Purpose of This Summary
This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about breast cancer screening. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.
Reviewers and Updates
This summary is reviewed regularly and updated as necessary by the PDQ Screening and Prevention Editorial...
Achieving balance between the benefits and harms of screening is especially important for women with a life expectancy of 5 years or less. Such women might have end-stage renal disease, severe dementia, terminal cancer, or severe comorbid disease with functional dependencies in activities of daily living. Early cancer detection and prompt treatment are unlikely to reduce morbidity or mortality within a woman's 5 years of expected survival, but the negative consequences of screening will occur immediately. Abnormal screening may trigger additional testing, with the attendant anxiety. In particular, the detection of a low-risk malignancy would probably result in a recommendation for treatment, which could impair rather than improve quality of life, without improving survival. Despite these considerations, many women with poor life expectancy due to age or health status often undergo screening mammography. A sizable proportion of patients with advanced cancer continue to undergo cancer screening tests that do not have a meaningful likelihood of providing benefit. For example, among women with advanced cancer compared with controls, at least 1 screening mammogram was received by 8.9% (95% confidence interval [CI], 8.6%–9.1%) versus 22.0% (95% CI, 21.7%–22.5%).
Screening mammography in women older than 65 years often results in additional diagnostic testing in 85 per 1,000 women, with cancer diagnosed in 9 women. The testing is often accomplished over many months, which may cause anxiety. While screening mammography may yield cancer diagnoses in approximately 1% of elderly women, many of these cancers are low risk. A study of California Medicare beneficiaries aged 65 to 79 years demonstrated this clearly. The relative risk (RR) of detecting localized breast cancer was 3.3 (95% CI, 3.1–3.5) among screened women. Diagnosis of metastatic cancer was reduced among screened women (RR = 0.57), suggesting a benefit of mammography screening in elderly women, though it comes with an increased risk of overdiagnosis.
Screening women in their 80s and 90s should be performed on a case-by-case basis, with comorbid diseases and life expectancy taken into consideration when making this decision.
There is no evidence for performing screening mammography in average-risk women younger than 40 years.
Approximately 1% of all breast cancers occur in men. Most cases are diagnosed during the evaluation of palpable lesions, which are generally easy to detect. Treatment consists of surgery, radiation, and systemic adjuvant hormone therapy or chemotherapy. Because of the rarity of the disease, it is extremely unlikely that any screening modality would be useful.
Individuals at Increased Risk of Breast Cancer and Thus Possibly With More to Gain From Screening