Abstract Background: Neoadjuvant chemotherapy (NAC) is increasingly used in the treatment of breast cancer and has been utilized in multiple clinical trials assessing the efficacy of novel therapies. Pathologic complete response (pCR) following NAC is associated with improved survival outcomes in breast cancer and pCR is a commonly used endpoint in clinical trials. Despite improvements in breast cancer survival using modern treatment regimens, Black women continue to experience worse survival outcomes as compared to White women. The objective of this study was to evaluate the association between race and clinical outcomes, specifically pCR rate, recurrence free survival and overall survival, in patients undergoing neoadjuvant chemotherapy at our institution. Methods: We conducted a retrospective review of patients who completed at least 75% of the recommended cycles of neoadjuvant chemotherapy for breast cancer between 2010 and 2016 and underwent surgery. Receptor subtypes were defined as HR+/HER2-negative, HER2+ or triple-negative. The association between race and pCR, defined as ypT0/ypTis ypN0, and survival endpoints of overall survival and recurrence free survival were analyzed using multivariable logistic regression and Cox proportional hazard models. Results: A total of 532 women met the inclusion criteria, 323 (60.7%) were White, 188 (35.3%) were Black and 21 (3.9%) were other/unknown. Median follow-up was 65 months. The receptor subgroups consisted of 195 (36.7%) HR+/HER2-negative cancers, 193 (36.3%) HER2+ cancers and 144 (27.1%) triple-negative cancers. No significant association between race and receptor subtype (p=0.55) or pre-treatment clinical stage (p=0.96) was observed. The overall observed pCR rate was 19% for Black patients and 27% for White patients, demonstrating a significantly different pCR rate by race in multivariate analysis (odds ratio of pCR White vs Black of 1.75; p=0.02). The largest discrepancy in pCR rate between White and Black patients was within subjects with triple-negative disease (pCR rate 44% White patients vs 27% Black patients, p=0.03). There was no association between recurrence free survival and race in univariate analysis (p=0.15). A significant difference in overall survival by race was observed using multivariable Cox proportions hazard model (hazard ratio Black vs White 1.77; p=0.03). Conclusions: In this retrospective analysis of patients receiving neoadjuvant chemotherapy, Black patients experienced a significantly lower pCR rate compared to White patients, with the biggest gap identified within triple-negative breast cancers. During the study period, Black patients also experienced a lower overall survival rate compared to White patients. Differences in the ability to achieve a pCR may be a contributing factor to the worse survival outcomes of Black patients. Citation Format: Chad Livasy, Erin Donahue, Brittany Neelands, Lejla Hadzikadic-Gusic, Terry Sarantou, Mckenzie Needham, Alicia Patrick, Arielle Heeke, Antoinette Tan, Richard White. Racial Differences in Pathologic Complete Response Rate and Overall Survival Following Neoadjuvant Chemotherapy for Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-09-11.

Abstract Background Metaplastic breast cancer (MpBC) is a rare and aggressive subtype of breast cancer that presents with high tumor stage and a poor prognosis. MpBC tumors tend to have worse outcomes compared to other non-metaplastic triple-negative breast cancers (TNBC). Although MpBC has been described as chemotherapy resistant, chemotherapy remains a mainstay of treatment. MpBC tumors can be further characterized by their specific histologic pattern. The existing literature on outcomes of MpBC by histologic pattern is limited, with varying results regarding response rate and overall survival (OS). Identifying a pattern of MpBC that has better response to treatment could help tailor treatment recommendations. Methods A retrospective chart review was performed and identified 106 patients with early-stage, high-grade MpBC who were diagnosed at Levine Cancer Institute between January 1, 2010 and September 1, 2021. A matched control cohort (n=106) of patients diagnosed with non-metaplastic TNBC was selected based on propensity score matching on diagnosis date, age at diagnosis, race, pathologic staging, and tumor grade. Patient demographics, tumor characteristics, therapeutic interventions, residual cancer burden (RCB), and outcomes were collected. The associations between the histologic patterns of MpBC and disease characteristics were evaluated using chi-squared tests for categorical variables and Wilcoxon tests for continuous variables. We also examined the differences in RCB scores between the MpBC cohort and the non-metaplastic TNBC cohort who received neoadjuvant chemotherapy. Additionally, Kaplan-Meier and Cox proportional hazard analysis was performed to assess differences in recurrence free survival (RFS) and OS between the spindle cell/sarcomatous pattern versus all other patterns. Results For the entire group (n=212), median age at diagnosis was 58 years (range, 24-92); all patients were female; 66% White, 29% Black, and 5% unknown race. Most tumors were triple-negative (91%); 19%, 56% and 14% with Clinical Stage I, II, and III disease, respectively. A total of 63% of patients underwent radiation treatment and 76% received chemotherapy (43% neoadjuvant and 57% adjuvant). Recurrence after treatment occurred in 16% of all patients. In the MpBC cohort (n=106), the histologic patterns included spindle cell/sarcomatous (34%), squamous (17%), heterologous mesenchymal (31%), mixed (17%), and other (1%). Of those with MpBC who received neoadjuvant chemotherapy (n=32), RCB among the different histologic patterns was assessed. When comparing spindle cell/sarcomatous versus the other histologic patterns combined, there was no significant difference in RCB (p = 0.81), although more RCB III scores were recorded in the spindle cell/sarcomatous pattern compared to the other MpBC patterns (40% versus 30%). When assessing RFS and OS by histologic pattern in the entire MpBC cohort, spindle cell/sarcomatous tumors had inferior RFS (p = 0.0194) and OS (p = 0.0039) compared to the other MpBC patterns combined. When comparing RCB values between MpBC and non-metaplastic TNBC, there were numerically more RCB-III classes in the MpBC cohort as compared to the non-metaplastic TNBC. Conclusion MpBC is an aggressive and difficult breast malignancy to treat. Based on our single institution review, no correlation between RCB and the histologic pattern of MpBC was found, however, RFS and OS were worse among the spindle cell/sarcomatous pattern. Furthermore, the MpBC cohort had numerically higher RCB-III scores than the TNBC control cohort, which is in line with historical data. Citation Format: Ashley Matusz-Fisher, Annabel Chen, Erin Donahue, Courtney Schepel, Michelle Wallander, Chad Livasy, Richard White, Antoinette Tan, Lejla Hadzikadic-Gusic. Histologic Pattern and Outcomes in High-Grade Metaplastic Breast Cancer Compared to Triple-Negative Ductal Breast Cancer Counterparts: A Single Institution Retrospective Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS16-08.

Small studies have demonstrated the benefit of integrative oncology (IO) therapies in patients with breast cancer; however, referral patterns and timing of therapies are unknown. This study describes the referral pattern and utilization of IO services by young women with breast cancer.A retrospective review identified female patients, 40 years or younger, with a breast cancer diagnosis between 2014 and 2019, and a documented IO consultation. Patient demographics, cancer characteristics, treatments, reasons for seeking and timing of IO consultation, and IO treatment modalities were analyzed. The IO program treated 64 young women with a median age of 38.6 years. Clinical staging was primarily IA (27%), IIA (34%), or IIB (27%), and 64% of patients were clinically node negative with no evidence of metastasis. Women utilized the IO program for recurrence risk reduction and for treatment-related adverse effects (TRAEs), most commonly vasomotor complaints (44%). Therapies utilized were acupuncture (36%), healing touch (28%), oncology massage (30%), and other (75%; music therapy, therapeutic art, spiritual care, meditation, t'ai chi, yoga, and nutrition), which were commonly initiated during treatment (69%).Our data suggest that young women utilize IO services to reduce their future cancer risk and TRAEs, but they are often referred after standard cancer care treatments have begun. Future studies could examine the optimal timing for IO intervention.