Primary tumor location predicts the site of local relapse after nipple-areola complex (NAC) sparing mastectomy

Purpose To assess the oncological safety of nipple-areola complex (NAC) sparing mastectomy in breast cancer patients. Methods From 2010 to 2015, 518 breast cancer patients were submitted to NAC sparing mastectomy. Breast MRI and intraoperative assessment of the subareolar (SD) and proximal (ND) nipple ducts were performed to predict NAC involvement. Significant associations between pre-and postoperative variables with SD/ND involvement and with the risk of local recurrence were retrospectively investigated. Results SD/ND were involved in 26.1% of the cases. Final pathology of SD/ND was predicted by tumor-NAC distance at MRI and intraoperative pathology with 75 and 93% accuracy, respectively. NAC involvement was more frequent in case of positive ND than positive SD (68.3 vs. 38.3%; p = 0.003). Fourteen (2.7%) local relapses developed over a mean follow-up of 33 months. Ki-67 >= 25% (p = 0.002) and high tumor grade (p = 0.027) correlated with local recurrence. Most relapses developed in the subcutaneous tissue of the quadrant where the primary tumor was located (12/14; 85.7%). No local relapses occurred in patients who received post-mastectomy radiotherapy as compared to patients who did not, although they had a higher rate of positive surgical margins (40.5 vs. 16.2%; p = 0.000). Conclusions NAC involvement can be predicted by MRI and intraoperative pathology of ND/SD. Local recurrences after NAC sparing mastectomy almost invariably develop in the same quadrant where the primary tumor was located and in highly proliferative tumors.