Stefanick is chairwoman of the WHI investigator group, and Liu was the principal investigator for the WHI in Cincinnati until 2001.
The current research followed 15,730 of the original WHI participants for an average of three years after the trial ended.
The risk of cardiovascular problems was similar in the HRT and placebo groups (1.97 percent and 1.91 percent, respectively). However, there was a greater risk of overall cancer in the HRT group (1.56 percent of participants) as compared with the placebo group (1.26 percent). Most of this was explained by a heightened risk of breast cancer, the researchers said.
Lung cancer risk was slightly higher but not enough to draw any firm conclusions. "It's not such a big study that you can see all the things you need to see when you look across the population," Stefanick said. "The people who are actually studying cancer across the whole population will start to potentially identify other cancers that are related to the combination therapy."
Death from any cause was 15 percent higher in the HRT group than in the placebo group.
Putting all these factors together, the risks of combined HRT exceed the benefits, the authors stated.
"The really important message for women is they need to get a mammogram if they've stopped using hormones," Stefanick said. "They shouldn't think everything is fine. They need to get a mammogram to make absolutely sure. Once they've stopped the hormones, you have a better chance of detecting them."
Follow-up data in the estrogen-alone arm of the WHI is not yet available.
The National Heart, Lung, and Blood Institute has more on the Women's Health Initiative.
SOURCES: Marcia Stefanick, Ph.D., professor, medicine, Stanford University; James Liu, M.D., chairman
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