Henschke CI, et al. - This study is performed to investigate the frequency/percentages of the largest noncalcified nodule (NCN), lung cancer cell types and Kaplan–Meier (K-M) survival rates, separately for baseline and annual rounds. The outcome of this study uncovered that the important differences in the frequency of NCNs and frequency and aggressiveness of diagnosed cancers in baseline and annual repeat should be recognized for an optimal regimen of screening.