Women got another scare this week in the latest news on hormone replacement therapy and cancer. "Cancer Risk Stays After Hormone Therapy," blared the Washington Post on its front page (albeit below the fold); the Los Angeles Times noted, "Hormone Drugs Had Lasting Breast Cancer Risk." In fact, the study published in the Journal of the American Medical Association found that the increase in breast cancers after stopping HRT wasn't statistically significant—which means it could have been due to pure chance The study did find that a woman's risk of developing any sort of cancer was somewhat higher three years after going off hormones. But even that was based on what some researchers say is a questionable statistical analysis called a "global risk index."
I'm fortunate enough to have an office situated next to U.S. News health columnist Bernadine Healy, who as former head of the National Institutes of Health initiated the Women's Health Initiative trial on which these findings are based. We've spent the week discussing our frustration with how these news reports might scare the wits out women who legitimately need to take hormones for severe hot flashes, night sweats, and mood swings. And those women who've already gone off hormones, who now think the extra breast cancer risk will linger for three years or more. For an accurate take on the study, check out Dr. Healy's column.
What do you make of these findings? I asked Roger Lobo, a professor of obstetrics and gynecology at Columbia University who has published research on other WHI data but was not associated with this study. "When you get into the journal paper, you see that nothing is really statistically significant," he says. The researchers combined all the cancers together to show that the overall risks outweighed the overall benefits; individually, the differences are not meaningful. Not the increase in breast cancer, nor the increase in lung cancer, nor the decrease in hip or spine fractures due to osteoporosis. (Previous WHI findings show a small but real increased risk of breast cancer and heart disease while women take HRT and a decreased risk of fractures and colon cancer.) So let's just suppose that the increased breast cancer risk of about 25 percent at three years after stopping hormones was in fact shown to be due to hormone use. Given that the average non-hormone-using 50-year-old woman's likelihood of developing breast cancer over the next 10 years is 2.8 percent, Lobo says, the increased risk would elevate her chances to 3.4 percent—not the sort of scary statistic that should keep you up at night. And, hey, we're just pretending here because this finding wasn't determined to be caused by hormones.
So where does this leave women? First of all, they should be comforted by the fact the studies are still ongoing to determine what effect hormones have on a woman's body. They should also keep in mind that the doses given to women in the WHI trial are about double what most women get today. "It usually doesn't take much to ease hot flashes and other symptoms," says Lobo. So if the increased risks are small at higher doses, they're probably minute at lower doses.
Above all, the landmark trial served an important purpose in determining that hormones shouldn't be used to "keep women young." The study showed that the overall risks of taking hormones—more heart attacks, blood clots, stroke and breast cancer—outweigh the overall benefits of fewer fractures and colon cancer. The common practice of giving postmenopausal women hormones to combat disease rightly fell by the wayside thanks to this important study.