Screening for lung cancer in individuals who never smoked: An IASLC Early Detection and Screening Committee Report

ABSTRACT Screening with Low-dose computed tomography (LDCT) of high-risk individuals with a smoking history reduces lung cancer mortality. Current screening guidelines and eligibility criteria can miss over 50% of lung cancers, and in some geographical areas, like East Asia, a large proportion of the missed lung cancers are in never-smokers. Although randomized trials demonstrated the benefits of screening for people who smoke, these trials generally excluded never-smokers. Thus, the feasibility and effectiveness of lung cancer screening of individuals never -smoked is uncertain. Several known and suspected risk factors for lung cancers in never-smokers such as exposure to secondhand smoke, occupational carcinogens, radon, air pollution, and pulmonary diseases, such as COPD and interstitial lung diseases and intrinsic factors, such as age are well noted. In this regard, knowledge of risk factors may make possible quantification and prediction of lung cancer risk in never-smokers. It is worth considering if and how never-smokers could be included in population-based screening programs. As the implementation of these programs is challenging in many countries due to multiple factors and the epidemiological differences by global regions, these issues will need to be evaluated in each country taking into account various factors, including accuracy of risk assessment and cost-effectiveness of screening in never-smokers. This report aims to outline current knowledge about risk factors for lung cancer in never-smokers, to propose research strategies for this topic, and initiate a broader discussion about lung cancer screening of never-smokers. Similar considerations can be made in current and ex-smokers, which don't fulfill the current screening inclusion criteria, but otherwise are at increased risk. Although screening of never-smokers may in the future be effectively conducted, current evidence to support widespread implementation of this practice is lacking.