Positive Nipple Margins in Nipple-Sparing Mastectomies: Rates, Management, and Oncologic Safety.

BACKGROUND

When a nipple margin of a nipple-sparing mastectomy (NSM) contains malignancy, current practice includes removal of the nipple or nipple areola complex (NAC). We evaluated rates and trends of positive nipple margins, subsequent management, and oncologic outcomes.

STUDY DESIGN

A retrospective chart review of all NSM at our institution from 2007 to 2014 was performed. A descriptive analysis was performed of patients with positive nipple/subareolar margins.

RESULTS

Among 1,326 NSM, 43 of 642 (6.7%) therapeutic and 3 of 684 (0.4%) prophylactic NSM had positive nipple margins. Nipple or NAC excision was performed for 39 of 46 (85%) positive nipple margins: 20 of 39 (51%) had nipple only and 19 of 39 (49%) had the entire NAC excised. Practice evolved to remove only the nipple and retain the areola for positive nipple margins: in 2007 to 2011, 7 of 17 (41%) underwent nipple-only excision compared with 14 of 22 (64%) in 2012 to 2014. Among 39 excised nipples/NAC, 28 (72%) contained no residual malignancy, while 8 contained ductal carcinoma in situ (DCIS), 2 had invasive lobular carcinoma, and 1 had invasive ductal carcinoma. With experience, rates of positive nipple margins for therapeutic NSM decreased from 11% (17 of 160) in 2007 to 2011 to 5.4% (26 of 482) in 2012 to 2014 (p < 0.05). At 36 month median follow-up, there were no recurrences in the nipple/NAC.

CONCLUSIONS

Early results suggest that excision of the nipple with retention of the areola is a safe approach for management of a positive nipple margin after NSM. With experience, low rates of positive nipple margins are possible in therapeutic NSM. Overall risk of nipple/NAC recurrence after NSM remains extremely low.