Racial and ethnic disparities in neoadjuvant chemotherapy patterns and outcomes in early-stage HER2-positive breast cancer

We examined neoadjuvant chemotherapy (NACT) use, pathological complete response (pCR) and the association with overall survival (OS) among patients with early-stage HER2-positive breast cancer (BC). Patients ≥18 years with stage I-III HER2-positive BC from 2010-2022 who had surgery and chemotherapy were identified. Of 195,023 patients treated with chemotherapy, 37.7% received NACT. NACT use increased from 18.6% in 2010 to 63.4% in 2022 (p < 0.001) and pCR rates rose from 21% to 47.6% (p < 0.001). Black patients were less likely to receive NACT (aOR = 0.96;95%CI 0.93-0.99) or achieve pCR (aOR = 0.86;95%CI 0.82-0.90) than White patients. pCR was associated with a reduction in the risk of death (aHR = 0.45;95%CI 0.42-0.48). 3-year OS increased from 91% in 2010 to 95% in 2019 for patients without a pCR (p < 0.001), and from 97% to 99% for patients with pCR (p = 0.002). Further research is needed to understand and address racial and ethnic disparities in treatment access and outcomes.