Simpler lung cancer screening criteria could capture more patients likely to benefit

Experts are calling for potential lung cancer screening criteria changes to help capture more eligible patients. 

Current guidelines seek to reach those most likely to benefit from low-dose CT scans while excluding those who don’t need them. However, emerging evidence suggests that total years smoked may better capture cancer risk than the current recommendations, which rely on pack years (packs per day x years smoked) and years since quitting, researchers detail in JAMA Internal Medicine. 

Pulmonologist Lauren E. Kearney, MD, and colleagues aimed to test this theory using National Health Interview Surveys data from 2024. They found potential benefit, calling for further exploration of this shift in eligibility criteria. 

“Smoke duration thresholds are simple to apply and identify more people who may benefit from [lung cancer screening] than [U.S. Preventive Services Task Force] criteria,” Kearney, with the Boston University School of Medicine, and co-authors wrote June 29. “However, they entail trade-offs between effectiveness and efficiency and population size. 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 included all ever-smoking adults between the ages of 40 and 80. It estimated screening benefit using a previously proposed model that calculates a person’s projected life expectancy increase from regular low-dose CT scanning. They then categorized estimates of life-years gained from screening into three groups, ranging from lowest to highest benefit. Researchers then compared USPSTF criteria with years-smoked criteria, including those who had smoked more than 20, 30 or 40 years. 

Their sample included a total of more than 57 million individuals who had smoked at one point in life, with an average of 26 years using cigarettes. The criterion of greater than 40 years smoked identified a slightly smaller screening population than USPSTF recommendations. Meanwhile, fewer years smoked incorporated larger populations—about 20 million when using the greater than 30 years mark and 32 million when using the 20-years smoked figure. 

USPSTF included 77% of individuals with the highest benefit from screening, while the 40-years-smoked mark included about 85%. Dropping to 30 years smoked bumped the number to 85% and 20 years increased it further to 99%. The criteria of greater than 40 years smoked, however, better excluded those compared to USPSTF (100% vs. 98%). Greater than 30 years smoked performed slightly worse (excluding 96%) and 20 years did substantially worse (excluding 69%). 

Among those selected for screening using 40-plus years smoked, about 69% were highest benefit and 0.1% were lowest, the authors found. Using a threshold of 30 years smoked added mostly intermediate-benefit individuals, while 20 years smoked added many in the lowest-benefit category. Kearney and colleagues note that the criterion of 40-plus years smoked was most efficient, with the fewest incremental screens per death prevented and life-years gained. 

“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,” the authors concluded. “Criteria should be implemented with individualized risk assessment, decision support, and capacity planning to balance benefits, harms, and feasibility.”

Read more, including potential study limitations, in JAMA.