Glioma
A glioma is a type of tumor that originates in the glial cells, which are the supportive cells surrounding and protecting neurons in the brain and spinal cord. Gliomas account for approximately 80% of all malignant brain tumors and can vary widely in their aggressiveness, from slow-growing low-grade tumors to highly aggressive high-grade tumors. They are classified by the specific type of glial cell they arise from and their grade, which determines their behavior and treatment approach.
What is it?
Gliomas are brain tumors that develop from glial cells, which normally function to support, nourish, and protect neurons in the central nervous system. There are three main types of glial cells that can give rise to gliomas: astrocytes (leading to astrocytomas), oligodendrocytes (leading to oligodendrogliomas), and ependymal cells (leading to ependymomas). The World Health Organization classifies gliomas into grades I through IV based on how abnormal the cells appear under a microscope and how quickly they are likely to grow and spread.
Low-grade gliomas (grades I and II) are slower-growing and may be present for years before causing symptoms. High-grade gliomas (grades III and IV), including glioblastoma multiforme (GBM), are aggressive tumors that grow and spread rapidly within the brain. Gliomas can occur at any age but are more common in adults, with peak incidence between ages 45-65 for high-grade tumors. Unlike many other cancers, gliomas rarely spread outside the central nervous system but can infiltrate extensively throughout the brain, making complete surgical removal challenging.
Important to Know
Symptoms of gliomas depend on the tumor’s size, location, and growth rate. Common symptoms include persistent headaches (often worse in the morning), new-onset seizures, progressive weakness or numbness on one side of the body, difficulty with balance or coordination, changes in personality or cognitive function, and vision or speech problems. Diagnosis typically begins with MRI imaging with contrast, which can reveal the tumor’s location, size, and characteristics. However, definitive diagnosis and grading require tissue sampling through biopsy or surgical resection. Treatment is multidisciplinary and may include maximal safe surgical resection, radiation therapy, chemotherapy, and increasingly, targeted molecular therapies based on specific genetic mutations in the tumor. Prognosis varies widely based on tumor grade, location, extent of surgical resection, patient age, and molecular characteristics of the tumor.