Mammograms: Huge Impact Seen on Reducing Cancer Deaths
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Regular Exercise May Help Breast Cancer Patients Live Longer
But what about women already diagnosed with breast cancer? Anne McTiernan, MD, PhD, notes that being overweight or obese reduces a woman's chance of surviving breast cancer. She and co-workers at Seattle's Fred Hutchinson Cancer Research Center set out to discover why.
A clue comes from the fact that after menopause, a woman's fat cells make the sex hormone estrogen. Estrogen can make existing breast tumors grow more quickly. So McTiernan's team calculated body mass index (BMI, a height-adjusted weight index) and measured body fat in 435 breast cancer patients. They also asked the women detailed questions about their physical activities.
Sure enough, the most obese women had significantly higher estrogen levels after menopause. They also had higher levels of the male sex hormone testosterone (yes, women have it, too), which can also make breast tumors grow faster. But the largest women also had lower blood levels of a substance -- sex hormone binding globulin -- that blocks sex-hormone action.
"Those women who were the most active had the highest level of sex-binding globulin," McTiernan says. "So it looks like physical activity is more than just a way to keep your body weight down. Weight reduction and increased physical activity may improve the prognosis for overweight and obese breast cancer patients."
McTiernan notes that these early findings still have to be proven in clinical trials before doctors can say for sure that more exercise will improve breast cancer survival.
Leitch says that the message from the study is that options are increasing for women to take an active role in surviving their disease.
"For a women diagnosed with breast cancer, the question is, 'If I make an intervention now, can I make a difference in how long I will live after getting breast cancer, or is that damage already done?'" she says. "Women diagnosed with breast cancer always want to do something themselves to change what is going to happen with their outcome -- they want to do something themselves."
The message isn't just for some women: one in eight U.S. women will develop breast cancer. In the year 2001, experts expect to see 193,000 new cases of advanced breast cancer and 46,400 new cases of early breast cancer.