Understanding Pediatric Brain Tumors
Just like adult brain tumors, pediatric brain tumors are masses of cells found in or on the brain that shouldn’t be there. They are the most common solid tumor found in children and the second most common type of pediatric cancer (behind leukemia). Still, they are rare, with about 4,000 new pediatric brain tumors diagnosed each year in the U.S.
Not all brain tumors are malignant (cancerous). In fact, about half of pediatric brain tumors are benign. And yet, given the space restrictions of the skull, even non-cancerous brain tumors can cause serious illness if they grow too large or compress a vital structure. That’s why it’s always best to alert your pediatrician right away if you notice signs of a brain tumor in your child
Types of pediatric brain tumors
There are numerous types of pediatric brain tumors, all with different risks and survival rates. Some are very slow growing while others are quite aggressive. Some begin within the brain (primary brain tumors) and others spread (metastasize) to the brain from other places in the body.
Many pediatric brain tumors are named for their location in or on the brain or spinal cord. One clue as to which type of brain tumor a child has is his or her age. Below are the most common pediatric brain tumors by age.
- Embryonal tumors (infant–age 4): These tumors form out of “leftover” cells from the child’s embryonic stage that never fully developed.About two-thirds of embryonal tumors form in the cerebellum, which is at the back of the brain near the spinal cord. These are called medulloblastomas
- Pilocytic astrocytomas (ages 5–10): As the most common type of pediatric brain tumor, astrocytomas account for about half of all childhood brain tumors. They form in supportive brain cells called astrocytes. Pilocytic astrocytomas, which are benign, are the most common astrocytoma.
- Malignant gliomas (ages 10–15): Tumors that develop from glial cells, a type of neural cell that makes up the brain’s supportive tissue, are called gliomas. There are two primary types of malignant gliomas — anaplastic astrocytomas and glioblastomas. They can form anywhere in the brain and are much more aggressive than pilocytic astrocytomas.
- Craniopharyngiomas and pituitary adenomas (ages 15–19): These slow-growing tumors develop in (pituitary adenomas) and around (craniopharyngiomas) the pituitary gland, which sits in the middle base of the brain. Even though they are typically benign, these tumors can cause neurological and endocrinological problems and affect vision.
Symptoms of brain tumors in children
The symptoms of pediatric brain tumors vary based on location of the tumor, tumor type and age of the child. Often, the first sign of a brain tumor in infants is an enlarged head. This is because the tumor takes up space and pushes against the plates of the skull that haven’t yet fused together.
Other signs of brain tumors in children include
- Nausea and vomitin
- Irritability and changes in moo
- Blurred visio
- Difficulty thinking or rememberin
- Changes in hearin
- Balance problem
The vast majority of children who experience these symptoms do not have brain tumors. Still, you should alert your child’s doctor to any new or worsening symptoms so they may be evaluated
What causes pediatric brain tumors?
Scientists are unsure what causes brain tumors in children. Some tumors develop as a result of abnormal genes that were either inherited from a parent or mutated before birth. Inherited syndromes, such as neurofibromatosis, tuberous sclerosis, Li-Fraumeni syndrome, can increase a child’s risk for brain tumors. However, this is rare. The vast majority of pediatric brain tumors occur in children without a family history of brain tumors
Children who have previously received radiation treatment to the head, such as for leukemia or cancer that metastasized to the brain, have an increased risk of developing brain tumors. Such tumors usually take about 10 to 15 years to develop following treatment.
Diagnosing brain tumors in children
If your child is displaying signs of a brain tumor, contact your pediatrician right away. Call 911 if your child has a seizure for the first time.
The first step to diagnosing a brain tumor is for your child’s doctor to take a medical history, including details of your child’s symptoms. This is followed by a neurological exam. Next, imaging will be ordered, usually an MRI. MRIs provide detailed images of the brain without using radiation. Occasionally, CT scan are used to obtain images of the brain, especially if a child is unable to remain still for long periods of time or if your doctor needs to have images of the blood vessels near a tumor.
Some brain tumors, including astrocytomas or brain stem gliomas, can be diagnosed with imaging alone. However, most brain tumors require biopsy (collecting a sample of the tumor) to determine their type and grade (how aggressive a tumor is). A biopsy can be obtained with a needle through a small incision or surgically. If surgery is used, your child’s neurosurgeon will remove the entire tumor or as much as the tumor as possible and send it to a lab for testing
Treatment for brain tumors in children
Pediatric brain tumors are treated in much the same ways brain tumors are treated in adults: with surgery, radiation therapy, chemotherapies and/or targeted therapy. The type of treatment your child receives will depend on several factors, including the location of the tumor, the tumor type and your child’s age.
Many slow-growing brain tumors can be treated with surgery alone. Malignant tumors and benign tumors that are causing serious neurological symptoms often require some combination of treatment in addition to surgery. Sometimes surgery is performed not to remove the tumor but to reduce its size to alleviate pressure on vital structures and alleviate symptoms, such as seizures or headaches.
Oftentimes, a craniotomy is needed to access brain tumors in children. This type of surgery involves temporarily removing a section of the skull to give the surgeon access to the area of the brain containing the tumor. The section of bone is then replaced at the completion of the surgery. Patients typically spend up to a week in the hospital following craniotomy with recovery lasting six to eight weeks.
The neurosurgeons at Rady Children’s have the skills and expertise to biopsy and remove brain tumors using minimally invasive techniques. Using specialized scopes, our neurosurgeons can remove pituitary adenomas with a keyhole approach designed to reduce recovery time and blood loss in children.
Rady Children’s neurosurgeon Michael Levy, M.D, is involved in research to develop new surgical techniques and technologies, including robotic and three-dimensional endoscopes, and high-definition 3-D monitors, enabling surgeons a better view inside the brain
Radiation therapy may be used following surgery to get rid of any remaining tumor cells or in place of surgery if the tumor is located in a particularly sensitive or difficult-to-access area of the brain. Because brain cells develop so rapidly in the first few years of life and are more sensitive to radiation, this treatment is generally only considered in children older than 3
Chemotherapy is most frequently used in conjunction with surgery and/or radiation therapy to treat more aggressive pediatric brain tumors. Sometimes chemotherapy is delivered directly to the tumor site during surgery, or it may be administered orally or intravenously at prescribed intervals. Chemotherapy may be used in place of radiation to treat brain tumors in children 3 and younger.
Targeted therapy is a newer type of drug therapy that interferes with specific proteins in the body that tumor cells rely on to grow and spread. Currently, only a couple of targeted therapies are approved for the treatment of pediatric brain tumors, and they’re most often used as a second line of defense when chemotherapy fails.
Long-term outlook for children with brain tumors
With a five year survival rate of 84, most children can expect to fully recover from pediatric brain tumors. Malignant brain tumors have a five-year survival rate of 76%. Of these, aggressive gliomas and certain embryonal tumors called atypical teratoid and rhabdoid tumors have the lowest survival rates of all pediatric brain tumors.
Even successful brain tumor treatment can cause side effects that last long after therapy has ended or may not show up until years later. Such side effects include developmental delays, cognitive disabilities, reproductive difficulties and an increased risk of other cancers. The pediatric physicians at Rady Children’s Hospital take these risks into account and weigh them carefully when designing your child’s treatment plan.
Treating pediatric brain tumors at Rady Children’s
Childhood brain tumors require highly specialized care to accurately diagnose and treat. It’s vital to seek out physicians with expertise in pediatric brain tumors to ensure your child receives the most effective treatment with the lowest risks of long-term side effects.