There is some evidence that hormone therapy in postmenopausal women may cause endometrial hyperplasia, which is a condition in which the uterus lining is unusually thick. The evidence linking hormone therapy to the risk of endometrial cancer remains inconclusive. These findings were recently published in Cochrane Database Systematic Reviews.
Around menopause, falling levels of circulating estrogen can have an adverse effect on health and well-being. One of the ways that doctors ease the symptoms of menopause is to prescribe hormone therapy, which is typically taken as estrogen only or as estrogen combined with progestogen.
However, there remain concerns about whether hormone therapy raises the risk of endometrial hyperplasia or endometrial cancer. Researchers sought to investigate this matter by searching for clinical trials available on academic search engines and clinical trial databases. Their search included all relevant studies published until July 22, 2024.
Read more about endometrial cancer signs and symptoms
The research team focused on three forms of hormone therapy: unopposed estrogen (ie, estrogen only), continuous combined estrogen and progestogen (ie, both estrogen and progestogen are taken together), and sequential combined estrogen and progestogen (ie, estrogen is taken continuously and progestogen is added on some days of the month).
A total of 72 studies encompassing 42 multicenter trials and 40,652 women were included in this analysis. Based on the data contained in these studies, researchers concluded that unopposed estrogen probably raises the risk of endometrial hyperplasia at the one-year mark and beyond. In addition, sequential combined hormone therapy may raise the risk of endometrial hyperplasia at the one-year mark compared with placebo.
However, researchers found that an analysis comparing continuous combined hormone therapy with sequential combined hormone therapy were inconclusive; there was simply not enough data for a conclusion to be drawn either way. Similarly, researchers were unable to reach a definite conclusion regarding the link of any hormone therapy with endometrial cancer.
“Further research should focus on different combined hormone therapy regimens that may reduce the risk of these outcomes,” the authors wrote.
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