Assessment of response of esophageal carcinoma to induction chemotherapy.

Endoscopic ultrasonography (EUS) is currently considered the best available technique for the local staging of esophageal cancer. In a prospective study 11 patients with esophageal squamous cell carcinoma were investigated to evaluate the usefulness of EUS in the assessment of response to induction chemotherapy. Response to chemotherapy was evaluated by means of history of dysphagia, endoscopy, computed tomography (CT) and EUS to assess relief of clinical symptoms, reduction of tumor bulk and depth of tumor invasion (T-stage). One patient was excluded because EUS failed. Tumor response was best correlated with relief of dysphagia and by tumor bulk reduction as determined on endoscopy and CT. We found it not useful to measure reduction of tumor bulk with EUS because of tumor compression by the instrument, stenosis, or the hypoechoic thickening of the esophageal wall caused by an inflammatory reaction after chemotherapy. There was no change in EUS T-staging after induction chemotherapy compared to prechemotherapy assessment. EUS T-staging after induction chemotherapy was accurate in 6 of 10 patients compared to the histopathologic examination of the resected specimen. There was EUS T3-overstaging in 4 patients, caused by partial or complete replacement of the tumor by an inflammatory reaction due to chemotherapy. We conclude that inflammatory changes induced by chemotherapy lead to EUS overstaging of the T stage thus making it a less reliable tool in restaging after chemotherapy.