Glioblastoma

Glioblastoma (GBM), also known as glioblastoma multiforme or grade 4 astrocytoma, is the most aggressive and most common primary malignant brain tumor in adults. Classified by the World Health Organization as a grade 4 glioma, it arises from astrocytes, the supportive glial cells of the central nervous system. Glioblastoma primarily affects the brain, most commonly the cerebral hemispheres, and is characterized by rapid, infiltrative growth into surrounding brain tissue, areas of necrosis, and robust new blood vessel formation (neovascularization). Key molecular subtypes include IDH-wildtype glioblastoma (the vast majority of cases) and, less commonly, tumors with IDH mutations, which carry a somewhat better prognosis. Symptoms depend on tumor location and size and may include persistent or worsening headaches, seizures, progressive neurological deficits such as weakness or numbness on one side of the body, speech difficulties, cognitive and personality changes, vision problems, and nausea or vomiting due to increased intracranial pressure. Symptoms often develop rapidly over days to weeks, reflecting the tumor's aggressive growth pattern. The current standard of care for newly diagnosed glioblastoma involves maximal safe surgical resection followed by concurrent radiation therapy and temozolomide chemotherapy (the Stupp protocol), followed by adjuvant temozolomide. Tumor treating fields (TTFields), a device-based therapy delivering alternating electric fields to the brain, may also be used in combination with temozolomide. Methylation of the MGMT gene promoter is an important biomarker that predicts better response to temozolomide. Despite multimodal treatment, prognosis remains poor, with a median overall survival of approximately 14 to 16 months and a five-year survival rate of less than 10%. Most cases are sporadic, though rare familial clustering has been observed, and prior ionizing radiation exposure is the only well-established environmental risk factor. Ongoing research includes immunotherapy, targeted molecular therapies, and novel drug delivery approaches.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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