LEARNING CURVE FOR ENDOSCOPIC SUBMUCOSAL DISSECTION OF EARLY GASTRIC CANCER BASED ON TRAINEE EXPERIENCE

Background and Aim: There have been few previous reports on endoscopic submucosal dissection (ESD) learning curve for early gastric cancer (EGC) so we retrospectively assessed this subject based on experience of our trainees. Methods: Trainees in our center start performing ESDs for lesions in lower third of stomach with hands-on support by experts during first 10 cases and then perform ESDs by themselves primarily with verbal guidance from experts. They are gradually assigned to perform ESDs in middle and upper thirds of stomach. From January 1999 to December 2008, 464 EGC patients, who underwent ESD performed by 13 trainees, were assessed by dividing ESD cases into five training periods (A, 1-10; B, 11-20; C, 21-30; D, 31-40; and E, 41-50). We compared data from B to C, D and E. Results: Lesions in lower third were A/59%, B/57%, C/55%, D/36% and E/40% with B significantly higher than D (p<0.01) and E (p<0.05). Mean tumor sizes were A/13.9 +/- 7.5mm, B/18.3 +/- 11.4mm, C/19.0 +/- 12.5mm, D/19.3 +/- 11.7mm and E/16.8 +/- 10.3mm. En-bloc resection rate was 100% in every period. Delayed bleeding / perforation rates were A/0%/1.8%, B/2.8%/1.9%, C/1.9%/2.9%, D/1.1%/0% and E/2.1%/2.1%, respectively. Lower third procedure times were A/76 +/- 39, B/90 +/- 61, C/70 +/- 48, D/60 +/- 50 and E/55 +/- 26 minutes with B significantly longer than D and E (p<0.05). Middle and upper third procedure times were A/104 +/- 80, B/115 +/- 68, C/106 +/- 67, D/134 +/- 86 and E/96 +/- 55 minutes. Conclusion: Step-by-step training was highly effective with 100% en-bloc resection rate and few complications. Learning curve point for our trainees to acquire performing ESD in lower third of stomach was 30 cases.