What are gliomas?

Glioma is a term used to describe a group of tumors that start in the glial cells in the brain. These cells support the function of the main brain cell type, the neuron.

Gliomas often happen in the cerebral hemispheres of the brain. These are the largest, outermost part of the brain that control many functions, including movement, speech, thinking, and emotions. 

But gliomas can also start in the brain stem. The brain stem is the lower inner part of the brain that controls breathing, blood pressure, and heartbeat. Gliomas can start in the optic nerves and cerebellum too. The cerebellum is the lower back part of the brain that deals with balance, coordination, vision. and other functions. 

Gliomas can be tumors that are not cancer (benign) or cancer (malignant). They make up about 3 in 10 of all tumors that start in the brain. Benign brain tumors may still need to be treated. This is because benign tumors, especially if they are big, can press on normal brain tissue and cause problems. As they grow, all brain tumors can increase the pressure inside the skull. This is also called increased intracranial pressure.

There are different types of gliomas. The category that a glioma falls into depends on the type of glial cell it comes from. These are types of gliomas:

  • Astrocytoma. This type of glioma is a tumor that comes from astrocytes, the star-shaped glial cells in the brain. The fastest-growing astrocytomas are called glioblastomas.

  • Oligodendroglioma. These gliomas start in oligodendrocytes. These are glial cells that normally form a cover for nerve fibers in the brain.

  • Oligoastrocytoma. These gliomas are a mix of abnormal oligodendrocytes and astrocytes.

  • Ependymoma. This type of glioma starts in the ependymal cells lining the fluid-filled cavities of the brain (ventricles) and spinal canal. They are most common in children and rare in adults.

  • Ganglioglioma. This is a very rare glioma that can occur in the brain or spine. It forms from both glial cells and nerve cells. Most are benign.

What causes gliomas?

Experts aren’t sure what causes brain tumors. In a small number of people, genetic disorders, such as neurofibromatosis type 1 or 2, von Hippel-Landau disease, or tuberous sclerosis, can cause them. Exposure to radiation to the brain may also play a factor. There's no known way to prevent gliomas or other brain tumors.

What are the symptoms of gliomas?

Symptoms largely depend on where the tumor is in the brain and how big it is. These are some common symptoms:

  • Headaches

  • Seizures

  • Nausea and vomiting

  • Appetite loss

  • Vision or hearing problems

  • Balance problems, such as dizziness and trouble with walking

  • Slurred speech

  • Muscle or nervous system problems, such as weakness or paralysis

  • Mood, personality, or behavior changes

  • Stroke-like symptoms

Many of these may be caused by other health problems. It's important to see a healthcare provider if you have these symptoms. Only a healthcare provider can tell if you have a brain tumor.

How are gliomas diagnosed? 

Your healthcare provider will ask you about your health history, your symptoms, risk factors, and family history of disease. A physical exam will be done with a focus on your nervous system. Your reflexes, vision, balance, and speech may be checked. If your provider thinks you may have a glioma or another type of brain tumor, you may need an imaging test like an MRI or CT scan. Often, a stereotactic (needle) biopsy is needed to remove a small piece of tumor (sample) to diagnose the type of glioma. The tissue sample is sent to a lab for a pathologist to closely look at under a microscope. More tests will be done on the tissue.

After a diagnosis of glioma, you’ll need more tests. These help your healthcare providers learn more about the tumor, including the type of glioma it is. They can help show if it's grown into nearby areas or spread to other parts of your body. The test results help your healthcare providers decide the best ways to treat the tumor.


Some kinds of cancer are given a number called a stage, but gliomas are not. They don't have a formal staging system. Gliomas are given a grade. This is a measure of how much the cancer cells look like normal cells. A scale of 1 to 4 is used. The grade is written using Roman numerals I (1), II (2), III (3), and IV (4). Grade I tumors grow slowly and don’t invade nearby tissues. Grade IV gliomas (glioblastomas) tend to be the fastest-growing tumors. These tumors have areas of dead tissue, as well as blood vessel growth. These need the most aggressive treatment. Grades II and III fall in between.

The grade of a glioma is important to know when deciding how to treat this tumor. Ask your healthcare provider to explain the details of your cancer to you in a way you can understand.

How are gliomas treated?

These treatments may be used for glioma:

  • Surgery. This is often the preferred first treatment for gliomas and other brain tumors. If the tumor can be removed without risking nervous system damage, your healthcare provider may remove as much of the tumor as possible. Surgery may be the only treatment needed for low-grade tumors.

  • Radiation therapy. This can be used to destroy any tumor cells that remain after surgery. Some gliomas can’t be removed without risking brain damage. If this is the case, radiation can be used to slow or stop tumor growth and ease symptoms.

  • Chemotherapy (chemo). This treatment uses strong medicines that stop the growth of abnormal cells. Chemo can be given by mouth (oral), through an IV (intravenous line), applied to the tumor during surgery, or put into the fluid around the brain through a shunt. Chemo tends to be used for faster-growing tumors.

  • Targeted therapy. Certain types of gliomas might be treated with targeted therapy. These medicines target certain parts of cancer cells that make them different from normal cells. This means they focus on damaging tumor cells and cause less damage to healthy cells.

  • Alternating electric field therapy. It may also be called tumor treating fields (TTFields) and is used for grade IV glioblastoma. TTFields is used to treat newly diagnosed patients who might benefit from it. It is done by applying electrodes on top of the skin of your head and delivering a low intensity current.

Many times, more than one kind of treatment is used. For instance, you may have surgery, and then radiation is given to the part of the brain where the tumor was removed. Chemotherapy may be given at the same time as the radiation therapy for glioblastoma.

Some gliomas can be hard to treat. If you or a family member has been diagnosed with a glioma, you may want to ask your healthcare provider if there are clinical trials of newer treatments that you should consider. Taking part in a clinical trial means you get the best treatment available today. You might also get new treatments that are thought to be even better.

Talk with your healthcare providers about your treatment choices. Make a list of questions. Think about the benefits and possible side effects of each choice. Discuss your concerns with your provider before making a decision. You may want to think about getting a second opinion, if there's time. A second opinion can help give you peace of mind about your treatment decision.

How do I manage a glioma?

Your chances of recovering from a glioma depend on many things. These include your age, overall health, and the size, location, and type of glioma. For lower grade gliomas, if the entire tumor is removed, you may fully recover. But sometimes it's hard to remove gliomas. Your healthcare provider is your best source of information about your likely outcomes (prognosis). They know your medical situation best.

If your motor skills, balance, or other functions have been affected by the treatment of your glioma, your healthcare provider may advise physical therapy and occupational therapy. These can help you to regain your strength and relearn some skills. Occupational therapy can also help you learn new ways of doing everyday tasks.

This diagnosis carries a major emotional impact for both the person and their family. Ask your healthcare team for mental health resources to help deal with the complex emotions that go along with gliomas.

Key points about gliomas

  • Glioma is a term used to describe a group of tumors that start in the glial cells in the brain.

  • Gliomas make up about 3 in 10 of all tumors that start in the brain.

  • Experts aren’t sure what causes brain tumors. In a small number of people, genetic disorders can cause them. Exposure to radiation to the brain may also play a factor.

  • Surgery is often the preferred first treatment for gliomas and other brain tumors.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test, treatment or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your healthcare provider if you have questions, especially after office hours or on weekends.

Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Luc Jasmin MD
Online Medical Reviewer: Susan K. Dempsey-Walls APRN
Date Last Reviewed: 8/1/2023
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