Pathologic Complete Response in Breast Cancer Patients Receiving Anthracycline- and Taxane-Based Neoadjuvant Chemotherapy Evaluating the Effect of Race/Ethnicity

BACKGROUND: The current study was conducted to evaluate the influence of race/ethnicity and tumor subtype in pathologic complete response (pCR) following treatment with neoadjuvant chemotherapy. METHODS: A total of 2074 patients diagnosed with breast cancer between 1994 and 2008 who were treated with neoadjuvant anthracycline- and taxane-based chemotherapy were included. pCR was defined as no residual invasive cancer in the breast and axilla. The Kaplan-Meier product-limit was used to calculate survival outcomes. Cox proportional hazards models were fitted to determine the relationship of patient and tumor variables with outcome. RESULTS: The median patient age was 50 years; 14.6% of patients were black, were 15.2% Hispanic, 64.3% were white, and 5.9% were of other race. There were no differences in pCR rates among race/ethnicity (12.3% in black, 14.2% in Hispanics, 12.3% in whites, and 11.5% in others, P = .788). Lack of pCR, breast cancer subtype, grade 3 tumors, and lymphovascular invasion were associated with worse recurrence-free survival (RFS) and overall survival (OS) (P <= .0001). Differences in RFS by race/ethnicity were noted in the patients with hormone receptor-positive disease (P = .007). On multivariate analysis, Hispanics had improved RFS (hazard ratio [HR], 0.69; 95% confidence interval [95% Cl], 0.49-0.97) and OS (HR, 0.63; 95% CI, 0.41-0.97); blacks had a trend toward worse outcomes (RFS: HR, 1.28 [95% Cl, 0.97-1.68] and OS: HR, 1.32 [95% Cl, 0.97-1.81]) when compared with whites. CONCLUSIONS: In this cohort of patients, race/ethnicity was not found to be significantly associated with pCR rates. On a multivariate analysis, improved outcomes were observed in Hispanics and a trend toward worse outcomes in black patients, when compared with white patients. Further research was needed to explore the potential differences in biology and outcomes. Cancer 2010;116:4168-77. (C) 2010 American Cancer Society.