title: Effect of prior biopsy sampling, tattoo placement, and snare sampling on endoscopic resection of large nonpedunculated colorectal lesions.
abstract: BACKGROUND
  Endoscopic manipulations, including biopsy sampling, tattoo application on the lesion itself, and sampling of the lesion with a polypectomy snare, are frequently performed on large nonpedunculated colorectal lesions ≥ 20 mm (LNCL) before referral for endoscopic resection.
  
  
  OBJECTIVE
  To assess the effect of prior manipulations on the technical difficulty and recurrence rates of subsequent endoscopic treatment.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Two referral centers.
  
  
  METHODS
  Patients with LNCL referred for endoscopic resection.
  
  
  METHODS
  Endoscopic resection.
  
  
  METHODS
  En-bloc resection rate, rate of successful complete endoscopic resection without the need for ablation of visible residual, recurrence rate on follow-up, independent predictive factors for en-bloc resection, complete resection without ablation of visible residual, and recurrence.
  
  
  RESULTS
  A total of 132 lesions was analyzed: 46 lesions without any prior manipulation, 44 with prior biopsy sampling only, and 42 with prior advanced manipulation including tattoo and/or snare sampling. The en-bloc resection rate was 34.8% for nonmanipulated lesions, 15.9% for lesions with prior biopsy sampling, and 4.8% for lesions with prior advanced manipulation (P = .001). Complete endoscopic resection without the need for ablation of visible residual was performed in 93.5% of nonmanipulated lesions, 68.2% of lesions with prior biopsy sampling, and 50% of lesions with prior advanced manipulation (P < .001). Recurrence rates were 7.7%, 40.7%, and 53.8% in the 3 groups (P = .001). In multivariate analysis, prior biopsy sampling was an independent predictor for inability to perform complete resection without ablation of visible residual (odds ratio .24, P < .05) and for recurrence (odds ratio 11.5, P = .004) compared with nonmanipulated lesions. Prior advanced manipulation was an independent predictor for inability to perform en-bloc resection (odds ratio .024, P = .001), for inability to perform complete resection without ablation of visible residual (odds ratio .081, P < .001), and for recurrence (odds ratio 18.8, P = .001).
  
  
  CONCLUSIONS
  Retrospective study.
  
  
  CONCLUSIONS
  Prior biopsy sampling and advanced manipulation have significant deleterious effects on endoscopic treatment of LNCL.
authors.affiliation: Institute for Digestive Research, Soonchunhyang University College of Medicine, Seoul, Korea.
authors.forename: Hyun Gun
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Department of Gastroenterology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Nirav
authors.initials: N
authors.lastname: Thosani
authors.affiliation: Department of Gastroenterology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Subhas
authors.initials: S
authors.lastname: Banerjee
authors.affiliation: Department of Gastroenterology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Ann
authors.initials: A
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, Stanford University School of Medicine, Stanford, California, USA; VA Palo Alto Health Care System, Palo Alto, California, USA.
authors.forename: Shai
authors.initials: S
authors.lastname: Friedland
mesh_terms: D000236:Adenoma / Q000473:pathology / Q000601:surgery*; D000368:Aged; D001706:Biopsy; D003111:Colonic Polyps / Q000473:pathology / Q000601:surgery*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D003430:Cross-Sectional Studies; D004210:Dissection; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D013653:Tattooing