Risk factors for positive margins in conservative surgery for breast cancer after neoadjuvant chemotherapy.

Abstract Background Breast conservative surgery after neoadjuvant chemotherapy intends to remove any residual tumor with negative margins. The purpose of this study was to analyze the preoperative clinical-pathological factors influencing the margin status after conservative surgery in breast cancer patients receiving neoadjuvant chemotherapy. Methods A retrospective study of 91 breast cancer patients undergoing neoadjuvant chemotherapy (92 breast lesions) during the period 2006–2013. A Cox regression analysis to identify baseline tumor characteristics associated with positive margins after breast conservative surgery was performed. Results Of all cases, 71 tumors were initially treated with conservative surgery after neoadjuvant chemotherapy. Pathologic exam revealed positive margins in 16 of the 71 cases (22.5%). The incidence of positive margins was significantly higher in cancers with initial size >5 cm ( P =.021), in cancers with low tumor grade ( P =.031), and in patients with hormone receptor-positive cancer ( P =.006). After a median follow-up of 45.2 months, 7 patients of the 71 treated with conservative surgery had disease recurrence (9.8%). There was no significant difference in terms of disease-free survival according to the margin status ( P =.596). Conclusions A baseline tumor size >5 cm, low tumor grade and hormone receptor-positive status increase the risk for surgical margin involvement in breast conservative surgery after neoadjuvant chemotherapy.