CNN: HRT Increases Breast Cancer Death Risk, Study Confirms

October 19th, 2010
04:01 PM ET

HRT increases breast cancer death risk, study confirms

A study published in Journal of the American Medical Association confirms that postmenopausal women who take combined hormone replacement therapy (HRT) are at an increased risk of dying from breast cancer.

"Women on combined hormone therapy with estrogen plus progestin were twice as likely to die from breast cancer compared to women receiving placebo," says medical oncologist and study author Dr. Rowan Chlebowski.

The researchers looked at more than 16,000 postmenopausal women who were part of a large government study called the Women's Health Initiative. The women took either Prempro, a drug made by Pfizer that combines both estrogen and progestin, or a placebo or sugar pill. In 2002 the study was stopped early after five and a half years of treatment because of concerns about heart health, breast cancer and other health problems. This latest research looks at 11 years of follow-up on the health of these women and the authors found that those who had used the therapy were not only more likely to develop but to die from breast cancer.

For decades women have been prescribed HRT – medications containing female hormones to replace the ones the body no longer produces after menopause. These drugs can be very effective at alleviating the hot flashes, night sweats and other discomforts of menopause. They have also been shown to help with bone health and may decrease the risk of colon cancer. But HRT, long heralded as being protective for heart health, has not lived up to its billing and women are now warned about the possible increase risk for heart attack and stroke. Last year a study found that combined HRT also increased a woman's risk of dying from lung cancer.

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Dr. Peter Bach, pulmonologist from Memorial Sloan-Kettering Cancer Center in New York, who was not involved in the most recent study, wrote an editorial published in the journal editorial. It reads in part: "It took a lot of work for these investigators to unwind what ended up being a lot of incorrect assumptions about the safety of hormone replacement therapy particularly with combined agents like Prempro."

Pfizer, maker of Prempro, released a statement in response to the study: "As a science-based company, we take this analysis seriously. It is important to view the data in the full context of both the symptoms of menopause as well as the extensive body of information – developed over more than 60 years – on the known benefits and risks of hormone therapy."

The use of combined HRT declined sharply in the United States after the HRT part of the Women's Health Initiative study was stopped in 2002. Researchers have subsequently seen a decline in the rate of new breast cancer cases. 15 to 20 percent of postmenopausal women now take HRT, down from 35 to 40 percent prior to the study.

Medical experts recommend that if women choose HRT, they take the lowest dose for the shortest duration. Check with your doctor about what is right for you and for information about other therapies that may help alleviate unpleasant menopausal symptoms.

The results of the estrogen only arm of the Women's Health Initiative trial will be released later this year. Estrogen only therapy is the preferred HRT treatment for women who, because of a hysterectomy, no longer have a uterus.

Post by: Leslie Wade - CNN Medical Producer