Periodic breast cancer screening in seven foreign countries.

Highly structured breast cancer screening programs with mammography are being introduced in seven foreign countries as a health-care entitlement. Routine screening starts either at 40 years of age or 50 years of age and is usually biennial. In the US, costs (except for Medicare and special programs) and how screening is conducted are dealt with in the private sector; guidelines specify mammography screening at shorter intervals starting at 40 to 49 years of age and include annual clinical breast examination. Provisions of screening programs have been influenced by results of efficacy studies and often by resource considerations. These results show a consistent picture of benefits of screening at 50 years of age and older; the international evidence for younger women is less clear.