A prospective comparison of video colonoscopy and CT colonography in asymptomatic patients screened for colorectal cancer.

BACKGROUND AND OBJECTIVE: It was theaim of this study to compare the sensitivity and specificity oflow-dose CT colonography (CTC) with that of optical colonoscopy(OC) in asymptomatic patients undergoing these tests in a screeningprogram for colonic cancer. PATIENTS AND METHODS: 58 patients (meanage 62.6 years) were included. They underwent low dose CTC and,immediately afterwards, colonoscopy. The colonoscopists were unawareof the CTC findings. A „second look” was performedif a lesion seen in CTC had been missed in the first colonoscopy. RESULTS: A total of 150 lesions weredetected and histologically confirmed. 136 were found to be polypoidlesions, classified as either hyperplastic polyps (n = 66)or polyps with intraepithelial neoplasia (n = 70).In the per-patient analysis only 22.4 % of patientshad no polypoid lesion, 27.6 % had at least onehyperplastic and 50.0 % had at least one adenomatouslesion. Sensitivity for adenomas of all size categories was calculated55.7 % for CTC and 92.9 % forOC. This marked difference (both for the detection of individuallesions and the per-patient analyses) does not reach significancein the two-sided McNemar test. CONCLUSIONS: There was a high prevalenceof lesions with intraepithelial neoplasia in this screening group.OC had a higher sensitivity than CTC in the detection of lesionssmaller than 10 mm.