title: Technical difficulty according to location, and risk factors for perforation, in endoscopic submucosal dissection of colorectal tumors.
abstract: BACKGROUND
  Colorectal endoscopic submucosal dissection (ESD) is a widely accepted treatment for colorectal tumors, but is technically more difficult and has a higher risk of complications such as perforation than gastric ESD. Few studies have investigated the factors associated with technical difficulty and perforation in colorectal ESD. This study aimed to evaluate the technical difficulty according to location, and the risk factors for perforation, in colorectal ESD.
  
  
  METHODS
  This retrospective study included 134 consecutive colorectal tumors treated by ESD in 122 patients at the Division of Endoscopy of Hokkaido University Hospital and the Department of Gastroenterology of Kitami Red Cross Hospital from November 2011 to February 2013. To evaluate the technical difficulty of performing ESD for colorectal tumors at specific locations, the en bloc R0 resection rate, specimen diameter, procedure speed, and procedure time were compared among tumor locations using the χ (2) test or analysis of variance. Risk factors for perforation were identified by multiple logistic regression analysis.
  
  
  RESULTS
  The en bloc R0 resection rate was 86.6 % (116/134), the mean tumor diameter was 27.1 mm, and the mean procedure time was 63.5 min. The mean speed of procedures was significantly slower in the sigmoid colon (24.7 min/cm(2)) than in other areas. Perforation occurred in nine cases (6.7 %). Submucosal fibrosis was the only factor independently associated with perforation (odds ratio 5.684, 95 % confidence interval 1.307-24.727).
  
  
  CONCLUSIONS
  ESD was slower for sigmoid colon tumors than for tumors in other areas, suggesting that ESD was technically more difficult in the sigmoid colon than in other colorectal areas. Submucosal fibrosis was independently associated with perforation during colorectal ESD.
authors.affiliation: Department of Gastroenterology, Kitami Red Cross Hospital, Kitami, Japan, mizu@gc4.so-net.ne.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mizushima
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Kato
authors.forename: Ichiro
authors.initials: I
authors.lastname: Iwanaga
authors.forename: Fumiyuki
authors.initials: F
authors.lastname: Sato
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Kubo
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ehira
authors.forename: Minoru
authors.initials: M
authors.lastname: Uebayashi
authors.forename: Shouko
authors.initials: S
authors.lastname: Ono
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Mabe
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery*; D000236:Adenoma / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000601:surgery; D015179:Colorectal Neoplasms / Q000601:surgery*; D004210:Dissection / Q000009:adverse effects / Q000379:methods; D016099:Endoscopy, Gastrointestinal / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery*; D007416:Intestinal Perforation / Q000209:etiology*; D007431:Intraoperative Complications / Q000209:etiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012007:Rectum / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors