The purposes of EMR, ESD and their conditions for use.

Curative endoscopic mucosal resection (EMR) is widely used in Japan for early gastric cancer. Endoscopic submucosal dissection (ESD) is a newly developed endoscopic enbloc resection of superficial gastrointestinal lesions. In the report of Hirasaki (1), the author adopted ESD involving the use of an insulated-tip diathermic knife. They compared patient backgrounds, the one-piece resection rate, complete resection rate, operation time, bleeding rate, perforation rate, and blood pressure between the elderly group and the non-elderly group. As a result, there was no significant difference in the outcome resulting from ESD between the two groups. Indications of ESD (EMR) have been defined in the “Gastric Cancer Treatment Guidelines” (2) by the Japanese Gastric Cancer Association. Radical endoscopic treatment can be indicated for lesions not more than 2 cm in diameter, as long as the depth of invasion is the mucosal layer without accompanying lymph node metastasis. Following these indications, it is possible to effectively use EMR to deal with some lesions for which ESD is indicated. Our original method of endoscopic mucosal resection using a cap-fitted panendoscope, which is called EMRC (3), is advantageous in that it is simple and relatively easily applied at almost any location within the stomach. In addition, the size of the specimen obtained by en bloc resection is approximately 2 cm and repeated resection is possible. According to the report by Ida et al (4), if the diagnosis of mucosal cancer from the resected specimen at the initial EMR is histologically correct, then local cure can be achieved with endoscopic treatment, including cases of recurrence, with appropriate follow-up and use of concomitant techniques such as piecemeal resection and coagulation therapy. It is important to pay attention to the fact that the frequency of submucosal invasion is approximately 40% in type I and IIa+IIc type lesions, and 20% in type IIc+Ul lesions (5). We suppose that the wider the indications expand, the higher the infiltration rate becomes. At the same time, the possibility of vascular invasion increases, even if no lymph node metastasis occurs. Carefully planned on-the-job training is necessary to master the technique of ESD, and also a physician needs great control while performing ESD. Thus, we expect ESD to expand the indications to lesions which are impossible to treat using conservative technique and to lower the frequency of invasion and complications. When the results of more cases treated by ESD are accumlated, it will be possible to evaluate it properly.