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) could accurately measure the locoregional response to chemoradiotherapy in patients with carcinoma of the esophagus. Seventeen patients with esophageal carcinoma underwent EUS examination before and on completion of chemoradiotherapy. The EUS findings were correlated with the results of histologic examination 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 treated 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 progression. No patient demonstrated downstaging of die primary tumor according to classical EUS criteria. In 10 of 17 patients a reduction in maximum tumor 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 carcinoma had experienced a complete pathologic response. These four patients had 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-treatment 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 accuracy of EUS examination in patients with carcinoma of the esophagus treated by chemoradiotherapy was poor. EUS did not detect downstaging of the primary tumor, even in the presence of a complete pathologic response. EUS assessment of maximum tumor depth was a better measure of response to therapy.