Women taking hormone replacement therapy to combat hot flashes, night sweats, and other menopausal symptoms may be wondering whether to flush their pills after hearing the latest frightening news. Not only does one popular brand raise the risk of breast cancer, but it raises the risk of being diagnosed with a more aggressive tumor that's more likely to kill them, according to a study published Tuesday in the Journal of the American Medical Association. Many experts believed that breast cancers caused by hormone therapy tended to be slower-growing and less life-threatening, but this new finding suggests otherwise. It also suggests that the increased breast cancer risk lingers even years after women go off the hormones. "These appear to be long-standing effects," says Peter Bach, an epidemiologist at Memorial Sloan-Kettering Cancer Center in New York who wrote an editorial that accompanied the study. "We don't know if the risks ever reverse."
The new finding is based on a clinical trial involving more than 16,000 postmenopausal women ages 50 to 79; they were randomly assigned to take hormones or placebos for several years until the trial, called the Women's Health Initiative, was abruptly halted in 2002 due to initial data indicating that the risks of taking hormones—such as strokes, heart disease, and breast cancer—outweighed the benefits. Since then, researchers have continued to follow nearly 13,000 of the WHI participants, which led to this week's breast cancer finding.
It's important to note that the increased risks, while significant, are still very small. Roughly 4.5 percent of those who took a combination of estrogen and progestin, called Prempro, developed invasive breast cancer during the study compared to 3.6 percent of those who took placebos; roughly 24 percent of the breast cancers diagnosed in the hormone therapy group had spread to the lymph nodes—which lowers the chance of survival—compared to 16 percent of breast cancers diagnosed in the placebo group. And the risk of dying from breast cancer during the study was minute in both groups: 3 in 1,000 for the hormone takers compared to 1 in 1,000 for the placebo group.
Still, the thought of women increasing their risk of a life-threatening disease just for symptom relief doesn't sit well with Bach. While far fewer women are taking postmenopausal hormones now than they did a decade ago, many continue to be prescribed one of the many varieties of estrogen available as a patch, cream, pill, or vaginal ring. (Women who haven't had hysterectomies must also take progesterone pills or synthetic progestins to avoid the heightened risk of uterine cancer that comes from using estrogen on its own.) In Bach's opinion, the U.S. Food and Drug Administration ought to review the latest data to determine if these therapies should remain on the market: "Would these drugs be approved today knowing what we now know about the risks?"
Not so fast, say gynecologists who specialize in treating menopause symptoms. "This is one study, a very powerful study, and I will share the results with my patients, but I don't think it makes the case for removing hormones from the market," says Isaac Schiff, chief of obstetrics and gynecology at Massachusetts General Hospital in Boston, who was not involved in the research. "Some women may still be willing to accept these risks," to feel better, he says. Indeed, writer Cynthia Gorney described in an April New York Times Magazine piece that although she once stopped hormone therapy out of fear for her health, she went back on an estrogen patch because it was the only treatment that lifted the depression she experienced after menopause. "I started taking estrogen because I was under the impression that I was going crazy," she wrote, "which turns out to be not as unusual a reaction to midlife hormonal upheaval as I thought."