A study of the mass screening for the lung cancer in atomic bomb survivors. Clinical trends in relation to times of screening

For evaluating the significance of mass screening for lung cancer in atomic bomb survivors, results of the screening were compared between the previous 5 years (1981-1985) and recent 5 years (1989-1993). The previous years involved 39,363 subjects (16,825 males and 22,538 females; 50->70 years old) and the recent years, 55,891 subjects (23,396 males and 32,495 females; 40->70 years old). The screening was the direct chest roentgenography alone in the previous years, and in the recent years, the roentgenography plus cytodiagnosis of sputum (for high-risk subjects). The roentgenograms were read by 2 experts according to the standard criteria. Lung cancer was recognized in 41 subjects (104/100,000) in the previous years and in 65 subjects (116/100,000) in the recent years. Any particular trend was seen neither between tissue types and exposure conditions nor between exposure conditions. The proportion in stage I patients was slightly larger in the recent years. (K.H.)