title: Determining the optimal surveillance interval after a colonoscopic polypectomy for the Korean population?
abstract: OBJECTIVE
  Western surveillance strategies cannot be directly adapted to the Korean population. The aim of this study was to estimate the risk of metachronous neoplasia and the optimal surveillance interval in the Korean population.
  
  
  METHODS
  Clinical and pathological data from index colonoscopy performed between June 2006 and July 2008 and who had surveillance colonoscopies up to May 2015 were compared between low- and high-risk adenoma (LRA and HRA) groups. The 3- and 5-year cumulative risk of metachronous colorectal neoplasia in both groups were compared.
  
  
  RESULTS
  Among 895 eligible patients, surveillance colonoscopy was performed in 399 (44.6%). Most (83.3%) patients with LRA had a surveillance colonoscopy within 5 years and 70.2% of patients with HRA had a surveillance colonoscopy within 3 years. The cumulative risk of metachronous advanced adenoma was 3.2% within 5 years in the LRA group and only 1.7% within 3 years in the HRA group. The risk of metachronous neoplasia was similar between the surveillance interval of <5 and ≥5 years in the LRA group; however, it was slightly higher at surveillance interval of ≥3 than <3 years in the HRA group (9.4% vs. 2.4%). In multivariate analysis, age and the ≥3-year surveillance interval were significant independent risk factors for metachronous advanced adenoma (P=0.024 andP=0.030, respectively).
  
  
  CONCLUSIONS
  Patients had a surveillance colonoscopy before the recommended guidelines despite a low risk of metachronous neoplasia. However, the risk of metachronous advanced adenoma was increased in elderly patients and those with a ≥3-year surveillance interval.
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Jung Lok
authors.initials: JL
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Jae Myung
authors.initials: JM
authors.lastname: Cha
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Hye Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Jung Won
authors.initials: JW
authors.lastname: Jeon
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Min Seob
authors.initials: MS
authors.lastname: Kwak
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Hyun Phil
authors.initials: HP
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Kwang Ro
authors.initials: KR
authors.lastname: Joo
authors.affiliation: Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.
authors.forename: Joung Il
authors.initials: JI
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
keywords: Colonoscopy; Colorectal neoplasms; Guideline; Polypectomy; Surveillance