Formerly our colorectal ESD training required preceding mastery of gastric ESD, but we have changed the system so that it can be started irrespective of gastric ESD experiences since 2014. Here, we present the course of a trainee who was trained in the new training system. The trainee had an experience of 40 gastric and 5 colorectal ESD at another institution. At the first step of the new training system, the teaching expert taught the following points to the trainee ; how to operate endoscope at will to meet the pre-determined objective criteria, and how to perform colorectal ESD in a pig colon model. After that, the trainee was allowed to perform colorectal ESD practice, starting with rectal lesions, under full back-up by the expert. 20 colorectal lesions were treated by the trainee within six months. The en bloc and self-completion resection rates were both 100%. The mean procedure time was 106 minutes with a mean tumor size of 36.6 mm. Thus, the trainee who had a limited experience of ESD at another hospital could perform colorectal ESD safety under our training system. We believe intensive coaching before ESD practice and full-back up by an expert in the initial step of ESD practice are necessary.
