Computed tomography colonography for the diagnosis or exclusion of colorectal neoplasia

Milverton J, Ellery B, Gum D, Newton S, Kessels S, Vogan A, Merlin T
Record ID 32015000101
Original Title: Application 1269
Authors' objectives: Computed Tomography Colonography (CTC) involves the use of a computed tomography (CT) scanner to image the patients colon. This is a preferable alternative to a barium enema and an alternative to colonoscopy when the latter is considered potentially dangerous for the patient or if a colonoscopy has been unable to examine the whole of the colon. Although there are variations in the technique used, CTC nearly always involves laxative preparation of the bowel beforehand, followed by distension of the colon with air or gas while the patient is on the CT scanner. The scan is then performed without sedation (usually taking only a few minutes or less), and the images obtained are subsequently examined by the radiologist using special computer software to enable a diagnosis. CTC is currently subject to a Medicare rebate in Australia, but for only limited indications. The applicants are seeking to expand the indications to reflect current 'best practice'.
Authors' results and conclusions: Comparative safety - Based on limited evidence, computed tomography colonography (CTC) is at least as safe as double contrast barium enema (DCBE). Although there is a radiation risk associated with CTC, it is lower than that associated with DCBE. No evidence on safety of CTC versus delayed colonscopy could be made, although as colonscopy is a more invasive procedure than CTC, it may be assumed that CTC has superior safety outcomes. Comparative effectiveness - The 4-year survival rate for patients receiving CTC is the same as for those receiving DCBE. It is unknown if there is any survival benefit associated with CTC compared with delayed colonscopy. CTC is more sensitive than DCBE, but is slightly less specific than DCBE. Economic evaluation - As there was no evidence to support any difference in survival rates between the two testing strategies, and due to poor evidence-base, the cost-effectiveness of CTC compared with DCBE was estimated in terms of incremental cost per additional positive diagnosis (colorectal cancer (CRC) or large polyp). The prevalence of CRC and large polyps was assumed to be 3.1% and 6.7%, respectively based on published Australian data. The estimated incremental cost per additional CRC or large polyp diagnosed for CTC compared with DCBE was $19,380. Thus for every additional $200,000 spent, approximately one additional CRC and nine large polyps will be diagnosed. Based on the linked evidence comparing the accuracy of CTC and DCBE, the ICER ranged from $18,200 per additional CRC or large polyp diagnosed when the sensitivities of CTC and DCBE were 0.97 and 0.64, respectively, to $48,200 per additional CRC or large polyp diagnosed when the sensitivities of CTC and DCBE were assumed to be 0.59 and 0.48, respectively.
Project Status: Completed
Year Published: 2014
English language abstract: An English language summary is available
Publication Type: Not Assigned
Country: Australia
MeSH Terms
  • Colonography, Computed Tomographic
  • Colorectal Neoplasms
  • Sensitivity and Specificity
  • Predictive Value of Tests
  • Diagnosis
Organisation Name: Adelaide Health Technology Assessment
Contact Address: School of Public Health, Mail Drop 545, University of Adelaide, Adelaide SA 5005, AUSTRALIA, Tel: +61 8 8313 4617
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Copyright: Adelaide Health Technology Assessment (AHTA)
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