Greater understanding of the prognosis for patients with lung cancer in Japan according to detection pathway would clarify the effect of population-based screening programs and the related diagnostic environment. We explored the clinical characteristics and net survival (NS) of patients with lung cancer by detection pathway with Japanese National Cancer Registry (NCR) database of patients registered between 2016 and 2020. Eligible patients were categorized based on detection pathway: Screening, Incidental, and Other groups. We estimated 1, 2, and 3 year NS. Of 565,044 patients with lung cancer in the NCR, 563,244 met the eligibility criteria and were included in this study: 95,081 patients in the Screening (16.9%), 254,569 in the Incidental (45.2%), and 200,850 in the Other groups (35.7%). In the Screening, Incidental, and Other groups, 69.5%, 88.6%, and 83.4% of patients, respectively, were aged ≥ 65 years, and 50.5%, 49.6%, and 14.0% of patients, respectively, had localized disease at diagnosis. The most common initial treatment was surgery in the Screening (62.5%) and Incidental (46.2%) groups, while chemotherapy was most frequently used in the Other group (48.6%). The 3 year NS was 75.2% (95% confidence interval: 74.9%-75.6%) in the Screening group, 56.3% (56.0%-56.6%) in the Incidental group, and 29.4% (29.2%-29.7%) in the Other group. In the subgroup analysis, 3 year NS for localized disease was 96.3% (95.9%-96.7%), 83.9% (83.6%-84.3%), and 76.9% (76.1%-77.6%), respectively, for the Screening, Incidental, and Other groups. Screening may play a key role in early detection and is likely to contribute to survival outcomes.
Koto et al. (2026) studied this question.