Plasma Metabolites And Risk Of Radiation-Induced Esophagitis: A Secondary Analysis From A Prospective Study

Aim: Metabolic profiling was performed on plasma samples obtained prior to and during radiation therapy (RT) for locally advanced lung cancer to identify metabolites predictive of RT-induced esophagitis. Patients and Methods: Patients received cisplatin/etoposide with RT as part of a prospective dose-escalation study (n=24). Plasma samples were collected at baseline, weeks 2 and 5 during RT, and 6 weeks post-RT. Metabolites were measured by ultrahigh-performance liquid chromatography-tandem mass spectroscopy at each time-point. Metabolite concentrations were compared between patients developing grade 0-1 and those with grade 2 or more esophagitis. Results: At baseline, 23 metabolites differed significantly (p<0.05) between patients with grade 0-1 esophagitis and those with grade 2 or esophagitis. Sixty-seven metabolites were different at week 2. None reached statistical significance (q<0.05) after corrections for multiple comparisons. On random forest modeling, the predictive accuracy of the metabolite data was 33% at baseline and 50% at 2 weeks. Conclusion: No individual metabolite or group of metabolites was predictive of acute RT-induced esophagitis.