| Background. Surveillance colonoscopy has been routinely recommended for patients following potentially curative surgery for colorectal cancer. The goal is to detect intraluminal recurrences and new cancers at an early stage, thereby allowing early treatment leading to improved survival.; Objectives. The objectives of this study were to examine the utilization and outcomes associated with surveillance colonoscopy in Alberta patients diagnosed with colorectal cancer between 1983–1995.; Methods. Eligible patients were selected from the Alberta Cancer Registry and linked to the Alberta Health Care Insurance Plan (AHCIP) databases to capture colonoscopies performed within five years of surgery. Cancer clinic charts were reviewed to detect cancer recurrence and new cancers. Kaplan-Meier curves and survivor functions were used to describe the performance of colonoscopy and disease outcomes and the experiences of different groups were compared using Cox proportional hazards regression.; Results. The analysis sample was composed of 3918 patients, of whom 2021 (51.6%) underwent at least one post-operative colonoscopy. There was an increased hazard of undergoing a colonoscopy one year after surgery, consistent with prevailing guidelines for the timing of a first post-operative colonoscopy. Patients were most likely to undergo a post-operative colonoscopy if they were diagnosed in the 1990s, underwent surgery in Edmonton, underwent a pre-operative colonoscopy, had a surgeon who performed colonoscopies and were seen in a provincial cancer clinic. Younger age groups were more likely to undergo a colonoscopy than older age groups, however, it was not possible to determine the confounding effect of comorbidities on this association.; Disease outcomes were difficult to examine because of concerns about under ascertainment of cancer recurrence in older age groups, the low incidence rate for new cancer and the potential risks of lead time and length time bias. After 10 years following the date of the primary surgery, 95% of patients remained free of a second colorectal cancer.; Conclusions. Colonoscopy was commonly used following colorectal cancer surgery but marked variations in its use were associated with factors that would not have been predicted based on prevailing guidelines. Marked differences in disease outcomes associated with colonoscopy could not be demonstrated. |
