Neoadjuvant systemic therapy does not compromise local control after breast-conserving surgery: a single-center, propensity score matching study in China

BACKGROUND: To investigate ipsilateral breast tumor recurrence (IBTR) in patients who have undergone breast-conserving surgery (BCS) after neoadjuvant systematic therapy (NST). METHOD: Three hundred and twenty-one patients undergoing BCS after NST and 2,534 patients undergoing initial BCS from June 2008 to June 2017 at Fudan University Shanghai Cancer Center were retrospectively enrolled, and statistical analyses, including propensity score matching, were applied to compare IBTR-free survival. The main factors related to IBTR in the NST group were estimated utilizing univariate and multivariate analyses. RESULTS: After propensity score matching, the 3-year IBTR-free survival rates were 93.7% (95% CI, 90.6–96.8%) in the NST group and 96.9% (95% CI, 94.9–98.9%) in the matched initial BCS group at a median follow-up period of 58 months. IBTR-free survival did not differ statistically between the two groups (P=0.154). According to multivariate analysis in the NST group, tumor-infiltrating lymphocytes (TILs), epidermal growth factor receptor 2 (HER2) status and pathologic ductal carcinoma in situ (DCIS) constituent were the factors related to IBTR after BCS. CONCLUSIONS: BCS after NST and initial BCS have equivalent IBTR-free survival. BCS after NST is a safe and effective therapy in terms of IBTR.