[CT colonography vs. barium enema for the preoperative study of colorectal cancer in patients with incomplete colonoscopy].

Background And Objective: The complete preoperative evaluation of the colon is necessary in colorectal cancer owing to the frequency of synchronous tumors. The objective of this paper was to evaluate the utility of the computed tomography colonography (CTC) as opposed to barium enema (BEDC) when the colonoscopy was incomplete or impossible to perform.

Patients And Method: Group A: 50 patients with colorectal cancer with subsequent incomplete colonoscopy and BEDC. Group B: 40 patients with colorectal cancer with subsequent incomplete colonoscopy and CTC. As gold standard to match the tests, we carried out the pathological study of the surgical piece and the colonoscopy 3 months after surgery. In addition, we studied the degree of satisfaction, indirect effect and cost by test.

Results: There were no synchronous tumors. For the detection of colonic polyps, we obtained for the CTC the following values: Sensitivity = 85.7%, Specificity = 96.1%, PPV = 92.3%, NPV = 92.6%, CPP = 21,97 and CPN =0,15. And for BEDC, the values were: Sensitivity = 23.5%, Specificity = 92.8%, PPV = 80%, NPV = 71.7%, CPP = 3.26 and CPN = 0.82 (p < 0.001). The degree of satisfaction was greater with CTC than with BEDC (p < 0.05). There were no differences as far as indirect effect was concerned. The cost of CTC was 33.18 Euros and it was 42.42 Euros for BEDC.

Conclusion: CTC is better than BEDC both to confirm the presence of polyps in colon and to rule out the absence of them in patients in whom a complete the study of the colon by colonoscopy has not been possible.