Cancers of the brain
and nervous system are the most common type of childhood cancer. When discovered
early, these cancers often can be cured.
There are many different types of brain and nervous
system cancers, and doctors categorize them based on where the tumors are, the type
of cells involved, and how quickly they grow.
Here are some of the most common types of brain and nervous system cancers.
Brain Stem Glioma
The brain stem, located deep in the back of the brain, is made up of the midbrain,
pons, and medulla. These parts of the brain control the body's autonomic nervous system
(which is responsible for controlling body processes like breathing, digesting, sweating,
A tumor that develops in any area of the brain stem is called a brain stem
glioma. Tumors in the pons are called pontine gliomas (or
diffuse intrinsic pontine gliomas, DIPG). Pontine gliomas are the most common brain
stem gliomas, and also the most difficult to treat. Tumors
in the midbrain and medulla are less common, but usually easier to treat.
Symptoms of a pontine glioma may start suddenly and get worse very quickly. These
turning in of one eyeball
drooping of the eyelid or one side of the face
trouble speaking and walking
nausea and vomiting
Midbrain tumors may cause eye symptoms similar to pontine gliomas,
along with headaches and vomiting. This is due to increased pressure in the head caused
by the flow of cerebrospinal fluid being blocked. (Cerebrospinal fluid is a clear,
colorless liquid that delivers nutrients to the brain and spinal cord and "cushions"
them for protection.)
Tumors of themedulla cause swallowing problems
and limb weakness.
Because the brain stem is an area of the brain where surgery can be difficult,
brain stem gliomas are often treated with radiation
therapy (high-energy X-rays that kill cancer cells) and/or chemotherapy.
Ependymomas are tumors that develop in the brain cells that make cerebrospinal
fluid. They often develop in children under age 5.
Ependymomas are classified according to their location, and most don't spread (metastasize)
to other areas of the body. Those located in the top part of the brain are called
supratentorial ependymomas. Supratentorial ependymomas can cause
nausea, vomiting, and headaches from increased pressure within the brain, as well
as weakness and vision problems.
Ependymomas also can be found in the spinal
Tumors in the back of the brain are more common. These are called infratentorial
ependymomas. They can cause nausea, vomiting, and headache, and trouble with coordination.
Supratentorial ependymomas sometimes can be
cured by surgery alone. Infratentorial ependymomas usually need much more aggressive
treatment with surgery, chemotherapy, and radiation.
Primitive Neuroectodermal Tumor (PNET)
PNETs are a group of tumors that can happen anywhere in the brain. Types of PNETs
include medulloblastoma, posterior fossa PNET, supratentorial
PNET, and pineoblastoma. All of these tumors can metastasize
(spread) through the cerebrospinal fluid that surrounds the brain and the spinal cord.
PNET symptoms generally depend on their size and location, but common ones include:
headaches, nausea, and vomiting (especially in the morning) caused by increased
pressure in the head
weakness in the arms and legs
trouble with balance and coordination
Even though PNETs require aggressive treatment (including surgery, chemotherapy,
and radiation therapy), recent medical advances have made a cure possible for most
children who have them.
Optic Pathway Glioma
The optic pathway sends signals to the brain about what the eye sees. A tumor that
develops along this pathway is called an optic pathway glioma.
Optic pathway gliomas mostly affect kids under age 10. People with neurofibromatosis
type 1 (a genetic condition that causes tumors to grow on nerve tissue) have an increased
risk of developing them.
The most common symptom of an optic pathway glioma is progressive vision loss.
With slow-growing tumors, this may be hard to spot at first — especially in
younger children who can't describe what they're seeing. With fast-growing tumors
(or less aggressive ones that have reached a large size), vision problems become apparent
Kids also may start tilting their heads or having what appear to be developmental
delays like clumsiness during walking, speech difficulties, or behavior changes. A
condition called nystagmus (when the eyeballs appear to "jitter"
involuntarily) also can happen. Sometimes, a tumor that's pressing on the pituitary
gland can cause growth problems.
Optic pathway gliomas are usually treated with chemotherapy, although radiation
also can be used. Most kids do well with treatment.
Astrocytomas develop from star-shaped brain cells known as astrocytes. Astrocytomas
come in four major subtypes: pilocytic astrocytoma (grade I), fibrillary astrocytoma
(grade II), anaplastic astrocytoma (grade III), and glioblastoma multiforme (grade
Low-grade astrocytomas (grades I and II) in kids are highly curable
because they usually grow slowly, don't spread, and are fairly easy to remove unless
found in areas where surgery can be difficult (like the optic nerve). After surgery,
there's a chance that chemotherapy or radiation won't be needed.
High-grade astrocytomas (grades III and IV) are more aggressive,
more invasive, and harder to treat. Treatment usually includes surgery, chemotherapy,
Side Effects of Cancer Treatment
Kids who undergo radiation therapy or chemotherapy for a brain tumor often have
side effects. These
can include fatigue (being very tired), nausea, vomiting, and hair loss. These
side effects go away when treatment ends.
Long-term effects of treatment, called "late
effects," also can happen. These include learning
disabilities, seizures, growth disorders, hearing and vision problems, and
the possibility of developing a second cancer, including a second brain tumor.
Because these problems sometimes aren't noticed until years after treatment, careful
observation and regular screenings are needed to catch them as early as possible.