Postpolypectomy Colonoscopy Surveillance Guidelines: Predictive Accuracy for Advanced Adenoma at 4 Years

One hundred seventy-four patients did not complete the trial. Four patients were excluded late (no baseline adenoma), 88 died before the end of the trial (from causes unrelated to the trial), and 82 withdrew (72 did not have follow-up colonoscopy, 9 declined to participate, and 1 withdrew because of ill health).