title: Epidemiology and prognosis of synchronous colorectal cancers.
abstract: BACKGROUND
  The aim of this population-based study was to report on the incidence, treatment and prognosis of synchronous colorectal carcinomas.
  
  
  METHODS
  Data were obtained from the population-based cancer registry of Burgundy.
  
  
  RESULTS
  Between 1976 and 2004, 15 562 colorectal cancers were diagnosed. Some 3.8 per cent of patients had synchronous colorectal cancers. The risk of having synchronous cancers was higher in men (odds ratio (OR) 1.41 (95 per cent confidence interval (c.i.) 1.19 to 1.68)), when associated adenomas were present (OR 2.02 (95 per cent c.i. 1.69 to 2.41)), when there were adenomatous remnants on pathological examination (OR 2.10 (95 per cent c.i. 1.73 to 2.55)) and in patients aged over 75 years (OR 1.31 (95 per cent c.i. 1.08 to 1.59)). Synchronous tumours were more often located on the same intestinal segment, although the correlation was weak (kappa = 0.26). Resection for cure was performed in 74.8 per cent of synchronous cancers and 72.0 per cent of single cancers (P = 0.131). Five-year relative survival for synchronous (48.7 per cent) and single (48.3 per cent) cancers was almost identical. Stage, age, associated adenomas and adenomatous remnants were independent prognostic factors.
  
  
  CONCLUSIONS
  Synchronous colorectal cancers convey a similar prognosis to single tumours. Men and patients aged over 65 years with associated adenomas are more prone to multiple colorectal cancers.
authors.affiliation: National Institute of Health and Medical Research (INSERM) U866, Burgundy Digestive Cancer Registry, University of Burgundy and University Hospital Centre, Dijon, France.
authors.forename: M
authors.initials: M
authors.lastname: Latournerie
authors.forename: V
authors.initials: V
authors.lastname: Jooste
authors.forename: V
authors.initials: V
authors.lastname: Cottet
authors.forename: C
authors.initials: C
authors.lastname: Lepage
authors.forename: J
authors.initials: J
authors.lastname: Faivre
authors.forename: A-M
authors.initials: AM
authors.lastname: Bouvier
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000628:therapy; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000401:mortality* / Q000628:therapy; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors