Wide Local Excision Versus Oncoplastic Breast Surgery: Differences in Surgical Outcome for an Assumed Margin (0, 1, or 2 mm) Distance

Abstract Introduction Oncoplastic breast surgery (OBS) can be applied in larger tumors or in patients with high tumor-to-breast ratio without compromising oncologic safety. Inherent larger excisions may increase the probability of clear margins. We compare postoperative outcomes between simple wide local excision (WLE) and OBS assuming 3 different margin distances. Patients and Methods Single oncoplastic surgeon data between April 2014 and September 2016, including tumor and treatment details, for WLE or OBS were reviewed. Relative incidence of margin positivity at 3 assumed distinct margin distances (2, 1, and 0 mm) and reexcision rates were compared. Statistical comparisons were performed by the Student t and chi-square tests. Results Available data from 201 patients revealed similar patient age and respective tumor phenotypes between 2 cohorts (166 WLE and 35 OBS). Though both the preoperative (30 vs. 16 mm, P P  = .001) sizes were greater in the OBS group, margin positivity rates were significantly lower, at 1 mm (5.7% vs. 20.8%, P  = .036). Though similar rates of reexcision were observed, completion mastectomies were required in 5.4% of WLE versus 0 OBS. Similar rates of margin positivity and reexcision were observed between mammoplasties and chest wall perforator flaps. Conclusion OBS is not inferior to standard WLE at providing a safe and clear oncologic margin regardless of margin distance (up to 2 mm) despite larger tumor size. The additional benefit of improved cosmesis, particularly in patients with larger tumor-to-breast ratio, offers a suitable and safe alternative, thus increasing patient choice and reducing the incidence of reexcision and completion mastectomy.