Should Never-Smokers at Increased Risk for Lung Cancer Be Screened?

Abstract

Introduction Lung cancer in never-smokers ranks among the ten most common causes of death due to cancer worldwide and in the U.S. However, it is unknown whether never-smokers at elevated risk for developing lung cancer may benefit from lung cancer screening. Methods The MISCAN-Lung microsimulation model was used to assess the effects of lung cancer screening for simulated cohorts of never-smokers at different levels of relative risk (RR) for lung cancer compared to never-smokers at average risk. The benefits and harms of screening were estimated for each cohort and compared to those of a cohort of ever-smokers eligible for lung cancer screening according to the United States Preventive Services Task Force (USPSTF) criteria. Results The relative lung cancer mortality reduction in never-smokers was higher than the USPSTF eligible cohort (37% compared to 32%). However, the number of life-years gained per lung cancer death averted was lower (10.4 compared to 11.9) and the proportion of overdiagnosed cancers was higher (9.6% compared to 8.4%) for never-smokers compared to the USPSTF eligible cohort, as never-smokers are diagnosed at a later age. The estimated number of screens per lung cancer death averted ranged from 6,162 for never-smokers at average risk to 151 for never-smokers with a RR of 35, compared to 353 for the USPSTF eligible cohort. Conclusions Never-smokers with RRs of 15-35 have similar to better trade-offs between benefits and harms compared to ever-smokers recommended for lung cancer screening by the USPSTF guidelines. For most never-smokers, lung cancer screening is not beneficial.

Risk prediction models for selection of lung cancer screening candidates: A retrospective validation study

“…All participants in the CT arm ( n = 26,722) and chest radiography (CXR) arm ( n = 26,730) of the NLST and ever-smoking participants in the CXR arm ( n = 40,600) and control arm ( n = 40,072) of the PLCO were included in the analysis. Never-smokers in the PLCO were not considered, as (1) not all lung cancer risk prediction models can be applied to never-smokers and (2) never-smokers are unlikely to reach levels of risk that allow them to benefit from screening [13,25]. …”

Screening for Lung Cancer

“…97 Never smokers were found to require a relative risk 15 to 35 times that of the average never smoker to have the potential to benefit from screening. 98 Impact of Comorbidity and Quality of Life: For lung cancer screening to be effective, earlier stage lung cancer must be discovered than would have been without screening, the patient must be healthy enough to undergo treatment of early-stage disease, and the patient must not have competing causes of death that would substantially diminish the effect of screening. The population enrolled in the NLST met this basic tenant, so much so that of the 347 stage I lung cancers discovered during screening, only 7 (2%) were treated with radiation alone, suggesting the population was largely able to tolerate surgery.…”

Low Dose Lung CT Screening in an Asian Population

“…What about expanding inclusion criteria to include neversmokers? To date, several studies have explored the feasibility of expanding current LDCT guidelines to include neversmokers (17,18). In fact, it is estimated that between 10% and 25% of all lung cancers occur in never-smokers worldwide.…”

“…In fact, it is estimated that between 10% and 25% of all lung cancers occur in never-smokers worldwide. Using sophisticated risk modeling it has been calculated that there would be a relatively greater reduction in lung cancer mortality for never-smokers if included in current screening studies (provided inclusion of environmental (passive) smoke exposure, exposure to carcinogens, and a family history of lung cancer), although the number of life-years gained per lung cancer death would be lower, and the proportion of overdiagnosed lung cancers higher (18).…”