The article by Steven Heitman and colleagues1 ignores health human resource realities in Canada. The only logical strategy for people aged 50–74 years at average risk of developing colorectal cancer (CRC) is to start with computerized tomographic (CT) colonography and proceed to full colonoscopy with polypectomy on the same day when polyps greater than 5 or 10 mm in diameter are found.
The Canadian health care system does not have the capacity to offer colonoscopies to everyone aged 50–74 years who is at average risk. Access to gastrointestinal specialty care is limited in many parts of Canada.2 In 2001, only 3857 colonoscopies were performed per 100 000 Ontarians aged 50–74 years.3 From 1992 to 2001, only 15.7% of Ontarians aged 50–74 years had at least one colonoscopy; 16.7% underwent double-contrast barium enema.3
There are resource planning advantages to a „CT colonography first” strategy. It takes 15 min for an experienced endoscopist to perform a full diagnostic colonoscopy and an additional 5–10 min for a polypectomy. For 100 000 people undergoing CRC screening (27.2% of them will have polyps greater than 5 mm in diameter1), the „CT colonoscopy first” strategy will require 3692 endoscopy days. A colonoscopy for the people in this group who are found to have polyps will use only 1417 endoscopy days.
There are 2 questions that need to be addressed with regard to CRC screening programs. The first is whether CT colonography should replace double-contrast barium enema as a screening tool. The second concerns the optimal interval for repeating CT colonography.