Follow-up to women's health initiative produces surprising results

“This latest study reinforces the original finding that combined hormone therapy of estrogen plus progestin should not be taken for the purpose of reducing disease in post-menopausal women,” Chlebowski said. “These findings also reinforce the need for monitoring for cancer in women who have taken the combination of estrogen plus progestin.”

Dr. Chlebowski is a medical oncologist who has led several prior reports focusing on hormone effects on malignancies, including breast and colorectal cancer. He was a member of the team of researchers, led by Gerardo Heiss, M.D., of the University of North Carolina, Chapel Hill, N.C., who authored the March 5 JAMA report on a follow-up study of post-menopausal women enrolled in the Women’s Health Initiative. Dr. Chlebowski is available for comment for reporters seeking further insight into the study’s findings.

About the Women’s Health Initiative

The Women’s Health Initiative (WHI) trial began in 1993 to measure the effect of estrogen plus progestin on reducing disease in post-menopausal women. It included 16,608 postmenopausal women and assessed whether conjugated equine estrogens (CEE) plus medroxyprogesterone acetate (MPA) prevents heart disease and hip fractures and increases the risk of breast cancer.

The trial was stopped in 2002 when data indicated an increased risk of breast cancer and a failure to demonstrate an overall health benefit of the therapy. Further analysis showed that women taking the two hormones had higher risks of cardiovascular disease, coronary heart disease, stroke and venous thromboembolism and lower risks of fracture and colorectal cancer.

About the Follow-Up Study

After stopping intervention, WHI followed the trial participants using the same study protocol of semi-annual monitoring to identify and classify study outcomes, in order to evaluate the effects of stopping hormone therapy.

Post intervention information for the period July 8, 2002 to March 31, 2005 was available on 95% of the women. The JAMA article reports on health outcomes at three years after the intervention was stopped (mean of 2.4 years of follow-up).

In the three years after stopping hormone therapy women who previously used estrogen plus progestin no longer had an increased risk of cardiovascular disease (heart disease, stroke, and blood clots) compared with women on placebo.

The lower risk of colorectal cancer and fractures seen during the trial in women who previously used estrogen plus progestin disappeared after stopping the combined hormone therapy.

But the risk of all cancers combined in women who previously used estrogen plus progestin increased after stopping the intervention compared to those previously on placebo. This was due to increases in a variety of cancers, including lung cancer.

After stopping the hormone therapy, mortality from all causes was somewhat higher in women who previously used estrogen plus progestin compared with those taking a placebo. -Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA BioMed)