Low-dose CT screening for lung cancer reduced lung cancer mortality in Hitachi City

Purpose: To detect early, curable lung cancer, screening using low-dose CT (CT screening) was initiated in Japan and Western countries around the early 1990s. Material and methods: In 2013, the National Lung Screening Trial (NLST) reported that annual CT screening for high-risk participants leads to a 16% reduction in lung cancer death. In Hitachi City, CT screening for citizens 50 years of age or older was started in 1998, and 30% of the citizens had received a CT examination at least once by 2006. Results: We reported excellent survival (5-year survival of 90%) of 210 patients with lung cancer detected by CT screening. Based on a time trend analysis, a significant reduction (24%) in lung cancer mortality was observed 4 to 8 years after the introduction of CT screening among Hitachi residents. CT images can detect numerous smoking-related factors represented by pulmonary emphysematous change (CT emphysema). If we can evaluate the risk of respiratory disease according to these images, the benefits of screening are expected to increase further. Conclusion: To establish the effectiveness of CT screening for the general population, an optimum screening schedule is desired based on the risk of individuals. In addition, long-term follow-up is necessary to evaluate the effects of radiation exposure.