Purpose: The aim of the study was to investigate the predictive role of pretreatment metabolic tumor volume (MTV) in patients with squamous cell carcinoma of locally advanced esophageal cancer treated with definitive chemoradiotherapy.
Patients and methods: Ninety patients received pretreatment with (18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT, and two types of MTVs were measured on the basis of either a maximal standardized uptake value (SUVmax) of 2.5 (MTV2.5) or a fixed threshold of 20% (MTV20%). Overall survival (OS) and disease-free survival (DFS) were examined, and independent prognosticators were identified by Cox regression analysis.
Results: On a median follow-up of 15 months, 51 patients were seen to have died because of tumor recurrence or other illnesses. Multivariate analysis of OS revealed that MTV20%>40 ml was the only predictor of outcome with a lower 1-year OS [P=0.003, hazard ratio (HR)=2.29, 95% confidence interval (CI) 1.36-3.91]. Two independent predictors of DFS were MTV20%>40 ml (P=0.02, HR=1.78, 95% CI 1.09-2.91) and stage IV disease (P=0.01, HR=1.84, 95% CI 1.12-3.03).
Conclusion: Pretreatment MTV20% is a novel marker for OS and DFS in patients with unresectable locally advanced esophageal cancer treated with definitive chemoradiotherapy. Treatment intensification must be considered for patients with higher MTVs.