Impact of neoadjuvant chemotherapy on surgical outcomes among patients with hormone receptor positive breast cancer

Background: Pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) is a surrogate for outcome, but not necessarily conversion to BCT eligibility. We sought to examine the impact of NACT on surgical decision making among HR+ patients. Methods: Our IRB-approved breast cancer database was queried for patients who underwent NACT, including the clinicopathologic data and surgeon's pre- and post-NACT assessment. Surgical conversion rate (SCR) was defined as patients ineligible for BCT prior to NACT, who were given the choice following NACT. Results: Among 289 patients, pCR rates were highest among patients with HER2-enriched subtype (60%) and lowest in patients with luminal A disease (4%). Overall, the BCT rate was 41%, while 28% opted for bilateral mastectomy across subtypes. Despite a low pCR, the SCR was still high (54%) among patients with the luminal A subtype. Conclusion: Despite poor pCR rates, NACT still has potential to improve surgical outcomes among hormone receptor positive patients. The surgical conversion rate is a superior measure of the impact of NACT on surgical decision making than examining BCT rates.