No Association of Positive Superficial and/or Deep Margins with Local Recurrence in Invasive Breast Cancer Treated with Breast-Conserving Surgery

PURPOSE We evaluated the effect of positive superficial and/or deep margin status on local recurrence (LR) in invasive breast cancer treated with breast-conserving surgery (BCS) followed by radiotherapy. MATERIALS AND METHODS In total, 3,403 stage 1 and 2 invasive breast cancer patients treated with BCS followed by radiotherapy from January 2000 to December 2008 were included in this study. These patients were divided into three groups according to margin status: clear resection margin status for all sections (group 1, n=3,195); positive margin status in superficial and/or deep sections (group 2, n=121); and positive peripheral parenchymal margin regardless of superficial and/or deep margin involvement (group 3, n=87). The LR-free survival between these three groups was compared and the prognostic role of margin status was analyzed. RESULTS Across all groups, age, tumor size, nodal status, and human epidermal growth factor receptor 2 status did not significantly differ. High grade, positive extensive intraductal component, hormone receptor positivity, hormone therapy received, and chemotherapy not received were more prevalent in groups 2 and 3 than in group 1. Five-year LR rates in groups 1, 2, and 3 were 1.9%, 1.7%, and 7.7%, respectively. Multivariate analysis revealed that group 3 was a significant predictor for LR (hazard ratio [HR], 4.78; p < 0.001), but that positive superficial and/or deep margin was not (HR, 0.66; p=0.57). CONCLUSION Superficial and/or deep margin involvement following BCS is not an important predictor for LR.