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
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: 
Select and explain. 
A. Radiotherapy, B. Segment mandibulectomy, C. Marginal mandibulectomy involving removal of outer table only, D. Marginal mandibulectomy involving removal of upper half of mandible
A: Radiotherapy
Answer: A: Radiotherapy 
Explanation: Radiotherapy is absolutely contraindicated in carcinoma mandible because it can lead to osteoradionecrosis of mandible.