Coronary Calcium Screening and Incidental Lung Cancer Detection in Patients Ineligible for US Preventive Services Task Force Screening.

BACKGROUND: Current US Preventive Services Task Force lung cancer screening criteria exclude an estimated 40%-70% of individuals who ultimately develop lung cancer. Coronary calcium screening CT routinely captures thoracic anatomy and may provide an opportunity for earlier lung cancer detection outside established screening pathways. STUDY DESIGN: Retrospective cohort study of 9,702 adults undergoing coronary calcium screening CT at five hospitals within a single health system (2019-2022), excluding patients meeting 2021 U.S. Preventive Services Task Force screening criteria. Pulmonary findings were classified using 2017 Fleischner Society guidelines with longitudinal follow-up. Outcomes included pulmonary nodule detection, follow-up adherence, lung cancer diagnosis, stage at diagnosis, and modeled mortality, cost-effectiveness, radiation-associated harm, and unnecessary interventions. RESULTS: Actionable pulmonary nodules were identified in 1,136 patients (11.7%), of whom 486 (42.8%) completed recommended follow-up. Lung cancer was confirmed in 18 patients (3.7% of those completing follow-up); 83.3% had stage I disease, all of whom underwent curative resection, with 100% overall survival after a mean follow-up of 49.5 months. Modeled implementation of full field-of-view reconstruction with universal follow-up was estimated to avert 339 deaths (95% uncertainty interval, 190-417) per 100,000 screened at an incremental cost of $5,856 per quality-adjusted life-year, with benefit-to-risk ratios exceeding 100:1. Histology-specific growth modeling suggested that 75% of cancers in the Non-Guideline Institutional cohort would have been detectable at least 12 months before diagnosis. CONCLUSIONS: Systematic assessment of thoracic structures already imaged during coronary calcium screening CT, combined with reliable guideline-concordant pulmonary nodule follow-up, may complement existing lung cancer screening by enabling earlier detection among patients outside current screening eligibility.