Women undergoing bilateral oophorectomy before menopause at reduced risk of gynecologic cancer: AJOG

On the contrary, the effect of bilateral oophorectomy on the risk of breast cancer remains controversial. In this study, Huo N and team investigated the association between premenopausal bilateral oophorectomy and the risk of subsequent cancer overall and by specific cancer type, using an established population-based cohort. These findings, in conjunction with the results of other studies showing the increased risk of multiple chronic conditions after premenopausal bilateral oophorectomy, may help women to better evaluate the risk to-benefit ratio of undergoing bilateral oophorectomy before spontaneous menopause for the prevention of ovarian and other cancers.

This population-based cohort study included all premenopausal women who underwent bilateral oophorectomy for a nonmalignant indication before the age of 50, between January 1, 1988 and December 31, 2007 in Olmsted County, Minnesota, and a random sample of age-matched (1 year) referent women who did not undergo bilateral oophorectomy. Women with cancer before oophorectomy (or index date) or within 6 months after the index date were excluded. Time-to-event analyses were performed to assess the risk of de novo cancer. Cancer diagnosis and type were confirmed using medical record review.

Over a median follow-up of 18 years, the risk of any cancer did not significantly differ between the 1562 women who underwent bilateral oophorectomy before natural menopause and the 1610 referent women. However, women who underwent bilateral oophorectomy had a decreased risk of gynecologic cancers but not of nongynecologic cancer. In particular, the risk of breast cancer, gastrointestinal cancer, and lung cancer did not differ between these 2 cohorts. Use of estrogen therapy through the age of 50 years in women who underwent bilateral oophorectomy did not modify the results.

In this population-based study, authors did not observe an association between premenopausal bilateral oophorectomy and risk of nongynecologic cancers, including breast cancer, among women at average risk of ovarian cancer. Thus, for the general population of women at average risk of ovarian cancer, these results suggest that the ovaries should not be removed before spontaneous menopause to reduce the risk of nongynecologic cancers including breast cancer. Considering the additional increased risk for long-term morbidity and mortality unrelated to cancer after premenopausal bilateral oophorectomy, the benefits of undergoing the surgery may not outweigh the possible risks for women with low absolute risk for developing ovarian or breast cancer.

This large cohort study showed that the risk of nongynecologic cancers, including breast cancer, was similar for women with premenopausal bilateral oophorectomy and referent women. Thus, bilateral oophorectomy should not be considered for the prevention of nongynecologic cancers, including breast cancer, in the general population. These findings, in conjunction with the results of other studies showing the increased risk of multiple chronic conditions after premenopausal bilateral oophorectomy, may help women to better evaluate the risk to-benefit ratio of undergoing bilateral oophorectomy before spontaneous menopause for the prevention of ovarian and other cancers.

Source: Huo N, Smith CY, Gazzuola Rocca L, et al. Risk of de novo cancer after premenopausal bilateral oophorectomy. Am J Obstet Gynecol 2022;226:538.e1-16