Predictive factors associated with involved margins in breast cancer treated with neoadjuvant chemotherapy followed by breast-conserving therapy.

INTRODUCTION:This study sought to identify predictive factors of involved surgical margins in breast-conserving surgery (BCS) after neoadjuvant chemotherapy (NAC) to help guide the surgical procedure. MATERIALS AND METHODS:Retrospective study of patients who had BCS after NAC between January 2008 and December 2013. OUTCOME MEASURE:tumor-involved margin, defined by tumor cells on ink for invasive cancer and tumor-free margin < 2 mm for DCIS. RESULTS:Ninety-seven patients were included. The median age of patients was 46 years old [28-71]. The initial average tumor size was 47.8 mm [+/- 18.6]. Twelve patients (12.4%) had involved tumor margins on final histology after BCS and NAC. According to the multivariate model including only preoperative variables of positive margins, initial ultrasound tumor size ≤ 27 mm (p = 0.045) and low SBR grade (p = 0.009) were independently associated with tumor-involved margins. According to the multivariate model including pre- and postoperative variables of positive margins, ductal carcinomain situ was also independently associated with tumor-involved margins (p = 0.021). CONCLUSION:Initial ultrasound tumor size ≤ 27 mm and low SBR grade were independently associated with tumor-involved margins. These preoperative data were very helpful to guide the surgical procedure in breast cancer.