The Women's Health Initiative — a large-scale trial of hormone replacement therapy (HRT) to combat the effects of menopause — was stopped in 2002 because researchers noticed an elevated risk of cardiovascular disease, stroke, blood clots and breast cancer in women who were taking one of the therapies being tested, a combination of estrogen and progestin.
Now, a new study has found further that these same women continue to have a higher than average risk of developing breast cancer, years after quitting the therapy.
"The concerning issue is the risk for all cancers remains significantly elevated, mostly because of breast cancer."
"Within a couple of years, the [increased] risk for stroke, serious blood clots and heart attack disappears, but so do the benefits to bone," added study author Marcia Stefanick, a professor of medicine at Stanford University. "The concerning issue is the risk for all cancers remains significantly elevated, mostly because of breast cancer."
Dr. James Liu, chairman of obstetrics and gynecology at MacDonald Women's Hospital at Case Medical Center in Cleveland, stressed that the results applied only to combination hormone therapy, not all types of HRT, and that they may change. "The good news is that these changes do reverse," he said. "There may be some lag time in the breast risk, but because the breast risk actually increases with age, independent of estrogen, women still should continue to have annual surveillance."
According to the new study, the risk of cardiovascular problems was similar in the HRT and placebo groups. However, there was a greater risk of overall cancer in the HRT group. Most of this was explained by a heightened risk of breast cancer. Lung cancer risk was only slightly higher, but death from any cause was 15 percent higher in the HRT group than in the placebo group.
Putting all these factors together, the risks of combined HRT exceed the benefits, the authors stated.
"The really important message for women is they need to get a mammogram if they've stopped using hormones," Stefanick said. "They shouldn't think everything is fine. They need to get a mammogram to make absolutely sure. Once they've stopped the hormones, you have a better chance of detecting them."