Weighing The Risks

For 6 million postmenopausal women, taking the hormones estrogen and progestin is a way of life. The combination is a form of hormone replacement therapy (HRT) prescribed to relieve hot flashes and night sweats caused by declining natural hormone levels during menopause and to prevent conditions such as coronary heart disease and osteoporosis.
In July, the National Institutes of Health (NIH) halted a large, federally funded clinical trial of the risks and benefits of estrogen and progestin three years early after finding a 26 percent increase in invasive breast cancer. In addition, the study reported a 29 percent increase in heart attacks, a 41 percent increase in strokes and double the risk of blood clots in women taking the hormone combination. 
Although the hormones were associated with fewer hip fractures and a decline in colon cancer, the NIH concluded these benefits did not outweigh the increased risk of invasive breast cancer and other adverse effects. 
The NIH trial involved 16,608 healthy women age 50 to 79 who randomly were given Prempro, the most popular brand of estrogen and progestin, or a placebo and followed an average of five years. The trial was one component of a group of studies called the Women's Health Initiative (WHI) begun in 1993 to evaluate therapies to prevent heart disease, osteoporosis and breast and colorectal cancer in postmenopausal women. A WHI study evaluating estrogen alone is due to end in 2005. 
The news that combination HRT increases heart attacks surprised many physicians who had assumed the hormones were beneficial to women's hearts, says Dr. Richard Joseph, a gynecologist on the staff of Baylor University Medical Center in Dallas.
"Earlier studies indicated that women on estrogen had lower rates of heart disease and less severe heart attacks. We think now that those women were healthier than the population as a whole and were closely followed, which may account for the good outcomes," he says. 
Although the results of the NIH study sound frightening, the risk to an individual woman actually is relatively low, Dr. Joseph says. For example, the 26 percent increase in breast cancer translates to an additional eight cases per 10,000 women during one year. This is reason for concern, but not for panic, he says. 
Like many physicians, Dr. Joseph has been deluged with calls from women wondering if they should stop their hormone treatment. He advises them to weigh the risks and benefits of HRT before making a decision.
"Every woman has a unique medical and family history, set of risk factors and lifestyle. Also, menopausal symptoms vary widely among women -- some have very mild disturbances while others can be incapacitated," he says. 
HRT remains a very effective treatment to relieve menopausal symptoms and, depending on a woman's individual situation, still may be appropriate, Dr. Joseph says. Since long-term use does not protect the heart, he recommends that women consult their physicians about other methods -- including medications and lifestyle changes -- to reduce their risk of coronary heart disease.

"Risks and Benefits of Estrogen Plus Progestin in Healthy Postmenopausal Women" was published in the July 17 issue of The Journal of the American Medical Association and is available online at www.jama.org.
Beal is a lecturer in Baylor's Louise Herrington School of Nursing, where she teaches "The Experience of Illness." She received her BS from Columbia University and her MN from Emory. She is a freelance health and medical writer.