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PurposeTo use a randomized design to compare patients' short- and longer-term experiences after computed tomographic (CT) colonography or colonoscopy.Materials and methodsAfter ethical approval, the trial was registered. Patients gave written informed consent. Five hundred forty-seven patients with symptoms suggestive of colorectal cancer who had been randomly assigned at a ratio of 2:1 to undergo either colonoscopy (n = 362) or CT colonography (n = 185) received a validated questionnaire to assess immediate test experience (including satisfaction, worry, discomfort, adverse effects) and a 3-month questionnaire to assess psychologic outcomes (including satisfaction with result dissemination and reassurance). Data were analyzed by using Mann-Whitney U, Kruskal-Wallis, and χ(2) test statistics.ResultsPatients undergoing colonoscopy were less satisfied than those undergoing CT colonography (median score of 61 and interquartile range [IQR] of 55-67 vs median score of 64 and IQR of 58-70, respectively; P = .008) and significantly more worried (median score of 16 [IQR, 12-21] vs 15 [IQR, 9-19], P = .007); they also experienced more physical discomfort (median score of 39 [IQR, 29-51] vs 35 [IQR, 24-44]) and more adverse events (82 of 246 vs 28 of 122 reported feeling faint or dizzy, P = .039). However, at 3 months, they were more satisfied with how results were received (median score of 4 [IQR, 3-4] vs 3 [IQR, 3-3], P < .0005) and less likely to require follow-up colonic investigations (17 of 230 vs 37 of 107, P < .0005). No differences were observed between the tests regarding 3-month psychologic consequences of the diagnostic episode, except for a trend toward a difference (P = .050) in negative affect (unpleasant emotions such as distress), with patients undergoing CT colonography reporting less intense negative affect.ConclusionCT colonography has superior patient acceptability compared with colonoscopy in the short term, but colonoscopy offers some benefits to patients that become apparent after longer-term follow-up. The respective advantages of each test should be balanced when referring symptomatic patients.

Original publication




Journal article



Publication Date





723 - 731


Department of Epidemiology and Public Health, University College London, University College Hospital, Level 2, Podium, 235 Euston Road, London NW1 2BU, England.


SIGGAR Investigators, Humans, Colorectal Neoplasms, Contrast Media, Colonography, Computed Tomographic, Colonoscopy, Chi-Square Distribution, Statistics, Nonparametric, Aged, Aged, 80 and over, Middle Aged, Patient Acceptance of Health Care, Female, Male, Surveys and Questionnaires