Overall, proctitis has a very low chance of becoming cancerous, but it may vary between different types of proctitis.
Generally speaking, if ulcerative proctitis involves only the rectum, the likelihood of cancer is very low and there is no need for colonoscopic monitoring.
In contrast, patients with extensive colitis or left-sided colitis need to have a colonoscopy every one to two years (for those at high risk) or every three to four years (for those at low risk) from the eighth year after the onset of initial symptoms to guard against cancer.