News Release

National study halted since health risks exceed benefits in postmenopausal women on estrogen

Peer-Reviewed Publication

University of North Carolina at Chapel Hill

(Embargoed) CHAPEL HILL – Researchers nationwide have halted the part of a 40-center study that involved trying to determine the risks versus the benefits of healthy postmenopausal women taking the hormones estrogen and progestin.

That's because after five years of data collection, the study clearly showed the risks outweighed the benefits, scientists said. Taking the combination appears to boost the chance of developing breast cancer somewhat and does not lead to the anticipated benefits in preventing heart attacks and strokes.

The National Heart, Lung and Blood Institute sponsors the continuing, larger project, which is known as the Women's Health Initiative. Institute officials were scheduled to hold a news conference at the National Press Club in Washington, D.C. Tuesday (July 9) to announce their action. A paper describing the findings in detail will appear online in JAMA-Express also on July 9 and in the July 17 issue of the Journal of the American Medical Association.

"This was a randomized, placebo-controlled trial of estrogen plus progestin in more than 16,000 women with a uterus," said Dr. Gerardo Heiss, professor of epidemiology at the University of North Carolina at Chapel Hill School of Public Health. "The estrogen plus progestin trial was stopped early -- after 5.2 years -- because of a 26 percent increased risk for breast cancer and also a lack of overall benefit. As soon as the increased risk for breast cancer was established, the independent data and safety monitoring board halted the study."

A second trial of estrogen alone in 11,000 women who have had hysterectomies continues unchanged, said Heiss, a member of the Women's Health Initiative steering committee. "We wish to express our appreciation and thanks to the 16,608 women who participated in this WHI study. They are true pioneers and have made an important contribution in answering a very important question for millions of women.

"Because of them, we now know the balance of risks and benefits of the estrogen plus progestin treatment most commonly prescribed in the United States for postmenopausal women who have a uterus," he said. "The bottom line is that estrogen plus progestin is not a viable option to prevent chronic disease."

Other UNC faculty, all with the schools of medicine or public health, involved in the research are Drs. Ellen Wells, assistant professor of obstetrics and gynecology; David Ontjes and Carla Sueta, professor and associate professor, respectively, of medicine; Kathy Light, professor of psychiatry; Pamela Haines, associate professor of nutrition; and Barbara Hulka, professor of epidemiology emeritus.

"Women should not be unduly alarmed since the increased risk of breast cancer for individual women in the trial, and in the population, is small, affecting less than one-tenth of 1 percent in any given year," Ontjes said. "However, if one adds up the increased risks over several years in the 7 million women taking the drugs, the drugs may cause tens of thousands of breast cancers."

Also seen were small increases in the risks for heart disease, stroke and blood clots, and there was little likelihood that continuation of the study would have revealed sufficient cardiovascular benefits to outweigh the risks, he said. Among the benefits, researchers observed moderate reductions in the chance of fractures and colorectal cancer in women in the trial.

Previous studies that did not use a blinded, random allocation to active pills versus placebo had suggested that taking estrogen plus progestin long-term might cut the risk of heart attacks in postmenopausal women by 40 percent to 50 percent, Ontjes said.

Estrogen is given to many women at the time of menopause to ease uncomfortable symptoms such as hot flashes and vaginal dryness. Progestin is usually added to reduce the likelihood that estrogen alone might produce uterine cancer. Estrogen is also given to menopausal women to reduce the rate at which their bones become thinner and eventually break.

"This is very valuable information that applies to a large spectrum of women in the United States, and we believe it will influence physicians' practice in this area," he said. "For individual women, however, there are often considerations that might influence their decision whether to take estrogen differently. Sometimes it's a difficult decision to make.

"We still need to learn about the long-term benefits and risk of taking estrogen alone, a very important question for millions of women who have had a hysterectomy," Ontjes said. "We do know that at this point in the other WHI hormone trial there is no difference in the risk for breast cancer in the women who are taking estrogen alone, so we hope that these participants will continue their commitment to the trial. They will be able to tell us the balance of risks and benefits of the most commonly prescribed estrogen treatment for postmenopausal women who do not need to take progestins."

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Other interventions are being studied in the Women's Health Initiative to learn whether, for example, reducing fat in the diet and supplementing calcium and vitamin D can improve the health of postmenopausal women, Heiss said. Results from the study of estrogen alone in women with intact uteruses might not be available for another two to three years.

Note: Ontjes can be reached at (919) 718-9512 Monday and 966-3336 Tuesday, Heiss will be at (919) 962-3253 the entire week.

By DAVID WILLIAMSON
UNC News Services


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