Lifestyle Changes Cut Breast Cancer Risk
Researchers Say Exercise and Diet May Prevent Some Cases of Breast Cancer
Sept. 3, 2009 -- More than 70,000 breast cancer cases a year in the U.S., or 40% of all cases, could be prevented with lifestyle measures like maintaining a healthy weight, eating well, exercising, and limiting alcohol consumption, a new analysis shows.
The joint project from the nonprofit research groups American Institute for Cancer Research and the World Cancer Research Fund represents the largest review ever of the research examining lifestyle and breast cancer.
Researchers analyzed nearly 1,000 studies, including 81 conducted since the data were last examined in 2007.
"It is now very clear that lifestyle is a strong modifiable risk factor for breast cancer, but I don't think women have really gotten the message," says Cancer Institute of New Jersey epidemiology professor Elisa Bandera, MD, PhD, who helped write the report.
"Women tend to overestimate the role of genetics in breast cancer and underestimate lifestyle," Bandera tells WebMD. "I don't know how many times I've heard a patient say, 'I can't have breast cancer. Nobody in my family has it.' Women are very concerned about breast cancer, and they need to know they can lower their risk with lifestyle."
Lose Weight to Lower Risk of Breast Cancer
Perhaps the biggest single thing a woman can do to lower her risk, especially after menopause, is maintain a healthy weight.
Obesity is now widely recognized as the most important modifiable risk factor for breast cancer among postmenopausal women, and it also increases a postmenopausal woman's chance of dying from the disease once she has it.
The National Cancer Institute estimates that as many as 18,000 deaths from breast cancer each year in the U.S. could be prevented in women over age 50 by maintaining a healthy weight throughout adulthood.
About three out of four breast cancers in this age group are fueled by the hormone estrogen, which is also produced in fat tissue. Estrogen levels in overweight, postmenopausal women are 50% to 100% higher than among lean women, according to the National Cancer Institute.
Breast cancers also tend to be detected later in overweight women, mainly because tumors are harder to detect with mammography.