High-Grade Glioma

What is a high-grade glioma?

A high-grade glioma (pronounced “glee-OH-ma”) is a fast-growing cancer that affects your child’s brain or spinal cord. A glioma is a mass of cells, or a tumor, that forms when glial cells grow out of control. Glial cells support neurons, or nerves, in the central nervous system. A glioma that’s considered “high-grade” spreads quickly.

High-grade gliomas may not always be curable. They’re challenging to treat because they grow rapidly into the brain or spinal cord. The cancer cells can invade between the healthy cells. This can make it difficult to remove the cancer without damaging the healthy tissue. Healthy cells and cancer cells become quickly bound together. As a result, gliomas may be hard to remove with surgery without damaging healthy tissue.

What grade is a high-grade glioma?

The World Health Organization (WHO) classifies gliomas as low grade (Grades 1 and 2) and high grade (Grades 3 and 4). High-grade gliomas grow faster than low-grade gliomas.

Adults may have gliomas that start as low grade and then progress to high grade. In contrast, high-grade gliomas in children usually start as high-grade. Low-grade gliomas in children are treatable and rarely progress to high grade.

Where do high-grade gliomas form?

Most high-grade gliomas form in the supratentorial compartment in the brain or in the brainstem.

• Supratentorial compartment: High-grade gliomas may form in the glial cells in the part of the brain that includes the cerebrum, the thalamus and the hypothalamus.
• Brainstem: High-grade gliomas may form in the part of the brainstem called the pons. These types of tumors are called diffuse intrinsic pontine gliomas (DIPG).

The tumor’s location is important because it will shape your child’s treatment options. For instance, tumors in the brainstem often can’t be safely removed through surgery.

Who is affected by high-grade gliomas?

Infants, children, adolescents and adults can get high-grade gliomas. But high-grade gliomas in infants and young children are different from those occurring in adolescents and adults. These differences mean that treatments differ in infants and young children.

How common are high-grade gliomas?

High-grade gliomas are the second most common type of malignant (cancerous) brain tumor in children. About 10% to 20% of childhood tumors affecting the central nervous system are high-grade gliomas.

What are the symptoms of a high-grade glioma?

Symptoms vary depending on the part of your child’s brain or spinal cord affected, their age and how quickly the tumor grows. Symptoms result from increased pressure and swelling from the tumor.

The most common symptom of a high-grade glioma is a headache, especially alongside other symptoms like nausea or vomiting. These headaches may feel particularly intense in the morning. Sometimes, they’re so severe that they wake your child from sleep.

Other symptoms include:

• Problems with vision, hearing or speech.
• Difficulty with muscle coordination or balance (ataxia).
• Confusion or memory loss.
• Sleepiness.
• Lack of energy.
• Seizures.

Infants with a high-grade glioma may become unusually fussy or irritable. You may notice changes in their eating habits. Their heads may grow larger, and the soft spots on the top of their head (one in the front and one in the back) may visibly bulge.

What causes a high-grade glioma?

Researchers aren’t sure what causes high-grade gliomas. In adults, previous radiation therapy is a factor that may raise the risk of getting a high-grade glioma. These same external or environmental risk factors may exist for children. More research is needed to be sure.

Certain rare inherited genetic syndromes may increase the risk of children developing a high-grade glioma. A genetic condition involves an abnormality or error in the genes, the code that tells cells how to work correctly.

These conditions include:

• Neurofibromatosis type-1 (NF1).
• Turcot syndrome.
• Li-Fraumeni syndrome.

Still, most children with high-grade gliomas don’t have a family history of them.

How are high-grade gliomas diagnosed?

Your child’s healthcare provider will review their symptoms and medical history. A brain scan, or imaging study, can show whether a tumor may be causing symptoms. A biopsy can show if a tumor is malignant (cancerous) or benign (noncancerous).

• Imaging: An MRI and a CT scan allow your provider to see tumors in your child’s brain or spinal cord. An MRI – especially a contrast-enhanced MRI – provides a more detailed image than a CT scan. An MRI uses magnets and radio waves to create images of internal structures on a computer screen. During a contrast-enhanced MRI, your child’s healthcare provider will inject a safe dye into their arm that makes the tumors show up more clearly on screen.
• Biopsy: A stereotactic biopsyallows your provider to pinpoint a tumor’s exact location and remove a small tissue sample for testing. Afterward, a lab specialist called a pathologist examines the cells to see if they’re high-grade glioma. They can also conduct tests that identify features of the cancer cells that may help with treatment. For example, your child may be eligible for new cancer treatments that are designed to work on specific types of cancer cells.

If possible, your provider may remove the entire tumor instead of taking a sample so that treatment (surgery) happens as part of the diagnosis.

Biopsies aren’t always possible with high-grade gliomas. Depending on the tumor’s location, removing a tissue sample may risk damaging essential parts of the brain, like the brainstem. If a biopsy isn’t an option, your child’s healthcare provider will rely on imaging for a diagnosis.

Can high-grade gliomas be cured?

It depends. Various factors play a role, including your child’s age, the type of gene changes in the cancer cells and how much of the tumor can be removed.

How are high-grade gliomas treated?

Treatments may involve removing the tumor, slowing its growth and helping ease symptoms.

Depending on the type of tumor, its location and other factors, many specialists may be involved in your child’s care. Their care team may include a neurosurgeon, a neuro-oncologist, a radiation oncologist, an endocrinologist, a nurse practitioner and a social worker, among others.

Treatments may include any of the following:

• Surgery: Surgery is the primary treatment for high-grade gliomas that can be safely removed. Your child’s healthcare provider will remove as much of the tumor as possible without damaging surrounding healthy tissue.
• Radiation therapy: Focal radiation therapy is a standard treatment for children ages 3 and up. Radiation therapy is usually avoided in younger children to allow brain development. During this treatment, a machine directs high-dose X-rays to the tumor, taking care to spare nearby healthy tissue. Radiation shrinks tumors, destroys cancer cells and helps improve symptoms.
• Chemotherapy: When radiation therapy is avoided in younger children, chemotherapy is given to slow the tumor growth. Chemotherapy uses drugs to destroy cancer cells. Still, the use of chemotherapy treatment with high-grade gliomas is debatable. While some chemotherapy drugs, like temozolomide, work well on some types of adult gliomas, these same treatments aren’t as effective in children.
• Palliative care: Palliative care professionals can advise you on decisions that prioritize your child’s quality of life during treatment. They can suggest strategies that help with symptom relief to help your child cope with their diagnosis.

High-grade gliomas often return (recur) following treatment. In that case, your provider may offer targeted therapies that target the abnormal molecules (caused by the genetic mutation) found in your child’s tumor. These molecular targeted therapies may be available through clinical trials. A clinical trial is a study that tests the safety and effectiveness of new treatments.

Your physician may be able to provide targeted therapy drugs outside of a clinical trial if they’re available in the market or if past testing has shown them to be effective against the type of glioma your child has.

What are the side effects of treatments for a high-grade glioma?

Talk to your provider about the potential side effects of various treatments. Your child’s provider will take care to spare healthy tissue during radiation treatment. Still, some tissue will likely be affected. Depending on which parts of the brain are impacted, radiation therapy can affect brain function, cause developmental disorders and disrupt hormone production.

Weigh the potential benefits of treatment against the risks with your child’s care team.

What can I expect if my child has a high-grade glioma?

Your child’s prognosis depends on many factors that their healthcare provider can discuss with you. Outcomes depend on the type of cells affected, cell characteristics, how much of the tumor your child’s provider is able to remove during surgery, etc.

Ask about what your expectations should be based on your child’s unique situation.

What is the survival rate for a high-grade glioma?

These tumors usually return after treatment. The five-year survival rate for high-grade gliomas in children is less than 20%. Still, these tumors are highly variable. They form in different places, and they contain cells with different characteristics. These differences will shape your child’s prognosis.

What questions should I ask my doctor?

• What are my child’s treatment options?
• How will the tumor’s location impact treatment options?
• What are the risks associated with treatment?
• What outcomes (results) should we expect from treatment?
• How can I care for my child during treatment?
• How often will my child need treatments and follow-up care to monitor their condition?

A note from Cleveland Clinic

Receiving a high-grade glioma diagnosis is difficult. The cancer spreads quickly, and tumors often recur after treatment. You may have to weigh the benefits of treatment frequently against potential side effects that you’d rather not have your child experience.

Take advantage of every available resource to help you, your child and your family during this time. Talk with your healthcare provider about treatment options, including clinical trials. Connect with palliative care resources if they’re available. Reassure your child that they’ll have constant support as you face this diagnosis together.