The study also noted that the use of estrogen produced better outcomes for younger women than for women in their 70s. Heart disease risk, colorectal cancer risk and the overall risk of dying were lower in women in their 50s compared to those in their 70s, according to the study. ???Women in their 50s - who are the best candidates for estrogen therapy - show the best benefit-to-risk profile for short-term use of estrogen therapy,??? said LaCroix. ???We now have a really good set of data on what happens after you stop taking hormones and you can use this information to discuss risks and benefits with your physician,??? she added.

In an accompanying editorial in the same issue of the journal, Dr. Graham Colditz, chief of the division of public health sciences at the Washington University School of Medicine in St. Louis, said the reduction in breast cancer may be because these women were already past menopause when the estrogen was given. ???There's an involution of breast cells after menopause, so there would appear to be fewer bad actors waiting to respond to the hormones,??? he said.

Colditz also noted that the International Agency for Research on Cancer had concluded that the body of evidence suggests that estrogen-only hormone therapy and combination HRT are carcinogenic, and added that this study did not address longer-term estrogen hormone therapy use, which a meta-analysis of 16 studies has linked with an increased risk of breast cancer. In addition, he and his co-author wrote, the study showed ???no substantial benefit??? to women who undergo estrogen hormone therapy, compared to women who do not. ???Women should use estrogen with caution,??? Colditz concluded. ???There are risks from taking hormone therapy. Even when using estrogen for one to two years for relief of menopausal symptoms, there are still risk-benefit issues to deal with.???

Dr. Sylvia Wassertheil-Smoller, a professor at Albert Einstein College of Medicine, said the study was not a blanket endorsement of hormone therapy. ???What it does say is if [menopause] symptoms are intolerable and a woman does not have a uterus, she may not be harmed by estrogen alone if she takes it for a relatively short time,??? she said.