title: Outcome of endoscopic submucosal dissection for colorectal tumors accompanied by fibrosis.
abstract: OBJECTIVE
  Colorectal endoscopic submucosal dissection (ESD) is a difficult procedure. We aimed to retrospectively assess the relationship between the outcome of ESD for colorectal tumors and the degree of fibrosis.
  
  
  METHODS
  We examined 203 consecutive patients with colorectal tumors larger than 20 mm in diameter who had undergone ESD at our hospital from November 2002 to June 2009. During ESD, the degree of submucosal fibrosis was classified into three types (F0-2). The relationship between the degree of fibrosis and the lesion characteristics and those between the outcome of ESD and the degree of fibrosis were analyzed.
  
  
  RESULTS
  In the cases of granular laterally spreading tumors, the incidence of F2 fibrosis in nodular mixed-type tumors was significantly higher than that in homogenous-type tumors. An increase in the experience of the operators caused significant improvements in the rates of complete en bloc resection (p = 0.022) and perforation (p = 0.03) in the cases of lesions with F0-1 fibrosis. By contrast, operator experience did not cause any significant improvements in the rates of complete en bloc resection and perforation in the cases of lesions with F2 fibrosis.
  
  
  CONCLUSIONS
  Experienced operators could safely perform complete en bloc resection in the cases of lesions with F0-1 fibrosis. However, in the cases of lesions with F2 fibrosis, the rate of complete en bloc resection was low and the perforation rate was high even when ESD was performed by an experienced operator.
authors.affiliation: Department of Medicine and Molecular Science, Graduate School of Biomedical Science, Hiroshima University, Minami-ku, Hiroshima, Japan.
authors.forename: Aki
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Sayaka
authors.initials: S
authors.lastname: Oba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanao
authors.forename: Shiro
authors.initials: S
authors.lastname: Oka
authors.forename: Masaharu
authors.initials: M
authors.lastname: Yoshihara
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000368:Aged; D003106:Colon / Q000473:pathology / Q000601:surgery*; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery*; D003937:Diagnosis, Differential; D018450:Disease Progression; D004210:Dissection / Q000379:methods*; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology / Q000601:surgery*; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome