Will taking hormones during menopause increase my cancer risk?

Hormone therapy significantly increases a woman's risk for specific cancers and other diseases, according to findings from a study of more than 16,000 women ages 50 to 79. The study was part of the Women's Health Initiative (WHI), sponsored by the National Institutes of Health.

Hormone therapy involves estrogen alone or estrogen plus progestin (a laboratory-made form of the female hormone progesterone). In this WHI study, half the women took estrogen plus progestin (specifically, Prempro) and half did not take hormones.

After five years of follow-up, the study found a 26 percent increase in breast cancer risk among the hormone users compared to the other group. This finding confirmed earlier studies linking hormone therapy to breast cancer. The study also found that hormone therapy increased the risk for heart disease, stroke, and blood clots.

The hormone therapy was found to have benefits as well, such as fewer cases of colon cancer and hip fractures.

On balance, the researchers concluded that the overall risks of hormone therapy were greater than the benefits. The study was stopped early in July 2002.

The health effects of estrogen alone are less clear. The best information on this question will come from a separate ongoingWHI study involving women who take estrogen alone. This study is expected to end in 2005.

Meanwhile, women should talk with their doctor about the benefits and risks of hormone therapy and other ways to deal with symptoms of menopause.

For more information, call the Cancer Information Service at 800-4-CANCER or visit the National Institutes of Health Web site and click on "Menopausal Hormone Therapy."

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