Annual lung cancer screening adherence drops after initial exam, underlining need for intervention

Lung cancer screening utilization drops after the initial baseline exam, underlining the need for intervention, according to research published Tuesday in JAMA Network Open. 

Providers for years have worked to boost annual low-dose CT imaging adherence rates—a proposed quality metric in screening programs. However, data linking loyalty to annual screening regimens, along with lung cancer outcomes, are lacking. 

A new study of over 10,000 individuals, imaged across multiple locations, finds that 61% of eligible adults undergo the initial CT exam in year 1 after baseline. However, this figure fell to 51% by year 2, with annual adherence tied to increased cancer diagnosis rates during both periods. 

Experts believe the results highlight the need for intervention to ensure patients screened the first time (T1) come back again for the second scan and beyond (T2). 

“These results suggest that if [lung cancer screening] programs were to proactively identify eligible individuals who miss T1 screening to reengage them for round T2 screening, they could make a meaningful impact on these patients’ clinical trajectory by detecting more early stage cancers and potentially averting downstream lung cancer-related deaths,” Roger Y. Kim, MD, a pulmonologist with the University of Pennsylvania in Philadelphia, and co-authors write March 18. “Moreover, these findings suggest that our pragmatic definitions of adherence capture clinically relevant information that directly corresponds to patient lung cancer outcomes.”

The retrospective study included adults ages 55-75 who were former or current smokers. Eligible subjects underwent a baseline CT exam sometime between 2015 and 2018 at one of five U.S. healthcare systems. Kim and colleagues shifted the normal way of looking at adherence rates in such studies. For those who received a negative baseline exam, year 1 adherence was defined as occurring 10-18 months after, while year 2 adherence was 22-30 months. Meanwhile, among those positive for lung cancer, adherence was 11-21 months after baseline and 28-36 months in year 2. 

In round 1, about 61.2% (or 6,141/10,033) were adherent to annual screening. This number fell to 50.5% in year 2 (5,028/9,966) among eligible patients. Year 1 adherence was “significantly” associated with year 2 adherence, the authors reported. Across 36 months of follow-up, 279 patients (or 2.7%) were diagnosed with lung cancer. Diagnosis rates also were higher among those who were adherent during both rounds. 

In a corresponding editorial, experts highlighted the link between year 1 and year 2 adherence as one of the study’s “most consequential” findings. 

“This is important as some individuals may be eligible for annual LCS for up to 30 years based on their age and smoking history and suggests that interventions need to focus on mitigating nonadherence to first follow-up after a baseline LDCT,” Francesca C. Duncan, MD, and Matthew Triplette, MD, MPH, with the universities of Indiana and Washington, respectively, wrote March 18. “Focusing on programmatic resources in the first follow-up period may provide a significant return on investment if individuals remain engaged over their screening lifetime. While not the focus of the study by Kim et al., individuals from rural and underserved settings, those of racial and ethnic minority populations, and those currently smoking are at higher risk of nonadherence to follow-up, and it is essential that these groups are included and emphasized in intervention development, adaptation, and evaluation.”