Lung cancer screening for never smokers: current evidence and future directions

Screening for lung cancer using low-dose computed tomography is an established means for early lung cancer detection in smokers, but the role of screening for never smokers is unclear. In the 13 lung cancer screening studies involving unselected never smokers, detection rates ranged from 0.1% to 1.1% and positive predictive values ranged from 0.4% to 4.5%. In three lung cancer screening studies involving selected never smokers, selection was based primarily on occupational asbestos exposure, environmental radon exposure and family history of lung cancer in first-degree relatives. Detection rates ranged from 0.3% to 2.6%, and positive predictive values ranged from 0.7% to 15%. Also, 80%-100% of lung cancer cases discovered by screening were early stage, with limited data suggesting survival benefit. Lung cancer screening for never smokers with selected risk factors may achieve detection rates similar to those of screening for high-risk ever smokers. However, further research on optimal subject selection, alternative screening methods and clinical/economic outcomes is needed.