title: Endoscopic submucosal dissection for colorectal tumors.
abstract: BACKGROUND
  Endoscopic submucosal dissection (ESD) is a state-of-the-art method that enables resection of larger tumors than those resectable by conventional endoscopic mucosal resection (EMR). However, the individual role of each method in the treatment of colorectal tumors remains undetermined.
  
  
  OBJECTIVE
  To consider the respective indications of ESD and EMR for colorectal tumors, we analyzed the results of the two treatments retrospectively.
  
  
  RESULTS
  Tumors treated by ESD (44 tumors) were significantly larger, more often located in the rectum and more often coexistent with cancer than those treated by EMR (512 tumors). EMR was used in the majority of adenomas, and showed high rates of both one-piece resection (OPR) and complete resection (CR) for adenomas less than 20 mm. However, for adenomas and cancers greater or equal to 20 mm, the CR rate for EMR was significantly lower than that for ESD because of the incidence of OPR with a positive lateral margin (16% vs 0% with ESD vs EMR). Histopathology (cancer), size (> or =20 mm) and macroscopic type (laterally spreading tumors) were shown to be significant risk factors for that incidence. For tumors with these factors, ESD showed a higher CR rate than did EMR. However, ESD required longer operating times and tended to have a higher rate of perforation compared with EMR. ESD was aborted halfway in seven cases due to technical difficulties and perforation.
  
  
  CONCLUSIONS
  ESD and EMR have different characteristics as treatment for colorectal tumors. Careful evaluation of the lesion and of the balance between benefits and risks are mandatory before selecting either of these treatments for colorectal tumors.
authors.affiliation: Center of Gastroenterology, Maebashi Red Cross Hospital, Maebashi, Gunma, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Iizuka
authors.forename: S
authors.initials: S
authors.lastname: Okamura
authors.forename: Y
authors.initials: Y
authors.lastname: Onozato
authors.forename: H
authors.initials: H
authors.lastname: Ishihara
authors.forename: S
authors.initials: S
authors.lastname: Kakizaki
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000601:surgery; D000236:Adenoma / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery*; D007416:Intestinal Perforation / Q000209:etiology; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors