Did you know that breast cancer risk increases with age, and can be influenced by one's level of physical activity, diet, family history, age of first menstrual period, age at first live birth, use of hormone therapy, and previous cancer diagnosis?
Almost 200,000 women are diagnosed with breast cancer in the United States each year, making it the second leading cause of cancer deaths. Signs of breast cancer may include a lump, dimpling and pitting of breast skin, bloody discharge from the nipple or discharge from only one breast, or thickening of the breast skin and changes in breast size or shape1,2,3,4 Some women may not have any signs at all. Experts estimate that 38% of breast cancers in the United States can be prevented through lifestyle changes, such as those described below5.
The following are risks which may increase a woman’s risk for breast cancer. Some of these risks can be reduced by changes you can make.
Risk Factors that You Can Control
- Combination hormone replacement therapy, including estrogen and progestin. These hormones have been given to women in order to control postmenopausal conditions. In addition to breast cancer, long-term combination hormone replacement therapy increases your risk of heart disease and blood clots1.
- Obesity. There is convincing evidence that being overweight increases your risk of breast cancer, especially in women who have gone through menopause. Therefore, chose a diet low in fat, with lots of fresh fruits and vegetables, limit sugary drinks and processed foods, and exercise regularly1,2,3,5.
- Alcohol consumption. Having two or more drinks each day increases your risk of getting breast cancer by about 25 percent (A drink is defined as 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof liquor). Decreasing alcohol consumption has been associated with decreased cancer risk1,2,4. Therefore, it is recommended that women have no more than one alcoholic drink per day4,5.
- Physical Activity. Evidence is growing that physical activity reduces breast cancer risk. In one study, as little as 1¼ to 2½ hours per week of brisk walking reduced a woman's risk by 18%. Walking 10 hours a week reduced the risk even more4. Exercise can also help maintain a healthy weight, further reducing risk1. The American Cancer Society recommends 45 to 60 minutes of intentional physical activity 5 or more days a week in order to reduce your risk of breast cancer4.
- Birth Control Methods. There is some evidence that women who have used birth control pills have a slightly greater risk of breast cancer than women who have never used them. The increased risk appears to decline once a woman stops using birth control pills and returns to normal after ten years4.
- Tobacco Smoke. Recent research also indicates that exposure to tobacco smoke may increase the risk of breast cancer6,7.
- Having Children and Breastfeeding. Pregnancy decreases estrogen (a female sex hormone) production, which protects women, especially those who have children at a younger age1,2,4. Some studies also suggest that breastfeeding, especially if it is continued for 1 ½ to 2 years, lowers breast cancer risk4,5.
Risk Factors that You Cannot Control
- Estrogen, the primary female sex hormone. Women who have their first period before age 12, and those who experience late menopause, have increased breast cancer risk.
- Genetic factors, including mutations in the BRCA1 and BRCA2 genes. About 5 to 10 percent of breast cancers are thought to be hereditary. Discussing your family history with your doctor can help you determine whether genetic testing is appropriate3.
- Mammograms are the best method to detect breast cancer early when it is easier to treat and before a lump may be big enough to feel or cause symptoms. Men and women should talk to their health care provider about which tests are right for them and when to get them. The American Cancer Society recommends yearly mammograms starting at age 404. Other groups recommend a mammogram every other year for women aged 50 to 748.
- Women should be aware of any changes in their breasts. Women should seek medical advice if they detect any change in the shape or fell of their breasts.
- Eat a healthy, low fat diet, full of fresh fruits and vegetables and limit sugary drinks and processed foods (see also our Smart Tip on The Power of a Healthy Diet).
- Exercise regularly, 30 minutes a day for three to five days a week (see also our Smart Tip on Physical Activity).
- Limit your alcohol consumption to no more than 1 drink per day.
The National Cancer Institute’s Breast Cancer Risk Assessment Tool can help you calculate your risk of developing breast cancer. You can access the tool at: http://www.cancer.gov/bcrisktool/ Follow up with your doctor to discuss the results after taking the test.
Additional Smart Tips
Passive Smoke - Secondhand smoke, also know as environmental tobacco smoke, is the smoke that bystanders are exposed to when near a person who is smoking.
Cigarette Smoking - Lung Cancer is the #1 cancer killer for men and women in the United States and smoking causes about 90% of lung cancer deaths in men and 80% in women.
- http://www.mayoclinic.com (click on Health Information, and then Diseases and Conditions)
American Cancer Society Detailed Guide on Breast Cancer. Revised 9/6/12.
National Cancer Institute Fact Sheet on Secondhand Smoke and Cancer, reviewed 1/12/11.
- California Environmental Protection Agency, Office of Environmental Health Hazard Assessment. Secondhand Tobacco Smoke and Children’s Health.
Centers for Disease Control. Breast Cancer Screening. Updated September 17, 2012.