Metabolomics-based Discovery of Serum Biomarkers to Predict the Side-effects of Neoadjuvant Chemoradiotherapy for Esophageal Squamous Cell Carcinoma

Background/Aim: Neoadjuvant chemoradiotherapy has side-effects that adversely affect patients' quality of life. The aim of this study was to identify serum metabolite biomarkers that might be used to predict the side-effects of neoadjuvant chemoradiotherapy for esophageal squamous cell carcinoma (ESCC). Patients and Methods: Metabolomic analysis of serum samples from 26 patients with ESCC that were collected before neoadjuvant chemoradiotherapy was performed. The metabolites associated with hematological toxicity or nephrotoxicity were evaluated. Results: Serum levels of glutaric acid, glucuronic acid, and cystine were significantly higher in hematological toxicity, and phosphatidylcholines and phosphatidylethanolamines exhibited a tendency to be higher in those with hematological toxicity. The serum level of pyruvic acid was significantly lower in nephrotoxicity, and lysophosphatidylcholines and lysophosphatidylethanolamines tended to be lower in those with nephrotoxicity. Conclusion: Our study found that serum levels of some metabolites differed significantly between patients with and without hematological or renal side-effects. These metabolites may be useful biomarkers for predicting hematological toxicity or nephrotoxicity after neoadjuvant chemoradiotherapy for ESCC.