Diffuse intrinsic pontine glioma (DIPG) is a rare type of brain cancer that usually affects children.
What Happens in DIPG?
In DIPG, a tumor forms in the stem of the brain in an area called the pons. It’s in the lower part of the brain that controls vital body functions like blood pressure, heart rate, swallowing, eyesight and eye movement, balance, and breathing.
DIPG is a kind of glioma, or a tumor that starts in the brain’s glial cells. They’re also called pontine tumors or pontine gliomas.
Who Gets It?
DIPG almost always affects children between the ages of 4 and 11. It’s very rare in adults. About 200 to 400 children are diagnosed with DIPG each year. Boys and girls are equally likely to get it.
What Are the Symptoms of DIPG?
DIPG tumors spread quickly, so your child’s symptoms may worsen in a short time. The tumor grows and presses against the pons, causing problems with body functions controlled by this part of the brain. You might notice your child has:
- Balance and walking problems
- Trouble chewing or swallowing food
- Speech problems
- Eye problems like control of eye movement, double vision, or droopy eyelids
- Quick loss of hearing or deafness
- Nausea and vomiting
- Headaches in the morning or after they vomit
- Drooping face, often on one side only
- Weakness in their arms or legs
As tumors grow, DIPG may cause life-threatening symptoms like severe breathing or heartbeat problems.
What Causes DIPG?
While DIPG tumors may have certain genetic changes (the doctor will call them mutations), this isn’t a disease that children get from their parents. It doesn’t come from exposure to anything in the world around them either, like smoke, chemicals, or radiation. There’s no way to prevent DIPG or lower your child’s risk of getting it.
Doctors think DIPG may be linked to how a child’s brain grows. Tumors tend to appear at an age when the brain is changing fast. During this time, there’s a high amount of a type of brain cell that may drive DIPG tumor growth.
How Is DIPG Diagnosed?
They may do tests like:
Imaging. Brain scans like CT scans help confirm a DIPG diagnosis. Your child may also need a test called magnetic resonance spectroscopy (MRS), which looks for chemicals in cells. The doctor could pair it with a scan called an MRI to look for signs that the tumor comes from glial cells.
The doctor might inject a contrast dye before the MRI to show the tumor more clearly. The tumor’s location in the pons, how it has spread into other tissues, and unclear edges all suggest DIPG.
Biopsy. Children with unusual symptoms or MRI results may need a biopsy to confirm a DIPG diagnosis. For DIPG, a doctor called a pediatric neurosurgeon can do a test called stereotactic biopsy. They’ll drill a small hole in your child’s skull, insert a needle, and remove a piece of the tumor. A doctor called a pathologist examines the tissue for signs of DIPG.
How Is DIPG Staged?
Doctors usually stage DIPG tumors based on MRI or biopsy results. Low-grade DIPG tumor cells, or in stages I or II, are closer to normal cells. High-grade DIPG tumor cells, or in stages III or IV, are more aggressive cancers.
How Is DIPG Treated?
DIPG treatment options include surgery and radiation, and chemotherapy.
Radiation. This is the main DIPG treatment. The doctor beams high-energy X-rays at the tumor in a series of sessions. Children with DIPG may need five daily radiation therapy sessions a week and up to 30 or more sessions in total.
Radiation therapy helps to shrink the tumor for most children with DIPG. This treatment may also relieve your child’s symptoms. When radiation shrinks the tumor, it eases pressure on your child’s brain. It can also extend a child’s life by several months.
But the benefits of radiation therapy are usually temporary. Within a few months, the tumors often start to grow again. If that happens, children may be able to repeat radiation therapy to add more months to their lives.
Chemotherapy. Newer, experimental chemotherapy drugs and biologics may be used along with radiation therapy to treat DIPG. No drugs have shown success at treating this cancer. In one new treatment option for DIPG, doctors inject targeted cancer drugs directly into the tumor to try to make treatment more effective.
Surgery. Surgery to remove the tumor usually isn’t an option. These tumors aren’t solid masses that are easy to take out. There’s a high risk of damage to healthy brain tissue in surgery. Surgery could even be fatal.
Also, DIPG tumor cells spread into areas with healthy brain cells. It’s hard to remove all the cells. Any that are missed will start to grow again later and form new tumors.
What’s the Outlook for a Child With DIPG?
The outlook for children with DIPG isn’t good. Doctors will work to keep your child comfortable. At this time, medications can’t treat the disease; just the symptoms. Only 10% of children with DIPG live for 2 years after they’re diagnosed, and less than 1% survive for 5 years.