The role of CT colonography as a colorectal cancer screening test is uncertain.
Dr Daniele Regge and colleagues compared participation and detection rate with sigmoidoscopy, and CT colonography in a screening setting.
The researchers conducted 2 randomized clinical trials.
In the participation randomized controlled trial, individuals, aged 58 years, living in Italy, were randomly assigned to be invited to flexible sigmoidoscopy or CT colonography screening.
In the detection randomized clinical trials, residents in northern Italy, aged 58–60, giving their consent to recruitment, were randomly allocated to CT colonography or flexible sigmoidoscopy.
|Participation was 30% for CT colonography|
Polyps ≥6 mm at CT colonography, or ‘high-risk’ distal lesions at flexible sigmoidoscopy, were referred for colonoscopy.
The team's main outcome measures included participation rate, detection rate of advanced adenomas or colorectal cancer.
The research team noted that participation was 30% for CT colonography, and 27% for flexible sigmoidoscopy.
Among men, participation was higher with CT colonography than with flexible sigmoidoscopy.
In the detection randomized controlled trial, the research team found that 2673 subjects had flexible sigmoidoscopy, and 2595 had CT colonography, the advanced neoplasia detection rate was 5% with flexible sigmoidoscopy and 5% with CT colonography.
The researchers found that distal advanced neoplasia detection rate was 4% with flexible sigmoidoscopy, and 3% with CT colonography.
Proximal advanced neoplasia detection rate was 1% for flexible sigmoidoscopy vs 3% for CT colonography.
Dr Regge's team concludes, "Participation and detection rate for flexible sigmoidoscopy and CT colonography were comparable."
"Advanced neoplasia detection rate was twice as high in the proximal colon and lower in the distal colon with CT colonography than with flexible sigmoidoscopy."
"Men were more likely to participate in CT colonography screening."