Racial/Ethnic Differences and Trends in Pathologic Complete Response Following Neoadjuvant Chemotherapy for Breast Cancer

Abstract

The purpose of this study was to evaluate nationwide trends in pathologic complete response (pCR) and its racial variations for breast cancer. The National Cancer Database was queried for women from 2010 to 2017 with non-metastatic breast cancer who underwent neoadjuvant chemotherapy. The primary endpoints, pCR and overall survival, were evaluated using Cochran-Armitage test, logistic, and Cox regression multivariable analyses. A total of 104,161 women were analyzed. Overall, pCR improved from 2010 to 2017 (15.1% to 27.2%, trend p < 0.001). Compared to non-Hispanic White (NHW) women, Hispanic White (HW) women were more likely to have pCR for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-positive tumors (adjusted odds ratio (aOR) 1.29, 95% confidence interval (CI) 1.08–1.53, p = 0.005). Black women were less likely to have pCR for HR-HER2+ tumors (aOR 0.81, 95% CI 0.73–0.89, p < 0.001) and triple negative (aOR 0.82, 95% CI 0.77–0.87, p < 0.001) tumors, but more likely for HR+HER2- tumors (aOR 1.13, 95% CI 1.03–1.24, p = 0.009). Among patients who achieved pCR, Asian or Pacific Islander (API) women were associated with better survival (adjusted hazards ratio (aHR) 0.52, 95% CI 0.33–0.82, p = 0.005) than NHW women. Despite positive trends in pCR rates, the likelihood of pCR and survival outcomes may be intricately dependent on racial/ethnic groups and tumor receptor subtypes.