Incidentally Detected Lung Cancer in Persons Too Young or Too Old for Lung Cancer Screening in a Mississippi Delta Cohort

Abstract

IntroductionLung cancer risk in screening age-ineligible persons with incidentally detected lung nodules is poorly characterized. We evaluated lung cancer risk in two age-ineligible Lung Nodule Program (LNP) cohorts. MethodsProspective observational study comparing 2-year cumulative lung cancer diagnosis risk, lung cancer characteristics, and overall survival between low-dose computed tomography (LDCT) screening participants aged 50 to 80 years and LNP participants aged 35 to younger than 50 years (young) and older than 80 years (elderly). ResultsFrom 2015 to 2022, lung cancer was diagnosed in 329 (3.43%), 39 (1.07%), and 172 (6.87%) LDCT, young, and elderly LNP patients, respectively. The 2-year cumulative incidence was 3.0% (95% confidence intervals [CI]: 2.6%–3.4%) versus 0.79% (CI: 0.54%–1.1%) versus 6.5% (CI: 5.5%–7.6%), respectively, but lung cancer diagnosis risk was similar between young LNP and Lung CT Screening Reporting and Data System (Lung-RADS) 1 (adjusted hazard ratio [aHR] = 0.88 [CI: 0.50–1.56]) and Lung-RADS 2 (aHR = 1.0 [0.58–1.72]). Elderly LNP risk was greater than Lung-RADS 3 (aHR = 2.34 [CI: 1.50–3.65]), but less than 4 (aHR = 0.28 [CI: 0.22–0.35]). Lung cancer was stage I or II in 62.92% of LDCT versus 33.33% of young (p = 0.0003) and 48.26% of elderly (p = 0.0004) LNP cohorts; 16.72%, 41.03%, and 29.65%, respectively, were diagnosed at stage IV. The aggregate 5-year overall survival rates were 57% (CI: 48–67), 55% (CI: 39–79), and 24% (CI: 15–40) (log-rank p < 0.0001). Results were similar after excluding persons with any history of cancer. ConclusionsLNP modestly benefited persons too young or old for screening. Differences in clinical characteristics and outcomes suggest differences in biological characteristics of lung cancer in these three patient cohorts.