Current status of screening for lung cancer.

Three parallel studies on screening for lung cancer, supported by the National Cancer Institute, were carried out by the Mayo Clinic, Johns Hopkins Medical Institutions, and Memorial Sloan-Kettering Center from 1971 to 1982. No significant mortality improvement was established that could be attributed to cytologic screening examinations. Many stage I lung cancers were detected by radiographic screening, with excellent changes for long-term survival. Patients with stage I cancers who were operated on had significantly better survival rates than those who failed to undergo surgery. Statistical modeling, however, indicates that long-term annual screening of a high-risk population would decrease lung cancer mortality by no more than 18%.