An observational study indicated that lung cancer screening criteria based on the duration of smoking, specifically 20, 30, or 40 years, may identify more individuals who could benefit from screening compared to current U.S. Preventive Services Task Force (USPSTF) recommendations. A threshold of at least 40 years of smoking was found to be more effective at excluding individuals least expected to benefit from screening than the USPSTF criteria.

Researchers used 2024 National Health Interview Survey (NHIS) data for the study. The study analyzed lung cancer screening criteria based on the minimum number of years smoked, comparing them with USPSTF recommendations. These years-smoked thresholds ranging from 20 to 40 years captured a greater proportion of individuals likely to benefit most from low-dose CT screening than USPSTF eligibility criteria.

Physician Lauren Kearney, one of the researchers, stated, "Smoke duration thresholds are simple to apply and identify more people who may benefit from [lung cancer screening] than USPSTF criteria." She added, "However, they entail trade-offs between effectiveness and efficiency and population size." Kearney said, "Decision-makers must weigh these trade-offs according to priorities such as resource availability and the imperative to avoid missing those who may gain the most."

The study categorized individuals into three groups using the Life-Years from Screening–CT model, which estimates the projected increase in a person's life expectancy due to screening. These groups included individuals who gained the greatest, intermediate, and least benefit in life-years. The NHIS data included 57 million individuals between 40 and 80 years old who had smoked previously. The mean age of these individuals was 59.1 years, 55% of whom were men, and the mean years smoked was 26.

While USPSTF guidelines captured 77% of the highest-benefit individuals, the smoking duration threshold of 40 years captured 85%. The 40-year smoking criterion excluded 100% of those expected to benefit the least, whereas the USPSTF criteria excluded 98% of this group. Among individuals selected by the 40-year smoking criterion, 68.8% were in the highest-benefit category, and only 0.1% were in the lowest-benefit category. A 20-year smoking threshold captured almost all individuals with the highest chance of benefit but also expanded the screen-eligible population and included many individuals with the lowest screening benefit.

Iakovos Toumazis, a researcher at the University of Texas MD Anderson Cancer Center in Houston, noted that no single simplified eligibility rule can fully capture the variations in lung cancer risk among individuals who have smoked. Toumazis and colleagues suggested that combining simplified eligibility rules with individualized risk prediction could be a path forward. Kearney stated, "Given the trade-offs identified in this study, the choice of years-smoked criterion should reflect priorities including efficiency vs maximal capture of high-benefit individuals." She also said, "Criteria should be implemented with individualized risk assessment, decision support, and capacity planning to balance benefits, harms, and feasibility." Kearney noted, "Emerging evidence suggests total years smoked may better capture risk than current guidelines," adding, "the optimal years-smoked threshold for screening remains uncertain."