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: Medicine
[{'content': 'Which of the following tumors has got the best prognosis? \nSelect and explain. \nA. Cerebellar pilocytic astrocytoma, B. Grade IV astrocytoma, C. Medulloblastoma, D. Ependymoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cerebellar pilocytic astrocytoma is Grade - I astrocytoma and is associated with best prognosis. Grade - IV astrocytoma is Glioblastoma multiforme and has worst prognosis. Grade - II astrocytoma is low-grade (fibrillary) astrocytoma, mixed oligoastrocytoma. They are relatively slow growing astrocytomas. These patients have 5 yr survival rate of 34% without treatment and 70% with radiation therapy. Grade - III astrocytoma is anaplastic astrocytoma. These patients often related to seizures, neurologic deficits, headaches, or changes in mental status. Individuals with grade 3 astrocytoma have a median survival time of 18 months with treatment (radiation and chemotherapy).', 'role': 'assistant'}]