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.
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.
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.