title: Survival after colorectal cancer in patients with Crohn's disease: A nationwide population-based Danish follow-up study.
abstract: OBJECTIVE
  Patients with Crohn's disease (CD) are at increased risk of colorectal cancer (CRC), but little is known about the impact of CD on CRC prognosis. Based on nationwide population-based registries, we compared survival among CRC patients with CD and CRC patients without CD.
  
  
  METHODS
  We used the Danish Cancer Registry and the Danish Hospital Discharge Registry to identify all patients diagnosed with CRC, with and without CD, in Denmark between 1977 and 1999. We ascertained the stage distribution at the time of CRC diagnosis and 1- and 5-yr survival both for patients with Crohn-associated CRC and patients with non-Crohn CRC. Cox regression was used to compute hazard ratios (HRs), adjusting for gender, age, calendar year, and stage.
  
  
  RESULTS
  We identified 100 CRC patients with CD and 71,438 CRC patients without CD. At the time of diagnosis, patients with CD were younger, but stage distributions were similar in the two groups. The overall HR for CRC with CD compared to CRC without CD was 1.82 (95% CI 1.36-2.43) after 1 yr of follow-up, and 1.57 (95% CI 1.24-1.99) after 5 yr of follow-up. Subanalyses showed that the effect of CD on CRC survival was more pronounced in the youngest patients (0-59 yr), in men, and in patients whose tumors had regional spread.
  
  
  CONCLUSIONS
  We found that CD worsens the prognosis of CRC, particularly CRC with regional spread.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus C, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Larsen
authors.forename: Hanne
authors.initials: H
authors.lastname: Mose
authors.forename: Mette
authors.initials: M
authors.lastname: Gislum
authors.forename: Mette V
authors.initials: MV
authors.lastname: Skriver
authors.forename: Peter
authors.initials: P
authors.lastname: Jepsen
authors.forename: Bente
authors.initials: B
authors.lastname: Nørgård
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000209:etiology / Q000401:mortality*; D003424:Crohn Disease / Q000150:complications / Q000401:mortality*; D003718:Denmark / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries; D015996:Survival Rate