title: Learning curve for endoscopic submucosal dissection of gastric neoplasms.
abstract: BACKGROUND
  Endoscopic submucosal dissection (ESD) is a widely accepted method for the treatment of early gastrointestinal neoplasms.
  
  
  OBJECTIVE
  To investigate the learning curve of ESD performed by a single endoscopist focusing on developing the performance of dissection, shortening the procedure time, and preventing complications.
  
  
  METHODS
  Records of 120 consecutive ESD procedures performed by a single endoscopist with an ESD knife from December 2007 to April 2013 were collected. For analysis of the learning curve, total procedures were divided into four periods, each comprising 30 sequential ESD procedures. Adjusted procedure time (min) was calculated as specimen area [π×long length (mm)×short length (mm)/4]÷procedure time. The parameters assessed were the en-bloc resection rate, complete resection rate, duration and speed of procedure time, and related complications.
  
  
  RESULTS
  Procedure times were significantly longer with lesions located at the upper third of the stomach and with the specimen sizes exceeding 1500 mm. There were significant differences in the adjusted overall procedure time from the first to the third quarter (19.9±11.0 vs. 30.3±11.8, P=0.01) and to the fourth quarter (19.9±11.0 vs. 35.8±15.7, P<0.01), and from the second to the third quarter (21.1±8.3 vs. 30.3±11.8, P=0.04) and to the fourth quarter (21.1±8.3 vs. 35.8±15.7, P<0.01).
  
  
  CONCLUSIONS
  ESD for gastric neoplasms can be performed with a steady speed after the experience of 60 ESD procedures with proper clinical outcomes. Further studies with different endoknives will be required for ESD operators as a reference.
authors.affiliation: Department of Internal Medicine, Dongguk University Ilsan Hospital, Graduate School, Goyang, Korea.
authors.forename: Kyong Hee
authors.initials: KH
authors.lastname: Hong
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Shin
authors.forename: Jae Hak
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000601:surgery*; D000236:Adenoma / Q000473:pathology / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence; D004210:Dissection / Q000009:adverse effects / Q000193:education / Q000379:methods; D004496:Education, Continuing / Q000379:methods; D005260:Female; D005773:Gastroscopy / Q000009:adverse effects / Q000193:education* / Q000379:methods; D006801:Humans; D007432:Intraoperative Period; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000473:pathology / Q000601:surgery*