Time Course of Tumor Metabolic Activity During Chemoradiotherapy of Esophageal Squamous Cell Carcinoma and Response to Treatment

Abstract
Purpose To evaluate the time course of therapy-induced changes in tumor glucose use during chemoradiotherapy of esophageal squamous cell carcinoma (ESCC) and to correlate the reduction of metabolic activity with histopathologic tumor response and patient survival. Patients and Methods Thirty-eight patients with histologically proven intrathoracic ESCC (cT3, cN0/+, cM0) scheduled to undergo a 4-week course of preoperative simultaneous chemoradiotherapy followed by esophagectomy were included. Patients underwent positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) before therapy (n = 38), after 2 weeks of initiation of therapy (n = 27), and preoperatively (3 to 4 weeks after chemoradiotherapy; n = 38). Tumor metabolic activity was quantitatively assessed by standardized uptake values (SUVs). Results Mean tumor FDG uptake before therapy was 9.3 ± 2.8 SUV and decreased to 5.7 ± 1.9 SUV 14 days after initiation of chemoradiotherapy (−38% ± 18%; P < .0001). The preoperative scan sho...