In a large multicenter cohort study of more than 10,000 adult patients undergoing lung cancer screening, investigators found that adherence to annual screening was significantly associated with increased cancer detection and higher rates of early-stage diagnosis, but adherence rates declined substantially following baseline screening, suggesting that it is a critical lung cancer screening quality metric. Only half of eligible patients returned for second-year screening.
In the study, published in JAMA Network Open, investigators analyzed data from adult patients who underwent baseline lung cancer screening (LCS) between 2015 and 2018 across five U.S. health care systems in the Population-Based Research to Optimize the Screening Process–Lung Consortium.
The study population included 10,170 patients aged 55 to 75 years who formerly or currently smoked and underwent baseline LCS. The median age was 65 years (53.2% male). Most participants (58.7%) were current smokers at the time of screening.
The investigators found that adherence to annual LCS dropped from 61.2% during the first follow-up round (T1) to 50.5% during the second round (T2). Patients who were adherent during T1 were significantly more likely to be adherent during T2 compared with those who were not.
Over the 36-month follow-up period, 2.7% (n = 279) of the patients were diagnosed with lung cancer. The incident lung cancer diagnosis rates were 1.3%, 0.7%, and 0.8% during rounds T0, T1, and T2, respectively.
Notably, lung cancer diagnosis rates were substantially higher among the patients who were LCS adherent vs those who were nonadherent during both round T1 (1.0% vs 0.2%, P < .001) and T2 (1.3% vs 0.2%, P < .001).
The investigators also found a statistically significant difference in cancer stage distribution. Among patients who were diagnosed with lung cancer during round T2, a greater proportion of early-stage cancers (stage 0, I, or II) were detected in those who were adherent to screening compared with those who were not (73.0% vs 25.0%, P = .006).
Led by Roger Y. Kim, MD, MSCE, of the University of Pennsylvania, the investigators developed what they described as a "pragmatic definition" of annual LCS adherence based on baseline Lung-RADS (Lung computed tomography [CT] Screening Reporting & Data System) scores. Among patients with negative baseline screening results (Lung-RADS 1 or 2), T1 and T2 adherence was defined as chest CT within 10 to 18 months and 22 to 30 months after baseline, respectively. For positive baseline screening results (Lung-RADS 3 or 4), T1 and T2 adherence was defined as chest CT within 11 to 21 months and 28 to 36 months after baseline.
Notably, the investigators found that T1 adherence was not associated with lung cancer diagnosis during round T2.
"This simplified approach directly accounts for the heterogeneity of immediate diagnostic testing and procedures often following positive baseline LCS results (ie, those in which a nonbenign-appearing pulmonary nodule is detected) by phase-shifting the appropriate time frame for subsequent annual LCS rounds back a few months," the study authors explained.
The findings aligned with previous microsimulation modeling studies that suggested significant decreases in lives saved when screening adherence dropped, but this study represented the first large-scale empirical evidence linking adherence directly to cancer outcomes.
"These results suggest that if LCS 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," the study authors concluded.
Disclosures can be found in the study.
