title: Primary sclerosing cholangitis and colorectal carcinoma in patients with chronic ulcerative colitis: a case-control study.
abstract: BACKGROUND
  Controversy persists regarding primary sclerosing cholangitis (PSC) as a risk factor for colorectal carcinoma in patients with chronic ulcerative colitis. Small sample size and differing endpoints have contributed to variation among reported studies. This large case-control study was conducted to examine the possible association between PSC and colon carcinoma in patients with ulcerative colitis.
  
  
  METHODS
  From Mayo Clinic records spanning 1976-1994, 171 cases with both ulcerative colitis and colorectal carcinoma and 171 contemporaneous controls with ulcerative colitis but no colorectal neoplasia matched with regard to age, gender, extent, and duration of colitis were identified. The diagnosis of PSC required cholangiographic confirmation. Analysis employed a multivariate logistic regression model.
  
  
  RESULTS
  The prevalence of PSC was similar in cases (18%) and controls (15%) (P = 0.54). The adjusted odds ratio for colorectal carcinoma with PSC was 1.23 (95% confidence interval, 0.62-2.42).
  
  
  CONCLUSIONS
  Based on this large case-control study, there was no association between PSC and colorectal carcinoma in patients with ulcerative colitis.
authors.affiliation: Division of Gastroenterology and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
authors.forename: K W
authors.initials: KW
authors.lastname: Nuako
authors.forename: D A
authors.initials: DA
authors.lastname: Ahlquist
authors.forename: W J
authors.initials: WJ
authors.lastname: Sandborn
authors.forename: D W
authors.initials: DW
authors.lastname: Mahoney
authors.forename: D M
authors.initials: DM
authors.lastname: Siems
authors.forename: A R
authors.initials: AR
authors.lastname: Zinsmeister
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D015209:Cholangitis, Sclerosing / Q000150:complications / Q000453:epidemiology*; D002908:Chronic Disease; D003093:Colitis, Ulcerative / Q000150:complications*; D003110:Colonic Neoplasms / Q000150:complications / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D015995:Prevalence; D012004:Rectal Neoplasms / Q000150:complications / Q000209:etiology*; D012307:Risk Factors