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Surveillance patterns after curative-intent colorectal cancer surgery in Ontario


Background — Post-operative surveillance following curative-intent resection of colorectal cancer (CRC) is variably performed due to existing guideline differences and to the limited data supporting different strategies.

Objectives — To examine population-based rates of surveillance imaging and endoscopy in patients of Ontario following curative-intent resection of CRC with no evidence of recurrence, as well as patient or disease factors which might predispose certain groups to more frequent versus less frequent surveillance. To provide insight into the care patients receive in the presence of conflicting guidelines, in efforts to help improve care of CRC survivors by identifying any potential underuse or overuse of particular surveillance modalities, or inequalities in access to surveillance.

Method — A retrospective cohort study was conducted using data from the Ontario Cancer Registry and several linked databases. Ontario patients undergoing curative-intent CRC resection, from 2003 to 2007, were identified excluding patients with probable disease relapse. In the five-year period following surgery, the number of imaging and endoscopic examinations was determined.

Results — There were 4960 patients included in the study. Over the five-year post-operative period, the highest proportion of patients who underwent post-operative surveillance received the following number of tests for each modality examined: 1-3 abdominopelvic computed tomography (CT) scans (2073 patients, 41.8%), 1-3 abdominal ultrasounds (AUS) (2443 patients, 49.3%), no chest CTs, 1-3 chest x-rays (2385 patients, 48.1%), and 2 endoscopies (1845 patients, 37.2%). Odds of not receiving any abdominopelvic imaging (CT or AUS) were higher in those who did not receive adjuvant chemotherapy (OR 6.99, 95% CI 5.26-9.35) or those living in certain geographic areas, but were independent of age, gender, and income. Nearly all patients (4473, 90.2%) received ≥1 endoscopy at some point during the follow-up period.

Conclusion — In contrast to findings from similar studies in other jurisdictions, most Ontario CRC survivors receive post-operative surveillance with imaging and endoscopy and care is equitable across socio-demographic groups, although unexplained geographic variation in practice exists and merits further investigation.



Tan J, Muir J, Coburn N, Singh S, Hodgson D, Saskin R, Kiss A, Paszat L, El-Sedfy A, Grunfeld E, Earle C, Law C. Can J Gastroenterol Hepatol. 2014; 28(8):427-33. Epub 2014 Jul 11.

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