Untreated Brain Cancer: Survival Estimates and Prognostic Factors

Survival without treatment varies dramatically by tumor type, grade, location, and patient factors:

• Glioblastoma (WHO grade 4): Median survival ~3–6 months; highly aggressive.
• Anaplastic astrocytoma (grade 3): Median ~12–18 months.
• Low‑grade gliomas (grade 2): May survive years to decades with slow growth.
• Meningioma (typically benign): Often indolent; survival can exceed 10–20 years.

Average overall survival for untreated malignant brain tumors is approximately 3–6 months, but individual outcomes range from weeks to many years. Factors influencing prognosis include age, performance status, extent of resection (if any), molecular markers (IDH mutation, MGMT methylation), and supportive care.

Urgent consultation with a neuro‑oncologist is essential to discuss diagnosis, treatment options (surgery, radiation, chemotherapy, clinical trials), and realistic expectations.