By Liz Szabo, USA TODAY
For many women, breast cancer is the most frightening of all diseases — partly because there are few clear steps they can take to avoid it.
Breast cancer survivor Renee Nicholas, 36, participates in a Pilates class in Austin. Exercising can help women after a diagnosis, but it also lowers the risk of getting breast cancer in the first place.
Yet experts say women can embrace one prevention strategy with unequivocal benefits: exercise. “One of the most important ways women can think about prevention is by maintaining a healthy weight throughout adulthood,” says the American Cancer Society‘s Susan Gapstur. “Ways to achieve that are clearly through eating a healthy diet and being physically active.”
There’s no way to eliminate all risk of cancer, which can strike even the healthiest people in their prime, experts acknowledge. But avoiding extra pounds reduces the risk of not only breast cancer, but tumors of the kidneys, esophagus, colon and uterine lining, says the National Cancer Institute. Staying lean also reduces risk of heart disease, stroke, diabetes, joint problems and other ailments.
In the Women’s Health Initiative, a landmark government-funded study, postmenopausal women who walked 30 minutes a day lowered their breast cancer risk by 20%.
Overall, obese women are 30% to 50% more likely to develop breast cancer than women at a healthy weight, says the NCI’s Rachel Ballard-Barbash.
But obesity’s relationship to breast cancer is complex. Obesity is most clearly linked to postmenopausal breast cancer. That’s partly because body fat raises levels of estrogen, which fuels most breast cancers, says Patricia Ganz of the University of California-Los Angeles. After menopause, when a woman’s ovaries shut down, her estrogen levels normally fall dramatically. Heavy women, however, continue to have higher estrogen levels, adding more fuel to tumors.
In a long-running American Cancer Society study, women who gained 21 to 30 pounds after age 18 were 40% more likely to develop breast cancer than women who stayed within 5 pounds of their youthful weight. Those who gained more than 70 pounds doubled their risk of breast cancer. Obesity may contribute to breast cancer in a number of ways, Ballard-Barbash says. Women who are heavy and inactive tend to have higher insulin levels than women who are active and trim. A growing field of research suggests that the hormone insulin and a similar protein called insulin-like growth factor also may send signals to breast tumors that help them get bigger, Ballard-Barbash says. Exercising, however, can help regulate insulin.
“If you can’t make time for being phsyically active in your daily life, plan to make time for being sick,” Ballard-Barbash says. She recommends women try to exercise every day, even if it’s just a walk. “I don’t buy that it’s not feasible. … I exercised through three pregnancies. If people don’t want to commit to this, they can commit to having a loss of function in their middle years.”
More ways to reduce your breast cancer risk
• Maintain a healthy weight. Obesity has been linked to many kinds of cancer.
• Limit alcohol consumption. Moderate drinking, or defined as two drinks a day, increases a woman’s risk of breast cancer by more than 20%, compared with women who don’t drink at all. Over a lifetime, that boosts a woman’s risk of breast cancer from 1 in 8 to nearly 1 in 6.
• Watch radiation. Reduce unnecessary radiation exposure, such as from CT scans.
• Avoid or limit use of hormone replacement therapy. Long-term use of hormones has been linked to ovarian and breast cancer.
• Time childbearing. If practical, have your first child by age 30.
• Breast-feed as long as possible, or at least several months.
• Consider medications. If you’re at high risk, for instance, if you have several close relatives with the disease, talk to your doctor about medications such as tamoxifen or raloxifene. While these can cut the risk of breast cancer, they cause their own side effects.
• Beware of chemicals. Limit exposure to estrogen-like chemicals, such as BPA, found in many plastics and the lining of metal cans. Also limit exposure to phthalates, chemicals that interfere with the hormone system, often found in plastics, fragrances and cosmetics.