title: The risk of colorectal cancer in inflammatory bowel disease: a hospital-based cohort study from Korea.
abstract: OBJECTIVE
  Limited data are available on the incidence and risk factors of colorectal cancer (CRC) in Asian patients with inflammatory bowel disease (IBD).
  
  
  METHODS
  Information on 5212 Korean patients with IBD (2414 with Crohn's disease [CD] and 2798 with ulcerative colitis [UC]) was retrieved from the IBD registry of Asan Medical Center. Data on CRC incidence for the entire Korean population were derived from the Korean Statistical Information Service.
  
  
  RESULTS
  During 39,951 person-years of follow-up (17,679 for CD and 22,272 for UC), 30 patients (12 with CD and 18 with UC) developed CRC. The standardized incidence ratio (SIR) of CRC was 6.0 (95% confidence interval [CI], 3.10-10.48) for CD and 1.68 (95% CI, 1.00-2.66) for UC; it was 9.69 (95% CI, 5.01-16.93) for CD with colonic involvement and 4.31 (95% CI, 2.46-7.00) for extensive UC. The SIR was also increased in patients diagnosed with IBD at younger than 30 years old. CRC location was the low rectum in 11 of 12 CD patients (91.7%). The cumulative probability of rectal cancer was higher in CD patients with a perianal fistula than in those without a perianal fistula (p = 0.02).
  
  
  CONCLUSIONS
  A high prevalence of perianal fistulas in Korean CD patients may be the cause of the predominance of low rectal cancer in this population and the higher SIR of CRC in Koreans than in Westerners. In contrast, the SIR of CRC in Korean UC patients may be similar to that in Western UC patients.
authors.affiliation: Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Ho-Su
authors.initials: HS
authors.lastname: Lee
authors.forename: Sang Hyoung
authors.initials: SH
authors.lastname: Park
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.forename: Byong Duk
authors.initials: BD
authors.lastname: Ye
authors.forename: Ji-Hun
authors.initials: JH
authors.lastname: Kim
authors.forename: Seon-Ok
authors.initials: SO
authors.lastname: Kim
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Soh
authors.forename: Seohyun
authors.initials: S
authors.lastname: Lee
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Bae
authors.forename: Hyo Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Yang
authors.forename: Kyung-Jo
authors.initials: KJ
authors.lastname: Kim
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Byeon
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Myung
authors.forename: Yong Sik
authors.initials: YS
authors.lastname: Yoon
authors.forename: Chang Sik
authors.initials: CS
authors.lastname: Yu
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000150:complications*; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D003424:Crohn Disease / Q000150:complications*; D005260:Female; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000150:complications*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012003:Rectal Fistula / Q000150:complications*; D012042:Registries; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D055815:Young Adult
keywords: Crohn’s disease; Korea; colorectal cancer; inflammatory bowel disease; ulcerative colitis