Association Between Changes in Myocardial F-18 Fluorodeoxyglucose Uptake and Cardiac Toxicity or Overall Survival for Inoperable NSCLC Patients Receiving Chemoradiation.

PURPOSE/OBJECTIVE(S) Previous studies have shown that increased cardiac uptake of 18F-fluorodeoxyglucose (FDG) on positron emission tomography (PET) may be an indicator of myocardial injury after radiotherapy. Our study aimed to investigate the predictive value of changes in myocardial 18F-FDG uptake for cardiotoxicity and overall survival (OS) in patients with inoperable NSCLC receiving definitive chemoradiation. MATERIALS/METHODS One hundred and fifty unresectable locally advanced NSCLC patients enrolled in a retrospective study who had undergone pre- and post-chemoradiation FDG-PET imaging were evaluated. Our primary endpoint was grade ≥ 3 cardiac toxicity. Patient clinicopathologic factors, dosimetric parameters for the whole heart and cardiac substructures, and myocardial changes within the irradiated fields on 18F-FDG PET were utilized to seek the best predictive model for cardiotoxicity. Competing risk analysis and Cox regressions analysis were performed. RESULTS At a median follow-up interval of 35 months, twenty-six patients (17.3%) developed grade ≥ 3 cardiac everts. Twenty-nine patients (19.3%) showed increased myocardial FDG uptake within the irradiated fields associated with the heart dosimetric parameters. The best multivariable model based on the lowest Akaike information criterion for predicting grade ≥ 3 cardiotoxicity included the following covariates: pre-existing cardiac disease, changes in pre- and post-chemoradiation myocardial SUVmean (∆SUVmean), and mean heart dose. Subanalysis showed that pre-existing cardiac disease, ∆SUVmean, and mean left anterior descending dose were significantly associated with grade ≥ 3 acute coronary syndrome/congestive heart failure events. ∆SUVmean and grade ≥ 3 cardiac toxicity were independent indicators of OS. CONCLUSION ∆SUVmean was an independent indicator of grade ≥ 3 cardiac toxicity and OS in unresectable locally advanced NSCLC patients receiving definitive chemoradiation. Changes in myocardial uptake of FDG is a promising biomaker for predicting radiation-induced cardiotoxicity.