Prophylactic mastectomies (PM) are performed to reduce the risk of breast cancer. Occasionally an occult carcinoma is found in PM specimens. Given the high morbidity of axillary lymph node dissection (ALND), some perform prophylactic sentinel lymph node biopsy (SLNB). We undertook a study to examine if prophylactic SLNB is indicated in all patients undergoing PM.A retrospective review of all PM between 2004 and 2010 was performed. The stage of tumor on the disease side and the pathologic findings in the prophylactic breast were analyzed. The number of SLN and the frequency of lymph node metastases were evaluated.A total of 199 PM on 184 patients were performed: 169 contralateral PM and 30 bilateral PM. Of the 199 PM, 12 had occult carcinomas (6.0%): 10 non-invasive, 1 microinvasive and 1 T1b invasive tumor. 153 of 199 PM specimens had prophylactic SLNB, of which only 2 had a positive SLN that originated from the index side of the breast.Although it is not uncommon to find occult carcinomas in the prophylactic breast, it is rare for the occult carcinoma to spread to the lymph nodes. Therefore, routine prophylactic SLNB is not indicated in patients undergoing PM.
