title: Impact of endoscopist withdrawal speed on polyp yield: implications for optimal colonoscopy withdrawal time.
abstract: BACKGROUND
  In 2002, a U.S. Multi-Society Task Force on Colorectal Cancer recommended that the withdrawal phase for colonoscopy should average at least 6-10 min. This was based on 10 consecutive colonoscopies by two endoscopists with different adenoma miss rates.
  
  
  OBJECTIVE
  To characterize the relationship between endoscopist withdrawal time and polyp detection at colonoscopy, and to determine the withdrawal time that corresponds to the median polyp detection rate.
  
  
  METHODS
  Procedural data from out-patient colonoscopies performed at the Mayo Clinic, Rochester during 2003 were reviewed. Endoscopists were characterized by their mean withdrawal time for a negative procedure and individual polyp detection rate.
  
  
  RESULTS
  A total of 10 955 colonoscopies performed by 43 endoscopists were analysed. Median withdrawal time was 6.3 min (range: 4.2-11.9); polyp detection rate was 44.0% (all polyps), 29.8% (< or = 5 mm), 5.9% (6-9 mm), 6.7% (10-19 mm), 2.1% (> or = 20 mm). Longer withdrawal time was associated with higher polyp detection rate (r = 0.76; P < 0.0001); this relationship weakened for larger polyps (r = 0.19 for polyps 6-9 mm, r = 0.28 for polyps 10-19 mm, r = 0.02 for polyps > or = 20 mm). Overall median polyp detection rate corresponded to a withdrawal time of 6.7 min.
  
  
  CONCLUSIONS
  Our findings support a colonoscopy withdrawal time of at least 7 min, which correlates with higher colon polyp detection rates.
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo College of Medicine, Rochester, MN, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Simmons
authors.forename: G C
authors.initials: GC
authors.lastname: Harewood
authors.forename: T H
authors.initials: TH
authors.lastname: Baron
authors.forename: B T
authors.initials: BT
authors.lastname: Petersen
authors.forename: K K
authors.initials: KK
authors.lastname: Wang
authors.forename: F
authors.initials: F
authors.lastname: Boyd-Enders
authors.forename: B J
authors.initials: BJ
authors.lastname: Ott
mesh_terms: D000236:Adenoma / Q000175:diagnosis; D002983:Clinical Competence; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000175:diagnosis; D003111:Colonic Polyps / Q000175:diagnosis* / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors