High-grade glioma

What it is

A high-grade glioma is a glioma that grows quickly and behaves aggressively — generally grade 3 or grade 4 in the WHO system. High-grade gliomas, which include glioblastoma, require prompt and intensive treatment.

Understanding High-grade glioma

High-grade gliomas grow rapidly, infiltrate surrounding brain, and appear aggressive under the microscope (often with rapid cell division and, in grade 4 tumors, features such as abnormal blood vessel growth or necrosis). They include grade 3 gliomas (such as grade 3 IDH-mutant astrocytoma or oligodendroglioma) and grade 4 tumors (such as glioblastoma, IDH-wildtype, and grade 4 IDH-mutant astrocytoma). Because they progress quickly, high-grade gliomas are typically treated with a combination of surgery, radiation, and chemotherapy, and sometimes additional therapies. The outlook varies substantially by the specific type and molecular features — for example, IDH-mutant tumors generally carry a better outlook than IDH-wildtype glioblastoma. Understanding high-grade gliomas clarifies a category requiring intensive, multimodal treatment, while recognizing that outcomes still depend on the specific diagnosis.

Why it matters

Understanding high-grade gliomas helps patients and families see that these aggressive tumors require prompt, intensive treatment — while recognizing that the outlook still varies by the specific type and molecular features.