The purpose of this study was to compare the success rate of re-excision and breast-conserving surgery (BCS) between patients who received neoadjuvant chemotherapy and those who did not. Methods: In this retrospective cohort study, 256 women who had clinical T2 breast cancer and planned to receive, as initial treatment either BCS (n= 197) or neoadjuvant chemotherapy (n= 59) between January 2009 and December 2012 were included. The data, including age, initial tumor size, mammographic microcalcification, ultrasound multifocality and axillary nodal status, were collected. The pathologic tumor size, p-multifocality, histologic type, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, Ki-67, ductal carcinoma in situ (DCIS) and extensive intraductal component (EIC) were also reviewed. The re-excision and BCS success rates were investigated. Univariate analysis and regression model were used. To reduce the effect of selection bias, propensity score matching-based analysis was also performed. Results: Of the 256 patients, 178 patients (90.4%, 178/197) in the non-neoadjuvant group and 56 patients (94.9%, 56/59) in the neoadjuvant group received BCS (p= 0.406). In propensity-matched cohorts (n= 118), the re-excision rate was similar in the two groups (35.6% in neoadjuvant group vs. 35.6% in non-neoadjuvant group, p= 1.000). BCS success rate was slightly higher in neoadjuvant group (94.9%, 56/59) than in non-neoadjuvant group (86.4% [51/59], p= 0.205). In logistic regression model, clinicopathologic factors associated with re-excision were pathologic multifocality (odds ratio [OR], 4.56; p= 0.0142), high Ki-67 (≥ 50%) (OR, 0.7; p= 0.0243) and DCIS component (OR, 2.67; p= 0.0261). Conclusion: This study showed that neoadjuvant chemotherapy could increase the success rate of BCS but could not decrease that of re-excision. The re-excision rate is more associated with pathologic finding rather than the effect of neoadjuvant chemotherapy.
