CANCER
Oestrogen-only HRT can double ovarian cancer risk in postmenopausal women
A study presented at the recent ASCO meeting made the finding in postmenopausal women with prior hysterectomy
June 19, 2024
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Ostrogen alone in women with prior hysterectomy significantly increased ovarian cancer incidence and mortality in postmenopausal women, findings from a study presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago have demonstrated.
Two decades after the landmark Women's Health Initiative (WHI) changed the way clinicians thought about hormone therapy and cancer, follow-up from two of the WHI's randomized trials have also found that oestrogen and progesterone together did not increase ovarian cancer risk and significantly reduced the risk of endometrial cancer.
Rowan Chlebowski from the Lundquist Institute in Torrance, California, presented these results from the latest WHI findings, at the ASCO meeting.
Dr Chlebowski and his colleagues conducted an analysis from two randomized, placebo-controlled trials, which between 1993 and 1998 enrolled nearly 28,000 postmenopausal women aged 50-79 years without prior cancer from 40 centers across the US
In one of the hormone therapy trials, 17,000 women with a uterus at baseline were randomized to combined equine oestrogen plus medroxyprogesterone acetate, or placebo. In the other trial, about 11,000 women with prior hysterectomy were randomized to daily oestrogen alone or placebo. Both trials were stopped early: the oestrogen-only trial due to an increased stroke risk, and the combined therapy trial due to findings of increased breast cancer and cardiovascular risk.Mean exposure to hormone therapy was 5.6 years for the combined therapy trial and 7.2 years for estrogen alone trial.