Diffuse Intrinsic Pontine Glioma

What is diffuse intrinsic pontine glioma (DIPG)?

Diffuse intrinsic pontine glioma (DIPG) is a malignant (cancerous) tumor that forms in your child’s brainstem. It’s considered an incurable, high-grade glioma. High-grade gliomas are tumors that begin in cells in your child’s central nervous system (CNS), including cells in the brain and spinal cord. These tumors grow fast and spread rapidly throughout the CNS.

The condition’s name provides clues about the type of tumor, including why it’s so difficult to treat.

• Diffuse: DIPG isn’t a single mass of cells. Instead, the cancer cells in the tumor are diffuse, or spread out alongside healthy cells. It’s difficult to remove these tumors through surgery without harming healthy tissue.
• Intrinsic: DIPG is “intrinsic to” or inside the part of your child’s brainstem called the pons.
• Pontine: The pons is an essential part of the brainstem that controls blood pressure, heart rate and breathing. It also controls vision, hearing, speech, muscle coordination and balance. Diffuse intrinsic pontine gliomas are dangerous, in part, because they affect this crucial part of your child’s brain.
• Glioma: A glioma is a tumor made of glial cells that turned into cancer cells. Glial cells protect nerves, or neurons, in the central nervous system.

What is the difference between diffuse intrinsic pontine glioma (DIPG) and diffuse midline glioma (DMG)?

Diffuse intrinsic pontine glioma (DIPG) is a type of diffuse midline glioma (DMG). In the past, these terms were used interchangeably. Diffuse midline glioma forms in the middle part of the brain, including the pons, thalamus and spinal cord. Diffuse intrinsic pontine glioma forms specifically in the pons.

Both DIPG and DMG are high-grade gliomas. Still, there are differences between the two that will shape which treatments your healthcare provider may recommend for your child.

Who is affected by diffuse intrinsic pontine glioma (DIPG)?

Children of any age or sex may develop these tumors. Still, they’re most commonly diagnosed in children ages 5 to 9.

Adults can also get diffuse intrinsic pontine glioma (DIPG), but this is rare.

How common is diffuse intrinsic pontine glioma (DIPG)?

It’s rare. Between 150 to 300 children in the U.S. are diagnosed with these tumors each year. Most gliomas that affect children are low-grade and treatable. Only about 10% of pediatric brain tumors are DIPG.

What are the symptoms of diffuse intrinsic pontine glioma (DIPG)?

DIPG grows fast, and symptoms progress rapidly. Signs and symptoms to watch out for in your child include:

• Eye problems (blurry vision, seeing double, uncontrollable or odd eye movements).
• Headaches, especially morning headaches and headaches that improve after vomiting.
• Trouble with walking, muscle coordination or balance (ataxia).
• Droopy eyelids or drooping on one side of the face.
• Difficulty chewing or swallowing.
• Weakness in the arms or legs.
• Nausea and vomiting.
• Slurred speech.

What causes diffuse intrinsic pontine glioma (DIPG)?

With DIPG, cells that should mature into glial cells become cancer cells instead. Then, the cancer cells grow out of control.

Unlike many other cancers, DIPG doesn’t seem to be related to environmental risk factors (like exposure to cigarette smoke or radiation).

Your child may be at greater risk if they have a rare disorder called Li-Fraumeni syndrome. Also, cell mutations, or changes, can cause DIPG. A mutation in a protein, called H3K27M, can cause glial cells to become cancer cells instead.

How is diffuse intrinsic pontine glioma diagnosed?

Usually, a biopsy is needed to confirm a cancer diagnosis, but this isn’t always possible with DIPG. Instead, your healthcare provider will likely consider your child’s symptoms alongside imaging studies to diagnose DIPG.

• Magnetic resonance imaging (MRI): An MRI produces detailed images of your child’s tumor. It can show whether it’s spread beyond the pons. DIPG has a distinct appearance on an MRI. An experienced radiologist (an imaging studies expert) can distinguish it from other types of brain stem tumors.
• Stereotactic biopsy: Your provider may use a small, hollow needle to remove parts of the tumor for testing (biopsy) if it’s safe to do so. Often, it’s impossible to remove tissue from the pons without risking damage to your child’s brainstem. A biopsy related to DIPG should only occur in a clinic that performs high volumes of these procedures.

How is diffuse intrinsic pontine glioma (DIPG) treated?

Current treatments for DIPG may extend your child’s life for a short time, but they can’t get rid of the cancer completely. The brain stem is made of neural tissue that controls many vital functions of your child’s body. Removing the tumor would damage these essential neural structures.

Your healthcare provider will recommend non-surgical treatments instead:

• Radiation therapy: Radiation therapy is the primary treatment for DIPG. A machine directs energy to the tumor during the procedure, sparing the nearby healthy tissue. Radiation shrinks the tumor, destroys cancer cells and helps improve symptoms. Your child will likely receive radiation therapy daily for six weeks.
• Corticosteroids: Your healthcare provider may prescribe drugs that reduce inflammation, called corticosteroids, before or after your child’s radiation therapy. Corticosteroids can reduce swelling in the brain that’s causing your child’s symptoms. They can also reduce inflammation following radiation. Unfortunately, corticosteroids also cause unpleasant side effects, including hunger, weight gain, mood swings, etc. Weigh the potential benefits of corticosteroids against the risks with your provider.
• Chemotherapy: Standard cancer treatments like chemotherapy don’t work with DIPG. Still, your provider may recommend that your child participate in research studies that combine chemotherapy treatments with radiation therapy.
• Palliative care: Palliative care professionals can work with you and your care team to ensure that your child’s care plan prioritizes their quality of life. Palliative care can provide medical, emotional and spiritual support to help you, your child and family navigate a DIPG diagnosis.

Your provider may recommend that your child enrolls in a clinical trial. A clinical trial is a study that researches the safety and effectiveness of new treatments. Researchers have identified characteristics of DIPG cancer cells that can inform new therapies — including molecular targeted therapy and immunotherapy — which may be available through a clinical trial.

For example, researchers know that many of the cancer cells in DIPG contain a mutation called H3K27M. New, experimental treatments that target cancer cells with this mutation (and others) are currently being developed and tested in clinical trials.

Is diffuse intrinsic pontine glioma (DIPG) curable?

Diffuse intrinsic pontine glioma isn’t curable. Radiation therapy is the most effective treatment currently available. Radiation for DIPG extends a child’s life and temporarily improves their symptoms and quality of life. Newer, more effective treatments are needed to improve the prognosis of this aggressive cancer.

How long can a child live with diffuse intrinsic pontine glioma (DIPG)?

Without treatment, most children survive six months following their diagnosis. On average, radiation therapy can extend the survival timeline to nine to 11 months. Less than 10% of children survive beyond two years.

What questions should I ask my doctor?

Work closely with your care team to understand the factors that will play a role in your child’s care plan and prognosis.

Questions to ask include:

• What treatments would you recommend?
• How often will my child receive treatments?
• How often will my child need follow-up appointments to monitor their cancer?
• How can we manage the side effects of cancer treatment?
• Can you connect us with palliative care resources and support groups?

A note from Cleveland Clinic

Learning that your child has diffuse intrinsic pontine glioma may be the most difficult news you receive as a parent. As you navigate treatment decisions in the months ahead, take advantage of every resource available. Speak openly with your child’s care team about what to expect with this disease. Connect with palliative care professionals if these resources are available to you. Reach out to friends and family members for support. Most importantly, connect with your child. Communicate that you’re on this journey alongside them every step of the way.