The Role of Computed Tomographic Colonography in Colorectal Cancer Screening

Abstract

Objective: We conducted a literature review to identify the current state of knowledge regarding the optimal clinical use of computed tomographic colonography (CTC) in Canada, based on accuracy, patient safety, and costeffectiveness.Methods: Articles were retrieved from PubMed and the Cochrane Library. Retrieved studies were included based on relevance and appropriateness as determined by reviewing titles and abstracts. Studies were excluded if they were duplicated, grey literature, or non-peer-reviewed. Of the studies remaining after exclusions, reference lists were scanned to obtain further relevant articles.Results: The literature reports comparable accuracy for detecting cancers and large polyps, yet CTC is less sensitive than colonoscopy for detecting small polyps. Most would agree that CTC is safer than colonoscopy, yet it is not without risk or adverse events. Lastly, although the true costs of CTC vs. colonoscopy are complex, the literature consistently demonstrates that CRC screening with CTC is less cost-effective than screening with colonoscopy.Conclusion: Unless there are modifications to CTC that improve cost-effectiveness and/or accuracy, the future of CRC screening in Canada will remain reliant on colonoscopy. CTC is beneficial as an alternative to colonoscopy, but should remain available for selected indications. CTC has value, however, it has fallen short of initial expectations. patients are considered legally impaired for 24 hours after the procedure, and therefore, are absent from work or school during this time. 7CRC is the third most common cancer in Canada among men and women and there is strong evidence to support population-wide screening. 1,8 This article reviews the optimal clinical use of CTC in Canada, based on test accuracy, patient safety, and cost-effectiveness. MethodsThe literature review was conducted using PubMed and Cochrane Library. The literature search applied MESH terms in PubMed and keywords in Cochrane (Figure 1). The search strategy was as follows: 'CT colonography' and 'cost-effectivess' or 'safety' or 'accuracy' or 'colonoscopy' , which retrieved 1,373 studies. Literature searches were not restricted by year of publication or journal. Studies were assessed based on relevance and appropriateness by reviewing titles and abstracts. Additionally, studies were excluded if they were duplicated, not English language, grey literature, or non-peer-reviewed. Of the studies remaining after exclusions, reference lists were scanned to obtain further relevant articles. In total, 27 articles were considered relevant and appropriate based on their contribution to the literature and were included in the review. ResultsThe initial studies assessing the accuracy of CTC reported promising results, but had significant variability and methodological shortcomings. Fenlon et al. published the first study evaluating CTC in 1999. 9The authors assessed the ability of CTC to detect polyps in 100 patients being screened for CRC, using colonoscopy as the gold standard. They reported a sen...