title: Probability of high-risk colorectal neoplasm recurrence based on the results of two previous colonoscopies.
abstract: BACKGROUND
  Current guidelines for the surveillance colonoscopy interval are largely based on the most recent colonoscopy findings.
  
  
  OBJECTIVE
  We aimed to evaluate differences in the probability of high-risk neoplasm recurrence according to the two previous colonoscopy findings.
  
  
  METHODS
  This was a retrospective cohort study from a tertiary-care center. A total of 4,143 subjects who underwent three or more colonoscopies for screening or surveillance purposes from January 2001 to December 2011 were enrolled. We compared the probability of high-risk neoplasm detection on follow-up colonoscopies after the second colonoscopy based on risk categories in both the second and first colonoscopies.
  
  
  RESULTS
  At the final colonoscopy, 370 participants (8.9 %) had high-risk neoplasms. In patients with a normal second colonoscopy, the probability of high-risk neoplasm recurrence was different between those with normal, low-risk, and high-risk findings at the first colonoscopy (3.8, 6.8, and 17.7 %, respectively). The hazard ratio of a high-risk neoplasm at the final colonoscopy for patients with a normal second and low-risk first colonoscopy over a normal second and normal first colonoscopy was 3.07 (95 % CI 2.04-4.64, P < 0.001). The hazard ratio of high-risk neoplasm at the final colonoscopy for patients with a normal second and high-risk first colonoscopy over a normal second with normal first colonoscopy was 7.88 (95 % CI 4.90-12.67, P < 0.001).
  
  
  CONCLUSIONS
  The rate of high-risk colorectal neoplasm recurrence differs according to the two previous colonoscopy findings. Therefore, surveillance intervals could be adjusted not just only by the most recent colonoscopy findings but also by considering two previous colonoscopy findings.
authors.affiliation: Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Park
authors.forename: Seungbong
authors.initials: S
authors.lastname: Han
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Hye-Sook
authors.initials: HS
authors.lastname: Chang
authors.forename: Jaewon
authors.initials: J
authors.lastname: Choe
authors.forename: Yunsik
authors.initials: Y
authors.lastname: Choi
authors.forename: Hoonsub
authors.initials: H
authors.lastname: So
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Yang
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Myung
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Kim
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Byeon
mesh_terms: D000236:Adenoma / Q000453:epidemiology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D012189:Retrospective Studies; D018570:Risk Assessment