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.

This study aimed to determine the clinicopathologic factors, including tumor elasticity, affecting neoadjuvant chemotherapy response in breast cancer. Methods: Among 95 patients who received neoadjuvant chemotherapy for clinical stage IIa-IIIc primary breast cancer, 75 underwent strain elastography assessments. The patients were divided into soft and hard tumor groups based on the Tsukuba elasticity scoring system. Pathologic factors, including tumor cellularity and stromal characteristics, were evaluated using core needle biopsy specimens collected before neoadjuvant chemotherapy. Pathologic complete response (pCR) was defined as the absence of invasive carcinoma in the breast and axillary lymph nodes. Residual cancer burden (RCB) was also calculated in 79 cases. Results: Twenty-two patients achieved pCR (23.2%). The rates of estrogen receptor (ER) negativity (p= 0.04), progesterone receptor (PR) negativity (p= 0.03), and nuclear grade 3 (p= 0.03) were higher in patients with pCR than those in patients without pCR. The rates of PR negativity (p= 0.03), nuclear grade 3 (p= 0.01), and high tumor-infiltrating lymphocyte (TIL) levels (p= 0.04) were significantly higher in the favorable RCB group (RCB-0 and I) than those in the unfavorable RCB group (RCB-II and III). No significant difference in tumor elasticity was observed between the groups (p= 0.30). Hormone receptor (HR) negativity was an independent predictor of favorable RCB in the multivariate analysis (p= 0.04). Conclusion: Tumor elasticity was not associated with pCR or RCB. HR negativity was an independent predictor of favorable RCB.