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Offering lung cancer screening to everyone with a 20-year smoking history could expand access to screening, identify more cancers, and reduce disparities, new research suggests.

In an analysis of nearly 1 million US veterans, researchers estimated that a simplified approach to lung cancer screening — based on smoking duration rather than pack-years — would expand screening eligibility by nearly 30% and reduce potentially missed lung cancers by over 70%.

Those shifts would be especially pronounced among women and Black individuals — two groups that are underserved by current screening criteria.

The results, presented at the American Society of Clinical Oncology (ASCO) 2026, come at a time when some groups are revisiting their lung cancer screening guidelines.

And they support smoking duration as a “simpler, more sensitive, and more equitable metric for screening eligibility,” researcher Brendan T. Heiden, MD, MPHS, Washington University School of Medicine in St. Louis, St. Louis, told meeting attendees.

Toward a Better Metric

Current guidelines from the US Preventive Services Task Force (USPSTF) recommend annual lung cancer screening with low-dose CT for adults aged 50-80 years who have at least a 20 pack-year smoking history and either currently smoke or quit within the past 15 years.

The 20 pack-year metric is equivalent to smoking a pack of cigarettes per day for 20 years. Because it requires patients to remember their smoking intensity over decades, it can be challenging to calculate and translate into care, Heiden said.

As it stands, few Americans who are eligible under current USPSTF guidelines actually undergo lung cancer screening, at about 15%-20%, Heiden noted. Meanwhile, mounting evidence suggests that many lung cancers occur in individuals who never meet those eligibility criteria.

Boosting screening uptake, Heiden said, is not enough: There’s a need to revisit eligibility itself to reach more high-risk individuals.

Some groups are already taking steps in that direction. Recently updated guidelines from the National Comprehensive Cancer Network (NCCN) added a category 2B recommendation supporting screening for individuals with at least a 20-year smoking history, regardless of pack-years. (The guidelines also say former smokers are eligible no matter how long ago they quit.)

For their study, Heiden’s team sought to estimate the performance of that smoking-duration metric against current USPSTF pack-year criteria. They used Veterans Health Administration data on over 980,000 veterans whose smoking histories were prospectively collected; lung cancer diagnoses were identified through the Veterans Affairs Central Cancer Registry.

Most of the included veterans (67%) had a smoking history; their mean age was 64 years, and 21% were Black.

Overall, the researchers found that basing eligibility on 20-year smoking duration would substantially expand access to screening: Among veterans with a smoking history, 68% qualified for screening under current USPSTF criteria compared with 87% using the smoking-duration approach.

The gains were especially pronounced among women and Black individuals (who, based on prior research, typically smoke less intensely than White males). Under USPSTF criteria, only about 55% of female and Black veterans qualified for screening compared with 83% for both groups under the smoking-duration criterion.

Importantly, Heiden said, people meeting the smoking-duration threshold remained at substantially elevated risk for lung cancer, suggesting the broader screening criteria were not merely capturing low-risk smokers.

The 5-year lung cancer incidence among veterans eligible under the smoking-duration approach was 1.59% — 11 times the rate of 0.14% among never smokers.

Perhaps most striking, Heiden said, the proportion of potentially missed cancers dropped from 13% with the pack-year metric to just 4% using the smoking-duration metric — a relative reduction of more than 70%.

Again, women and Black individuals would see the largest gains: Among Black veterans, potentially missed cancers fell from 25% to 6%, whereas among female veterans they declined from 22% to 7%.

Optimal Approach Still Unclear

The analysis had limitations, including a predominantly male veteran population whose smoking exposure was far greater than that of the general US population, indicating high inherent lung cancer risk.

But the results support what the NCCN has already done, according to Mary Reid, PhD, MSPH, BSN, a member of the group’s lung cancer screening guideline panel and chief of cancer screening, survivorship and mentorship at Roswell Park Comprehensive Cancer Center in Buffalo, New York.

“Doing the calculation for pack-years can be difficult,” Reid told Medscape Medical News. “Smoking duration is easier to calculate and really the way to go.”

The USPSTF does not comment on individual studies outside of its recommendation development process.

At the meeting, study discussant Katharine A. Rendle, PhD, called the work “impressive,” citing the size of the cohort and strength of the data.

It’s particularly noteworthy that the simpler screening criteria improved sensitivity for all veterans, while largely eliminating disparities, according to Rendle, of the Abramson Cancer Center at the University of Pennsylvania in Philadelphia.

Still, she said, further research could better define the optimal screening strategy.

“Smoking duration is a promising approach, but in my opinion, guidelines likely need to account for the underlying risk in the population,” Rendle said, noting that current smoking prevalence in the US population is about 10%.

She suggested future studies consider other smoking-duration thresholds, such as 30 or 40 years, and look at other outcomes, including life-years gained.

“It’s critical that we prioritize strategies that maximize potential benefit from screening — not just identify those at lung cancer risk — given downstream costs and burden on populations and healthcare systems,” Rendle said.

The study had no commercial funding. Heiden, Rendle, and Reid had no relevant disclosures.