Response evaluation with endoscopic ultrasound and computed tomography in esophageal squamous cell carcinoma treated by definitive chemoradiotherapy

Background and Aim We assessed the feasibility of combined endoscopic ultrasound and computed tomography on response evaluation in patients with esophageal squamous cell carcinoma treated by definitive chemoradiotherapy, and the impact of response on prognosis. Methods Sixty patients treated by definitive chemoradiotherapy were followed by miniprobe endoscopic ultrasound and computed tomography. The post-treatment esophageal wall thickness was measured by miniprobe endoscopic ultrasound. Metastatic tumors were evaluated by computed tomography. The correlation between post-treatment image findings and prognosis was evaluated. Results Twenty-four patients (40%) had esophageal stricture after chemoradiotherapy, which limited complete evaluation by endoscopy. Miniprobe successfully penetrated all strictures to measure post-treatment esophageal wall thickness. Both post-treatment esophageal wall thickness  30 months, 16.8 months and 7.1 months, respectively (P < 0.001). On multivariate analysis, treatment response is the strongest independent prognostic factor (hazard ratio 3.65, P = 0.006) regardless of baseline tumor-node-metastasis staging and chemoradiation regimen. Conclusions Response evaluation by miniprobe endoscopic ultrasound and computed tomography can predict the prognosis of esophageal squamous cell carcinoma patients treated by definitive chemoradiotherapy. Those who were judged as poor responder should receive additional treatment to improve outcome.