OUTLINE: Patients are randomized to one of two screening arms. Arm I: Patients receive routine medical care, an annual nursing assessment, and an annual chest x-ray. Any new abnormality identified is further evaluated through standard acceptable medical interventions. Arm II: Patients receive routine medical care, an annual nursing assessment, and an annual spiral CT scan of the chest. If an abnormal mass greater than 10 mm in diameter or 5-10 mm in diameter and highly suspicious for malignancy is detected, chest x-ray and tissue diagnosis is obtained. If the abnormal mass is 10 mm or less in diameter, a thin section high resolution image of the mass is obtained. If this image is normal or benign, annual spiral CT scanning is continued. If the image is indeterminate, a repeat high resolution scan is performed in 3 months. If the image is unchanged at 3 months, annual spiral CT scanning is continued. If the mass is larger at 3 months, chest x-ray and tissue diagnosis is performed. Screening continues for 5 years in the absence of disease detection.