Findings from the randomised controlled trial reported by Esther M Stoop and colleagues in The Lancet Oncology provide important new data for adherence rates and overall programmatic yield for screening with optical colonoscopy and CT colonography. Particularly, results from this trial show a significant 55% improvement in screening participation with CT colonography over colonoscopy, which is a crucial component to the overall success of a screening programme. The overall programmatic yield (per...