What is the prognosis for a brain tumor?

Prognosis for Brain Tumors

Brain tumor prognosis varies dramatically by tumor grade and histology, with glioblastoma carrying a median survival of 12-15 months and less than 5% five-year survival, while lower-grade gliomas and oligodendrogliomas have substantially better outcomes. 1, 2, 3

Prognosis by Tumor Type and Grade

Glioblastoma (WHO Grade IV)

• Median survival: 12-15 months 3
• 1-year survival: approximately 33% 2
• 2-year survival: 27.2% with temozolomide plus radiotherapy (vs 10.9% with radiotherapy alone) 2
• 5-year survival: 9.8% with combined therapy (vs 1.9% with radiotherapy alone), though some sources report <5% overall 1, 2, 4
• Recurrence rate: nearly 90% 5
• This is the most lethal primary brain tumor in adults, accounting for 49% of all malignant brain tumors 2

Anaplastic Astrocytoma (WHO Grade III)

• Median survival: 2-5 years 3
• 5-year survival: 27% 1
• Prognosis is intermediate between glioblastoma and oligodendroglioma 1

Anaplastic Oligodendroglioma (WHO Grade III)

• 5-year survival: approximately 50% 1
• 20-year survival with chemotherapy (PCV): 37% (vs 13.6-14.9% without chemotherapy) 2
• This histologic subtype has markedly better prognosis due to sensitivity to chemotherapy, particularly in tumors with 1p/19q codeletion 1, 2

Grade II Gliomas (Low-Grade)

• More than half of low-risk patients eventually experience disease progression, though the timeline can be prolonged 1
• These tumors can behave aggressively in high-risk patients 1

Critical Prognostic Factors

The most important prognostic factors are histologic diagnosis, age, and performance status. 1

Poor Prognostic Indicators:

• Age >35-40 years (most consistent factor) 1, 6, 4
• Low Karnofsky performance status (<70) 1, 6
• Incomplete tumor resection 1
• Large tumor size (>6 cm) or rapidly increasing volume 1, 6
• Tumor crossing midline 1
• Intracranial hypertension or neurological deficits 1, 6
• Uncontrolled epilepsy 1, 6
• Tumor location in functional zones or involvement of deep structures 1, 6
• Contrast enhancement on MRI 1, 6

Favorable Prognostic Indicators:

• Lower tumor grade 1
• Good performance status and intact neurological function 1
• Complete tumor resection 1
• Age <50 years 1
• Pure oligodendroglioma histology with 1p/19q codeletion 1, 2
• MGMT promoter methylation (predicts better response to temozolomide) 1

Overall Survival Statistics

• Five-year survival for all malignant brain tumors combined: approximately 36% 2
• Annual incidence: 5-7 per 100,000 individuals 1, 2
• Peak incidence: fifth and sixth decades of life 1
• Annual deaths in the United States: >15,000 2

Common Pitfalls in Prognostication

Imaging changes after treatment can mimic tumor progression due to blood-brain barrier disruption from surgery, radiation, or corticosteroid tapering, making accurate assessment of therapeutic response difficult 1

Inter-tumor and intra-tumor heterogeneity significantly complicates prognosis, as glioblastomas demonstrate high variability even within the same tumor 5, 7

Cognitive deficits in brain tumor patients may impair their ability to understand prognosis and participate in treatment decisions, creating ethical challenges in end-of-life planning 3