title: A retrospective study on the use of post-operative colonoscopy following potentially curative surgery for colorectal cancer in a Canadian province.
abstract: BACKGROUND
  Surveillance colonoscopy is commonly recommended following potentially curative surgery for colorectal cancer. We determined factors associated with patients undergoing a least one colonoscopy within five years of surgery.
  
  
  METHODS
  In this historical cohort study, data on 3918 patients age 30 years or older residing in Alberta, Canada, who had undergone a potentially curative surgical resection for local or regional stage colorectal cancer between 1983 and 1995 were obtained from the provincial cancer registry, ministry of health and cancer clinic charts. Kaplan-Meier estimates of the probability of undergoing a post-operative colonoscopy were calculated for patient, tumor and treatment-related variables of interest.
  
  
  RESULTS
  A colonoscopy was performed within five years of surgery in 1979 patients. The probability of undergoing a colonoscopy for those diagnosed in the 1990s was greater than for those diagnosed earlier (0.65 vs 0.55, P < 0.0001). The majority of the difference was seen at one-year following surgery, consistent with changes in surveillance practices. Those most likely to undergo a colonoscopy were those under age 70 (0.74 vs 0.50 for those age 70-79, P < 0.0001), who underwent a pre-operative colonoscopy (0.69 vs 0.54, P < 0.0001), and who underwent a resection with reanastomosis (0.62 vs 0.47 for abdominoperineal resection, P < 0.0001) by a surgeon who performs colonoscopies (0.68 vs 0.54, P < 0.0001).
  
  
  CONCLUSIONS
  The majority of patients undergo colonoscopy following colorectal cancer surgery. However, there are important variations in surveillance practices across different patient and treatment characteristics.
authors.affiliation: Department of Medicine University of Calgary, Calgary, Alberta, Canada. rhilsden@ucalgary.ca
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hilsden
authors.forename: Heather E
authors.initials: HE
authors.lastname: Bryant
authors.forename: Lloyd R
authors.initials: LR
authors.lastname: Sutherland
authors.forename: Penny M A
authors.initials: PM
authors.lastname: Brasher
authors.forename: Anthony L A
authors.initials: AL
authors.lastname: Fields
mesh_terms: D000328:Adult; D000368:Aged; D000416:Alberta; D003113:Colonoscopy / Q000706:statistics & numerical data* / Q000639:trends; D015179:Colorectal Neoplasms / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D011182:Postoperative Care / Q000379:methods; D011184:Postoperative Period; D012042:Registries; D012189:Retrospective Studies; D012812:Sigmoidoscopy / Q000706:statistics & numerical data