The validity of low-dose CT screening for lung cancer in heavy smokers was supported by the results of National Lung Screening Trials (NLST) conducted in the U.S.A. The present study investigated the appropriateness of the introduction of low-dose CT screening for lung cancer in Japanese smokers aged between 55 and 74 years old, in terms of cost-effectiveness and age. To examine changes in the shift from conventional chest radiography (CR) to low-dose CT (LDCT) screening for lung cancer, we estimated the incremental cost-effectiveness ratio (ICER) using Iinuma’s mathematical model, and also conducted sensitivity analysis to determine the requirements for the introduction of a population-based screening. As the result, the incremental cost for one life-year saved was one million yen or lower when the costs of the screening were 8,000 and 6,000 yen and the recall rate was 10% for male and female smokers aged 55 to 59 years old, respectively. The recall rate was smaller when the interval between cancer screenings was two years, and the subjects were males. The higher the age of the subject, the smaller the incremental cost. In conclusion, at present, the mean cost of the LDCT test is approximately 10,000 yen in Japan. With a reduction in this cost by a few thousand yen, all Japanese smokers aged 55 to 74 years will be able to undergo LDCT screening for lung cancer annually
