Computed tomography (CT) colonography demonstrated greater clinical efficacy and cost savings than stool DNA testing for colorectal cancer screening, according to results of a study published in Radiology.
"Among the safe, minimally invasive colorectal cancer screening options, CT colonography is more effective at preventing and detecting cancer—and is also more cost-effective—than stool DNA testing," stated study author Perry J. Pickhardt, MD, the John R. Cameron Professor of Radiology and Medical Physics at the University of Wisconsin School of Medicine and Public Health in Madison. "Furthermore, CT colonography can provide for extracolonic screening for things like osteoporosis and cardiovascular disease."
Background and Study Methods
"In the US, conventional colonoscopy remains the dominant screening test for colorectal cancer, despite the fact that it is the most expensive and invasive option," Dr. Pickhardt said.
As rates of colorectal cancer diagnoses in younger patients have been increasing, the U.S. Preventive Services Task Force lowered the recommended age for starting frequent colorectal cancer screenings to 45.
Researchers sought to determine which less invasive screening method is more effective, now that both stool DNA testing and CT colonography are more accessible due to Medicare coverage expansions. They examined both screening methods in a head-to-head comparison of clinical efficacy and cost-effectiveness.
They constructed a Markov model based on natural history evidence for colorectal polyps and applied it to a hypothetical cohort of 10,000 people, representing the 45-year-old U.S. population.
Screening was simulated beginning at 45 years and ending at 75 years in 1-year intervals. The simulated individuals were assigned health states based on whether they developed colorectal lesions or not.
Three strategies of screening were assessed in the model: multitarget stool DNA testing every 3 years, conventional CT colonography with immediate polypectomy for all polyps of ≥6 mm every 5 years, or the surveillance approach to CT colonography with 3-year follow-up for small polyps between 6 mm and 9 mm and polypectomy for larger polyps of ≥10 mm.
Study Results
Without screening, 7.5% of the study population developed colorectal cancer, which is consistent with current studies. The incidence was reduced by 59% with multitarget stool DNA testing, by 75% with conventional CT colonography, and 70% with surveillance CT colonography.
Programmatic costs per person for no screening was $4,955; $6,001 for multitarget stool DNA testing; $4,422 for conventional CT colonography; and $3,913 for surveillance CT colonography. For multitarget stool DNA testing, the estimated cost per quality-adjusted life year was $8,878, whereas both methods of CT colonography resulted in cost savings. However, the conventional CT colonography strategy was considered not as cost-effective as the surveillance CT colonography strategy, as costs related to more optical colonoscopies did not offset the corresponding small gains in quality-adjusted life years.
CT colonography methods also proved to be the most clinically efficacious approaches to colorectal cancer screening.
The researchers found that results were similar whether screenings began at age 50 or 65.
Disclosure: For full disclosures of the study authors, visit pubs.rsna.org.
