Dr. Len answers the question: “Does discontinuing hormone replacement therapy increase risk of breast cancer?”
Q: If I stop taking hormone replacement therapy, does the risk of breast cancer persist?
A: There has been a lot of discussion in the medical community over the past several years regarding the benefits and risks of using hormone replacement therapy (HRT) with estrogen and progestin, sometimes referred to as combined HRT, to reduce the symptoms of menopause.
In 2002, researchers reported evidence of significant harm—including an increase in breast cancer cases—in a study of women who used combined HRT. News of the study, called the Women’s Health Initiative, led many women to stop taking HRT, and an analysis released last year found that in 2003, there were 14,000 fewer breast cancer diagnoses than in 2002, a drop of nearly 7 percent.
Not everyone agreed that the decline in new invasive breast cancer cases was solely because of fewer hormone prescriptions. The decrease appeared so quickly that other factors, including fewer women getting annual mammograms, may have had an impact. If women weren’t getting screened, breast cancer couldn’t be diagnosed in the first place, but the actual percentage drop in screening did not appear to account for most of the reduction in breast cancer cases.
Now, a new analysis of what happened to women in the Women’s Health Initiative trial suggests no similar sudden decline in breast cancer cases in those who stopped HRT in 2002. The analysis, which appeared in a March issue of the Journal of the American Medical Association, showed that within three years of stopping the 2002 trial, the risk of breast cancer slightly increased while the benefits of combined HRT—lower risk of colon cancer and hip fractures—dissipated. The authors concede that further follow-up and research are needed.
So, does this mean stopping HRT doesn’t account for the decrease in breast cancers, and the decline was due entirely to other explanations, like screening? Probably not.
Further follow-up in the coming years is needed before we can say for certain how the new, more conservative recommendations regarding HRT treatments will impact the number of newly diagnosed breast cancers. What we will most likely find is that all of these factors are important.
For women struggling with the symptoms of menopause, the message remains the same: If you are a woman age 40 or over and at average risk, use HRT with caution, at the lowest effective dose for the shortest time in consultation with your health care professional, and have a mammogram and clinical breast examination every year.
Len Lichtenfeld, MD, is deputy medical officer for the American Cancer Society.