This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'Treatment of choice for squamous anal carcinoma is \nSelect and explain. \nA. Abdominoperineal resection, B. Laser, C. Chemoradiotherapy, D. Platinum based chemotherapy', 'role': 'user'}, {'content': "Answer: C \nExplanation: Radiotherapy with concurrent chemotherapy (Chemoradiotherapy) is the standard of care for patients with nonmetastatic squamous cell anal cancer. Most patients treated with chemoradiotherapy have an excellent prognosis. Nigro Regime :Initial radiotherapy for 3 weeks 3000 rads (30 Gy total) to perineum and pelvis. Then chemotherapy--5 FU, for 4-5 days; is a radiosensitizer, staed on 1st day of as 1000 mg/m2 continuous infusion. Mitomycin C is 15 mg/m2 as single dose on 1st day of . Reference : page 987 SRB's manual of surgery 5th edition", 'role': 'assistant'}]