Breast cancer screening has proved to be efficacious only in clinical trials or structured programs. However, little is known of its effectiveness as a regular practice. This study is an assessment of breast cancer screening in regular practice in a Spanish area of 350,000 inhabitants through analysis of existing sources of information. It is evident that this screening is insufficient, inefficient, very variable, nonspecific, and probably ineffective, although there is insufficient information to prove it. The immediate implementation of a well structured and accredited screening program is essential to overcome the current limitations.
