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': 'Radical mastoidectomy is done for - \nSelect and explain. \nA. ASOM, B. CSOM, C. Atticoantral cholesteatoma, D. Acute mastoiditis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Modified radical mastoidectomy is the surgery of choice for atticoantral cholesteatoma. However, in some situations\xa0it is not possible to remove it safely, radical mastoidectomy is indicated.\n\nIndications of radical mastoidectomy\n\nWhen all cholesteatoma cannot be safely removed, e.g. that invading eustachian tube, round window niche, perilabyrinthine or hypotympanic cells.\nIf previous attempts to eradicate chronic inflammatory disease or cholesteatoma have failed.\nAs an approach to petrous apex.\nRemoval of glomus tumor.\nCarcinoma middle ear. Radical mastoidectomy followed by radiotherapy is an alternative to en bloc removal of temporal bone in carcinoma middle ear.', 'role': 'assistant'}]