Radiology: Volume 259: Number 2-May 2011
Perry J. Pickhardt, MD Cesare Hassan, MD Steve Halligan, MD Riccardo Marmo, MD
Purpose: To perform a systematic review and meta-analysis of pub¬lished studies assessing the sensitivity of both computed tomographic (CT) colonography and optical colonoscopy (OC) for colorectal cancer detection.
Materials and Methods: Analysis followed Preferred Reporting Items for System¬atic Reviews and Meta-Analyses recommendations. The primary data source was the results of a detailed PubMed search from 1994 to 2009. Diagnostic studies evaluating CT colonography detection of colorectal cancer were as¬sessed by using predefined inclusion and exclusion crite¬ria, in particular requiring both OC and histologic confir¬mation of disease. Studies that also included a mechanism to assess true-positive versus false-negative diagnoses at OC (eg, segmental unblinding) were used to calculate OC sensitivity. Assessment and data extraction were per¬formed independently by two authors. Potential bias was ascertained by using Quality Assessment of Diagnostic Ac-curacy Studies guidelines. Specific CT colonography tech-niques were cataloged. Forest plots of per-patient sensitiv¬ity were produced on the basis of random-effect models. Potential bias across primary studies was assessed by us¬ing the I2 statistic. Original study authors were contacted for data clarification when necessary.
Results: Forty-nine studies provided data on 11 151 patients with a cumulative colorectal cancer prevalence of 3.6% (414 can¬cers) . The sensitivity of CT colonography for colorectal can-cer was 96.1% (398 of 414; 95% confidence interval [CI]: 93.8%, 97.7%). No heterogeneity (I2 = 0%) was detected. No cancers were missed at CT colonography when both cathartic and tagging agents were combined in the bowel preparation. The sensitivity of OC for colorectal cancer, derived from a subset of 25 studies including 9223 patients, was 94.7% (178 of 188; 95% CI: 90.4%, 97.2%). A moder-ate degree of heterogeneity (i2 = 50%) was present.
Conclusion: CT colonography is highly sensitive for colorectal cancer, especially when both cathartic and tagging agents are combined in the bowel preparation. Given the relatively low prevalence of colorectal cancer, primary CT colonog¬raphy may be more suitable than OC for initial investiga¬tion of suspected colorectal cancer, assuming reasonable specificity.