BOSTON — Interim results from a large military study comparing virtual and optical colonoscopy for colorectal cancer screening suggest the two methods are comparable in sensitivity and specificity, said Maj. Richard P. Moser III, MC, USA.
If final results of the 8-year screening virtual colonoscopy (VC) trial confirm this, they will be seen as validating the 2003 trial (N. Engl. J. Med. 2003;349: 2191–200) that put VC on the map for colorectal cancer screening, said Dr. Moser of Walter Reed Army Medical Center in Washington.
Speaking at an international symposium sponsored by Boston University, Dr. Moser said the trial includes 3,000 average-risk subjects.
Its goals are to validate the 2003 trial, to evaluate the effectiveness and cost-effectiveness of VC screening, and to gather data on the short-term natural history of 6- to 9-mm polyps.
Patients undergoing VC screening are sent to same-day optical colonoscopy (OC) if they have a polyp measuring 10 mm or more, or three polyps measuring at least 6 mm, Dr. Moser said. Patients with fewer than three medium-sized polyps are randomized to either same-day colonoscopy or 1-year VC follow-up. Patients with no polyps are randomized to either same-day OC or 5-year VC follow-up.
Interim results suggest that for polyps measuring at least 6 mm, VC has a sensitivity of about 90% vs. about 97% for OC. The specificity of VC was 73% vs. 80% specificity found in the 2003 trial, indicating a tendency to identify too many polyps.