Study objective: To evaluate the feasibility of lung cancer screening using low-dose spiral CT as a part of annual health examinations.
Design: Nonrandomized, screening practice.
Methods: From April 1998 to August 2000, CT screening was performed as a part of annual health examinations on a total of 7,956 individuals who belonged to the Hitachi Employee's Health Insurance Group. Of those participants, 5,568 were rescreened 1 year later. When a noncalcified solitary pulmonary nodule (SPN) >or= 8 mm was detected on CT screening, a detailed CT scan was carried out approximately 1 month later.
Results: During the baseline screening, a total of 2,865 noncalcified SPNs were detected among the 7,956 participants. Primary lung cancer was histologically confirmed in 40 patients (41 lesions). The prevalence was 0.44% of all participants from the baseline, and 0.07% from the repeated screening. Thirty-five of 41 tumors were stage I. Current or former smokers represented only 17 of 40 cases. The detection rate was rather high in female participants.
Conclusion: Low-dose spiral CT seems to be a promising method for screening early lung cancer as a part of annual health examinations. Female and nonsmoking subjects should be included in the baseline screening. However, for yearly repeat screening, the participants may be selected on the basis of gender, smoking history, and results at the baseline screening.