title: Clinical risk factors for perforation during endoscopic submucosal dissection (ESD) for large-sized, nonpedunculated colorectal tumors.
abstract: BACKGROUND
  The possible risk of colonic perforation during endoscopic submucosal dissection (ESD) for colorectal tumors is a barrier to wide application. This retrospective study was performed to evaluate the risk and the predictive factors for perforation during ESD procedure.
  
  
  METHODS
  Between October 2006 and November 2010, a total of 499 consecutive patients (mean age 60.0 ± 11.3 years) who underwent ESD for large-sized (≥ 20 mm), nonpedunculated colorectal tumor were analyzed. First, incidence rate and clinical course of perforation were evaluated. Second, patient-related variables (age, sex, history of aspirin or antiplatelet agents, and comorbidity), endoscopic variables (tumor size, location, and type), procedure-related variables (experience of procedures, procedure time, and materials of submucosal injection), and pathologic diagnosis were analyzed.
  
  
  RESULTS
  The mean size of the lesions was 28.9 mm. The overall en bloc resection rate was 95.0%. Perforation occurred in 37 out of 499 patients (7.4%). Thirty-four patients could be successfully treated conservatively. The type (laterally spreading tumor) and the location (right-sided colon) of the tumors, less experience of the procedure (<100 cases) in each endoscopist, and submucosal injection without hyaluronic acid were associated with higher frequency of perforation (all P < 0.05). On multivariate analysis, laterally spreading type of tumor [odds ratio (OR) 4.10, 95% confidence interval (CI) 1.17-14.34] and submucosal injection with hyaluronic acid (OR 0.31, 95% CI 0.13-0.72) were independent predictive factors.
  
  
  CONCLUSIONS
  Perforation rate was 7.4%, and most cases could be successfully managed nonsurgically. In case of laterally spreading type of tumor, more caution is needed during submucosal dissection and long-lasting submucosal cushion is important for preventing perforation.
authors.affiliation: Department of Surgery, Daehang Hospital, Bangbae-3dong Seocho-gu, Seoul 137-820, Korea. ejlee1009@naver.com
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Jae Bum
authors.initials: JB
authors.lastname: Lee
authors.forename: Yong Sung
authors.initials: YS
authors.lastname: Choi
authors.forename: Suk Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Doo Han
authors.initials: DH
authors.lastname: Lee
authors.forename: Do Sun
authors.initials: DS
authors.lastname: Kim
authors.forename: Eui Gon
authors.initials: EG
authors.lastname: Youk
mesh_terms: D000368:Aged; D044682:Colon, Ascending / Q000601:surgery; D003110:Colonic Neoplasms / Q000473:pathology / Q000601:surgery*; D003113:Colonoscopy / Q000009:adverse effects*; D004210:Dissection / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery; D007416:Intestinal Perforation / Q000209:etiology*; D007431:Intraoperative Complications / Q000209:etiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D012811:Sigmoid Neoplasms / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D047368:Tumor Burden