This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
[{'content': 'Most common presentation of carcinoma of the right colon: \nSelect and explain. \nA. Anaemia, B. Mass, C. Obstruction, D. Diarrhoea', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (Anaemia) Ref: Bailey, 24th ed, p. 1178Carcinoma colon is usually asymptomatic and may present as anaemia in locally advanced cases.Macroscopic varieties:annular type : most common symptom is obstructivetubular : most common symptom is bleedingulcerative: most common symptom is bleedingcauliflower type: least malignantcarcinoma colon occurs more commonly on the left side and the rectum.Most common site-Rectosigmoid junction- 59%RectumSigmoid colonTNM staging Ca right colonCa left colonUsually presents lateUlcerate with chronic insidious blood loss- leading to anaemia anaemia> fatigue> mass RIFMore well formed stools than right -so obstructiveAlteration of bowel habits > palpable lump > abdominal distension with pain.Ca sigmoidPain usually colicky from onsetTenesmus Bladder symptoms- This is not uncommon and may sometimes lead to colovesical fistula- (Bailey, 24th ed, p. 1178)Risk factors for the development of colorectal cancerDiet: Animal fatHereditary syndromes (autosomal dominant inheritance)Polyposis coliNonpolyposis syndrome (Lynch syndrome)Inflammatory bowel diseaseUreterosigmoidostomyTobacco use', 'role': 'assistant'}]