The Latest Wisdom on Hormone Therapy
The news almost five years ago that hormone therapy might harm rather than protect women's health surprised researchers and led to a sharp decline in the number of women taking the drugs. Since the Women's Health Initiative findings showed that combined estrogen and progesterone therapy raises the risk of stroke, heart disease, and breast cancer, more studies have trickled out, refining what we know about how hormones alter the risk of those diseases. Three released in the past month have added to the evidence, including two this week examining hormone therapy's link to breast and ovarian cancer. Here's a wrap-up of the changing wisdom on HT:
What's the latest news on hormones and breast cancer?
The number of new breast cancer cases fell by nearly 7 percent in 2003. Now, a study published in the New England Journal of Medicine shows that the rate leveled off and stayed low in 2004. The findings support–though don't confirm–that the mass abandonment of hormone therapy in mid-2002 played a role in the decline of breast cancer incidence. In other words, they suggest the WHI study was right.
What kind of evidence backs that up beyond the timing of the decline?
Two things, says Peter Ravdin, an oncologist at the University of Texas M.D. Anderson Cancer Center in Houston and the leader of the study. First, the drop occurred only in women over 50, which is exactly who was using hormone therapy en masse until 2002. "The other strong link is that the majority of the decrease is in estrogen receptor positive breast cancers," he says. Those tumors are fueled by estrogen, either when it's produced naturally by the woman or taken via hormone therapy.
Still, this kind of study can never prove the role of hormones. Other proposed causes for the drop include a drop in the detection of new cases as the number of women being screened by mammograms has declined. The rate of screening mammography dropped 3.2 percent in women ages 30 to 65 between 2000 and 2003. No one knows why, but possibly women who went off HT thought their risk for breast cancer was low enough that they could skip their annual mammogram.
And what about ovarian cancer?
Another study, published this week in the online version of the Lancet, attributed to HT an extra 1,000 ovarian cancer deaths between 1991 and 2005 in the U.K. Researchers found more ovarian cancer in hormone therapy users–about 2.6 cases per thousand women using hormones, compared with 2.2 cases per thousand in women who weren't using them. Ovarian cancer increases weren't noted in the 2002 WHI data, but that study was far smaller: just under 17,000 women, compared with nearly a million in the U.K study. So an increase in the disease might not have shown up. Mary Daly, director of the Margaret Dyson Family Risk Assessment Program at Fox Chase Cancer Center in Philadelphia, says the link isn't definite, however. "Maybe women who take hormone therapy are different in some other way" that might raise their risk of the disease, she says.
What do we know now about hormones and the heart?
When the WHI data on heart risk was analyzed according to age and the number of years since menopause, it suggested that there's no additional risk of heart attack among women in their 50s who are on HT. But it seems that the further a woman gets from menopause, the greater the odds that hormones will hurt her heart. "That's very important for younger women who want to use hormones for short-term treatment of menopausal symptoms," says Jacques Rossouw, a researcher for the National Heart, Lung, and Blood Institute and an author of the study, which appeared in the Journal of the American Medical Association. "It's a reasonable option if they're within 10 years of menopause. Further than that, think long and hard about using them."
Are all hormones the same?
No, but it's still unclear exactly how they differ. These studies are referring to combined therapy–estrogen plus progesterone. Short-term use of estrogen alone doesn't seem to boost the risk of breast cancer, for reasons that are not understood. It does carry an additional risk of uterine cancer and isn't used in women who still have a uterus. Both estrogen alone and the combined therapy increased the risk of the heart problems and stroke. The new ovarian cancer study didn't find that risk varied by type of HT.
How does age factor in?
The heart study showed that the younger, the better, when it comes to taking HT. That may be true for cancer, too, says Ravdin. Since the disease already strikes older women more than younger, adding HT to the mix may multiply the risk of problems.
So what's the bottom line?
The basic advice hasn't changed: HT may be prescribed in the short term to relieve symptoms, but beyond a few years–and the further you are from menopause–the greater the risk. Talk to your doctor about how your individual risk balances out the potential benefits of HT. Those individual risks may include family history of cardiac disease and breast cancer as well as a history of clots while using oral contraceptives, both of which may signal a higher risk of heart problems, says Daly.