title: Learning curve for endoscopic submucosal dissection of large colorectal tumors.
abstract: OBJECTIVE
  No studies have previously described the learning curve for colonic endoscopic submucosal dissection (ESD). The aim of the present study was to describe the learning curve for ESD of large colorectal tumors based on a single colonoscopist's experience.
  
  
  METHODS
  ESD was carried out for 120 colorectal tumors in 115 patients (68 males, median age 70 years). All procedures were carried out by a single experienced colonoscopist. The cases were grouped chronologically into three periods: (1st): cases 1-40; (2nd): cases 41-80; and (3rd): cases 81-120.
  
  
  RESULTS
  The learning curve was the changes in proficiency over time. Proficiency was expressed as procedure time per unit area of specimen. In the 1st, 2nd and 3rd periods, the proficiencies were 18.9, 12.6 and 12.9 (min/cm(2) ), respectively. The proficiencies in the 2nd and 3rd periods were significantly shorter than in the 1st period (t-test, P < 0.05). The en-bloc resection rates of the 1st, 2nd and 3rd periods were 92.5% (37/40), 90% (36/40) and 97.5% (39/40), respectively. The en-bloc and R0 resection rates of the 1st, 2nd and 3rd periods were 85% (34/40), 77.5% (31/40) and 92.5% (37/40), respectively. The perforation rates of the 1st, 2nd and 3rd periods were 12.5% (5/40), 5% (2/40) and 5% (2/40), respectively.
  
  
  CONCLUSIONS
  Based on our analysis of the learning curve, approximately 80 procedures must be carried out to acquire skill with ESD for large colorectal tumors. However, approximately 40 procedures were sufficient to acquire skill in avoiding perforations during the ESD procedure.
authors.affiliation: Department of Gastroenterology, Saku Central Hospital, Saku, Nagano, Japan. kinichi1@janis.or.jp
authors.forename: Kinichi
authors.initials: K
authors.lastname: Hotta
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Oyama
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Shinohara
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Miyata
authors.forename: Akiko
authors.initials: A
authors.lastname: Takahashi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Akihisa
authors.initials: A
authors.lastname: Tomori
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D002983:Clinical Competence; D003113:Colonoscopy / Q000193:education*; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D004210:Dissection / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D013997:Time Factors