Overview of guidelines for screening.

Controlled trials of screening for breast cancer have proven that (1) for women older than 50 years of age, screening with single-view or two-view mammography, at intervals of 1 to 3 years, with or without clinical examination reduces mortality; (2) annual screening with two-view mammography and clinical examination and emphasis on breast self-examination (BSE) can reduce mortality for women from 40 to 49 years of age; (3) screening this age group with single-view mammography, at intervals of 20 months or longer, without clinical or BSE results in excess mortality in women screened; (3) screening this age group annually with poor quality mammography, weakly interpreted, with some clinical examination results in excess deaths in screened women. If screening women 40 to 49 years of age is to be suggested there is no reason to suggest a model that has been proven to be counterproductive.