Estrogen cleared of raising breast cancer risk for most

Experts say the results strengthen the belief that estrogen remains safe for short-term relief from menopausal symptoms such as hot flashes, and should not be taken to prevent development of breast cancer or any other disease.

"Estrogen for symptoms of menopause is clearly the most effective approach," said Jane Kotchen, a professor of epidemiology at the Medical College of Wisconsin who was involved in the study. "Other remedies don't come close."

"There are still risks associated with hormone replacement therapy," said Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, which was not involved in the study. For example, estrogen therapy increases the risk of stroke, he said.

"If you must take hormone replacement, you need to have a discussion with your doctor about the benefits and risks, knowing that one risk you can take off the table is breast cancer," Lichtenfeld said.

The results, published Tuesday in the Journal of the American Medical Association, are from the Women's Health Initiative, a government-funded study best known for its landmark finding in 2002 that taking estrogen and progestin after menopause raised the risk of certain cancers, including breast cancer, and heart problems. The studies involved more than 48,000 postmenopausal women, including nearly 1,200 from Milwaukee, who were followed for about eight years.

Although that part of the study was halted in July 2002, a smaller portion involving women taking estrogen alone continued until March 2004, when participants were told to stop taking the pills because of an increased risk of stroke. Taking estrogen without progestin raises the risk of uterine cancer, so estrogen alone is prescribed only for women who have had a hysterectomy.

"A lot of women became confused after the stories saying that hormones caused breast cancer," said Marcia L. Stefanick, lead author of the study and a professor of medicine at Stanford Prevention Research Center. "But the majority of women who are taking hormone therapy are just taking estrogen because they've had a hysterectomy. Those women got the wrong message, because the earlier findings didn't relate to them."

The current study was an analysis of data from almost 11,000 women, including 286 from Milwaukee, involved in the estrogen-only trial. The women were followed for about seven years.

Though there was no difference in breast cancer risk between women taking estrogen or the placebo, women at lower risk for breast cancer were able to further decrease their risk for development of the disease, Stefanick said.

However, women at high risk - such as those with strong family history - tended to have an increased risk with estrogen use, she said.

The study also found that estrogen may decrease the risk of early stage breast cancer, particularly ductal carcinoma in situ, the most common type of non-invasive breast cancer.

"The downside from a breast point of view is that the women on estrogen had to have more short-term follow-up with mammograms, and that can be stressful," said James A. Stewart, an oncologist and professor of medicine at the University of Wisconsin's Comprehensive Cancer Center in Madison, who was not involved in this study.

According to the study, more women taking estrogen had abnormal mammograms after the first year than women taking the placebo. Those women had to have mammograms more frequently than the recommended annual exam.

Though the latest findings from the Women's Health Initiative are reassuring, many others have produced troubling trends. In February, two separate reports from the initiative determined that eating a low-fat diet would not reduce women's risk of cancer or heart disease and that calcium and vitamin D supplements did not protect against bone fractures and colon cancer as was thought.

In 2004, estrogen was found to slightly increase the risk of Alzheimer's disease and other forms of dementia in postmenopausal women.

From the April 12, 2006 editions of the Milwaukee Journal Sentinel

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