This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'The preferred initial treatment for carcinoma of the anal canal is \nSelect and explain. \nA. Abdominoperineal resection, B. Abdominoperineal resection followed by radiotherapy, C. Radiotherapy alone, D. Chemoradiation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: #Treatment is by chemoradiotherapy in the first instance # Associated with HPV # More prevalent in patients with HIV infection # May affect the anal verge or anal canal # Lymphatic spread is to the inguinal lymph nodes # Uncommon tumour, which is usually a squamous cell carcinoma # Major ablative surgery is required if the above fails Ref: Bailey & Love&;s Sho Practice of Surgery,E25,Page-1269', 'role': 'assistant'}]