Lung Cancer CT Screening and Lung-RADS in a Tuberculosis-endemic Country: The Korean Lung Cancer Screening Project (K-LUCAS)

Background: Low-dose CT screening for lung cancer in a tuberculosis-endemic country may be less effective because of false-positive results caused by tuberculosis sequelae. Purpose: To evaluate the impact of tuberculosis sequelae at CT screening according to the American College of Radiology Lung CT Screening Reporting and Data System (Lung-RADS) using data from the Korean Lung Cancer Screening Project (K-LUCAS). Materials and Methods: This is a secondary analysis of K-LUCAS (ClinicalTrials.gov identifier NCT03394703), a nationwide Asian population-based, multicenter, prospective cohort study. Participants at high risk for lung cancer were enrolled between April 2017 and December 2018. Associations of tuberculosis sequelae with a positive screening result for lung cancer (defined as Lung-RADS categories 3 or 4) and diagnosis of lung cancer were analyzed with multivariable logistic regression. The diagnostic performance of Lung-RADS in predicting lung cancer was compared between participants with and participants without tuberculosis sequelae by using the chi(2) test. Results: A total of 11 394 participants (median age, 62 years; interquartile range, 58-67 years; 11 098 men) were evaluated. Positive screening results were found in 1868 of the 11 394 participants (16%); lung cancer was diagnosed in 65 of the 11 394 participants (0.6%). Tuberculosis sequelae were identified in 1509 of the 11 394 participants (13%) on the basis of CT scans. Tuberculosis sequelae were associated with positive CT screening results (odds ratio [OR] with one nodule, 1.22; 95% confidence interval [CI]:1.02, 1.45; P =.03), but no evidence was found of an association with lung cancer (OR, 0.9; 95% CI: 0.4, 1.6; P =.64). Specificity of Lung-RADS was higher for participants without tuberculosis sequelae (85% [8327 of 9829 participants]; 95% CI: 84.0%, 85.4%) than for those with tuberculosis sequelae (80% [1198 of 1500 participants]; 95% CI: 77.7%, 82%; P < .001). Sensitivity was not different between participants with tuberculosis sequelae (100% [nine of nine participants]; 95% CI: 62.9%, 100%) and those without tuberculosis sequelae (98% [55 of 56 participants]; 95% CI: 89.2%, 99.9%; P > .99). Conclusion: In an at-risk population, tuberculosis sequelae resulted in a reduced specificity of CT screening for lung cancer using the Lung CT Screening Reporting and Data System. (C) RSNA, 2020