Endoscopic ultrasonography is useful for monitoring the tumor response of neoadjuvant chemoradiation therapy in esophageal squamous cell carcinoma

Background Recently, neoadjuvant chemoradiation therapy (CRT) has been introduced for treatment of esophageal squamous cell carcinoma (ESCC). This study was performed to investigate the usefulness of endoscopic ultrasonography (EUS) in comparison with EUS findings before and after CRT, and histologic findings. Methods There were 33 patients with potentially resectable ESCC who underwent neoadjuvant CRT. Preoperative EUS and histologic findings were compared. EUS criteria were established on the basis of low and high echoic regions. Resected specimens were examined by hematoxylin-eosin, azan, and cytokeratin immunohistochemical staining. Results Azan and cytokeratin staining clearly delineated fibrous changes and residual tumor. Low echoic regions corresponded to residual tumor and high echoic spots corresponded to fibrosis. All 12 patients classified as grade 1 on EUS diagnosis had histologic grade 1 tumors. Nineteen of 21 cases that presented with high echo were grade 2 or 3. The prognosis according to EUS diagnosis was similar to the histologic effect. Conclusions Preoperative EUS findings reflected the histologic effect after neoadjuvant CRT. EUS is a useful tool to assess the effect for CRT and to predict the prognosis in ESCC patients.