[Efficacy of CT colonography versus colonoscopy in screening for colorectal cancer]

To determine the efficacy and effectiveness of CT colonography in comparison with those of colonoscopy in screening for colorectal cancer.

We systematically reviewed all the studies in the scientific literature that assessed the efficacy of CT colonography in screening for colorectal cancer. We excluded articles that assessed the efficacy of other screening techniques for colorectal cancer and those that used CT colonography in the diagnostic workup of suspected lesions or symptomatic patients. After a critical reading of the 213 references obtained, we selected nine studies.

The specificity of CT colonography in screening for colorectal cancer was high, although it decreased with the diameter of the polyp to be detected. The sensitivity of CT colonography in the detection of polyps less than or equal to 6mm in diameter was very low and heterogeneous, although it was higher for polyps greater than 9mm in diameter.

CT colonography has high specificity but very heterogeneous sensitivity, although in most cases it was not as sensitive or specific as conventional colonoscopy.