A100-09 Screening Eligibility and Survival Among Patients With Lung Cancer: A Korean Nationwide Cohort Study

Abstract Rationale Lung cancer screening (LCS) has demonstrated survival benefits among individuals with heavy smoking exposure, forming the basis of current age- and smoking intensity-based eligibility criteria. However, their applicability remains uncertain in Asia, where many cases occur outside current criteria, particularly among persons with no smoking history (PNSH). This study evaluated the proportions, characteristics, and survival outcomes of Korean patients with lung cancer according to international LCS eligibility. Methods This nationwide cohort study included 89,860 patients newly diagnosed with lung cancer in Korea between 2013 and 2018, prior to implementation of the national LCS program. Participants were followed from diagnosis until death or December 31, 2021. Patients were classified as meeting the 2023 American Cancer Society LCS eligibility criteria (aged 50-80 years with a smoking history of ≥ 20 pack-years PYs), individuals with 20 PYs, and PNSH within the same age range. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) for all-cause mortality (ACM), while multivariable Fine-Gray models were applied to estimate adjusted subdistribution HRs (aSHRs) for lung cancer-specific mortality (LCSM), accounting for competing risks. Additionally, outcomes were compared between patients aged 50-80 years and those diagnosed at a younger age (40-49 years), stratified by same smoking categories. Results Of all patients, 35.4% (31,084/89,860) were eligible for LCS, 44.1% (39,627/89,860) were PNSH, and 4.7% (4,232/89,860) were aged 50 years. Among individuals aged 50-80 years, the proportion diagnosed with distant metastatic disease was 40.9% in the LCS-eligible group, 41.1% in those with 20 PYs, and 36.9% in PNSH. Compared with the LCS-eligible group, risks of both ACM and LCSM were significantly lower among individuals with 20 PYs of smoking (aHR=0.95, 95% CI = 0.93-0.98 for ACM; aSHR=0.96, 95% CI = 0.93-0.99 for LCSM) and PNSH (aHR=0.86, 95% CI = 0.84-0.88 for ACM; aSHR=0.86, 95% CI = 0.84-0.88 for LCSM) aged 50-80 years. Compared with individuals aged 50-80 years, those aged 40-49 at diagnosis had a significantly lower risk of ACM and LCSM across all smoking categories (≥20PYs: aHR=0.56, aSHR=0.59; 20PYs: aHR=0.54, aSHR=0.57; PNSH: aHR=0.66, aSHR=0.67). Conclusions Current international LCS criteria exclude 64.6% of Korean patients, with a substantial proportion being PNSH. Ineligible patients aged 50-80 years had a lower risk of both ACM and LCSM than LCS-eligible patients, and younger patients demonstrated better survival outcomes. Population-specific strategies are needed to expand LCS eligibility and improve early detection and survival outcomes. This abstract is funded by: National R&D Program for Cancer Control through the National Cancer Center (NCC) funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HA23C0252).