In order to improve the efficiency and quality of mass screening for lung cancer and to establish a new system called the “Okayama Lung Project”, examinations which included dual and comparative reading of annual chest X-ray films, direct patient contact, and sputum cytology were studied.
Mass screening for lung cancer was conducted utilizing annual chest X-ray films obtained during mass screening for tuberculosis. A series of films was read and the identification numbers of each film showing evidence of any disease were recorded. Later, the entire series were independently read by the another radiologist blinded with respect to the first diagnosis (dual reading). Any chest X-ray with abnormal findings detected by dual reading was then compared with a previous film (comparative reading). For patients suspected of having lung cancer, direct contact was performed by the institution which would make a definitive diagnosis. Sputum cytology examination was conducted in the group at high risk for the hilar lung cancer. Using this new system, the time from mass screening to surgical resection was shortened by 50 days, and the detection rate in the high risk group for hilar lung cancer was elevated from 37.77/100, 000 to 46.44/100, 000. These results indicate that the Okayama Lung project is a satisfactory standard mass screening system for lung cancer.
Mass screening for Lung cancer