title: Lung cancer incidence in middle-aged men estimated by low-dose computed tomography screening.
abstract: Lung cancer incidence in general middle-aged men estimated by low-dose computed tomography screening has been unknown. We conducted a longitudinal study to estimate the incidence of lung cancer in general middle-aged Japanese men based on smoking status and to determine the optimal targets for lung cancer screening. The subjects were 14,058 Japanese men aged 40-59 years (mean age, 48.3 years; median age, 49 years) who underwent twice or more low-dose computed tomography screenings at Nippon Telegraph and Telephone East Corporation Izu Hospital at the baseline examination during 2000-2007. Medical records of subjects with abnormal findings were collected and analyzed. The lung cancer incidence in men aged 40-59 or 50-59 years based on smoking status by person-years method, and relative risks of current- and former-smokers compared with non-smokers were calculated. Mean follow-up period was approximately 3 years, and total person-years were 45,152. The incidence was 24.4 per 100,000 person-years in men aged 40-59 years (95% confidence interval (95% CI) 13.6-43.6), and 56.5 in men aged 50-59 (95% CI 31.6-101). No statistically significances were observed among non-, current- and former-smokers. However, the relative risk of the current-smokers aged 50-59 years with 40 or more pack-years, compared with non-smokers was 6.31 (95% CI 1.27-31.3), and was statistically significant. No significant differences in the lung cancer incidence existed among any smoking status in the Japanese men aged 40-59 years. In this population, men aged 50-59 years with 40 and more pack-years could be an optimal target for lung cancer screening. The small number of incident lung cancers resulting in the incidence and relative risks with the wide 95% CI and the participants' demographic biases were the limitations of our study. Our screening recommendations should be made with more caution.
authors.affiliation: Department of Healthcare Economics and Quality Management, Graduate School of Medicine, Kyoto University, Yoshidakonoe-Cho, Sakyo-Ku, Kyoto 606-8501, Japan. t-nojo@gc4.so-net.ne.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nojo
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Imanaka
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Ishizaki
authors.forename: Miho
authors.initials: M
authors.lastname: Sekimoto
authors.forename: Masahito
authors.initials: M
authors.lastname: Yoshino
authors.forename: Takashi
authors.initials: T
authors.lastname: Kurosawa
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Takao
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
mesh_terms: D000328:Adult; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008137:Longitudinal Studies; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009367:Neoplasm Staging; D012907:Smoking / Q000009:adverse effects; D014057:Tomography, X-Ray Computed / Q000379:methods*