Positive Margins After Oncoplastic Surgery for Breast Cancer.

[BACKGROUND] Oncoplastic techniques applied to breast-conserving surgery (BCS) allow large-volume resections without compromising cosmetic results. Level II oncoplastic techniques are based on mammoplasties. When required, they allow resection of more than 20 % of the breast volume; however, a subgroup of these patients will still have positive margins. The clinical management of positive margins after level II oncoplastic surgery (OPS) is a challenge.

[METHODS] All patients who had undergone level II oncoplastic techniques at The Paris Breast Center between 2004 and 2013 were reviewed. The choice of the optimal mammoplasty technique was based on the tumor location and the 'quadrant per quadrant atlas'.

[RESULTS] A total of 277 level II oncoplastic techniques were performed on 272 patients. The mean tumor size was 26 mm (range 2-160 mm), with a mean resected weight of 175 g (range 50-1540 g). The rate of positive margins was 11.9 %. Risk factors for positive margins identified in univariate analysis were histologic subgroup, tumor size, T stage and grade. In multivariate analysis, only patients with invasive lobular carcinoma had a significantly higher risk of positive margins. A second operation was required in 33 cases, and a third operation was required in three cases because of positive margins. Final breast conservation rate was 91 %.

[CONCLUSIONS] Level II OPS results in a low positive margin rate despite large tumor size. Patients with involved margins can be offered a second BCS if the remaining volume allows this.