Recommendation Statement From USPSTF: Screening for Breast Cancer

US Preventive Services Task Force (USPSTF)

Disclosures

December 17, 2009

In This Article

Considerations for Practice Regarding I Statements

Clinical Breast Examination

Potential preventable burden. The evidence for CBE, although indirect, suggests that CBE may detect a substantial proportion of cases of cancer if it is the only screening test available. In parts of the world where mammography is infeasible or unavailable (such as India), CBE is being investigated in this way.

Potential harms. The potential harms of CBE are thought to be small but include false-positive test results, which lead to anxiety and breast cancer worry, as well as repeated visits and unwarranted imaging and biopsies.

Costs. The principal cost of CBE is the opportunity cost incurred by clinicians in the patient encounter.

Current practice. Surveys suggest[1] that the CBE technique used in the United States currently lacks a standard approach and reporting standards. Clinicians who are committed to spending the time on CBE would benefit their patients by considering the evidence in favor of a structured, standardized examination.[2]

Digital Mammography

Potential preventable burden. Digital mammography detects some cases of cancer not identified by film mammography; film mammography detects some cases of cancer not identified by digital mammography. Overall detection is similar for many women. For women who are younger than 50 years or have dense breast tissue, overall detection is somewhat higher with digital mammography. It is not clear whether this additional detection would lead to reduced mortality from breast cancer.

Potential harms. The possibility of false-positive test results is similar for film and digital mammography. It is uncertain whether overdiagnosis occurs more with digital mammography than with film mammography.

Costs. Digital mammography is more expensive than film mammography.

Current practice. Some clinical practices are now switching their mammography equipment from film to digital. This may curtail the availability of film mammography in some areas.

Magnetic Resonance Imaging

Potential preventable burden. Studies of the use of contrast-enhanced MRI for breast cancer screening have been conducted only in very high-risk populations. In these studies, MRI detected more cases of cancer than did mammography. It is unknown whether detecting these additional cases of cancer would lead to reduced breast cancer mortality.

Potential harms. Contrast-enhanced MRI requires the injection of contrast material. Studies of MRI screening have shown that MRI yields many more false-positive results than does mammography. MRI has the potential to be associated with a greater degree of overdiagnosis than mammography.

Costs. MRI is much more expensive than either film or digital mammography.

Current practice. MRI is not currently used for screening women at average risk for breast cancer.

Screening Mammography in Women 75 Years or Older

Potential preventable burden. No women 75 years or older have been included in the multiple randomized clinical trials of breast cancer screening. Breast cancer is a leading cause of death in older women, which might suggest that the benefits of screening could be important at this age. However, 3 facts suggest that benefits from screening would probably be smaller for this age group than for women aged 60-69 years and probably decrease with increasing age: (1) the benefits of screening occur only several years after the actual screening test, whereas the percentage of women who survive long enough to benefit decreases with age; (2) a higher percentage of the type of breast cancer detected in this age group is the more easily treated estrogen receptor-positive type; and (3) women of this age are at much greater risk for dying of other conditions that would not be affected by breast cancer screening.

Potential harms. Screening detects not only cancer that could lead to a woman's death but also cancer that will not shorten a woman's life. Women cannot benefit from -- but can be harmed by -- the discovery and treatment of this second type of cancer, which includes both cancer that might someday become clinically apparent and cancer that never will. Detection of cancer that would never have become clinically apparent is called overdiagnosis, and it is usually followed by overtreatment. Because of a shortened life span among women 75 years or older, the probability of overdiagnosis and unnecessary earlier treatment increases dramatically after about age 70 or 75 years. Overdiagnosis and unnecessary earlier treatment are important potential harms from screening women in this age group.

Current practice. Studies show that many women 75 years or older are currently being screened.

Useful Resources

Other USPSTF recommendations on screening for genetic susceptibility for breast cancer and chemoprevention of breast cancer are available on the Agency for Healthcare Research and Quality Website (http://www.preventiveservices.ahrq.gov).

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