Hormone Therapy Trial Stopped Due to Increased Cancers and Heart Disease

Cancer and coronary risks of hormone therapy for postmenopausal women were found to outweigh the benefits of treatment.

• The Women’s Health Initiative trial of estrogen plus progestin was halted as researchers realized the risks of hormone therapy exceeded its benefits. Healthy postmenopausal women ages 50-79 received either hormone therapy or a placebo. The trial stopped after 5.6 years of follow-up because the researchers found an increased risk of invasive breast cancer in participants that were taking the estrogen+progestin pills. In addition, women who received hormone therapy had a higher risk of coronary heart disease, stroke, and venous thromboembolism compared to participants taking placebo pills.   In the same study, however, the estrogen+progestin therapy was shown to lower the risks for hip fracture and colorectal cancer.1