Only 13% of patients diagnosed with lung cancer met low-dose CT screening criteria

Only about 13% of patients diagnosed with lung cancer met low-dose CT screening criteria prior to the prognosis, according to a new single-center study. 

The disease remains the leading cause of cancer-related death in the U.S., with routine imaging known to reduce mortality. Given CT’s successes, the U.S. Preventive Services Task Force in 2021 expanded LDCT eligibility, cutting the minimum screening age (from 55 to 50) and smoking history threshold (30 pack-years to 20). 

USPSTF’s goal was to capture more high-risk individuals who were excluded from previous screening criteria, experts detailed July 17 in JACR. Researchers with the University of California, Irvine, sought to assess the impact of these changes using data from their own institution. 

“These findings emphasize two critical barriers to effective lung cancer screening: the limited reach of existing eligibility criteria and poor uptake even among eligible patients,” corresponding author Gelareh Sadigh, MD, an associate professor of radiology with UCI, and colleagues concluded. “Addressing these gaps will require more inclusive risk prediction models, and system-level interventions such as [electronic medical record] optimization and provider and patient education to improve screening uptake.”

The study incorporated patients ages 50 to 80 with a lung cancer diagnosis, who received care at the tertiary health system between 2018 and 2024. Screening eligibility was determined using available smoking history in the system’s electronic medical record, based on 2021 USPSTF criteria. The final sample included nearly 1,900 patients who were diagnosed with lung cancer. 

At the time of diagnosis, about 46% were never smokers, 45% were former smokers, and 9% were current smokers. Lung cancer screening eligibility was determined for 1,119 patients in the sample, with only 148 of them (or 13.2%) meeting the USPSTF’s requirements. Further analysis showed that women, those of Asian or mixed race, and Hispanic ethnicity were less likely to be eligible for lung screening. Among the 137 LCS-eligible patients, less than 10% (or 13) had received low-dose CT. 

In a subgroup analysis limited to current or former smokers, no sociodemographic factors were significantly associated with higher or lower odds of screening eligibility, the study found. When never-smokers were excluded, eligibility increased to 42%. Sadigh and colleagues noted that their findings are consistent with prior research, demonstrating a high proportion of Asian women who never smoked are diagnosed with the disease. 

“Although risk prediction models incorporating demographic, environmental, and genetic factors may improve inclusivity, their clinical implementation may be challenging due to providers’ time constraints and the higher probability of missing data needed to calculate risk,” the authors wrote. 

Smoking history is a critical piece of determining eligibility, they added. However, only about 60% of patients had sufficient structured smoking data in their records. Prior studies have shown that EMR smoking histories are often inaccurate or incomplete, tending to underestimate lifetime exposure and reducing observed eligibility. 

“In addition to patient and provider education, health system and EMR workflow modifications may improve documentation and screening,” Sadigh and co-authors advised. “Clinician-facing reminders and embedded guidance within LDCT ordering workflows have been shown to increase identification and completion of LCS.” 

Read more, including potential study limitations, in the Journal of the American College of Radiology.