Lung Cancer Screening: Study Explores Impact of Eligibility Differences by Smoking History

The current United States Preventative Services Task Force (USPSTF) lung cancer screening guidelines are “not impactful” for people who have never smoked and those who have quit for more than 15 years, according to a recent study.

The findings from the study were presented at the American Thoracic Society 2025 International Conference by a team from the Slone Epidemiology Center at the Boston University School of Public Health.

It was important to conduct the study because the current guidelines “prioritize individuals with significant smoking history for screening” and do not include those who have never smoked or have quit for a long period. However, the researchers explained that 10% to 20% of lung cancer cases occur in people who report never smoking. In addition, research shows that people who formerly smoked “remain at elevated risk beyond 15 years since quitting,” making it important to examine eligibility differences by smoking history to “refine current screening practices,” they said.

To address the knowledge gap, the research team identified 9,860 cases of lung cancer among participants in the Black Women’s Health Study, the Multiethnic Cohort Study, and the Southern Community Cohort Study. The participants were recruited from 1993 to 2009 and followed up until 2019. The researchers harmonized data to create a pooled cohort and described demographics, risk factors, and screening eligibility by smoking history and race.

Among the participants, 10% reported never smoking, with 52% reporting they currently smoked, 26% reporting a short-term history of quitting, and 22% reporting a long-term history of quitting.

Compared with patients who smoked, those who had never smoked were:

• More frequently female (74% vs 47%)
• Identified as Hispanic or Latino (19% vs 9%)
• Identified as Japanese American (30% vs 16%)
• Diagnosed with lung cancer at a later age (75 vs 71 years)

Among those who had smoked, the median age at diagnosis was the lowest in those who currently smoked (68 years), followed by those with a short-term history of quitting (73 years) and those with a long-term history of quitting (78 years). The researchers explained that this suggests that “smoking accelerates cancer onset and quit duration and cumulative tobacco exposure are associated with age at onset.”

In addition, those who had never smoked and those with a long-term quitting history had a longer median time from enrollment to diagnosis than those who currently smoked or had a short-term quitting history.

Screening eligibility differed among patients, with 41% of all patients eligible according to USPSTF 2021 guidelines versus 61% according to the PLCOall2014 risk model. Among the patients who were only eligible according to the PLCOall2014 risk model, 48% currently smoked, 42% had a long-term quitting history, and 10% had a short-term quitting history. The study authors highlighted that none of the patients who reported never smoking were eligible for screening according to either USPSTF 2021 guidelines or the PLCOall2014 risk model.

The study investigators also reported racial disparities among patients who had lung cancer but never smoked. They found that Native Hawaiians who never smoked had the highest median predicted risk and that Hispanic/Latino and Japanese American patients who never smoked “had the lowest predicted risks but the highest proportions of never-smoking cases.”

Based on these results, the study authors concluded that the current USPSTF screening guidelines “are not impactful” for those who never smoked or have a long-term quitting history, suggesting that “a risk model approach can better identify lung cancer cases but tends not to be well-calibrated among never-smoking individuals.” They emphasized that lung cancer screening approaches “should be tailored to account for never-smokers, who may benefit from a separate model.”

Source:

American Thoracic Society 2025 International Conference. Poster Board # 601.