Concept of ESD and its Current Status in Japan

Abstract

Originalarbeit 34Concept of ESD ! ESD was originally developed in Japan in order to achieve a reliable method for en-bloc resection of early gastric cancers [1]. Initially, the use of this technique was limited to gastric lesions, on account of maneuverability of the endoscope and the wall thickness of the stomach. But, with experience and advances in equipment it became possible to conduct ESD even in the colon and esophagus [2][3][4][5]. The most important aspects of this technique are to incise the mucosa surrounding the lesion, and to dissect completely the submucosa beneath that lesion. As a result, reliable en-bloc resection is achievable regardless of the size or location of the tumor (l " Fig. 1). In order to correctly evaluate the risk of local or regional metastasis after ESD the specimen must be handled and prepared so that the pathologist can assess (A) the risk of lymph node metastasis and (B) the completeness of resection. The depth of tumor extension, the degree of tumor differentiation and the presence of vascular infiltration are all key factors in assessing the risk for lymph node metastases. ESD provides an en-bloc specimen that enables the pathologist to confirm completeness of resection by assessing both lateral and vertical margins. The benefit of the ESD procedure compared to EMR is that local recurrence is greatly minimized if the entire lesion has been removed intact. This technique is applicable to relatively large and complex lesions, even those difficult to treat with conventional EMR. As a result, by employing ESD in selected cases one can avoid unnecessary surgery and can preserve GI function. Although complex and technically challenging, ESD completely redefines the whole concept of endoscopic resection for gastrointestinal tumors. Application of ESD! This technique is applicable to any tumor in digestive tract that can be visualized with an endoscope. The ideal lesions are superficial neoAbstract ! Endoscopic submucosal dissection (ESD) was developed in Japan for the "en-bloc" resection of early gastric cancer. Main advantages of ESD are the possibility of a histo-pathological evaluation of the entire specimen as well as a lower local recurrence rate compared to "piecemeal" resection. The article summarizes the concept of ESD and gives the an overview of the indications accepted for local treatment of early GI cancers. Technical problems resulting form difficult locations of the lesion are discussed as well as the technical prerequisites and the qualification of the endoscopist. The different steps of the procedure are illustrated on the basis of a gastric ESD.