The relationship of breast cancer epidemiology to screening recommendations.

The epidemiology of breast cancer involves several factors that may be useful in deciding to recommend breast cancer screening. Paramount among these factors is age. A family history of breast cancer may be a basis for modifying screening recommendations, but this may be appropriate only for a subset of women with breast cancer in a relative. Although there are several known risk factors for breast cancer, no single factor accounts for a large proportion of disease, and many patients with breast cancer have none of the recognized risk factors. A decision to forgo screening based on the absence of any single factor other than age may not be justified by current epidemiologic knowledge.