Incidence of Cancer and Role of Sentinel Lymph Node Biopsy in BRCA Mutation Carriers Undergoing Prophylactic Mastectomies

Introduction Breast surveillance in patients with BRCA mutations include mammography (MMG) and MRI. Patients may elect to undergo risk-reducing bilateral prophylactic mastectomies (BPM). Sentinel lymph node biopsies (SLNB) are frequently performed and associated with increased morbidity. This study sought to determine the correlation between preoperative imaging and the final pathology and evaluate the role of SLNB in these high-risk patients. Methods A prospective database identified BRCA patients who underwent BPM between 2006 and 2022. Imaging, pathology, and operative reports were reviewed. Results 170 patients with BRCA 1/2 mutations were identified. 162 (95.3%) had imaging within one year of BPM. Of these, 28 (17.3%) patients had a MMG/ultrasound, 53 (32.7%) had an MRI, and 81 (50%) had both; 21/162 (13.0%) patients had abnormal imaging. Bilateral SLNB were performed in 31 (18.2%) patients, of which 7 had abnormal imaging; unilateral SLNB were performed in 4 (2.4%) patients, of which 3 had abnormal imaging. 11/170 (6.4%) patients had a malignancy and only one (9%) of these patients had imaging abnormalities. 1/170 (0.6%) patient had an invasive carcinoma requiring an axillary lymph node dissection (ALND), and 10/170 (5.9%) patients had ductal carcinoma in situ (DCIS). 25/170 (14.7%) had ADH/ALH. Only 7/170 (4.1%) patients had imaging abnormalities and abnormal pathology. All SLNB and ALND performed demonstrated no metastatic disease. Discussion There is a high rate of discordance between preoperative imaging prior to surgery in BRCA patients undergoing prophylactic mastectomies and final pathology. This study does not support routine SLNB at the time of BPM.