Outline and Evaluation of the National Lung Screening Trial

Abstract

Objective. On November 2010, the findings from the National Lung Screening Trial (NLST) were disclosed due to the positive results obtained. In this report, the outline of the NLST is introduced and future actions to be taken in Japan are discussed. Methods. Based on the articles and meeting reports, major findings from the NLST and relevant events were reviewed. Results. In the NLST, 50,000 smokers were randomly allocated into CT or X-ray arms. Three annual low-dose CT and conventional X-ray examination were provided for each arm, respectively. The rate ratio for lung cancer deaths was 0.80 (95% confidence interval: 0.73-0.93) for the CT arm compared to the X-ray arm and that for all causes of deaths was 0.93 (95% confidence interval: 0.86-0.99), both decreased with statistical significance. The efficacy of low-dose CT screening for smokers will be discussed mainly based on randomized controlled trials (RCT) from the US and Europe, although there are no data for nonsmokers in those countries. Conclusion. Issues concerning lung cancer among nonsmokers should be discussed in Asian Countries. Regarding this point the data from Japan may be valuable. Currently, a research group supported by the 3^rd comprehensive cancer research grant (Principal investigator: Prof. M. Sagawa) is conducting small-scale RCT for nonsmokers. This should be increased to a large-scale study, to obtain results within a shorter study period.