Extracolonic findings at virtual colonoscopy: an important consideration in asymptomatic colorectal cancer screening

Virtual colonoscopy has been evaluated for use as a colorectal cancer screening tool, and in prior studies, it has been estimated that the evaluation of extra-colonic findings adds $28-$34 per patient studied.

As an ancillary study to a prospective cohort study comparing virtual colonoscopy to conventional colonoscopy for colorectal cancer detection, the investigators retrospectively determined the number and estimated costs of all clinic visits, imaging and laboratory studies, and medical procedures that were generated as a direct result of extra-colonic findings at virtual colonoscopy.

We enrolled 143 subjects who underwent CTC followed by conventional colonoscopy. Data were available for 136 subjects, and 134 (98%) had at least one extra-colonic finding on CT. Evaluation of extra-colonic findings was performed in 32 subjects (24%). These subjects underwent 73 imaging studies, 30 laboratory studies, 44 clinic visits, 6 medical procedures, and 44 new or return outpatient visits over a mean of 38 months following the CTC. The most common findings causing further evaluation were lung nodules and indeterminate kidney lesions. No extra-colonic malignancies were found in this study. A total of $33,690 was spent in evaluating extra-colonic findings, which is $248 per patient enrolled.

The cost of the evaluation of extra-colonic findings following virtual colonoscopy may be much higher in actual practice than is suggested by prior studies. This will impact the cost-effectiveness of using virtual colonoscopy for asymptomatic colorectal cancer screening and underscores the importance of standardizing the reporting of extra-colonic findings to encourage appropriate follow-up.