title: A population-based study of rectal cancer: permanent colostomy as an outcome.
abstract: OBJECTIVE
  The objectives of this study are to describe the utilization of surgery and of radiotherapy in the treatment of newly diagnosed rectal cancer in Ontario between 1982 and 1994, and to describe the probability of permanent colostomy at any time after the diagnosis of rectal cancer, as an outcome of the treatment of newly diagnosed rectal cancer.
  
  
  METHODS
  Electronic records of rectal cancer (International Classification of Diseases code 154) from the Ontario Cancer Registry (n = 18,695, excluding squamous, basaloid, cloacogenic, and carcinoid histology) were linked to surgical records from all Ontario hospitals, and radiotherapy (RT) records from Ontario cancer centers. Procedures occurring within 4 months of diagnosis, or within 4 months of another procedure for rectal cancer, were considered part of initial treatment. Multivariate analyses controlled for age, sex, and year of diagnosis.
  
  
  RESULTS
  Resection plus permanent colostomy was performed in 33.1% of cases, whereas local excision or resection without permanent colostomy was performed in 38.2%. Multivariate logistic regression demonstrated higher odds ratios (OR) for resection plus permanent colostomy in all regions of Ontario relative to Toronto. The OR for postoperative RT following local excision or resection without permanent colostomy varied among the regions relative to Toronto (e.g., OR Ottawa = 0.59, OR Hamilton = 0.76, OR London = 1.25). The relative risk (RR) of colostomy conditional upon survival within 5 years from diagnosis varied among regions relative to Toronto (e.g., RR Ottawa = 1.21, RR Hamilton = 1.20).
  
  
  CONCLUSIONS
  There is regional variation in the utilization of resection with permanent colostomy, and in the utilization of postoperative RT among cases not undergoing permanent colostomy. Regions with higher initial rates of resection plus permanent colostomy continue to experience higher probability of permanent colostomy 5 years after diagnosis of rectal cancer. Higher initial rates of permanent colostomy may be malleable to interventions aimed at improving overall outcomes.
authors.affiliation: Radiation Oncology Research Unit, Queen's University, Kingston, Ontario, Canada. larry.paszat@cancercare.on.ca
authors.forename: L F
authors.initials: LF
authors.lastname: Paszat
authors.forename: M D
authors.initials: MD
authors.lastname: Brundage
authors.forename: P A
authors.initials: PA
authors.lastname: Groome
authors.forename: K
authors.initials: K
authors.lastname: Schulze
authors.forename: W J
authors.initials: WJ
authors.lastname: Mackillop
mesh_terms: D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D015331:Cohort Studies; D003125:Colostomy / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D012044:Regression Analysis; D016896:Treatment Outcome