Epidemiologic and Survival Analyses of Lung Cancer in Nagano Prefecture: Impact of Serial Low-Dose Computed Tomography Screening

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Introduction Low-dose computed tomography (LDCT) screening for lung cancer has been implemented in many municipalities in Nagano prefecture. We analyzed epidemiologic and survival data of patients with lung cancer among municipalities in Nagano prefecture to evaluate the impact of LDCT. Methods This was a retrospective cohort study. Data regarding the number of LDCT screenings, population, and lung cancer deaths in each municipality in 2011 to 2020 were collected and collated with information from the population-based cancer registry. These data were compared between municipalities that had continuously implemented LDCT (LDCT [+], n=26) and those that had not (LDCT [−], n=11). Results The mean lung cancer crude mortality rate and standardized mortality ratio were significantly lower in LDCT (+) (82.2 ± 14.1 per 100,000 ( p < 0.02) and 69.7 ± 11.9 ( p < 0.005), respectively) than LDCT (−) (92.0 ± 10.1 per 100,000 and 81.6 ± 11.5, respectively). In addition, the mortality rate in each municipality was significantly negative correlated with the numbers of LDCT implementation in each municipality ( r = 0.39). With regard to the extent of lung cancer at diagnosis, the proportion of localized lung cancer was significantly higher in LDCT (+) (39.4 ± 7.4%) than in LDCT (−) (34.6 ± 7.4%), and the proportion of localized lung cancer in each municipality was positively correlated with the number of LDCT implementation. Conclusion This retrospective analysis in Nagano prefecture indicated that serial LDCT could contribute to a decrease in lung cancer mortality in the general population.