Newly reported data show adopting a 20-year smoking duration cutoff instead of a 20-pack-year cutoff to determine eligibility for lung cancer screening could significantly improve the proportion of patients with lung cancer who are eligible for screening. Additionally, such a move could eliminate racial disparities in screening eligibility. The research was presented on December 2 by investigator Alexandra Potter of Massachusetts General Hospital, Boston, at the IASLC’s North America Conference on Lung Cancer in Chicago.
Low-dose CT screening for lung cancer has been shown to reduce mortality from lung cancer by 20%, but determining guidelines for screening has been challenging.1 Currently, the 2021 United States Preventive Services Task Force (USPSTF) lung cancer screening guideline recommends screening for individuals meeting certain age and smoking requirements. However, many individuals at high risk for lung cancer, especially those from racial and ethnic minority groups, are ineligible because they have too few pack-years of smoking history.2
Increasing evidence shows pack-year smoking history to be an imperfect and biased measure of cumulative tobacco exposure that underestimates lung cancer risk among individuals who smoke less intensely (i.e., fewer cigarettes per day), such as racial and ethnic minorities. The use of pack-year smoking history to determine lung cancer screening eligibility in the current USPSTF guideline may unintentionally exclude many high-risk individuals, especially those from racial and ethnic minority groups, according to the research presented by Ms. Potter, who is co-founder and executive director of the American Lung Cancer Screening Initiative
The study evaluated whether replacing the “>20 pack-year” criterion in the USPSTF guidelines with a “>20-year smoking duration” criterion would improve the selection of individuals for screening. Ms. Potter and her team analyzed 49,703 individuals with a smoking history from the Southern Community Cohort Study (SCCS) and 22,126 individuals with a smoking history from the Black Women’s Health Study (BWHS).
Ms. Potter and her team found that under the 2021 USPSTF guideline, only 57.6% of Black lung cancer patients in the SCCS would have qualified for screening, with insufficient pack-years being a primary exclusion factor. However, a proposed change to a “>20-year smoking duration” criterion would significantly increase the screening eligibility of both Black and white lung cancer patients. Such a change would eliminate racial disparities in screening eligibility, with 85.3% of Black lung cancer patients and 82.0% of white lung cancer patients meeting the criteria under the new proposal, Ms. Potter said.
Screening eligibility would also increase among black women. In the BWHS cohort, using a 20-year smoking duration cutoff instead of a 20-pack-year cutoff increased the percentage of Black women qualifying for screening from 42.5% to 63.8%.
“Our research challenges current lung cancer screening practices and highlights the need for a reevaluation of screening criteria to ensure equitable access for all individuals at risk,” Ms. Potter said. “We anticipate that these findings will contribute to ongoing discussions within the medical community regarding the refinement of lung cancer screening guidelines.”
- 1. Duffy SW, Field JK. Mortality Reduction with Low-Dose CT Screening for Lung Cancer. N Engl J Med. 2020;382(6):572-573. doi:10.1056/NEJMe1916361
- 2. Kunitomo Y, Bade B, Gunderson CG, et al. Evidence of Racial Disparities in the Lung Cancer Screening Process: a Systematic Review and Meta-Analysis. J Gen Intern Med. 2022;37(14):3731-3738. doi:10.1007/s11606-022-07613-2