More than 20% of US women aged 40 to 49 years undergoing hysterectomy for benign disease have concomitant elective oophorectomy to prevent the subsequent development of ovarian cancer. In the Nurses’ Health Study, which followed outcomes among 30,117 women undergoing hysterectomy over 24 years, bilateral oophorectomy compared with ovarian conservation decreased the risk of incident ovarian and breast cancer. Oophorectomy, however, was associated with a higher risk of incident coronary heart disease, stroke, lung cancer and total cancers, and mortality from all causes.
This prospective cohort study provides updated mortality data for 28 years of follow-up among women enrolled in the Nurses’ Health Study. Long-term mortality after bilateral oophorectomy (n = 16,914) or ovarian conservation (n = 13,203) at the time of hysterectomy was compared in subgroups of women stratified by age at the time of surgery, use of estrogen therapy, presence of risk factors for coronary heart disease, and length of follow-up. Multivariable hazard ratios were determined for death from coronary heart disease, stroke, breast cancer, epithelial ovarian cancer, lung cancer, colorectal cancer, total cancer, and all causes.
More women with hysterectomy and bilateral oophorectomy died of all causes compared with women who had ovarian conservation (16.8% vs 13.3%, respectively); the hazard ratio was 1.13, with a 95% confidence interval of 1.06 to 1.21. Patients who underwent oophorectomy had a lower risk of death from ovarian cancer than did those who had ovarian conservation (4 vs 44) and before age 47.5 years had a lower risk of death from breast cancer. However, the risk of other cause-specific or all-cause mortality after oophorectomy was not reduced at any age. Bilateral oophorectomy was associated with significantly increased mortality among women younger than 50 years at the time of hysterectomy who had never used estrogen therapy. This increased risk was not found among women who were past or current users of estrogen therapy. Assuming a 35-year life span after oophorectomy in past and current smokers, the number needed to harm for all-cause death was 8, for coronary heart disease death was 33, and for lung cancer death was 50.
These findings show that bilateral oophorectomy increases mortality in women younger than 50 years who never used estrogen therapy and is not associated with increased survival at any age. The data indicate that a strategy of oophorectomy and estrogen therapy after surgery is not likely to be successful.