Bone mineral density and fractures after risk-reducing salpingo-oophorectomy in women at increased risk for breast and ovarian cancer

Abstract

Aim: Risk-reducing salpingo-oophorectomy (RRSO) reduces ovarian cancer risk in BRCA mutation carriers. RRSO is assumed to decrease bone mineral density (BMD) and increase fracture risk more than natural menopause. We aimed to compare BMD and fracture incidence after premenopausal RRSO to general population data and identify risk factors for low BMD and fractures after RRSO.

Methods: In 212 women with RRSO at premenopausal age, BMD was measured by dual energy X-ray absorptiometry. Fractures and risk factors were assessed by self-administered questionnaire. Fracture incidence after RRSO was compared to general practitioner data by using standardised incidence ratios (SIRs). Risk factors for low standardised BMD-scores and fractures were identified by regression analyses.

Results: Median age at RRSO was 42years (range 35-65) and duration of follow-up 5years (2-8). Standardised lumbar spine (Z=0.01, p=0.870) and femoral neck BMD (Z=0.15, p=0.019) were not lower than population BMD. Higher age at time of RRSO and use of hormonal replacement therapy were associated with higher, and current smoking with lower standardised BMD-scores. Sixteen women reported 22 fractures. Fracture incidence was not higher than expected from the general population (all fractures: 25-44years: SIR 2.12 [95% confidence interval (CI) 0.85-4.37]; 45-64years: SIR 1.65 [95% CI 0.92-2.72]).

Conclusion: Five years after RRSO, BMD and fracture incidence were not different than expected from the general population. Based on these data it appears safe not to intensively screen for osteoporosis within five years after RRSO, although prospective research on the long-term effects of RRSO on bone is warranted.

Keywords: Bone; Fractures; Genes, BRCA1, BRCA2; Osteoporosis; Ovariectomy.