February 11, 2011
Dear Mayo Clinic:
How often should I be screened for breast cancer? What about self-examinations?
There are no set rules that can be generalized to all women for breast cancer screening. A variety of factors influence the screening schedule that's right for you, including your age, family history of breast cancer and other risk factors. But most doctors in the United States use some guidelines as a starting point.
A mammogram — an X-ray of your breast — is the best available breast cancer screening test. Mammograms are sensitive, inexpensive and well-tolerated. Mammograms meet the criteria for a screening test that can detect breast cancer early (before tumors can be felt) and reduce deaths from breast cancer. Mammogram technology has also improved, and the newer digital mammograms are more accurate than X-ray film for younger women with dense breast tissue. A number of organizations have a variety of guidelines about when and how often women should get mammograms.
In 2009, the U.S. Preventive Services Task Force (USPSTF) — a group of health experts that reviews published research and makes recommendations about preventive health care — issued new mammogram guidelines. They recommended that screening mammograms be done every two years, beginning at age 50 for women at average risk for breast cancer. For women ages 40 to 49, the decision to begin every-other-year mammograms should be individualized, based on the patient's values regarding risks versus benefits. USPSTF found that there was not enough evidence that mammogram screening is effective for women age 75 and older, so they didn't include specific recommendations for this age group.
These USPSTF guidelines caused controversy because they were considerably different from the American Cancer Society (ACS) guidelines, as well as other organizations' recommendations. The ACS guidelines call for yearly screening mammograms beginning at age 40 for women at average risk of breast cancer.
The USPSTF guidelines support the benefit of screening mammograms in reducing deaths from breast cancer in women. However, the USPSTF says the benefits of screening mammograms don't outweigh the harms for women ages 40 to 49. Potential harms stated by the USPSTF may include false-positive results that lead to unneeded breast biopsies and accompanying anxiety and distress.
At this time, most U.S. health care organizations continue to follow the ACS guidelines and begin annual screening mammograms at 40 because the benefits include early detection and a reduction in the risk of dying from breast cancer. The earlier cancer is detected, the more treatment options are available.
The USPSTF guidelines also addressed breast self-exams. Because the technique can be difficult for many women to do correctly, the recommendation was that women — if they choose to do self-exams regularly — should be informed of the limitations associated with breast self-exams and be instructed in the proper technique by their providers.
Mayo Clinic has reduced its emphasis on monthly breast self-exams. Instead, Mayo encourages all women to engage in breast health awareness. This includes becoming familiar with your breasts in the course of your usual hygiene routines, so you'll notice new changes or abnormalities and can have them evaluated by your doctor.
Clinical breast exams performed by your health care provider should also be part of your routine breast cancer screening. The general recommendation is that women in their 20s and 30s have a clinical breast exam at least once every three years, and annually beginning at 40.
In addition to screening for possible abnormalities, clinical breast exams provide an opportunity for women to start a conversation with their health care providers regarding their risk factors, breast cancer screening and breast health awareness.
Despite the controversy between organizations, the current stance is that breast cancer screening should include annual mammography beginning at age 40 for average risk women. An awareness of the general recommendations is helpful. That way, you can have an informed discussion with your health care provider about your personal values and breast cancer risk factors. That conversation can help you determine the breast cancer screening schedule that will best fit your needs.
— Sandhya Pruthi, M.D., Breast Diagnostic Clinic, Mayo Clinic, Rochester, Minn.