title: Crohn's disease and cancer risk (Denmark).
abstract: OBJECTIVE
  The large number of studies of intestinal cancer among patients with Crohn's disease have provided inconsistent risk estimates in regard to risk of both colorectal and small intestinal cancer. We investigated incidence of cancer among Crohn's disease patients in comparison with the incidence in the general population of Denmark.
  
  
  METHODS
  From the Danish National Registry of Patients we identified 2645 patients who had been hospitalized with Crohn's disease during 1977-1989. Cancer incidence for up to 17 years was determined in the cohort and compared to an expected number derived from national cancer incidence rates.
  
  
  RESULTS
  The 15 observed cases of colorectal cancer were close to the expected number of 13.1 (SIR = 1.1; 95% CI 0.6-1.9), whereas the five cases of small intestinal cancer (three adenocarcinomas and two carcinoids) observed corresponded to an 18-fold increased risk (SIR = 17.9; 95% CI 5.8-42).
  
  
  CONCLUSIONS
  A potential excess of colorectal cancer among subgroups of patients with Crohn's disease was not detectable in the overall risk estimate for colorectal cancer. Only for small intestinal cancer was a significantly elevated risk found among these patients hospitalized with Crohn's disease.
authors.affiliation: Danish Cancer Society, Institute of Cancer Epidemiology, Copenhagen O. lene@cancer.dk
authors.forename: L
authors.initials: L
authors.lastname: Mellemkjaer
authors.forename: C
authors.initials: C
authors.lastname: Johansen
authors.forename: G
authors.initials: G
authors.lastname: Gridley
authors.forename: M S
authors.initials: MS
authors.lastname: Linet
authors.forename: S K
authors.initials: SK
authors.lastname: Kjaer
authors.forename: J H
authors.initials: JH
authors.lastname: Olsen
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000556:secondary; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002276:Carcinoid Tumor / Q000453:epidemiology / Q000556:secondary; D016022:Case-Control Studies; D015331:Cohort Studies; D015897:Comorbidity; D016001:Confidence Intervals; D003424:Crohn Disease / Q000175:diagnosis / Q000453:epidemiology*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D007414:Intestinal Neoplasms / Q000453:epidemiology* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution