Differences in disease presentation, and treatment outcomes of neoadjuvant chemotherapy for breast cancer among Hispanics in a minority-serving institution

Abstract Background: Response to neoadjuvant chemotherapy (NAC) for breast cancer varies by tumor characteristics and therapy regimen. Studies suggest that patient ethnicity is associated with differences in disease presentation, response to treatment, and outcomes. There exists a paucity of literature on the presentation and outcomes of NAC for breast cancer in Hispanic women. Methods: This is an IRB-approved retrospective study of breast cancer patients who underwent NAC at an NCI-designated Comprehensive Cancer Center from 2005-2020. We reviewed demographics, disease presentation, response to treatment, and outcomes. ER and PR status were categorized as low positive (1-9%), positive (≥ 10%) and negative. Treatment factors reviewed included completion of chemotherapy and type of surgery performed. Treatment response was noted as percent residual cellularity (0%, <10%, 10-30%, >30-80% and >80%) in the surgical specimen and pathologic stage. Outcomes were assessed as overall survival (OS) and recurrence. Results: 365 patients received neoadjuvant chemotherapy from 2005-2020, and 196 (53.7%) self-identified as Hispanic. Median follow-up was 13.65 years. Highest clinical stage at diagnosis was most frequently IIA (31.2%), followed by IIB (32.3%), with non-significant Hispanic ethnicity differences, although Hispanic patients presented with higher clinical prognostic stages: IIIA or higher (40.5% vs. 24.0%). Hispanics more frequently had grade 3 tumors (60% vs. 48%), ER low positive (10% vs. 7%) and ER negative (48% vs. 36%) (p=0.02). No significant differences were noted in triple negative disease or HER2 positive disease. Hispanics were diagnosed at younger average ages (48.9 vs. 53.0 years, p=0.001). No statistically significant differences were noted in time from diagnosis to NAC initiation, completion of chemotherapy, or surgical treatment received (lumpectomy vs. mastectomy, and sentinel node biopsy vs. dissection). Mastectomy was more likely for late-stage disease (OR=2.73, 95% CI: 1.66-4.49, p<0.001); Hispanic women with late-stage disease had 1.09-fold higher odds of receiving mastectomy, but this was non-significant (95% CI: 0.66-1.79). No significant ethnic differences were noted in pCR (p=0.69) or residual tumor cellularity (p=0.63). There was no significant association between residual cellularity and OS. OS rates were similar for Hispanic vs. Non-Hispanic women (HR: 1.15, 95% CI: 0.64-2.08, p=0.63). No difference was noted in ethnicity-based recurrence rates (21.4 vs. 20.1%). Conclusion: Self-identified Hispanic patients were diagnosed at a younger age, presented with higher ER negative and low-positive disease and worse prognostic clinical stage. However, given standard of care chemotherapy, there were no significant differences in their treatment response or outcomes compared to non-Hispanic patients. Citation Format: Sangeetha Prabhakaran, Christopher McNicoll, Vernon S. Pankratz, Nadja Falk, Jacklyn Nemunaitis, Jain Zhou, Payton A. Sandoval-Belt. Differences in disease presentation, and treatment outcomes of neoadjuvant chemotherapy for breast cancer among Hispanics in a minority-serving institution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3686.