What is a Brain Tumor?
A brain tumor occurs when there is a genetic change in normal brain cells. The cells grow and divide and become a mass of abnormal cells. These cells eventually become a tumor.
Brain tumors are the most common solid tumors in children and the second most common cause of childhood cancer (behind leukemia). Each year, about 4,000 children and teens in the US are diagnosed with a primary brain tumor (a tumor that starts in the brain).
Brain tumors that occur in infants and children are unlike brain tumors that occur in adults. They contain different cell types and need different treatment strategies. That is why children with a brain tumor need to receive care at a pediatric hospital with a specialized cancer program.
What is the Difference Between Benign and Malignant Tumors?
Brain tumors can be “benign” or “malignant.” A “benign” tumor does not contain cancer cells. If it is removed completely, it usually doesn’t come back. Most benign brain tumors don’t move into nearby tissue. They don’t often spread to other parts of the brain or spinal cord (metastasize). But they can cause symptoms like cancerous tumors depending on their size and location in the brain. Benign tumors should be followed carefully to make sure they don’t come back, even after they are removed..
Malignant brain tumors contain cancer cells. They are usually fast-growing and move into surrounding tissue. They can spread to other parts of the brain or spine. They don’t usually spread to other parts of the body. Malignant tumors grow more aggressively and need to be treated with chemotherapy or radiation in addition to surgery. The tumor may come back after treatment.
Benign and malignant brain tumors can have similar symptoms. They may cause damage that affects the brain’s vital functions.
Causes of Brain Tumors in Children
Brain tumors in children are not preventable. Experts don’t fully understand why they occur in children. Some factors increase a child’s risk of developing a brain tumor. These include having:
- A family history of brain tumors.
- Certain genetic conditions such as neurofibromatosis, von Hippel-Lindau disease Li-Fraumeni syndrome, and retinoblastoma.
- Previous radiation therapy for a brain tumor.
Types of Brain Tumors in Children
Many types of brain tumors can occur in children. The most common type of brain tumor is glioma. These tumors begin from glial cells. These cells support functions of the nervous system. Gliomas can be high-grade or low-grade. High-grade gliomas spread more quickly and aggressively than low-grade gliomas.
Examples of gliomas are astrocytomas, ependymomas and optic nerve gliomas. .
- Astrocytomas typically occur in the cerebellum. This is the area of the brain that plays a role in most of the body’s physical movement.
- Ependymomas represent 5-10% of childhood brain tumors. They usually begin in the lining of the ventricles (large open structures deep in the brain) or in the spinal cord, near the cerebellum. Ependymomas can be slow growing compared to other brain tumors.
- Optic nerve gliomas usually start in the optic nerve. This nerve sends messages from the eyes to the brain. They can cause vision issues and problems with hormones since they occur at the base of the brain where hormone control is located.
Embryonal tumors typically occur in babies and young children. They start in the brain’s fetal (embryonic) cells and tend to be fast-growing and aggressive. Examples of embryonal tumors are atypical teratoid/rhabdoid tumors and medulloblastoma.
- Atypical teratoid / rhabdoid tumors (ATRT) are most likely to occur in infants and very young children. They often occur in the cerebellum (which controls movement, balance and posture) or the brain stem (which controls breathing, heart rate and muscles used to see, hear, move, talk and eat).
- Medulloblastoma commonly occurs in children and young adults. These tumors usually appear near the middle of the cerebellum. It tends to grow quickly, blocking cerebrospinal fluid from draining. This causes high intracranial pressure, with symptoms such as headaches, vomiting and nausea. Medulloblastoma used to be considered a type of primitive neuroectodermal tumor (PNET). But that term is no longer used.
Mixed Neuronal-Glial Tumors
Another category of brain tumors is mixed neuronal-glial tumors. These tumors have abnormal neuron cells and abnormal glial cells. Examples of mixed neuronal-glial tumors are ganglioglioma, subependymal giant cell tumors and pleomorphic xanthoastrocytoma.
- Ganglioglioma are usually small and noncancerous. They may develop slowly.
- Subependymal giant cell tumors may occur in children and adults who have a condition called tuberous sclerosis.
- Pleomorphic xanthoastrocytoma are often diagnosed in children between 10-20 years old. They may be benign (noncancerous) or malignant (cancerous). They may spread to other parts of the brain and spine.
Additional Types of Brain Tumors that Affect Children
- Choroid plexus tumors typically occur in children age 2 and younger. They can be cancerous (choroid plexus carcinoma) or noncancerous (choroid plexus papilloma). Both choroid plexus tumor types can affect functions of nearby brain structures.
- Diffuse midline glioma (DMG) (formerly known as diffuse intrinsic pontine glioma, or DIPG) is a type of brain tumor that comes from glial cells. Normally glial cells surround, protect, and support other cells in the brain. But in a tumor, they continue to grow without stopping. This may lead to compression (squeezing) and hurting other parts of the brain.
- Germ cell tumors include germinoma, teratoma, embryonal carcinoma and yolk-sac tumors.
- Meningeal tumors, such as meningioma, come from the membranes (meninges) around the brain and spinal cord. These tumors tend to be noncancerous and slow growing. They may press on nearby brain tissue, nerves or vessels as they grow. This can cause headaches, seizures, weakness on one side of the body and problems with vision and communication.
- Tumors arising from non-neuroepithelial tissue occur in the tissues covering the brain and spinal cord. One example is craniopharyngiomas. These types of tumors may push on nerves, blood vessels or brain structures around the pituitary gland. Another example is pineal region tumors, which occur near the pineal gland.
Signs & Symptoms of Brain Tumors in Children
The brain controls learning, memory, the senses, emotions, movement and coordination. As a brain tumor grows, it can affect any of these functions, depending on its type, size and location.
Symptoms may occur when the tumor presses on a nerve or damages certain parts of the brain. Symptoms may also occur when a tumor blocks cerebrospinal fluid that is supposed to flow through and around the brain.
The most common symptoms of a brain tumor in children include:
- Headache, especially in the middle of the night or early in the morning
- Nausea or vomiting
- Problems with walking or balance
- Changes in speech, vision or hearing
- Early puberty
- Numbness or tingling in the arms or legs
- Poor growth
- Problems with memory
- Changes in mood, personality or ability to concentrate
- Seizures, which can include jerking or twitching muscles or staring into space
The symptoms of a brain tumor can also be symptoms of many other, less serious medical issues. They can be easy to miss early on. Some parents say they saw subtle signs for weeks or months before their child was diagnosed with a brain tumor. Others report that the symptoms came on suddenly. If you have concerns about your child’s symptoms, make an appointment with their primary care doctor.
Diagnosing Brain Tumors in Children
Two types of doctors typically diagnose children with brain tumors.
- A pediatric oncologist — A doctor specializing in diagnosing and treating tumors and cancers in children.
- A pediatric neuro-oncologist—A doctor specializing in diagnosing and treating brain tumors in children.
An accurate diagnosis is essential. It helps the care team develop a personalized treatment plan.
Several tests can help the doctor determine whether a brain tumor is present. These can include:
- A neurological exam — Tests your child’s reflexes, muscle strength, sensation, eye and mouth movement, coordination and alertness.
- Imaging tests — Detailed pictures of the brain’s structures and possible signs of a tumor. Imaging tests may include:
- Computed tomography (CT) scans
- Magnetic resonance imaging (MRI)
- Nuclear medicine imaging, such as positron emission tomography (PET)
- Lumbar puncture / spinal tap — Involves using a needle to remove a small amount of cerebrospinal fluid (the fluid surrounding the brain and spinal cord) for testing.
- Lab tests — Help identify the cell type and understand how aggressive the cancer is. A neurosurgeon can remove a tumor tissue during surgery. They may also use a stereotactic needle biopsy, which is less invasive than surgery.
- Genetic tests — Test results may help the care team personalize the treatment plan based on the tumor’s genetic markers.
Treating Brain Tumors in Children
Surgery often is the first step in treating brain tumors in children. The goal is to remove as much of the tumor as possible without damaging healthy brain tissue. Sometimes, tumors are small and can be removed without too much difficulty. But if the tumor is large or located close to sensitive regions of the brain, surgery involves more risk. The neurosurgeon may only be able to remove some of the tumor or decide not to do surgery.
Pediatric neurosurgeons use advanced techniques to remove brain tumors in even the most difficult-to-access locations of the brain. These neurosurgeons use minimally invasive procedures to avoid harming areas of the brain that control speech, movement and other vital functions. For example, they use endoscopic endonasal surgery to access tumors located at the bottom of the skull (also called skull-base tumors). This means going through the nostrils rather than the skull to remove the tumor.
Other treatments for brain tumors include:
- Chemotherapy — Anticancer drugs that attack tumor cells.
- Stem cell transplant (also referred to as bone marrow transplant) — A stem cell transplant involves preserving a patient’s healthy bone marrow and giving high-dose chemotherapy. The healthy cells are then returned to the patient to help encourage the recovery of the immune system.
- Proton therapy is one of the most precise and advanced forms of radiation therapy that destroys cancer cells while minimizing damage to nearby healthy tissues and organs.
- Shaped-beam stereotactic radiation therapy delivers high doses of radiation using custom-shaped beams to difficult-to-reach areas.
- Intensity-modulated radiation therapy allows physicians to modify the intensity of radiation beams and deliver radiation that conforms to the tumor’s shape.
- Immunotherapy is designed to help the body’s own immune system fight cancer cells.
- Targeted antibody therapies are drugs that bind to antibodies found on cancer cells. This “tags” the mutations (changes) or markers on cancer cells so that the immune system can better recognize and destroy them.
Scientists are continually discovering new ways to treat brain tumors in children and minimize the side effects of treatment. Sometimes, experimental therapies offer the best hope for a cure. If the pediatric neuro-oncologist believes your child would benefit from experimental therapies, they will talk to you about joining a clinical research trial.
The care team will follow your child closely to monitor their symptoms, treatment response, side effects and emotional well-being. They may recommend therapies that provide additional support, such as:
- Child life therapy
- Pain management
- Holistic therapies, including massage therapy, reflexology and yoga
- Music therapy
During and after treatment, the neuro-oncology team may recommend physical and occupational therapy to help your child regain lost motor skills and muscle strength. If the cancer or treatment affects your child’s speech or language abilities, a speech-language pathologist can help them regain their skills.
What is the Prognosis for Children with a Brain Tumor?
The long-term outlook for children with cancer depends on many factors, including:
- The tumor type, size and location
- How advanced the disease was at diagnosis
- The child’s age and overall health
Prompt medical attention and aggressive therapy are essential for the best prognosis. When treatment is successful, families need to think about the chance that the cancer and cancer treatment may cause health problems later in life. These can include an increased risk for heart, lung and kidney disease, intellectual challenges, fertility issues or secondary cancers. A supportive brain tumor survivorship program can provide medical care and psychosocial support through adulthood.