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': 'Abdomino-Perineal resection is done in colorectal carcinoma on the basis of: March 2013 (h) \nSelect and explain. \nA. Age of the patient, B. Distance from anal verge, C. Fixity of tumour, D. Hepatic metastasis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Distance from anal verge Colorectal carcinoma MC site: Rectum, MC site in colon: Sigmoid colon MC type: AdenoCa Presentation of right sided tumour: Anemia Left sided tumour presents as: Obstruction/ pain Risk factors: -- Increased dietary fats & oil, -- Elevated serum cholesterol, -- Ulcerative colitis & Crohns disease, -- Familial adenomatous polyps MC site of metastasis: Liver (33% patient may have metastasis) Treatment of choice: Surgery', 'role': 'assistant'}]