The 2021 U.S. Preventive Services Task Force (USPSTF) recommendations for lung cancer screening expanded eligibility, but racial disparities remain. New research suggests that different criteria for eligibility—smoking for 20 years rather than 20 pack-years—nearly eliminated these disparities, according to findings published in the Journal of Clinical Oncology.

The 2021 recommendation calls for annual CT screening starting at age 50 for people who have a smoking history of 20 pack-years or more, regardless of when they quit. A pack-year is equivalent to smoking one pack of 20 cigarettes every day for a year. While pack-year smoking history has long been used as a criterion for lung cancer screening, it can leave out more racial and ethnic minority individuals.

Chi-Fu Jeffrey Yang, MD, of Massachusetts General Hospital, and colleagues wanted to see whether smoking duration might be a better screening criterion. They compared differences in screening eligibility between people with more than a 20-year smoking history and those with a 20 pack-year history.

The researchers used data from two cohort studies: the Southern Community Cohort Study (SCCS) and the Black Women’s Health Study (BWHS). The study population included 49,703 people from the SCCS cohort and 22,126 people from the BWHS cohort.

In the SCCS cohort, only 58% of Black people with lung cancer met the 2021 USPSTF criteria, while 85% made the cut for screening on the basis of smoking duration. Similarly, in the BWHS cohort, using smoking duration would make 64% eligible for screening compared with only 43% under the 2021 USPSTF criteria. In comparison, 72% of White individuals with lung cancer meet the USPSTF pack-year criteria, while 82% meet the proposed smoking duration criteria.

“Use of a 20-year smoking duration cutoff instead of a 20-pack-year cutoff greatly increases the proportion of patients with lung cancer who would qualify for screening and eliminates the racial disparity in screening eligibility between Black versus White individuals,” wrote the researchers. “[S]moking duration has the added benefit of being easier to calculate and being a more precise assessment of smoking exposure compared with pack-year smoking history.”

But changing the criteria is not without drawbacks.

“While the proposed smoking duration substitution would mitigate the disparity in screening eligibility between Black and White people, there was a notable decrease in specificity, which could reduce the cost-effectiveness of screening and subject people with a low risk of cancer to the harms of screening,” Hasmeena Kathuria, MD, and Renda Soylemez Wiener, MD, MPH, of the Boston University Chobanian and Avedisian School of Medicine, wrote in an accompanying editorial.

While more Black people are likely to be eligible under the proposed criteria, “they will not, however, be at greater risk of harm than White individuals,” the researchers argued. “Furthermore, the very low risk of harm from lung cancer screening must be considered, as always, in the context of the life-saving potential of early lung cancer detection.”

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