Changes in lifestyle can impact cancer prevention.
Potentially harmful side effects restrict chemoprevention agents to women with a high risk of breast cancer. But in terms of sheer number, more average-risk women ultimately get breast cancer.
For these women , changes in exercise and diet may be the best prevention bet. “We need to look further than synthesized drugs,” says Carol Fabian, MD. “Behavioral modifications may be just as effective.”
Diet and exercise certainly affect breast cancer risk. For example, studies show women who eat a Mediterranean diet rich in fruits and vegetables throughout their lives have a reduced risk of breast cancer. A direct relationship between breast cancer and alcohol use has been made, with the risk being slightly raised even with one to two drinks a day. This absolute risk increase is very small and possibly offset by a small protective effect on the heart from light to moderate alcohol use. Research has also demonstrated an association between moderate to vigorous exercise and decreased breast cancer risk among premenopausal and postmenopausal women.
What isn’t known is whether mid-life course corrections can make a difference. “Will an exercise program taken up by a middle-age at-risk woman markedly reduce her risk of breast cancer? As a scientist, I don’t know that,” says Victor G. Vogel, MD. While the data for exercise is encouraging but inconclusive, the American Cancer Society recommends moderate to vigorous exercise for 45 to 60 minutes five or more days per week.
Mediterranean, low-fat and high-produce diets are all under clinical investigation. The Women’s Intervention Nutrition Study (WINS) reduced fat content in the diets of postmenopausal women with breast cancer, and concluded it may reduce the risk of recurrence. The Women’s Healthy Eating and Living, or WHEL, study is currently looking at a similar population, but features a diet rich in fruits and vegetables. Investigators are crunching numbers and plan to release findings later this year.
“If it does nothing for breast cancer it still does an awful lot for heart and bones and mental health,” says Dr. Vogel. “It’s still a very prudent recommendation for people, as much as possible, to try to maintain or achieve ideal body weight.”
On the horizon could be interventions that start at age 15 instead of 45. “Phytoestrogens—soy and flaxseed—probably work best when we start around adolescence,” says Dr. Fabian.