HRT Breast Cancer Risk Increases Long After Therapy EndMar 5, 2008 | Parker Waichman LLP Premarin and Prempro, could increase a woman's breast cancer risk long after she has finished HRT. A new hormone study—the first follow-up to the landmark Women's Health Initiative (WHI)—reveals that although heart problems linked with combination HRT in postmenopausal women decreases when the hormones are stopped, the risk of breast cancer increases even after women stop HRT. This finding was published in the March 5 issue of the Journal of the American Medical Association. The original trial, which studied 16,608 postmenopausal women, was abruptly stopped in 2002 when links were revealed between postmenopausal women taking combination HRT—estrogen and progestin—and an increased risk of cardiovascular disease, stroke, blood clots, and breast cancer.
"Within a couple of years, the [raised] 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." A study in the Archives of Internal Medicine last week found women taking combined HRT for about five years had a higher risk of abnormal mammograms and breast biopsies, which may decrease the effectiveness of these methods for detecting breast cancer. Stefanick is chairwoman of the WHI investigator group, and Liu was the principal investigator for the WHI in Cincinnati until 2001.
That the associated heart trouble may not be permanent is promising. The new risks for other cancers—specifically lung tumors—in women who were on estrogen-progestin treatment for about five years, has researchers and other experts concerned. Those risks "were completely unanticipated," said Dr. Gerardo Heiss of the University of North Carolina in Chapel Hill, lead author of the follow-up analysis.
The new study involved 15,730 of the original WHI participants for an average of three years after that trial ended and found 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 as compared with the placebo group. During that time, those who'd taken hormones but stopped were 24 percent more likely to develop any kind of cancer than women who'd taken dummy pills during the study. 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." Follow-up data in the estrogen-alone portion of the WHI is not yet available.
The authors said the new results send the same message they've been advocating ever since the study ended which is that health risks from estrogen-progestin pills outweigh their benefits and should only be used to relieve hot flashes and other menopause symptoms in the lowest possible dose for the shortest possible duration.