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

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 < .001) and postoperative tumor (30 vs. 19 mm, 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.