Screening for Breast Cancer: Recommendations from the U.S. Preventive Services Task Force

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The summary below is from the full reports titled "Screening for Breast Cancer: Recommendations and Rationale" and "Breast Cancer Screening: A Summary of the Evidence for the U.S. Preventive Services Task Force." They are in the 3 September 2002 issue of Annals of Internal Medicine (volume 137, pages 344-346 and pages 347-360). The first report was written by the U.S. Preventive Services Task Force; the second report was written by LL Humphrey, M Helfand, BKS Chan, and SH Woolf.

What is the U.S. Preventive Services Task Force?

The U.S. Preventive Services Task Force (USPSTF) is a group of health experts that reviews published research and makes recommendations about preventive health care.

What is the problem and what is known about it so far?

The goal of screening for breast cancer is to find breast cancer at early, treatable stages. Ways to screen for breast cancer include breast self-examination (women feel for lumps in their own breasts), clinical breast examination (doctors or nurses examine women's breasts for lumps), and mammography. Mammography is an x-ray of the breast that often shows breast tumors before they are large enough to feel. Experts do not all agree about whether mammography decreases breast cancer death rates. The disagreement is strongest for mammography in 40- to 49-year-old women.

How did the USPSTF develop these recommendations?

The USPSTF evaluated published research about the risks and benefits of breast self-examination, clinical breast examination, and screening mammography.

What did the authors find?

The USPSTF found fair evidence that women 40 to 69 years of age who have screening mammography every 1 to 2 years die of breast cancer less frequently than women who do not have screening mammography. The benefits increase as women become older. Inviting 838 women 50 to 69 years of age to have mammography will prevent one breast cancer death. Inviting 1792 women 40 to 49 years of age to have mammography will prevent one breast cancer death. There are few studies of mammography for women 70 years of age and older. The potential harms of mammography include anxiety, procedures, and costs that result from mammograms that suggest cancer when there is none (false positives). The USPSTF found no evidence that breast-self examination or clinical breast examination reduced breast cancer death rates. Other experts have drawn different conclusions from the same evidence; they decided to exclude the results of some studies because of weaknesses in the study methods. The USPSTF also found weaknesses in these studies but did not think the weaknesses justified ignoring the studies' results.

What does the USPSTF suggest that patients do?

The USPSTF recommends that women 40 years of age and older consider having screening mammography every 1 to 2 years. Women should understand that there is a possibility that they will have false-positive results on mammography. They should then weigh the potential risks (anxiety and additional procedures, such as breast biopsy) and the benefits (reduction in breast cancer death rates for women their age) when deciding whether to get mammography. For women 70 years of age and older, the USPSTF recommends screening mammography every 1 to 2 years unless a woman has other serious illnesses that are likely to reduce her life expectancy.

What are the cautions related to these recommendations?

The USPSTF found that almost all of the studies of breast cancer screening had weaknesses. As better studies become available, recommendations about breast cancer screening may change.