Glioma

Overview

What is a glioma?

A glioma is a tumor that forms when glial cells grow out of control. Normally, these cells support nerves and help your central nervous system work. Gliomas usually grow in the brain, but can also form in the spinal cord.

Gliomas are malignant (cancerous), but some can be very slow growing. They’re primary brain tumors, meaning they originate in the brain tissue. Gliomas don’t usually spread outside of the brain or spine, but are life-threatening because they can:

  • Be hard to reach and treat with surgery.
  • Grow into other areas of the brain.

Are there different types of gliomas?

There are three main types of gliomas, grouped by the type of glial cell they start in. Some gliomas contain multiple types of cells. Healthcare providers call these mixed gliomas. They categorize each type of glioma as low-, mid- or high-grade based on how fast they grow and other features.

Gliomas include:

  • Astrocytomas, including glioblastomas and diffuse intrinsic pontine gliomas (DIPGs): These tumors start in cells called astrocytes. Glioblastomas are astrocytomas that are very aggressive or grow fast. They are the most common malignant brain tumor in adults. Astrocytomas are common gliomas in children. A rare but very aggressive form of brain cancer in children is DIPG. It forms in the brain stem and mostly affects children.
  • Ependymomas: These tumors start in ependymocytes, a type of glial cell. Ependymomas usually form in the ventricles of the brain or the spinal cord. They may spread through cerebrospinal fluid (the fluid that surrounds and protects the brain and spinal cord), but don’t spread outside the brain or spine. Ependymomas make up about 2% of all brain tumors. They’re more common in children than adults.
  • Oligodendrogliomas: These tumors start in glial cells called oligodendrocytes. Oligodendrogliomas tend to grow more slowly but can become more aggressive over time. Like ependymomas, they rarely spread outside the brain or spine. They’re more common in adults than children. Oligodendrogliomas account for about 1% to 2% of all brain tumors.

Who is at risk of getting a glioma?

Anyone can develop a glioma, but the following factors may increase your risk:

  • Age: Gliomas are most common in older adults (over 65) and children (under 12).
  • Ethnicity: White people may be more likely to develop gliomas than other races.
  • Family history: Some inherited genetic disorders may increase your risk of gliomas.
  • Gender: Gliomas are slightly more common in men than women.
  • Radiation or toxin exposure: Repeated or prolonged exposure to radiation or certain chemicals may increase your risk.

How common are gliomas?

About 80,000 people are newly diagnosed with primary brain tumors each year in the U.S. Approximately 25% of these are gliomas.

Symptoms and Causes

What causes gliomas?

Research suggests that changes to DNA lead to the development of brain tumors and spinal cord tumors like gliomas. Our genes contain DNA. They give instructions to cells about how to grow and multiply. Mutations, or changes, to the DNA in our genes can cause cells to multiply out of control.

It’s possible to inherit genetic mutations from your parents. They can also occur suddenly during your lifetime.

What are the symptoms of gliomas?

Symptoms of gliomas may include:

  • Aphasia (problems with speaking and communicating).
  • Changes in your vision or vision loss.
  • Cognitive problems (trouble thinking, learning or remembering).
  • Difficulty walking or keeping your balance.
  • Dizziness.
  • Headaches.
  • Hemiparesis (weakness or numbness on one side of the body).
  • Nausea and vomiting.
  • Personality or behavioral changes.
  • Seizures.

What are the complications of gliomas?

Potentially life-threatening complications of gliomas include:

  • Brain hemorrhage (bleeding in the brain).
  • Brain herniation (brain tissue moves outside its normal position in the skull).
  • Hydrocephalus (fluid buildup in the brain).
  • Pressure inside your skull.
  • Seizures.

Diagnosis and Tests

How are gliomas diagnosed?

Your healthcare provider evaluates your symptoms and reviews your medical history. They’ll also do a complete physical and neurological exam.

MRIs and CT scans are the most common imaging scans for brain tumors. Your healthcare provider looks for tumors in your brain, as well as tumors elsewhere in your body.

If your healthcare provider sees an abnormal mass on your imaging scans, they’ll do a biopsy. A biopsy is a procedure to analyze a sample of tissue. The biopsy will help them determine:

  • If the tumor is cancerous.
  • If the tumor is the result of an abnormal gene.
  • The type of cells in the tumor.
  • The grade (aggressiveness) of the tumor.

Management and Treatment

How is a glioma treated?

Your treatment plan for a glioma depends on several factors, including:

  • If you’ve had brain cancer treatment in the past.
  • The location, type and size of the tumor.
  • Your age.
  • Your health.

For most people, surgery is the first treatment for a glioma. A surgeon may be able to remove all of the tumor they can see, if it’s easily accessible. But gliomas can be hard to remove completely, especially hard to reach or near delicate areas of the brain.

Additional treatments, such as chemotherapy and radiation therapy, should follow surgery. These are adjuvant therapies, meaning they destroy any remaining cancer cells or parts of the tumor after surgery. But if a tumor is inoperable, your provider might use chemotherapy or radiation therapy as your primary treatments.

Surgery

A craniotomy (open brain surgery) is the most common type of surgery to remove gliomas. Depending on the size and location of the tumor, you may be a candidate for laser ablation. This minimally invasive surgery uses heat from a laser to destroy all or part of a brain tumor.

A surgeon may use special techniques, such as imaging or brain mapping, to guide the surgery. Brain mapping shows which areas of your brain control vital functions. This information helps your surgeon avoid removing or harming healthy brain tissue.

Radiation

Radiation therapy uses powerful doses of radiation to destroy tumors. Your healthcare provider may recommend radiation therapy for gliomas. Radiation therapy targets the exact shape of the tumor, minimizing the risk of damage to surrounding tissues.

You may also receive a form of radiation therapy called brachytherapy. A healthcare provider applies radiation sources close to the tumor to treat it. The sources release radiation without harming nearby tissues.

Chemotherapy

Chemotherapy is the use of drugs to destroy cancer cells. It treats many types of cancer. This treatment may be oral of intravenous.

Temozolomide is a common chemotherapy medicine that is given to improve the efficacy of radiation therapy.

Prevention

How can I prevent gliomas?

Most risk factors for gliomas, such as age and race, aren’t controllable. But early detection and treatment of low-grade gliomas may slow or prevent their progression into high-grade gliomas. If brain tumors run in your family, you may want to consider genetic testing. Talk to your healthcare provider or a genetic counselor about the risks and benefits of genetic testing.

It is also a good idea to:

  • Limit radiation exposure to your head.
  • Maintaining a healthy lifestyle.

Outlook / Prognosis

What is the outlook for people with gliomas?

Survival rates for gliomas vary by tumor type, tumor grade and a person’s age. Certain mutations can also affect the prognosis. The older someone is when they’re diagnosed and treated, the worse the outlook. The five-year survival rate for adults and children is highest for low-grade ependymomas, oligodendrogliomas and astrocytomas. It’s lowest (between 6% and 20%) for glioblastomas.

Living With

What should I do if I have a glioma?

After treatment, stay in close communication with your healthcare provider. You’ll need regular imaging scans to see if the cancer returns.

Brain cancer treatment can cause damage to healthy brain tissue. Rehabilitation with physical therapists or occupational therapists can help you regain skills like walking, speaking and remembering.

Support groups for you and your family can help you manage the physical and emotional challenges of living with a brain tumor.

What should I ask my healthcare provider?

If you have a glioma, you may want to ask your provider the following questions:

  • What is the cancer’s type and grade?
  • What treatments are right for me?
  • Will treatment affect my cognitive function?
  • Are there clinical trials I can take part in?
  • Can the cancer come back after treatment?

A note from Cleveland Clinic

Gliomas are tumors that form in glial cells in the brain and spinal cord. They’re usually cancerous. It’s rare for gliomas to spread to other areas of your body. But they can grow quickly through the brain and spine and are life-threatening. Most people with gliomas need a combination of treatments. These may include surgery, radiation therapy or chemotherapy. Young people with low-grade, or slow-growing, gliomas have the highest chance of survival.

Last reviewed by a Cleveland Clinic medical professional on 10/20/2021.

References

  • American Cancer Society. Brain and Spinal Cord Tumors in Adults. (https://www.cancer.org/cancer/brain-spinal-cord-tumors-adults) Accessed 10/28/2021.
  • American Cancer Society. Brain and Spinal Cord Tumors in Children. (https://www.cancer.org/cancer/brain-spinal-cord-tumors-children) Accessed 10/28/2021.
  • American Society of Clinical Oncology (ASCO). Brain Tumor: Risk Factors. (https://www.cancer.net/cancer-types/brain-tumor/risk-factors) Accessed 10/28/2021.
  • Canadian Cancer Society. Chemotherapy for brain and spinal cord tumours. (https://www.cancer.ca/en/cancer-information/cancer-type/brain-spinal/treatment/chemotherapy) Accessed 10/28/2021.
  • Mesfin FB, Al-Dhahir, MA. Gliomas. (https://www.ncbi.nlm.nih.gov/books/NBK441874/) [Updated 2020 Aug 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Accessed 10/28/2021.
  • National Organization for Rare Disorders (NORD). Glioma. (https://rarediseases.org/rare-diseases/glioma) Accessed 10/28/2021.

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