Nodule Detection by CT Screening of Chest

Abstract

Lung cancer screening using helical computed tomography (CT) has been carried out at the "Anti-lung cancer association, Tokyo" since 1993. We found 43 lung cancer cases (0.163%) during the 18-year period before introducing helical CT, but 76 lung cancer cases (0.436%) in 11 years after introducing helical CT. Among the cases detected in the screening period using helical CT, 74% were in stage IA, and the average size of the primary tumors was 17.3 mm. These data were better than in the screening period without helical CT. Of the 76 lung cancer cases detected after the introduction of helical CT, 19 cases (25%) were visible chest X-ray films, but 70 cases (92%) were visible on CT. We had 52 cases detected on repeated CT screenings, 41 cases (79%) of these cases were retrospectively found to have had a primary tumor overlooked previous CT screening images. In this seminar, former CT screening images of lung cancer cases were presented and we discussed how to improve earlier diagnosis.