4535 Is endoscopic ultrasound accurate in the restaging of esophageal cancer following chemoradiation?

Abstract

OBJECTIVE: Endoscopic ultrasound (EUS) is an important tool in staging of esophageal tumors, however its utility following chemoradiation for restaging or predicting complete or partial response remains unclear. These qualities would be highly desirable, as clinical course may be changed and surgery could be avoided entirely in some cases, reducing morbidity and mortality. In addition, few studies have looked at surrogate EUS markers that may help improve predictive value, beyond the TNM system. This study seeks to review the experience with EUS following chemoradiation for esophageal cancer at our medical center, as well as to evaluate its ability to predict response based on change in tumor thickness as a surrogate marker. METHODS: Between 3/98 and 8/99, 13 consecutive patients with esophageal cancer underwent EUS staging pre and post chemoradiation regimens, prior to esophagectomy and pathologic staging. 6 additional patients had EUS following chemoradiation administered elsewhere, prior to surgery. 18 patients had distal esophageal adenocarcinoma; 1 patient had proximal squamous cell carcinoma. Oncologists determined chemotherapy and radiation regimens individually. TNM staging and maximal tumor thickness were noted in all cases and compared with pathologic findings. RESULTS: Post chemoradiation EUS accurately predicted pathologic stage in only 4/19 patients (21%). Post chemoradiation EUS correctly demonstrated T stage in 12/19 patients (63%) and N stage in 9/19 (47%). In those undergoing pre and post chemoradiation EUS, cases demonstrating reduction in T stage when comparing initial EUS T stage to final pathologic T stage showed an average change in maximal tumor thickness of 6.15mm (N=6). Those without change in T stage showed an average of 1.2mm tumor thickness reduction (N=7). In those who had downgrading of EUS T stage from pre to post chemoradiation EUS, average change in maximal tumor thickness was 5.8mm, and all matched final pathologic T stage (N=5). If T stage remained the same on both EUS, average change in maximal tumor diameter was 2.9mm (N=8). CONCLUSIONS: The predictive value of post chemoradiation EUS was low and not useful to guide clinical decision making. Accuracy for T staging was better when compared to N staging, but still remained suboptimal to make important clinical decisions. However, it may be possible to define a threshold of change in tumor thickness that would be predictive of clinical response. More studies are needed to appropriately define this threshold.