Impact of Duration of Diagnostic Workup on Prognosis for Early Lung Cancer

Introduction: Growth assessment for pulmonary nodules is an important diagnostic tool; however, the impact on prognosis due to time delay for follow-up diagnostic scans needs to be considered. Methods: Using the data between 2003 and 2019 from the International Early Lung Cancer Action Program, a prospec-tive cohort study, we determined the size-specific, 10-year Kaplan-Meier lung cancer (LC) survival rates as surrogates for cure rates. We estimated the change in LC diameter after delays of 90,180, and 365 days using three representative LC volume doubling times (VDTs) of 60 (fast), 120 (moderate), and 240 (slow). We then estimated the decrease in the LC cure rate resulting from time between computed tomography scans to assess for growth during the diagnostic workup. Results: Using a regression model of the 10-year LC sur-vival rates on LC diameter, the estimated LC cure rate of a 4.0 mm LC with fast (60-d) VDT is 96.0% (95% confidence interval [CI]: 95.2%-96.7%) initially, but it would decrease to 94.3% (95% CI: 93.2%-95.0%), 92.0% (95% CI: 90.5%- 93.4%), and 83.6%(95% CI: 80.6%-86.6%) after delays of 90, 180, and 365 days, respectively. A 20.0-mm LC with the same VDTs has a lower LC cure rate of 79.9% (95% CI: 76.2%-83.5%) initially and decreases more rapidly to 71.5% (95% CI: 66.4%-76.7%), 59.8% (95% CI: 52.4%- 67.1%), and 17.9% (95% CI: 3.0%-32.8%) after the same delays of 90, 180, and 365 days, respectively. Conclusions: Time between scans required to measure growth of lung nodules affects prognosis with the effect being greater for fast growing and larger cancers. Quanti-fying the extent of change in prognosis is required to un-derstand efficiencies of different management protocols. (c) 2023 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Automated summary

Growth assessment of pulmonary nodules is important for diagnosis, but the impact of time delay for follow-up diagnostic scans on prognosis needs to be considered. Using data from the International Early Lung Cancer Action Program, the study estimated the decrease in lung cancer cure rate resulting from delays in CT scans. The findings suggest that the time between scans affects prognosis, particularly for fast-growing and larger cancers.