Outcomes of lung cancer screening by low-dose computed tomography in the health screening program

Low-dose computed tomography (LDCT) screening reduces lung cancer mortality among high-risk smokers, but data from Southeast Asia remain limited. This study evaluated the detection yield and risk factors of lung cancer among adults undergoing LDCT health screening in Thailand.

We retrospectively reviewed 4,478 adults aged 18-85 years who underwent LDCT between January 2019 and December 2023 at a tertiary private hospital in Bangkok. Scans were performed using a Philips IQon Spectral CT (256-slice, 120 kV, 30 mA, 1 mm slice thickness, radiation dose <1.5 mSv) and interpreted according to Lung Imaging Reporting and Data System (Lung-RADS) version 1.1. Lung-RADS 3-4X were confirmed histopathologically. Multivariable logistic regression identified predictors of lung cancer.

Among all participants, 1,980 (44.2%) were female and 84.0% were never-smokers, with a mean age of 56.9 years [standard deviation (SD) 12.5]. LDCT positivity was 55.8%, and 53 cancers (1.2%) were detected. Most were stage 0-IB (69.8%), with adenocarcinoma as the predominant histology (85%) and solid morphology (77.4%). Incidental findings occurred in 65.2%, most commonly coronary artery calcification (CAC) (39.8%). Independent predictors included age ≥55 years [adjusted odds ratio (OR) 4.82, 95% confidence interval (CI): 1.68-13.86], smoking history (P<0.001), CAC (adjusted OR 23.63, 95% CI: 2.09-266.98), and extrapulmonary malignancy (adjusted OR 173.54, 95% CI: 42.73-704.77).

LDCT health screening in an unselected Thai population detected a meaningful burden of early-stage lung cancer. The findings support age-based screening beginning at 55 years, highlighting the potential role of chronic inflammation and environmental injury, such as PM_2.5 exposure and prior tuberculosis.