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What's New - Estrogen Plus Progestin Study Stopped 348 Portland-area women involved in study at Kaiser Permanente's Center for Health Research National Study of Estrogen Plus Progestin Stopped Because Risks Outweigh Benefits (PORTLAND, Ore.) – A national study of the risks and benefits of estrogen plus progestin for women past the menopause is being stopped early because it is now clear that the risks of breast cancer and heart disease from taking the two hormones in combination outweigh the benefits. Nearly 400 women in the Portland-Vancouver area have been participating in the study since 1996 at Kaiser Permanente's Center for Health Research (CHR). CHR is the only Oregon site out of 40 clinical sites nationwide involving 16,608 postmenopausal women between 50 and 79 who have an intact uterus. This study is part of the Women's Health Initiative (WHI), which is sponsored by the National Heart, Lung and Blood Institute of the National Institutes of Health. Study participants began receiving letters on Monday informing them the study is being stopped because data showed that participants taking estrogen plus progestin had greater risks of breast cancer, coronary heart disease, stroke, and blood clots than comparable women taking placebo pills. Although the study found that estrogen plus progestin lowered the women's risks of hip fractures and colorectal cancer, these benefits did not outweigh the increased risks of breast cancer and heart disease. The study did not address the short-term risks and benefits of taking hormones for menopausal symptoms. The findings from the WHI investigators on the estrogen plus progestin study will be published in the July 17 issue of The Journal of the American Medical Association (JAMA). Because of the importance of the information, the study is being released early on Tuesday, July 9, as an expedited article on the JAMA Web site. (Full text version available to everyone at www.jama.com ). Full information is also available July 9 at the WHI website (www.whi.org). CHR researchers will contact women in the study for counseling and continued medical monitoring. "This study was designed to find out if the benefits of estrogen plus progestin for preventing heart disease, cancer, and osteoporosis outweigh the risks," says Cheryl Ritenbaugh, PhD, principal investigator for WHI at Kaiser Permanente's Center for Health Research. "We thank the women who volunteered to participate in this important study. Without them, we would still have no clear answer. The answers that we have are quite different than were anticipated when the study was designed in 1992. The results are now in, and the answer is definitive - the benefits don't outweigh the risks. The risks are relatively small, but the benefits are even smaller. Healthy women who are past the menopause and have an intact uterus shouldn't take these drugs on a long-term basis. The benefits these drugs show for reduced risk of hip fractures and colorectal cancer are overshadowed by the increased risk of breast cancer, heart attacks, strokes, and blood clots. "One of the most surprising findings in our study," Ritenbaugh adds, "was that the estrogren/progestin combination increases postmenopausal women's risk of heart disease" Dozens of previous observational studies suggested that this hormone combination protected average women against heart disease.Recently, however, some small clinical trials have shown that it doesn't protect women with existing heart disease. The results published last week of a larger clinical trial called HERS (Heart and Estrogen/progestin Replacement Study) showed that the two-hormone combination doesn't protect against heart attacks among 2,600 older women who already have heart disease. HERS, however, was not large enough to comment definitively on cancer, stroke, or osteoporosis. The lead author of the study, Denise Grady, was quoted in the Wall Street Journal as saying the HERS finding 'is probably the next to the last nail' in the coffin of hormone use. Ritenbaugh says, "Borrowing her line, I would say the WHI study is the 'last nail' in the coffin. The WHI study, the largest clinical trial of estrogon/progestin, has now shown that it does not protect average postmenopausal women ages 50-79 against heart disease and stroke. "Another surprise," continues Ritenbaugh, "was the finding of a significantly increased risk of breast cancer beginning as early as five years after the start of combination hormone therapy. We found this increased risk three years earlier than the planned end of the study, so thousands of women can now benefit from knowing this early result. "These findings pose difficult choices for women," Ritenbaugh says. "They should talk with their physicians before making a decision about taking or stopping this hormone combination. Use of estrogen plus progestin to prevent disease is no longer justified. Women who are concerned about their health should adopt the healthy behaviors that are known to help prevent both cancer and heart disease - eating a healthy diet that is low in fat and high in fruits and vegetables, getting plenty of exercise, stopping smoking, and maintaining a health body weight. Women who are concerned about osteoporosis should make sure they get plenty of calcium and exercise, and should consult their physicians about other drug choices, such as alendronate." A separate WHI study of the use of estrogen alone versus placebo by 10,739 women who had had a hysterectomy is continuing. The trial of estrogen alone is extremely important because the balance of risks and benefits of taking only estrogen is still uncertain. At this time in the estrogen only study, there is no evidence of increased risk of breast cancer in women taking active hormone compared to women taking placebo. The WHI also has two other large ongoing studies to evaluate the effects of low-fat eating on cancer and heart disease, and the effects of calcium/vitamin D supplements on fractures and colon cancer. These studies should provide additional definitive answers by 2005. Ritenbaugh adds that the "WHI investigators will be doing more detailed analyses on the results from the combined-hormone-therapy trial. Additional articles will be appearing in the coming months on breast cancer, heart disease, stroke, quality of life, and other outcomes. With the continued participation of the 60,000 women in the WHI clinical trials, including women from the estrogen plus progestin trial who are now in follow-up, we are looking to continue providing important answers for women through 2005." Specific findings from the WHI study from women taking estrogen plus progestin compared to women taking a placebo include:
The WHI results mean that during one year among 10,000 women who are taking estrogen plus progestin there would be the following number of excess health problems compared to a similar group of 10,000 women not taking the two hormones:
In addition, six fewer women will have colorectal cancer, and five fewer will have a hip fracture. "This is a relatively small annual increase in risk for individual women," says Jacques Rossouw, MD, acting director of WHI. "Individual women who have participated in the trial and women in the population who have been on estrogen and progestin should not be unduly alarmed. However, even small individual risks over time, and on a population-wide basis, add up to tens of thousands of these serious adverse health events." The Women's Health Initiative is sponsored by the National Heart, Lung and Blood Institute in collaboration with four other components of the National Institutes of Health - the National Cancer Institute, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, the National Institute on Aging, and the Office of Research on Women's Health. WHI involves more than 161,000 women at 40 clinical centers who are participating in a set of clinical trials or an observational study. The clinical trials are designed to test promising but unproven treatments for heart disease, breast and colorectal cancer, and osteoporosis. In addition to the trials of estrogen alone and estrogen plus progestin, other trials are studying a low-fat eating pattern and calcium/Vitamin D supplementation. Kaiser Permanente's Center for Health Research, founded in 1964, is a non-profit research institute located in Portland, Oregon and Honolulu, Hawaii. Its mission is to discover and advance knowledge to improve health. Kaiser Permanente Northwest is a group practice health care organization providing care to about 455,000 people in Northwest Oregon and Southwest Washington. For more infomation contact: Released: July 9, 2002 |
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Updated 9 July 2002 |