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: ENT
[{'content': 'An old man who is edentulous, presents with squamous cell carcinoma in buccal mucosa that has developed and infiltrated to the alveolus. Following is not indicated in treatment: \nSelect and explain. \nA. Radiotherapy, B. Segment mandibulectomy, C. Marginal mandibulectomy involving removal of outer table only, D. Marginal mandibulectomy involving removal of upper half of mandible', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Radiotherapy is absolutely contraindicated in carcinoma mandible because it can lead to osteoradionecrosis of mandible.', 'role': 'assistant'}]