Isoechoic tumor extension improves the accuracy of endoscopic ultrasound gastrointestinal cancer staging

Introduction: EUS is currently the best modality available for gastrointestinal cancer staging. Its accuracy in differentiating between T2 and T3 disease remains suboptimal. Since therapeutic decisions for esophageal and rectal cancers are based on this distinction, we have attempted to identify sonographic criteria that may help improve this accuracy. In our pilot study, the presence of Isoechoic Tumor Extension (ITE) has been found to be one such sonographic criterion. However, the sample size in that study was small. We report here an extension of this earlier work, with a larger sample size. Hypothesis: ITE is a reliable sonographic criterion that helps differentiate between early and advanced hollow viscous gastrointestinal cancers. Methods: Patients with resectable hollow viscous gastrointestinal cancers were evaluated by EUS preoperatively and were staged. In the absence of ITE, they were classified as early disease (T1 or T2). In the presence of ITE, they were classified as advanced disease (T3 or T4). The results were compared to surgical pathology which served as the "gold standard". Results: 31 patients, referred for preoperative EUS staging, were included in this study. The cancer distribution was as follows: 19 rectal, 5 esophageal, 5 gastric, 2 miscellaneous (1 anal, 1 ampullary). Based on the surgical pathology, the staging distribution was as follows: 13 advanced cancer, 18 early cancer. EUS was able to identify 11/13 patients with advanced cancer (sensitivity of 85%), and 16/18 patients with early cancer (specificity of 89%). Conclusions: ITE is a useful endosonographic criterion that helps differentiate between early and advanced hollow viscous gastrointestinal cancers.