CT Colonography Screening Significantly Outperforms Cologuard in CRC Prevention

Emerging research indicates that computed tomography colonography (CTC) offers a 16% higher reduction in colorectal cancer (CRC) incidence compared to multitarget stool DNA (mt-sDNA) testing, commonly known as Cologuard. This finding, presented in a simulated study published in the journal Radiology, highlights the clinical and cost-effectiveness of CTC as a superior screening tool for CRC.

In this study, researchers, including lead author Dr. Perry J. Pickhardt, a professor in the Department of Radiology at the University of Wisconsin School of Medicine and Public Health, analyzed data from a hypothetical cohort of 10,000 45-year-old participants. They compared the outcomes of no CRC screening, mt-sDNA testing, conventional CTC (CTC conv), and surveillance CTC (CTC surv). The results showed that CTC conv reduced CRC incidence by 75%, while CTC surv achieved a 70% reduction, compared to a 59% reduction for mt-sDNA testing.

The study also projected the potential mortality reduction rates assuming 100% adherence to screening protocols: 72% for mt-sDNA, 80% for CTC conv, and 82% for CTC surv. Dr. Pickhardt stated, "Colorectal screening with noninvasive tests has the potential to substantially reduce the population incidence of colorectal cancer, providing safer options relative to primary optical colonoscopy screening."

One of the critical advantages of CTC over mt-sDNA is its cost-effectiveness. The lifetime cost per person for mt-sDNA was estimated at $6,011, compared to $3,913 for CTC conv and $4,423 for CTC surv. Dr. Pickhardt and his colleagues concluded that mt-sDNA testing remains the least effective and most costly strategy, making it not a cost-effective alternative to the more efficient CTC strategies.

CTC screening offers a balanced, noninvasive option that enhances risk stratification compared to mt-sDNA, which primarily targets existing cancers. This makes CTC a potentially optimal middle-ground tool for CRC screening, as it avoids the invasiveness of colonoscopy while still providing effective cancer prevention.

The study, however, is not without limitations. The authors acknowledged that longitudinal changes in screening modalities, costs, and adherence were not explored in their simulation model. Additionally, the natural history of polyps sized 6 to 9 mm was derived from surveillance data from a single facility.

The implications of this research extend beyond individual patient care; they suggest a fundamental shift in CRC screening protocols. The findings advocate for increased adoption of CTC as a primary screening method, especially given its clinical efficacy and cost benefits.

As healthcare providers and policymakers consider these results, the future of CRC screening may see a transition towards more noninvasive methods like CTC, potentially reducing the burden of colorectal cancer on public health. This study underscores the necessity for ongoing research and reevaluation of current screening practices to optimize patient outcomes and healthcare costs.