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.