Prognosis of Brain Tumour Varies with Grade and histopathological diagnosis of tumour. For commonly seen astrocytic tumour prognosis is Low grade tumour (grade 2) The average survival time after surgery is 6 - 8 years. More than 40% of people live more than 10 years. High grade tumours  Grade 3: Anaplastic glioma About 27% of people diagnosed with a high grade Astrocytomas live for five years or more. Grade 4 Glioblastoma: The average survival time is 12-18 months - only 25% of Glioblastoma pati