Hormone Replacement May Raise Ovarian Cancer Risk
Additional risk disappears when therapy is stopped
THURSDAY, April 19 (HealthDay News) -- Women who use hormone replacement therapy (HRT) may be at increased risk of developing ovarian cancer, and its use in the United Kingdom may have resulted in an additional 1,000 deaths from the disease since 1991, according to a study published online April 19 in The Lancet.
Valerie Beral, of Cancer Research U.K., Oxford, U.K., and colleagues analyzed data from the Million Women Study, including 948,576 postmenopausal women with no previous history of cancer or bilateral oophorectomy. The women were followed for an average of 5.3 years for incident ovarian cancer (2,273 cases) and 6.9 years for death (1,591 subjects) during the follow-up.
Overall, 30 percent of the women were current HRT users, and 20 percent were past users. Current users had a 1.2-fold greater risk of incident ovarian cancer and a 1.23-fold greater risk of ovarian cancer death than never-users. There was no difference based on the type of HRT, and past users were not at increased risk. The highest risk was for serous tumors in women with epithelial cancer, with current users at 1.53 times the risk as never users.
Among current users of HRT there was an estimated one extra case per 2,500 users and one extra death per 3,300 users. "If this association is causal, use of HRT since 1991 has resulted in roughly 1,300 extra cases of ovarian cancer and 1,000 extra deaths from the malignancy in the U.K.," the authors wrote.