Study of hormone therapy shows some risks persist
By Andrew Stern
CHICAGO (Reuters) - A follow-up analysis of women taking hormone replacement therapy found that their heightened risk of breast cancer persisted even after they stopped taking the drug combination, researchers said on Tuesday.
The Women's Health Initiative study was halted prematurely in 2002 because of a 24 percent higher risk of breast cancer associated with the combination therapy of estrogen and progestin. Progestin is used to offset the heightened risk of uterine cancer from taking estrogen.
The original study found women taking the combination of hormones also doubled their risk of blood clots, and raised their risks of stroke and heart attack.
The overriding conclusion from the two Women's Health Initiative trials involving 27,347 post-menopausal women, aged 50 to 79, was that the overall risks of long-term use of hormone therapy outweighed the benefits.
The 2-1/2-year follow-up analysis, led by Gerardo Heiss of the University of North Carolina and published in the Journal of the American Medical Association, assessed through 2005 the health of 15,730 women who took the combination of hormones.
After the women stopped therapy, their heightened risk of breast cancer remained roughly the same. But their risks of heart attack, blood clots and stroke receded quickly back to levels among women who had not taken hormone therapy.
The ancillary benefits of combination hormone therapy -- lower risks of colon cancer and bone fractures -- also disappeared after therapy was stopped.
"The good news is that after women stop taking combination hormone therapy, their risk of heart disease appears to decrease," said Dr. Elizabeth Nabel, director of the National Heart, Lung, and Blood Institute, part of the U.S. National Institutes of Health that sponsored the original WHI study.
"However, these findings also indicate that women who take estrogen plus progestin continue to be at increased risk of breast cancer, even years after stopping therapy," Nabel said in a statement.
"The hormones' effects on breast cancer appear to linger," said Dr. Leslie Ford of the Division of Cancer Prevention at the NIH's National Cancer Institute. "These findings reinforce the importance of women getting regular breast exams and mammograms, even after they stop hormone therapy."
The WHI study, designed to examine whether hormone therapy prevented heart attacks, has been closely scrutinized. The surprise findings triggered a steep drop in the use of combination therapy and recommendations to employ lower dosages of the hormones for the shortest possible time.
In a news conference organized by drug maker Wyeth, the company, which is the leading maker of hormone replacement therapy, said the follow-up analysis was likely to add to the confusion for women faced with the decision about what to do about disruptive symptoms of menopause such as hot flashes, night sweats and vaginal atrophy.
For one thing, the company said, the women in the study tended to be older -- average age 63, compared to the early 50s for most women at the onset of menopause -- and many did not have menopausal symptoms when they began taking the therapy.
"In recent years there has been reanalysis of WHI findings that have shown that the increased risks associated with the older women, as described in this study, were not consistently shared by the younger women who participated in the study," said Wyeth's chief medical officer Gary Stiles.
(Editing by Cynthia Osterman)