CT colonography or colonoscopy: Which is more cost-effective when screening for colorectal cancer?

For screening strategies that may include more than two lifetime examinations, CT colonography screening for colorectal cancer (CRC) is more cost-effective than colonoscopy, according to a new study published by Radiology.

The authors used data from the Colonoscopy or Colonography for Screening (COCOS) trial, held in the Netherlands, and an advanced microsimulation model to compare the cost-effectiveness of these two screening methods.

Overall, CT colonography screening was found to have a higher participation rate (more than 33 percent) than colonoscopy screening (more than 21 percent) in the COCOS trial. According to the microsimulation model, CT colonography is more cost-effective when the provider’s screening strategy includes more than one or two lifetime screenings. If a screening strategy only includes one or two lifetime screenings, colonoscopy screening is actually more cost-effective.

CT colonography was also the preferred screening method when taking willingness-to-pay thresholds into account. Independent of such thresholds, CT colonoscopy is preferred.

“The results of this study confirm that, for people willing to participate in CRC screening, colonoscopy is more cost-effective than CT colonography screening,” wrote lead author Miriam P. van der Meulen, MD, department of public health at Academic Medical Center in Amsterdam, the Netherlands, and colleagues. “However, from a population’s perspective, with participation as observed in the COCOS trial, colonoscopy screening is less cost-effective than CT colonography screening if the latter offers more than two lifetime screenings.”

The authors emphasized that their research is relevant to healthcare providers throughout the world, not just in the Netherlands.

“Although this cost-effectiveness analysis is primarily performed for the Dutch situation, we believe the results are relevant for other situations as well,” they wrote. “Although absolute participation rates and costs may differ among countries, the relative differences between CT colonography and colonoscopy primarily determine the comparative effectiveness. We suspect these relative differences in participation and costs differ less among countries.”

Van der Meulen and colleagues also noted that both screening methods are better for patients than no screening at all, bringing up fecal immunochemical test (FIT) as another alternative.

“Because both colonoscopy and CT colonography are cost-effective in participants when compared with no screening, either test might be offered,” the authors wrote. “Another option is to subsequently offer different screening modalities to nonparticipants, starting with the most cost-effective screening test for participants. Colonoscopy could then be offered initially, while nonparticipants could be offered CT colonography (or FIT).”