Changes in Bone Mineral Density After Prophylactic Bilateral Salpingo-Oophorectomy in Carriers of a BRCA Mutation

IMPORTANCE: Preventive surgery is strongly recommended for individuals with a BRCA mutation at a young age to prevent ovarian cancer and improve overall survival. The overall effect of early surgical menopause on various health outcomes, including bone health, has not been clearly elucidated. OBJECTIVE: To evaluate the association of prophylactic bilateral salpingo-oophorectomy with bone mineral density (BMD) loss among individuals with a BRCA mutation. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study of participants with a BRCA mutation who underwent oophorectomy through the University Health Network, Toronto, Ontario, Canada, recruited participants from January 2000 to May 2013. Eligibility criteria included having a BRCA mutation, at least 1 ovary intact prior to surgery, and no history of any cancer other than breast cancer. Bone mineral density was measured using dual-energy x-ray absorptiometry before and after surgery. Data analysis began in December 2018 and finished in January 2019. MAIN OUTCOMES AND MEASURES: The annual change in BMD from baseline to follow-up was calculated for the following 3 anatomical locations: (1) lumbar spine, (2) femoral neck, and (3) total hip. RESULTS: A total of 95 women had both a baseline and postsurgery BMD measurement with a mean (SD) follow-up period of 22.0 (12.7) months. The mean (SD) age at oophorectomy was 48.0 (7.4) years. Among women who were premenopausal at time of surgery (50 [53%]), there was a decrease in BMD from baseline to follow-up across the lumbar spine (annual change, −3.45%; 95% CI, −4.61% to −2.29%), femoral neck (annual change, −2.85%; 95% CI, −3.79% to −1.91%), and total hip (annual change, −2.24%; 95% CI, −3.11% to −1.38%). Self-reported hormone therapy use was associated with significantly less bone loss at the lumbar spine (−2.00% vs −4.69%; P = .02) and total hip (−1.38% vs −3.21; P = .04) compared with no hormone therapy use. Among postmenopausal women at time of surgery (45 [47%]), there was also a significant decrease in BMD across the lumbar spine (annual change, −0.82%; 95% CI, −1.42% to −0.23%) and femoral neck (annual change, −0.68%; 95% CI, −1.33% to −0.04%) but not total hip (annual change, −0.18%; 95% CI, −0.82% to 0.46%). CONCLUSIONS AND RELEVANCE: This study found that oophorectomy was associated with postoperative bone loss, especially among women who were premenopausal at the time of surgery. Targeted management strategies should include routine BMD assessment and hormone therapy use to improve management of bone health in this population.