, median CASC frequency was 9.7 per million PBMCs and trended positively with body mass index, fat mass index (FMI), and percent android fat. Correlation was significant when BMI was dichotomized at > versus < 35 kg/m² (p = 0.02). For ten breast cancer survivors with a median BMI of 37 kg/m², median CASC frequency was 16.4 per million PBMCs. In univariate analyses, change in BMI, total fat and visceral fat were significantly correlated with change in CASC frequency. On multivariate analysis, change in visceral adipose had the strongest association with change in CASC frequency (p < 0.00078).

CONCLUSIONS

The association between the reduction in visceral adipose tissue and the decrease in frequency of circulating adipose stromal cells suggests that the latter might be a useful biomarker in clinical trials of obese breast cancer survivors undergoing a weight loss intervention.

Abstract P2-08-16: Impact of germline BRCA mutation status on survival in women with metastatic triple negative breast cancer

Background: 15-20% of patients with triple negative breast cancer (TNBC) harbor deleterious germline (g) BRCA1/2 mutations. Recent data suggests that in metastatic TNBC (mTNBC) gBRCA1/2 mutations are associated with response to PARP inhibitors (PARPi) and platinum chemotherapy. However, diagnosis of mTNBC is associated with short overall survival (OS) with no available biomarkers that can identify mTNBC patients with better prognosis.

Aim: Utilizing data from a prospective registry, the objective of this study was to investigate whether presence of gBRCA1/2 mutation impacts overall survival for patients with mTNBC treated prior to clinical availability of PARPi.

Methods: 643 patients with stage I-IV TNBC were enrolled in an IRB approved multisite prospective registry between 2011 to 2018. Clinical, demographic, and treatment information was collected and patients were followed for recurrence and survival. 100/643 patients had metastatic breast cancer (de novo stage IV disease or metastatic recurrence). OS (from the time of diagnosis of metastatic disease to death from any cause) was estimated according to the Kaplan-Meier method and compared among groups by log-rank test.

Results: For the 100 mTNBC patients, the median age at diagnosis of metastatic disease was 55 years, 17% were African American, 20% had novo stage IV and 80% had relapsed disease. 84% had visceral disease, 12% had bone-only disease, and 4% had lymph node only disease. Metastatic treatment: 87% received chemotherapy, 7% received radiation only without chemotherapy and 6% did not receive any treatment. No patients received treatment with PARP inhibitor. Among de-novo stage IV patients, 35% (7/20) had breast surgery for removal of primary tumor during their course of metastatic treatment. For all 100 patients, 12% (n=12) had gBRCA mutation; 72% (n=72) had no gBRCA mutation; and 16% (n=16) had unknown BRCA mutation status. When compared with non-carriers, gBRCA carriers were younger at time of metastatic diagnosis (median age 49 vs. 57 years, p=0.02). There was no difference in prevalence of visceral disease, de-novo stage IV disease or median lines of metastatic chemotherapy among gBRCA carriers and non-carriers. At a median follow up of 31 months, median OS for all patients is 21 months (95% CI 13-23 months). Median OS is 18 months (95% CI 15-27 months) for non-carriers and has not yet been reached for gBRCA mutation carriers (p=0.023). 3-year estimated OS is 63% in gBRCA carriers compared to 28% in non-carriers (p=0.02). On multivariate Cox regression analysis, gBRCA carrier status was associated with reduced risk of death (HR=0.33; 95%CI [0.23-0.91], p=0.033)

Conclusions: gBRCA mutation associated mTNBC patients have a clinically significant improved OS at 3 years compared to mTNBC patients without BRCA mutations (3-year OS of 63% vs 28%). Further research is needed to understand tumor and host biological reasons for this observation. Outcomes of gBRCA mutation associated mTNBC are likely to be further improved with availability of PARPi. Given that patients with gBRCA mutation are at risk for second breast/ovarian cancers, these findings also underscore need for further research regarding the role of prophylactic surgeries mTNBC with gBRCA mutation.

Citation Format: Larson K, Wang YY, Finke K, O'Dea AP, Khan Q, Nye L, Heldstab J, Godwin AK, Kimler BF, Sharma P. Impact of germline BRCA mutation status on survival in women with metastatic triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-16.

Pathological Response and Survival in Triple-Negative Breast Cancer Following Neoadjuvant Carboplatin plus Docetaxel

PURPOSE

Prognostic value of pathologic complete response (pCR) and extent of pathologic response attained with anthracycline-free platinum plus taxane neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) is unknown. We report recurrence-free survival (RFS) and overall survival (OS) according to degree of pathologic response in patients treated with carboplatin plus docetaxel NAC.

PATIENTS AND METHODS

One-hundred and ninety patients with stage I-III TNBC were treated with neoadjuvant carboplatin (AUC6) plus docetaxel (75 mg/m2) every 21 days × 6 cycles. pCR (no evidence of invasive tumor in breast and axilla) and Residual cancer burden (RCB) were evaluated. Patients were followed for recurrence and survival. Extent of pathologic response was associated with RFS and OS using the Kaplan-Meier method.

RESULTS

Median age was 51 years, and 52% were node-positive. pCR and RCB I rates were 55% and 13%, respectively. Five percent of pCR patients, 0% of RCB I patients, and 58% of RCB II/III patients received adjuvant anthracyclines. Three-year RFS and OS were 79% and 87%, respectively. Three-year RFS was 90% in patients with pCR and 66% in those without pCR [HR = 0.30; 95% confidence interval (CI), 0.14-0.62; P = 0.0001]. Three-year OS was 94% in patients with pCR and 79% in those without pCR (HR = 0.25; 95% CI, 0.10-0.63; P = 0.001). Patients with RCB I demonstrated 3-year RFS (93%) and OS (100%) similar to those with pCR. On multivariable analysis, higher tumor stage, node positivity, and RCB II/III were associated with worse RFS.

CONCLUSIONS

Neoadjuvant carboplatin plus docetaxel yields encouraging efficacy in TNBC. Patients achieving pCR or RCB I with this regimen demonstrate excellent 3-year RFS and OS without adjuvant anthracycline.

Use of a Small Animal Radiation Research Platform (SARRP) facilitates analysis of systemic versus targeted radiation effects in the mouse ovary

BACKGROUND

Radiation exposure is known to cause accelerated aging and damage to the ovary, but the contribution of indirect versus direct effects is not well understood. We used the Small Animal Radiation Research Platform (SARRP) (Xstrahl) to deliver radiation to precise fields equivalent to clinical practice, allowing us to investigate systemic versus targeted damage in a structure as small as the mouse ovary. The X-ray dose was kept constant at 1 Gy, but the field varied. Mice either received total body irradiation (TBI), radiation targeted to both ovaries (T2), or radiation targeted to one ovary (left) while the contralateral ovary (right) was spared (T1). Sham mice, handled similarly to the other cohorts but not exposed to radiation, served as controls. Two weeks post-exposure, ovaries were harvested and analyzed histologically to identify and count follicles within each ovary.

RESULTS

Radiation significantly reduced primordial follicles in the TBI and T2 cohorts compared to the Sham cohort. There were no significant differences between these two irradiated groups. These findings suggest that at 1 Gy, the extent of damage to the ovary caused by radiation is similar despite the different delivery methods. When investigating the T1 cohort, targeted ovaries showed a significant decrease in primordial and growing follicles compared to non-targeted contralateral ovaries.

CONCLUSIONS

These findings demonstrate that the SARRP is an effective strategy for delivering precise ionizing radiation to small organs such as mouse ovaries. Such tools will facilitate identifying the relative risks to ovarian function associated with different radiation fields as well as screening the efficacy of emerging fertoprotective agents.

Abstract 3261: Pilot study of the combination of bazedoxifene and conjugated estrogen to modulate risk biomarkers in women with hot flashes at increased risk for breast cancer

Uptake of anti-hormonal agents for primary prevention of breast cancer is poor due to concern about side effects, especially induction of menopausal symptoms. A combination of 20 mg bazedoxifene plus 0.045 mg conjugated estrogen is FDA approved (as Duavee®) for treatment of hot flashes and prevention of osteoporosis in postmenopausal women with a uterus. We undertook a pilot study to assess the feasibility of using this formulation as a breast cancer prevention agent in women at increased risk for development of breast cancer. Feasibility was to be assessed by accrual, retention, and documentation of a lack of enhanced proliferation in benign breast tissue acquired by random periareolar fine needle aspiration (RPFNA). Eligibility criteria included risk &gt;2X that of average risk woman for age group, postmenopausal having hot flashes or night sweats and not on systemic hormone replacement, and at least 500 cells on a baseline RPFNA. Women were ineligible if they had LCIS or DCIS, a BRCA1/2 germline mutation, had had a hysterectomy, or had &gt;4% Ki-67 positive cells by immunocytochemistry. Fasting blood draw, digital mammography with Volpara software, and DXA scan for body composition was performed at baseline along with QOL questionnaires. Women then received Duavee® daily for 6 months, followed by repeat of baseline tests. We accrued the first 20 subjects in 14 months. Many of the women followed in our cohort and interested in the trial were not eligible due to prior hysterectomy, prior LCIS or a high penetrance gene mutation. Thus accrual was slower than anticipated. All women have reported improvement in hot flash frequency and intensity. None have discontinued prematurely or had a study related serious adverse event. Fourteen women have completed the 6-month intervention and are evaluable for modulation of biomarkers. There have been no protocol-defined increases in proliferation (to &gt;2% Ki-67 for baseline Ki-67 &lt;1% or doubling if baseline Ki-67 ≥1%), with 10 of 14 paired specimens exhibiting a decrease. Ten women had Volpara fibroglandular assessments pre- and post-study with a median relative decrease of 11% (8 decreased and 2 increased). For the first ten subjects where serum hormones and growth factors were assessed in paired assays, favorable modulation was observed for estradiol, testosterone, SHBG, bioavailable testosterone, IGF-1, and the molar ratio of IGF1:IGFBP3. A primary prevention trial in symptomatic women appears feasible given the favorable initial results. The current pilot will continue to accrue so as to inform the design of a randomized, placebo-controlled Phase II trial of Duavee® in women at risk for breast cancer. Financial support provided by grants from the Breast Cancer Research Foundation (BCRF-16-049, BCRF-17-049). Duavee® provided by Pfizer, Inc. which was not involved in design, conduct, or analysis of the study.

Citation Format: Carol J. Fabian, Kandy R. Powers, Jennifer L. Nydegger, Amy L. Kreutzjans, Trina Metheny, Teresa A. Phillips, Lauren Nye, Carola M. Zalles, Bruce F. Kimler. Pilot study of the combination of bazedoxifene and conjugated estrogen to modulate risk biomarkers in women with hot flashes at increased risk for breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3261.

Clinicopathological correlation of PD-L1 expression in primary and metastatic breast cancer and infiltrating immune cells

Few studies have evaluated the expression of the programmed cell death-1 and its ligand-1 (PD-L1) in breast cancer. In this study, we correlated differential expression of PD-L1 in breast cancer (BC) and its microenvironment from a cohort of patients with BC, paired locally metastatic disease to regional lymph nodes (LNs) and nonpaired distantly metastatic disease (mets). PD-L1 expression was correlated with several pathologic and clinical parameters in tumor and tumor immune cells (ICs; CD3, CD4, CD8, CD20, and CD68) using the Ventana antibody (SP263) in 41 BCs, 46 paired mets in LNs, and 46 distant mets. There was 100% agreement for PD-L1 expression on tumor and ICs between BC and matched LN. PD-L1 is differentially expressed in primary BC and regional nodal disease. Expression correlated with higher grade, hormone receptor negativity, and highly proliferative tumors (P < .001). In LNs, the high positivity rate was driven by triple-negative status (70% versus 5%; P < .0001). In contrast, there was significantly near-total absence of PD-L1 expression in distant mets compared with BC and LNs (2%-4% in mets versus 17%-20% in BC and LN, P = .009). IC density varied in BC and metastatic tumors with predominance of CD3 and CD68 and near total absence of CD20 cells. PD-L1 expression was mainly associated with CD68 cells. There were consistent higher numbers of CD3 (CD8 > CD4) than CD20 cells in primary and metastatic tumors. Correlation of PD-L1 expression in BC and its microenvironment may be useful for the development of new treatment strategies.

Radiation-induced ovarian follicle loss occurs without overt stromal changes

Radiation damage due to total body irradiation (TBI) or targeted abdominal radiation can deplete ovarian follicles and accelerate reproductive aging. We characterized a mouse model of low-dose TBI to investigate how radiation affects the follicular and stromal compartments of the ovary. A single TBI dose of either 0.1 Gy or 1 Gy (Cesium-137 γ) was delivered to reproductively adult CD1 female mice, and sham-treated mice served as controls. Mice were euthanized either 2 weeks or 5 weeks post exposure, and ovarian tissue was harvested. To assess the ovarian reserve, we classified and counted the number of morphologically normal follicles in ovarian histologic sections for all experimental cohorts using an objective method based on immunohistochemistry for an oocyte-specific protein (MSY2). 0.1 Gy did not affect that total number of ovarian follicles, whereas 1 Gy resulted in a dramatic loss. At two weeks, there was a significant reduction in all preantral follicles, but early antral and antral follicles were still present. By five weeks, there was complete depletion of all follicle classes. We examined stromal quality using histologic stains to visualize ovarian architecture and fibrosis and by immunohistochemistry and quantitative microscopy to assess cell proliferation, cell death and vasculature. There were no differences in the ovarian stroma across cohorts with respect to these markers, indicating that this compartment is more radio-resistant relative to the germ cells. These findings have implications for reproductive health and the field of fertility preservation because the radiation doses we examined mimic scatter doses experienced in typical therapeutic regimens.

Gender Bias in Human Systemic Lupus Erythematosus: A Problem of Steroid Receptor Action?

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease resulting from abnormal interactions between T and B cells. The acquisition of SLE is linked to genetic susceptibility, and diverse environmental agents can trigger disease onset in genetically susceptible individuals. However, the strongest risk factor for developing SLE is being female (9:1 female to male ratio). The female sex steroid, estradiol, working through its receptors, contributes to the gender bias in SLE although the mechanisms remain enigmatic. In a small clinical trial, monthly administration of the estrogen receptor (ERα) antagonist, ICI182,780 (fulvestrant), significantly reduced disease indicators in SLE patients. In order to identify changes that could account for improved disease status, the present study utilized fulvestrant (Faslodex) to block ERα action in cultured SLE T cells that were purified from blood samples collected from SLE patients (n = 18, median age 42 years) and healthy control females (n = 25, median age 46 years). The effects of ERα antagonism on estradiol-dependent gene expression and canonical signaling pathways were analyzed. Pathways that were significantly altered by addition of Faslodex included T helper (Th) cell differentiation, steroid receptor signaling [glucocorticoid receptor (GR), ESR1 (ERα)], ubiquitination, and sumoylation pathways. ERα protein expression was significantly lower (p < 0.018) in freshly isolated, resting SLE T cells suggesting ERα turnover is inherently faster in SLE T cells. In contrast, ERα/ERβ mRNA and ERβ protein levels were not significantly different between SLE and normal control T cell samples. Plasma estradiol levels did not differ (p > 0.05) between SLE patients and controls. A previously undetected interaction between GR and ERα signaling pathways suggests posttranslational modification of steroid receptors in SLE T cells may alter ERα/GR actions and contribute to the strong gender bias of this autoimmune disorder.

The Conundrum of Omega-3 Fatty Acids in Cancer Prevention Studies: Which One? How Much? What Biomarkers?

Marine omega-3 fatty acids promote resolution of inflammation and have potential to reduce risk of obesity-related breast cancer. For prevention trials in obese women, inflammatory cytokines, aromatase, and measures of breast immune cell infiltration are logical, as are biomarkers of growth factor, adipokine, and estrogen signaling. Where best to look for marker change: in the circulation (easiest), in benign breast tissue (most relevant), or in visceral adipose (inflammation often most marked)? A null biomarker modulation trial may reflect limitations in design, source and dose of fatty acids, or biomarkers and should not lead to premature abandonment of marine omega-3 fatty acids for cancer prevention. Cancer Prev Res; 11(4); 187-90. ©2018 AACRSee related article by Gucalp et al., p. 203.

Abstract P4-10-06: Influence of older age on triple negative breast cancer (TNBC) clinical-pathological characteristics and outcomes

Background: The impact of age at diagnosis on clinical presentation and treatment delivery for triple negative breast cancer (TNBC) is unclear. Utilizing data from a prospective registry, the aim of this study was to further elucidate the age-dependent correlation between TNBC clinical-pathological features, and the implications of age-bias on treatment delivery and prognosis.

Methods: 480 subjects with stage I-III TNBC were enrolled in an IRB approved multisite prospective registry between 2011 and 2016. Clinical, demographic, treatment information was collected and patients were followed for recurrence and survival. Patients were categorized as older (&gt;60 years) or younger groups (&lt;60 years). Recurrence free survival (RFS) and overall survival (OS) were estimated according to the Kaplan-Meier method and compared among groups by log-rank test.

Results: 145 (30%) of 480 TNBC patients were older (&gt; 60 years) at time of diagnosis. Compared to younger patients, older patients were more likely to present with screen detected vs symptomatic cancer (47% vs 25% p=&lt;0.001), more likely to have node negative cancer (71% vs 61% p=0.030), stage I disease (42% vs 28% p=0.003), and low level (1-10%) ER or PR positivity (19% vs 12% p=0.046). Compared to the younger patients, older patients were less likely to have a BRCA1/2 mutation (6% vs 23% p=0.0002) but more likely to have a prior history of hormone positive breast cancer (7% vs 1% p=0.0002). Compared to younger counterparts, older patients were less likely to receive neo/adjuvant chemotherapy (93% vs 99% p=0.0006), and less likely to receive &gt; 4 cycles of neo/adjuvant chemotherapy (61% vs 78%, p=0.0003). Three year RFS for the entire cohort was 80% and was identical for older and younger patients at 80%. Three year OS for the entire cohort was 87% and was similar for older and younger patients. On multivariable analysis only tumor size and nodal status significantly impacted RFS.

Conclusions: A significant fraction (30%) of TNBC patients are older (&gt; 60 years) at time of diagnosis. Despite presenting a with more favorable disease stage, older TNBC patients did not demonstrate better outcomes compared to the higher risk younger patients. The underlying reasons for this observation may be tumor biology differences between older and younger TNBC patients or perhaps could be related to underutilization of appropriate systemic chemotherapy (39% of older patients received &lt; 4 cycles of chemotherapy). Further studies are warranted on this subject.

Citation Format: Mina A, Lehn C, Wang YY, Klemp JR, O'Dea AP, Elia M, Hoffmann M, Crane G, Sheehan M, Madhusudhana S, Jensen RA, Godwin AK, Khan QJ, Kimler BF, Sharma P. Influence of older age on triple negative breast cancer (TNBC) clinical-pathological characteristics and outcomes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-10-06.

Abstract P6-12-11: Feasibility and biomarker modulation due to high levels of moderate to vigorous physical activity as part of a weight loss intervention in older, sedentary, obese breast cancer survivors

We sought to demonstrate that older, sedentary, obese breast cancer survivors could achieve &gt; 200 minutes per week of moderate to vigorous physical activity (MVI PA) as part of a weight loss intervention; and to assess modulation of risk biomarkers. This level of PA in combination with moderate calorie restriction is associated with weight losses of &gt;10% in women without cancer, which in turn is associated with significant modulation of cancer risk biomarkers.

Eleven participants with BMI &gt; 30 kg/m2 enrolled in a 12-week program that consisted of moderate caloric restriction, weekly phone group behavioral sessions, and individualized exercise plans based on measured heart rate reserve. Women were provided an accelerometer with heart rate monitor linked to GarminConnect, membership to a YMCA, twice weekly supervised exercise sessions with a personal trainer, and weekly feedback regarding weight and physical activity progress. The goal was to increase MVI PA (≥45% heart rate reserve) gradually from &lt;60 to &gt;200 minutes per week.

The median age was 61, 5/11 women had received prior chemotherapy, and 7/11 were currently taking aromatase inhibitors. Median values of baseline anthropomorphic measures acquired by dual energy x-ray absorptiometry (GE Lunar iDXA) included BMI, 37.3 kg/m2; total mass, 97.5 kg; fat mass, 47.6 kg; visceral fat, 1.7 kg (range 1.4-3.0); and fat mass index, 17.6 kg/m2. The majority had a baseline VO2 peak in the poor range for their age. All 11 participants completed the intervention, with no reported serious adverse events. Median MVI PA achieved over weeks 5-12 was 161 minutes/week (range 48-320). VO2 peak was increased in 10/11 with a median relative change of 12% from baseline. All but one lost weight with an overall median of 8% total mass loss, which was associated with 13% total fat mass loss and 21% visceral fat mass loss. For those with MVI PA above the median, values were 11%, 17%, and 40%, respectively. Visceral fat mass loss was linearly correlated with minutes per week of MVI PA (p=0.032); these parameters in turn were associated with changes in a number of serum biomarkers, including adiponectin-leptin ratio, TNF-alpha, as well as circulating adipose stromal cells, a potential marker for metastasis. Insulin and hs-CRP were favorably modulated in almost all participants but change was not linearly correlated with activity or mass loss parameters; thus these may not be ideal biomarkers to document a dose response to level of MVI PA.

Conclusion: These results demonstrate that older, sedentary, obese breast cancer survivors can safely achieve a high level of MVI PA when provided a structured program that includes an exercise trainer. It is feasible to design a clinical trial for such breast cancer survivors to examine biomarker modulation as a function of level of physical activity.

Citation Format: Fabian CJ, Klemp JR, Burns JM, Vidoni ED, Nydegger JL, Kreutzjans AL, Phillips TL, Baker HA, Hendry B, John C, Amin AL, Khan QJ, Mitchell MP, O'Dea AP, Sharma P, Wagner JL, Hursting SD, Kimler BF. Feasibility and biomarker modulation due to high levels of moderate to vigorous physical activity as part of a weight loss intervention in older, sedentary, obese breast cancer survivors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-12-11.

Development and Characterization of an In Vitro Model for Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) is a major side effect of radiotherapy in cancer patients with no effective therapeutic options. RIF involves excess deposition and aberrant remodeling of the extracellular matrix (ECM) leading to stiffness in tissues and organ failure. Development of preclinical models of RIF is crucial to elucidate the molecular mechanisms regulating fibrosis and to develop therapeutic approaches. In addition to radiation, the main molecular perpetrators of fibrotic reactions are cytokines, including transforming growth factor-β (TGF-β). We hypothesized that human oral fibroblasts would develop an in vitro fibrotic reaction in response to radiation and TGF-β. We demonstrate here that fibroblasts exposed to radiation followed by TGF-β exhibit a fibrotic phenotype with increased collagen deposition, cell proliferation, migration and invasion. In this in vitro model of RIF (RIF_iv), the early biological processes involved in fibrosis are demonstrated, along with increased levels of several molecules including collagen 1α1, collagen XIα1, integrin-α2 and cyclin D1 mRNA in irradiated cells. A clinically relevant antifibrotic agent, pentoxifylline, and a curcumin analogue both mitigated collagen deposition in irradiated fibroblast cultures. In summary, we have established an in vitro model for RIF that facilitates the elucidation of molecular mechanisms in radiation-induced fibrosis and the development of effective therapeutic approaches.

Ovarian tissue cryopreservation in young females through the Oncofertility Consortium's National Physicians Cooperative

AIM

To characterize the clinical indications of females (<15 years old) undergoing ovarian tissue cryopreservation (OTC) through the Oncofertility Consortium's National Physicians Cooperative (OC-NPC).

PATIENTS & METHODS

The clinical indications of 114 females who underwent OTC were classified, and their incidence was compared with childhood cancer databases.

RESULTS

Leukemias/myeloproliferative diseases/myelodysplastic diseases and hemoglobinopathies were the most prevalent oncologic and nononcologic indications for OTC, respectively. The frequencies of malignant bone tumors and soft tissue and other extraosseous sarcomas were higher in the OC-NPC cohort relative to the general population, while CNS/intracranial/intraspinal neoplasms, retinoblastoma and hepatic tumors were lower.

CONCLUSION

Those opting for OTC through the OC-NPC are at highest fertility risk, indicating that the appropriate patient populations are being identified. [Formula: see text].

Keep your eye on the target<sup/>

This paper provides a historical perspective on the origin and development of Target Theory and how its central concepts have influenced the thought processes of radiation biologists for almost a century.

Cognitive functioning and quality of life following chemotherapy in pre- and peri-menopausal women with breast cancer

PURPOSE

The purpose of the study was to prospectively examine changes in subjective and objective cognitive functions and quality of life (QOL) for pre- and peri-menopausal women receiving chemotherapy for breast cancer and to explore potential predictors of cognitive changes.

METHODS

Participants were assessed as follows: prior to chemotherapy (T1), after cycle 3 (T2), within 2-3 weeks of completing adjuvant chemotherapy (T3) (N = 20), and 8+ years later (T4; n = 18). Objective cognitive function was measured with the High Sensitivity Cognitive Screen (T1, T3, T4). Subjective measures for cognitive function, depressive symptoms, fatigue, and mental and physical QOL were assessed at all time points. Estradiol levels were measured at T1, T2, and T3. The Functional Assessment of Cancer Therapy-Cognition and the MD Anderson Cancer Symptom Inventory item for neuropathy were administered at T4.

RESULTS

No significant changes in objective cognitive function were found. However, participants reported decreased cognitive function over the course of treatment accompanied by depressive symptoms and fatigue. Depression and fatigue returned to near-baseline levels at T4, but over half of the participants continued to report mild to moderate depression. Estradiol levels were not associated with cognitive function. Neuropathy and higher body mass index (BMI) were associated with persistent cognitive complaints at T4 (adjusted R ² = 0.712, p = 0.001). Higher QOL was correlated with better subjective cognitive function (r = 0.705, p = 0.002) and lower body mass index (r = - 0.502, p = 0.017) at T4.

CONCLUSIONS

Further investigation of BMI, neuropathy, and depressive symptoms as predictors of persistent cognitive dysfunction following chemotherapy for breast cancer is warranted.