The examiner's learning effect and its influence on the quality of endoscopic ultrasonography in carcinoma of the esophagus and gastric cardia

Background: The preoperative diagnosis of tumors of the esophagus and the g astric cardia is an important element in their stage-oriented therapy. The goal of the present study was to evaluate the accuracy of endosonographic u ltrasound (EUS) and to test its usefulness in tumor staging and the assessm ent of operability. Methods: A total of 139 tumors were scanned via EUS by one examiner less th an or equal to 14 days prior to resection (TNM staging per UICC, 1987). Results: The accuracy for completely traversable tumors was 60.8% for T1, 8 2.1% for T2, 77.5% for T3, and 33% for T4 stages. This accuracy was somewha t reduced in cases of nontraversable tumor stenosis (51.9%). In T staging, a significant case-dependent improvement in accuracy to 89.5% was found; th is was regarded as a learning effect. In N staging, we considered only thos e tumors that were resected by the transthoracic approach with systematic n ode dissection and complete EUS (n = 80). N-stage accuracy (T1-T4) was 71.3 %, and no improvement could be shown. To assess operability, discrimination between T1/T2 and T3/T4 tumors is crucial. Accuracy, sensitivity, and spec ifity can thus be improved significantly. Conclusions: The quality of EUS depends on the experience of the examiner. Reliable results can be obtained after >75 examinations have been done. EUS is a valuable tool in tumor staging when it is performed by an experienced examiner or under the direct supervision of such a person.