Patients with a higher risk of breast cancer due to a BRCA mutation may undergo preventive oophorectomy in order to reduce their risk. However, it is unclear how this procedure may affect a patient’s bone health in the case of a BRCA1 or BRCA2 mutation. According to a new retrospective, cohort study, women who undergo oophorectomy may be susceptible to postoperative bone loss.
“Individuals with a deleterious mutation in 1 of 2 breast cancer susceptibility genes, BRCA1 (OMIM 113705) or BRCA2 (OMIM 600185), face a high lifetime risk of developing ovarian cancer, estimated to be 49% for a BRCA1 mutation and 21% for a BRCA2 mutation,” the researchers wrote in JAMA Network Open. They added, “The association of oophorectomy with [bone mineral density] BMD is most evident among those who were premenopausal at the time of surgery, with a rapid decline within the first 2 years after surgery that appears to stabilize over time. To our knowledge, few studies have evaluated the association of preventive surgery with BMD loss in individuals with a BRCA1 or BRCA2 mutation.”
The study included patients who underwent oophorectomy through the University Health Network, Toronto, Ontario, Canada, between January 2000 and May 2013. Eligible patients had a BRCA mutation, had at least one intact ovary before surgery, and did not have a history of any cancer besides breast cancer. BMD was assessed pre- and postoperatively using dual-energy X-ray absorptiometry (DXA). The primary outcome was annual change in BMD from baseline to follow-up in the lumbar spine, femoral neck, and total hip.
BMD Differences Among Pre- vs. Postmenopausal Women
The final analysis included 95 women (mean age at surgery, 48 [7.4] years). Fifty (53%) of patients were premenopausal before surgery, and the remaining 45 (47%) were postmenopausal preoperatively. The mean ages among the pre- and postmenopausal women at the time of surgery were 44.0 (4.2) years and 52.4 (7.7) years, respectively. Overall, 43 (45%) women had a history of breast cancer. In the premenopausal group, 14 (28%) women had a history of breast cancer, compared to 29 (64%) in the postmenopausal group. Patients underwent their first postoperative DXA scan at a mean 22 (12.7) months after surgery.
Women who were premenopausal at the time of operation had a decrease in BMD from baseline to follow-up in all three anatomical locations (lumbar spine annual change, −3.45%; 95% confidence interval [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%). Compared to no hormone use, there was a significant association between the self-reported use of hormone therapy and less bone loss at the lumbar spine (−2.00% vs −4.69%; P = 0.02) and total hip (−1.38% vs −3.21; P = 0.04).
Women who were postmenopausal at the time of operation also had a significant decrease in BMD at 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 at the total hip (annual change, −0.18%; 95% CI, −0.82% to 0.46%).
“Although longitudinal studies are necessary to evaluate the long-term effect of oophorectomy on fracture risk, our study illustrates the need to implement routine screening of bone health in this high-risk population,” the authors suggested in their conclusion.