No Cancer Occurrences in 10-year Follow-up after Prophylactic Nipple-sparing Mastectomy.

Unlabelled: Prophylactic nipple-sparing mastectomies (NSM) have become increasingly common, although there is little long-term data on its efficacy in prevention of breast cancer. The objective of this study was to assess the incidence of breast cancer in a cohort of patients undergoing prophylactic NSM with a median follow-up of 10 years.

Methods: Patients receiving prophylactic NSM at a single institution from 2006 to 2019 were included in a retrospective nature. Patient demographics, genetic mutations, operative details, and specimen pathology were recorded, and all postoperative patient visits and documentation were screened for cancer occurrence. Descriptive statics were performed where appropriate.

Results: Two hundred eighty-four prophylactic NSMs were performed on 228 patients with a median follow-up of 120.5 ± 15.7 months. Roughly, a third of patients had a known genetic mutation, with 21% BRCA1 and 12% BRCA2. The majority (73%) of prophylactic specimens had no abnormal pathology. The most commonly observed pathologies were atypical lobular hyperplasia (10%) and ductal carcinoma in situ (7%). Cancer was identified in 10% of specimens, with only one case of lymphovascular invasion. Thus far, there have been no incidences of locoregional breast cancer occurrence in this cohort.

Conclusions: The long-term breast cancer occurrence rate in this cohort of prophylactic NSM patients at the time of this study is negligible. Despite this, continued surveillance of these patients is necessary until lifetime risk of occurrence following NSM has been established.