Is colonoscopy or CT colonography (CTC) more cost-effective when screening for colorectal cancer? Dutch researchers get to the bottom of this question in a study published online February 27 in Radiology.
Colonoscopy has long served as the reference standard for detecting colorectal cancer, according to first author Dr. Miriam van der Meulen and colleagues from Erasmus University Medical Center in Rotterdam, the Netherlands. But its numerous drawbacks -- the need for endoscopy, the risk of complications, and low rates of patient compliance with screening recommendations -- have encouraged clinicians to consider using CTC, also known as virtual colonoscopy, as a less-invasive alternative for screening.
Using data from the Colonoscopy or Colonography for Screening (COCOS) trial, the group performed a microsimulation model estimating the costs of and quality-adjusted life years (QALYs) gained from screening for colorectal cancer with either colonoscopy or CT colonography.
The investigators found that screening patients between 50 and 70 years of age once every 10 years led to a greater reduction in mortality and more QALYs gained with colonoscopy than with CTC -- when assuming a 100% participation rate. However, taking into account the observed screening participation rates of 21.5% for colonoscopy and 33.6% for CTC reversed this trend for the two imaging modalities.
| Colonoscopy vs. CT colonography for colorectal cancer screening | ||
| Colonoscopy | CTC | |
| Mortality reduction | 12.3 | 16.3 |
| Quality-adjusted life years gained | 22 | 29 |
| Total cost | $27,325 (22,335 euros) | $47,526 (38,846 euros) |
Regardless of participation rate, screening via colonoscopy consistently resulted in a lower total cost than using CT colonography, the authors noted. The only scenario in which CTC was more cost-effective overall was if participants underwent more than two screenings.
"On the basis of the 56% higher CT colonography participation observed in the COCOS trial, CT colonography screening for colorectal cancer is more cost-effective than colonoscopy screening," they wrote.
To that end, the researchers suggest CT colonography rather than colonoscopy for a national screening program due mainly to the considerably higher participation rate and willingness-to-pay threshold for CT colonography.
An alternative to offering a single modality "is to offer participants a choice between screening tests," they wrote. "Because both colonoscopy and CT colonography are cost-effective in participants when compared with no screening, either test might be offered."
