Serial endoscopic ultrasound in the assessment of response to chemoradiotherapy for carcinoma of the esophagus

The aim of the study was to assess whether endoscopic ultrasound (EUS) coul d accurately measure the locoregional response to chemoradiotherapy in pati ents with carcinoma of the esophagus. Seventeen patients with esophageal ca rcinoma underwent EUS examination before and on completion of chemoradiothe rapy. The EUS findings were correlated with the results of histologic exami nation of the esophagectomy specimen. The accuracy of EUS in these patients was compared with the accuracy of EUS in a control group of 17 patients tr eated by surgery alone. In 16 of 17 patients EUS-determined tumor (T) stage was unchanged following treatment and hi one patient there was T-stage pro gression. No patient demonstrated downstaging of die primary tumor accordin g to classical EUS criteria. In 10 of 17 patients a reduction in maximum tu mor depth of greater than or equal to 2 mm was observed (range 2 to 18 mm). Histologic examination revealed that four patients with squamous cell carc inoma had experienced a complete pathologic response. These four patients h ad significantly lower posttreatment EUS tumor depths compared to patients without a complete response (5.0 vs. 9.0 mm; P <0.05). Based on the post-tr eatment EUS examination, the accuracy was 59% for T stage and 59% for node (N) stage. The accuracy of EUS in patients treated by surgery alone was 94% for T stage and 91% for N stage, indicating a significant reduction in the accuracy of EUS in patients following chemoradiotherapy (P <0.05). The acc uracy of EUS examination in patients with carcinoma of the esophagus treate d by chemoradiotherapy was poor. EUS did not detect downstaging of the prim ary tumor, even in the presence of a complete pathologic response. EUS asse ssment of maximum tumor depth was a better measure of response to therapy.