Willingness to Pay for CT Colonography: A Survey of Patient Preferences

CT colonography (CTC) has received mixed reviews both in the radiology literature and in clinical practice. CTC is less invasive than optical colonoscopy (OC), is better for identifying polyps, and does not require sedation. However, its cost-effectiveness has been called into question, and there is a residual need for OC if the CTC findings are positive. Some radiologists are hesitant to perform CTC because of the time-intensive nature of its interpretation. Results of willingness-to-pay surveys can be informative about preferences and value placed on intangibles. The purpose of this study was to use such a survey to elicit the preferences of radiologists about CTC versus OC.

A vignette was presented in which the insurer covered OC at no charge but required out-of-pocket payment for CTC. The strengths and weaknesses of OC and CTC were listed. The respondents were asked how much they would be willing to pay for CTC; for CTC with perfect sensitivity, specificity, and accuracy; and for CTC that required no bowel preparation.

Twenty-eight of 42 radiologists preferred OC to CTC. One radiologist was indifferent. Four radiologists would reverse their preference and choose CTC if it had 100% sensitivity. Sixteen radiologists said they would prefer CTC if it had 100% specificity. If CTC eliminated the need for bowel preparation, 57% would prefer it to OC. Thirty-one (74%) radiologists preferred perfect sensitivity to perfect specificity.

Despite the less invasive nature of CTC, most radiologists who responded to the survey preferred OC for colorectal cancer screening, mostly because of the definitive nature of OC due to the capability of immediate biopsy of suspicious lesions and the lack of requirement for a second round of bowel preparation.