Screening for breast cancer. Report from Edinburgh Breast Screening Clinic.

As part of a trial to determine the feasibility of screening for breast cancer, 3952 women aged 40--59 years were screened once or more over two years. They represented 82% of those invited by a personal letter from their GPs. Each woman underwent mammography, two clinical examinations, and, usually, thermography. Further investigations included needle aspiration of cysts, xeromammography, and biopsy. Of the 125 women who underwent biopsy, 18 proved to have cancer. Because of the high response rate and consequent large sample of normal women the biopsy and cancer detection rates were low. Clinical examination and mammography together were more effective in detecting significant lesions than either procedure alone, and knowledge of the mammographic findings enabled the examiner to detect more abnormalities. Screening was expensive: each cancer detected cost about 6000 pounds, excluding data processing, surgical, and pathological costs. The clinic has now adopted a more simplified screening regimen, which should reduce costs, but more accurate imaging techniques and ways of identifying high-risk cases are needed.