Comparing downstream costs: CT colonography versus optical colonoscopy

Colonoscopy has long been the standard when it comes to colorectal cancer screening, but CT colonography has been gaining ground recently as a screening modality due to its less-invasive nature and comparable diagnostic quality. But what difference in costs exists following either CT colonography or optical colonoscopy?

Not much, according to results of a recent study published online April 15 in Academic Radiology, which compared downstream costs for each respective colorectal cancer screening modality for one year following the initial procedure. Researchers led by Hanna Zafar, MD, MHS, of the Hospital of the University of Pennsylvania in Philadelphia, performed a retrospective study of Medicare fee-for-service patients aged 66 years or older who underwent colorectal cancer screening using either CT colonography (531 patients) or optical colonoscopy (17,593 patients) between January 2007 and December 2008.

Their results showed that CT colonography screening led to higher unadjusted per-patient costs than colonoscopy when comparing the 12 months before and 12 months after initial evaluation, with a total difference of $175. After adjusting for potential demographic and socioeconomic factors that could influence referral to CT colonography over optical colonoscopy, higher costs for outpatient testing persisted for those receiving CT colonography, but the differences in adjusted total costs failed to be statistically significant between the modalities.

“Despite higher adjusted costs of both colonic and extracolonic testing after initial [CT colonography] compared to [optical colonoscopy], we found no differences in total downstream costs between either modality,” wrote Zafar and colleagues. “Total costs include many things such as care unrelated to the follow-up of colonic or extracolonic findings and care related to colonic and extracolonic follow-up that could not be isolated on claims (e.g., inpatient treatment of colorectal cancer, outpatient laboratory, and physician visits). The balancing effects of these other types of care may explain discordance between adjusted potential outpatient colonic and extracolonic costs and adjusted total, inpatient, and outpatient costs.”

As the issue of whether CT colonography should be covered by Medicare continues to be debated among healthcare industry leaders, Zafar and her team know those making the decisions on what is or isn’t covered can use all the scientific data and research they can get. “Although Medicare does not cover screening CTC, our results suggest that these modalities are equivalent from a downstream cost perspective,” wrote Zafar et al. “These findings are of value to payors and policy makers evaluating coverage of screening CTC.”