A 30-year-old white woman in the U.S. has about an 11 percent chance, on average, of developing invasive breast cancer by the time she is 80 years old. That’s one of the predictions of a new model developed by researchers at Johns Hopkins University and other institutions around the world, based on data from eight large population-based studies that included more than 35,000 women. The risk is even higher—sometimes much higher—for women who have a family history (mother or sister who has had breast cancer), gene variations, or other nonmodifiable factors such as early menarche (onset of menstruation) or late menopause. Of course, the actual risk varies, depending on a woman’s particular circumstances.
Here’s the good news that came out of the research: Some of the risk appears to be modifiable. Published in JAMA Oncology in October 2016, the study reported that up to 30 percent of breast cancer cases could be prevented if women follow four specific lifestyle strategies: Lose weight if they are overweight, don’t smoke, cut down on or eliminate alcohol, and steer clear of hormone therapy. Even better news for women at elevated risk: As the authors wrote, “the benefit this population could achieve by changing modifiable risk factors is expected to be larger for those who are at higher risk from nonmodifiable factors.” They might, in fact, be able to reduce their risk to that of women at average risk.
Because the study included data only from white women, the results may not apply to women of other races—though it makes sense for all women to follow these risk-reducing strategies since they provide general health benefits.
Similar findings came from a study a few years ago in Breast Research that analyzed data from more than 85,000 postmenopausal women. Those who maintained a healthy weight, limited alcohol, and exercised had a 15 to 25 percent reduced risk of breast cancer over a five-year period, compared to women who didn’t maintain such lifestyle habits.
Breast bets for preventing cancer
Whatever your breast cancer risk factors are, here are some basic steps to take:
- Maintain a normal body mass index (BMI) between 18.5 and 25. To calculate your BMI, multiply your weight (in pounds) by 703; divide the result by your height (in inches); then divide again by your height. Or use the BMI calculator.
- Be physically active at least 30 minutes most days. The American Cancer Society recommends at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise a week for adults, preferably spread throughout the week.
- Limit alcohol to one drink a day (5 ounces of wine, 12 ounces of beer, or 1½ ounces of 80-proof spirits). Better yet, drink only on occasion or not at all, especially if you know you are at high risk for breast cancer or if you have had breast cancer. In a review of studies published in June, researchers from the International Agency for Research on Cancer found a clear dose-response relationship between alcohol consumption and breast cancer.
- For treatment of menopausal symptoms, seek alternatives to hormone therapy. If you do opt for hormones, take the lowest effective dose for the shortest possible time.
- And, of course, if you smoke, quit.
Also see Alcohol and Breast Cancer Risk.