Prevention

No intervention is 100% guaranteed to prevent breast cancer occurrence. However, women have several options to reduce the risk of developing breast cancer.

• For women with especially strong family histories of breast cancer (such as those with BRCA1 or BRCA2 mutations), a prophylactic mastectomy (preventive removal of the breasts) may be considered. This appears to reduce the risk of developing breast cancer by at least 95%. These women may also consider a prophylactic oophorectomy (removal of the ovaries), which can reduce the risk of developing breast and ovarian cancers.
  
  
• Women who are at higher than normal risk for developing breast cancer may consider chemoprevention (the use of drugs to reduce breast cancer risk). Two drugs, tamoxifen (Nolvadex) and raloxifene (Evista), are approved to lower breast cancer risk. These drugs are called selective estrogen receptor modulators (SERMs). A SERM is a medication that blocks estrogen receptors in some tissues and not others. Women that have gone through menopause (postmenopausal) and women who have not (premenopausal) may take tamoxifen, whereas raloxifene is only approved for postmenopausal women. Each drug also has different side effects; talk with your doctor about whether you may benefit from chemoprevention for breast cancer. Read more about drugs to reduce breast cancer risk.
  
  
• Other ways to lower your risk of breast cancer include getting regular physical activity, staying at a normal weight, and limiting the amount of alcohol you drink. Learn about more lifestyle changes to prevent cancer.

Several breast cancer risk assessment tools have been developed to help a woman estimate her chance of developing breast cancer. The best studied is the Gail model (www.cancer.gov/bcrisktool). After entering some personal and family information, the tool provides a five-year and lifetime estimate of the risk of developing invasive breast cancer. Because it only asks for information about breast cancer in first-degree family members (mother, sister) and doesn’t include their age at diagnosis, the tool works best at estimating risk in women without a strong inherited breast cancer risk.

For most women, regular mammography and clinical breast examinations can help find early signs of breast cancer. In addition, women should become familiar with their own breasts. Checking your own breasts for lumps and changes with breast self-examination may help if performed correctly. Talk with your doctor for more information.

Screening guidelines

The U.S. Preventive Services Task Force (USPSTF) recommends that women 50 to 74 years old undergo mammography every two years, and the American Cancer Society (ACS) recommends yearly mammography beginning at age 40. Mammography is the best tool doctors have to screen for breast cancer and can detect a tumor that is too small to be felt. All women should talk with their doctors about mammography and decide on an appropriate screening schedule.

Occasionally, mammograms may miss a cancer. Other methods of breast imaging, such as ultrasound and magnetic resonance imaging (MRI), are not regularly used for screening purposes. However, they may be helpful for evaluating women at a higher risk for breast cancer, including women with a BRCA mutation and women who received radiation therapy for Hodgkin lymphoma. These other screening methods may also be used for those with a suspicious finding on physical examination or mammography. If there are suspicious findings on physical examination, further evaluation is necessary, even if the mammogram is interpreted as normal.

The USPSTF and ACS differ on their recommendations for clinical breast examination. The USPSTF recommends a clinical breast examination along with mammography, and the ACS recommends a clinical breast examination every one to three years until age 40, then annually. Breast self-examination has not been shown to lower deaths from breast cancer, but it is important for women to become familiar with their breasts so that they can be aware of any changes. Women are encouraged to discuss the frequency of screening with their doctors. Learn more about ASCO’s perspective on the 2009 USPSTF mammography screening guidelines.