This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Risk of malignancy in ulcerative colitis is more in -a) Onset in childhoodb) Extensive involvement of colonc) Disrupted architecture with crypt abscessesd) Pseudopolypse) Recurrence after treatment \nSelect and explain. \nA. ac, B. a, C. ad, D. ab', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Risk Factors for Cancer in Ulcerative Colitis patient\n• The duration of colitis\n• The extent of colonic involvement\n• The presence of concomitant PSC and family history of CRC\xa0(regardless of the family history of IBD)\n• Pancolitis (disease extending proximal to the splenic flexure) and disease diagnosed at a young age\n• UC-related CRC tends to be multicentric and evenly distributed throughout the colon. Tumour tend to be infiltrative, highly aggressive and poorly differentiated.\n• No significant difference between sporadic and UC-related CRC with respect to prognosis.', 'role': 'assistant'}]