The risk for colon cancer in patients with longstanding ulcerative colitis exceeding the rectum is increased and therefore patients should be enrolled in a surveillance program eight years after the diagnosis. Surveillance endoscopies are advised 8 to 10 years after the diagnosis of ulcerative colitis. The first decade every 3 years, the second decade every 2 years and thereafter every year Until today, most official international guidelines for endoscopic screening in patients with ulcerative colitis advise to take 4 random biopsies every 10 centimeters (with a minimum of 32) and of each suspected visible lesion using standard white light endoscopy.