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300 Longwood Avenue
Boston, MA 02115
(617) 355-6000
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My Child Has:
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Brain Tumors
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Childhood Brain Tumors
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Brain tumors are the most common solid tumors in children. Approximately 2,200 children and adolescents in the United States are diagnosed with a brain tumor each year. Today, more than half of all children diagnosed with a brain tumor will be cured of the disease. However, because of their location, the treatment for brain tumors is particularly complex. Furthermore, many children who are treated for brain tumors experience significant long-term problems, such as changes in intellectual and motor function. Consequently, these children require ongoing assessment and specialized care to help them function at school and throughout life as best as possible.
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The central nervous system (CNS) consists of the brain and spinal cord. The brain is an important organ that controls thought, memory, emotion, touch, motor skills, vision, respiration, temperature, hunger, and every process that regulates our body. The brain can be divided into the cerebrum, the brainstem, and the cerebellum:
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- cerebrum (supratentorial, or front of brain) - composed of the right and left hemispheres. Functions of the cerebrum include: initiation of movement, coordination of movement, temperature sensitivity, touch, vision, hearing, judgment, reasoning, problem-solving, emotions, and learning.
- brainstem (midline, or middle of brain) - includes the midbrain, the pons, and the medulla. Functions of this area include: movement of the eyes and mouth, relaying sensory messages (i.e., heat, pain, sound), hunger, respiration, consciousness, cardiac function, body temperature, involuntary muscle movements, sneezing, coughing, vomiting, and swallowing.
- cerebellum (infratentorial, or back of brain) - located at the back of the head, its function is to coordinate voluntary muscle movements and to maintain posture, balance, and equilibrium.
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The spinal cord contains bundles of nerve fibers that emanate from the brain and spread out to all parts of the body.
To protect all of these structures, the brain and spinal cord are encased in solid bones wrapped in a layer of tissue (meninges). In addition, the brain floats in a liquid called cerebral spinal fluid, which acts as a shock absorber. This fluid is made in small hollows within the brain, called ventricles.
The brain is connected to the face by twelve specific cranial nerves that control most eye, face and tongue movements.
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Types of brain tumors
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Although we do not know why one person gets brain cancer while another does not, we know it is not caused by drinking alcohol during pregnancy, watching television, drinking diet sodas or not eating enough vegetables. In general, brain tumors arise when a single cell makes a mistake.
The majority of brain tumors have abnormalities of genes involved in cell cycle control, causing uncontrolled cell growth. These abnormalities are caused by alterations directly in the genes, or by chromosome rearrangements which change the function of a gene.
In each cell are very long molecules known as chromosomes, which contain the genetic directions that determine such things as our height, hair color and the shape of our face. These chromosomes are a collection of genes that dictate to cells what they are to become (bone cells, brain cells, etc.) and where they will be located.
Genes also contain information that tells a cell when to divide, when to stop, or when to die. Most tumors are thought to arise when these control signals are accidentally damaged. There are many ways to damage a cell's control. Most pediatric brain tumors are thought to arise from an accident during normal cellular division that creates a mutant gene. A mutated gene may tell a cell to continue dividing, like having your foot stuck on the gas pedal, or it may not tell a cell to stop, like having no brakes. Either way, the cells divide in a way that they shouldn't, creating a tumor.
Most pediatric brain tumors require mutations in several genes. If you have your foot stuck on the gas, for instance, but the brakes still work, you don't have a problem. Cells have safeguards that should keep them from dividing or cause them to die if something has gone wrong. Cancer can't occur unless those safeguards fail.
Everyone has two copies of each gene, one from each parent. In order for a tumor to grow, both copies must be damaged. Genes are made up of DNA. Sometimes the cell kicks out large parts of the DNA, perhaps to get rid of some of the brake' genes. Other times, it amplifies large parts of the genetic material so that many more chromosomes than normal are present. Trying to find which genes have been mutated to allow a tumor to grow is like finding a needle in a haystack, but researchers all over the world are looking very hard.
Patients with certain genetic conditions (i.e. neurofibromatosis, von Hippel-Lindau disease, Li-Frameni syndrome, and retinoblastoma) also have an increased risk of developing tumors of the central nervous system. There have also been some reports of children in the same family who develop brain tumors even without any of these genetic syndromes.
Research has been investigating parents of children with brain tumors and their past exposure to certain chemicals. Some chemicals may change the structure of a gene that protects the body from diseases and cancer. Workers in oil refining and rubber manufacturing, and chemists have a higher incidence of certain types of tumors. Which, if any, chemical toxin is related to this increase in tumors is unknown.
Children who have received radiation therapy to the head as part of prior treatment for other malignancies are also at an increased risk for new brain tumors.
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Tumors are classified (named) according to a number of different principles. In the old days, tumors were named for how they looked under the microscope and often their location in the brain. As researchers have come to understand more about the cellular and molecular processes that separate the different groups of tumors, the names have changed. This is important because many tumors have more than one name. To make it even more confusing, different tumors can have the same name. Thus, it is critical to know not just the name that the pathologist (a doctor who specializes in analyzing body tissues on a cellular level) gave to the tumor, but also which staging (or naming) system was used.
Children's Hospital, Dana-Farber Cancer Institute, and Brigham and Women's Hospital, use the World Health Organization (WHO) classification system for most pediatric brain tumors. This system incorporates:
- the microscopic (histologic) appearance of the cells, which indicates what type of brain cell the tumor arose from
- the tumor's location within the brain
- the appearance of the cells themselves (anaplasia), which indicates how "aggressive " the cells are likely to be
Many pediatric brain tumors have a second important component to them after their name, which is the grade. This is an estimation of how aggressive or malignant a particular type of tumor is. For example, glial tumors (also called astrocytomas) come in four grades. Grade I is the lowest, meaning that these tumors tend to, on average, be less aggressive then their grade IV counterparts, which are usually highly malignant and very difficult to treat. The grade is based on a number of factors, such as how many cells are dividing at any one time or how atypical the cells look (compared to their normal counterpart).
Tumors can be classified as benign or malignant. Benign tumors are usually those that remain well encapsulated, without the ability to spread either locally or to distant sites. Complete removal of the tumor is usually sufficient treatment.
Malignant tumors are those that can spread and invade other areas, so that even if the tumor is surgically removed, other cells will grow back, continuing to invade. The classification of benign or malignant brain tumor can be very misleading. In particular, benign tumors can be fatal if they press on certain vital areas, or if they cannot be removed and continue to grow. All tumors of the central nervous system are dangerous.
Classifications are based on an analysis of the sample of the tumor obtained through a biopsy, a surgical procedure through which a small sample of the tumor is removed for examination. It is possible that a sample from a biopsy or partial removal may have missed areas of more aggressive disease, resulting in an under-estimation of the tumor's true nature.
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The following are the most common symptoms of a brain tumor. However, each child may experience symptoms differently. Symptoms vary depending on size and location of tumor.
Many symptoms are related to increased pressure in or around the brain. There is no spare space in the skull for anything except the delicate tissues of the brain and its fluid. Any tumor, extra tissue, or fluid can cause pressure on the brain and result in:
- increased intracranial pressure (ICP) - caused by extra tissue or fluid in the brain. Pressure may increase because one or more of the ventricles that drain cerebrospinal fluid (CSF, the fluid that surrounds the brain and spinal cord) has been blocked, causing the fluid to be trapped in the brain. Increased ICP can cause:
- headache
- vomiting (usually in the morning)
- nausea
- personality changes
- irritability
- drowsiness
- depression
- decreased cardiac and respiratory function, and eventually coma if not treated
Other symptoms vary depending upon which part of the brain the tumor affects:
- Symptoms of brain tumors in the cerebellum (back of brain), called infratentorial tumors, may include:
- increased intracranial pressure (ICP)
- vomiting (usually occurs in the morning without nausea)
- headache
- uncoordinated muscle movements
- problems walking (ataxia)
- Brain tumors in the brainstem (middle of brain) may compress nerves and cause symptoms that may include:
- seizures
- endocrine problems (diabetes and/or hormone regulation)
- visual changes or double vision
- headaches
- paralysis of nerves/muscles of the face, or half of the body
- respiratory changes
- increased intracranial pressure (ICP)
- clumsy, uncoordinated walk
- hearing loss
- personality changes
- Symptoms of brain tumors in the lower part of the brain often press on the cerebellum. Symptoms may include:
- problems walking (ataxia)
- increased intracranial pressure (ICP)
- loss of control of the nerves/muscles of the face
- Symptoms of brain tumors in the cerebrum (front of brain), called supratentorial tumors, may include:
- seizures
- visual changes
- slurred speech
- paralysis or weakness on half of the body or face
- increased intracranial pressure (ICP)
- drowsiness and/or confusion
- personality changes/impaired judgment
- short-term memory loss
- gait disturbances
- communication problems
- Symptoms of brain tumors in the optic pathway (eyes) may include:
- visual problems
- puberty or growth abnormalities
- Symptoms of tumors in the spine (usually spreading from a tumor at a higher point on the spinal cord) may include:
- bowel or bladder dysfunction
- back pain
- focal weakness or sensory loss, depending on where in the spine the disease is located
The symptoms of a brain tumor may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
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The different types of brain tumors include those listed below. For more information on each, including diagnosis and treatment, click on the type of tumor.
choroid plexus tumor
craniopharyngioma
dysembryoplastic neuroepithelial tumor
ependymoma
germ cell tumors (brain)
high-grade gliomas
- anaplastic astrocytoma
- diffuse pontine glioma (brain stem glioma)
- glioblastoma multiforme
- gliomatosis cerebri
low-grade gliomas
- cerebellar pilocytic astrocytoma
- cervico-medullary astrocytoma
- ganglioglioma
- oligodendroglioma
- optic pathway glioma
- pleomorphic xanthoastrocytoma
- tectal glioma
- thalamic/hypothalamic astrocytoma
medulloblastoma
meningioma
primitive neuroectodermal tumors (PNET)
rhabdoid tumor
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Prognosis greatly depends on:
- the type of tumor
- the extent of the disease
- size and location of the tumor
- presence or absence of metastasis
- the tumor's response to therapy
- the age and overall health of your child
- your child's tolerance of specific medications, procedures, or therapies
- new developments in treatment
As with any cancer, prognosis and long-term survival can vary greatly from individual to individual. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with a brain tumor. Side effects of radiation and chemotherapy, as well as second malignancies, can occur in survivors of brain tumors.
Rehabilitation for lost motor skill and muscle strength may be required for an extended amount of time. Speech therapists and physical and occupational therapists may be involved in some form of rehabilitation. More research is needed to improve treatment, decrease side effects of the treatment for this disease, and develop a cure. New methods are continually being discovered to improve treatment and to decrease side effects. For more information on the research, see the Brain Tumor Program.
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One of the major goals of the Pediatric Brain Tumor Program is to maximize the long-term function of each child. This is achieved through multidisciplinary monitoring and interventions, as needed, in wide range of areas, including:
- intellectual function
- endocrine evaluation and treatment
- neurologic assessment
- psychosocial care
- hearing, vision
- ovarian dysfunction
- motor function
Children treated for brain tumors frequently have changes in intellectual and motor function that affect their learning. Among several programs that address their special needs is the Back to School Program, which provides a variety of individualized services to ease children's return to school and maximize their ability to have a successful learning experience.
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The information on this website should not be taken as medical advice,
which can only be given to you by your personal health care professional. |
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Copyright © Children's Hospital Boston. All rights reserved. |
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