Breast cancer and earlier detection efforts. Realized and unrealized impact on stage.

• Objective. —To test our hypotheses that increased public and professional education in breast cancer detection (screening mammography, clinical breast examination, and breast self-examination) would lead to detection at earlier stages of disease with each of the three methods. Design and Setting. —A survey study of all pathologically diagnosed breast cancers in a defined geographic area (all nonfederal general hospitals in the state of Vermont) before (1975-1984, n=1652) and after (1989-1990, n=683) screening mammography became more commonly used. Main Outcome Measures. —Method of detection of breast cancer and stage at detection. Results. —The age-adjusted annual incidence rate of breast cancer among adult women was 99 per 100 000 during the years 1975 to 1984 compared with 169 per 100 000 during 1989-1990 ( P P P P P Conclusion. —The earlier stages of detection and the sudden increase in incidence could almost entirely be credited to screening mammography. Mammographic screening had a much greater impact on stage at detection in women aged 50 years and older than in those younger than 50 years. ( Arch Surg . 1993;128:510-514)