title: Endoscopic treatment of large colorectal tumors: comparison of endoscopic mucosal resection, endoscopic mucosal resection-precutting, and endoscopic submucosal dissection.
abstract: BACKGROUND
  Endoscopic mucosal resection (EMR) is a useful therapeutic technique for colorectal tumors. However, for tumors larger than 20 mm, the chance of piecemeal resection is high. Recently introduced endoscopic submucosal dissection (ESD) enables en bloc resection regardless of the tumor size. This study aimed to compare the effectiveness and outcomes of EMR, EMR-precutting (EMR-P), and ESD in the treatment of colorectal tumors 20 mm in size or larger.
  
  
  METHODS
  This study reviewed 523 nonpedunculated colorectal tumors (499 patients) 20 mm or larger that received endoscopic treatment (EMR in 140 cases, EMR-P in 69 cases, and ESD in 314 cases) from January 2004 to November 2009.
  
  
  RESULTS
  The mean sizes of the tumors were 21.7 ± 3.5 mm (EMR), 23.5 ± 5.6 mm (EMR-P), and 28.9 ± 12.7 mm (ESD). The ratios of adenocarcinomas were 15.7% (EMR), 29% (EMR-P), and 37.9% (ESD). The en bloc resection rates were 42.9% (EMR), 65.2% (EMR-P), and 92.7% (ESD), and the complete resection rates were 32.9% (EMR), 59.4% (EMR-P), and 87.6% (ESD). Perforation occurred in 2.9% of the EMR-P cases and 8% of the ESD cases. The recurrence rates were 25.9% (EMR; median follow-up period, 26 months), 3.2% (EMR-P; median follow-up period, 16 months), and 0.8% (ESD; median follow-up period, 17 months).
  
  
  CONCLUSIONS
  For the treatment of large, nonpedunculated colorectal tumors, ESD is more effective than either EMR or EMR-P. Although ESD is technically demanding, it has clinical significance by overcoming the limitations of both EMR and EMR-P.
authors.affiliation: Department of Surgery, Daehang Hospital, 481-10 Bangbae Seocho, 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: Suk Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Eui Gon
authors.initials: EG
authors.lastname: Youk
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D004210:Dissection / Q000379:methods; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000209:etiology; D011351:Proctoscopy / Q000379:methods*; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult