Brain Tumors

—most often the breasts, colon, kidneys, lungs, or skin—and

Description

Brain tumors vary considerably in their location in the brain, their speed

of growth, whether they are benign or malignant, and the specific symptoms

they produce. Brain tumors can cause damage by direct destruction

of normal brain tissue, by producing inflammation, or by growing so

large that they increase pressure inside the skull and interfere with the

functioning of other parts of the brain. Primary brain tumors can develop

within the brain tissue itself, within the meninges (the membranes that

cover and protect the brain and spinal cord), or within the nerves that

supply the brain and spinal cord.

In adults, the most common types of brain tumors are gliomas and

meningiomas. Gliomas, which account for 78 percent of malignant brain

tumors in adults, arise from glial cells, which are the supportive cells in

brain tissue that nourish nerve cells and hold them in place. Meningiomas

are tumors that arise in the meninges. Ninety percent of mengiomas

are benign; however, these tumors can still cause severe

complications and death because of their location.

The most widely used system for grading brain tumors was introduced

by the World Health Organization (WHO) in 1993. Grading
 ’s size, its location in the brain, and how fast

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symptoms for many years. They do not usually spread to other

parts of the brain and can often be removed completely by

surgery.

Grade I. These are slow-growing tumors that may not produce

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however, start to grow more rapidly and may spread into other

parts of the brain.

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spread rapidly into surrounding tissue. Their cells look different

from those in healthy surrounding tissue.

Grade III. Tumors in this category are always malignant and

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difficult to treat. Like Grade III tumors, their cells look very different

from healthy brain cells.

Grade IV. These tumors invade other tissues very quickly and are

Demographics

About 360,000 persons in the United States are living with a primary

brain tumor as of 2008, according to the National Institutes of Health,

with about 44,000 new cases of primary tumors reported each year. Primary

brain tumors account for about 2.5 percent of cancer deaths in the

United States each year

100,000 Americans die each year of metastatic brain tumors.

Brain tumors are the most common type of solid tumor in children,

and the second most common type of cancer in those below age fifteen.

Between 15 and 25 percent of all cancers in children are brain tumors. The

most common type of brain tumor in children is called a medullablastoma,

a highly malignant cancer that develops in the cerebellum (the part of the

brain just above the brain stem). This type of tumor is rare in adults.

Most types of brain tumors are equally common in men and women;

however, meningiomas occur slightly more often in women than in men.

Medulloblastomas are more common in boys than in girls. And although

most brain tumors are more common in Caucasians, meningiomas are

more common in African Americans than in members of other races.

Risk factors for brain tumors include:

—about 13,000 adults and children. About

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adults over age forty-five. Brain tumors in children are rare within

the first year of life; they occur most often in children between five

and eight years of age.

Age. Most brain tumors, whether benign or malignant, occur in

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of cancer.

Exposure to nuclear radiation or radiation therapy for another type

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Family history of brain tumors.

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Exposure to certain chemicals.

Causes and Symptoms

The causes of primary tumors of the brain were not completely understood

as of 2008; most researchers, however, think that defective genes are

responsible. Other theories include viruses, exposure to certain chemicals,

and disorders of the immune system.

Secondary brain tumors result from the spread of cancer that began

elsewhere in the body, with lung cancer the most common type. Brain

tumors can also develop from cancerous cells from the breast, kidneys,

colon, or skin. The cancerous cells break off from the primary tumor and

travel to the brain through the bloodstream.

The symptoms of a brain tumor may result from a primary tumor;

they may also be the earliest symptoms of a cancer that developed in

another organ. The most common warning signs include:

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person, or grow worse over time

Headaches, which may be most severe in the morning, new for the

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Nausea and vomiting

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vision

Problems with eyesight, such as seeing double or having blurred

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side of the body

Loss of sensation in an arm or leg, or weakness or paralysis on one

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Difficulty thinking or speaking, having trouble finding words

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Memory loss, confusion, or disorientation

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Seizures or convulsions

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Personality changes

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Hearing loss

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Difficulty walking normally, losing one’s balance, frequent falls

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Weakness and fatigue

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Symptoms of brain tumors in small children may include:

Hydrocephalus

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Increased head size

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In infants, bulging of the soft spot at the top of the skull

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Breathing problems or problems swallowing

Diagnosis

Headaches are the single most common symptom of brain tumors

in older children and adults, and the one most likely to bring

patients to see their doctor

severe or more frequent than those that the person has experienced

in the past.

Diagnosing a brain tumor requires a series of tests and examinations.

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doctor who specializes in treating disorders of the nervous system.

The neurologist will check the patient

reflexes, coordination, ability to speak clearly, changes in mood,

and ability to answer simple questions. These tests help to locate

the areas of the brain that might be affected by a tumor.

A family doctor will usually refer the patient to a neurologist, a’s balance, vision, hearing,

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magnetic resonance imaging (MRI), and positron emission tomography

(PET).

Imaging tests. These include computed tomography (CT) scans,

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electrical activity in different parts of the brain.

Electroencephalogram (EEG). This is a test that shows the levels of

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response to treatment for the tumor.

Blood and urine tests. These are used to monitor the patient’s

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rather than primary tumors.

Tests for cancer in other organs, since most brain cancers are metastatic

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removed for study under a microscope. For a brain tumor, the

biopsy may be done as part of an operation to remove the tumor

or as a separate procedure.

Biopsy. A biopsy is a procedure in which a sample of tissue is

Treatment

Treatment of brain tumors depends on their grade and location. Surgery

is usually the first stage. Removing as much of the tumor as possible

helps to relieve symptoms as well as slow the growth of the tumor. Some

Grade I tumors can be completely removed by surgery.

If the tumor is located in a part of the brain where it cannot be

entirely removed by surgery without risk to the brain stem or other parts

of the brain that control sight or hearing, or if the tumor is difficult to

distinguish from surrounding healthy tissue, the second line of treatment

is usually radiation therapy.

Chemotherapy can be given before or after radiation therapy. A

newer type of chemotherapy is combined with surgery. After removing

as much of the tumor as is possible and safe, the surgeon inserts wafers

containing slow-release anticancer drugs.

Treatment for brain tumors may also include rehabilitation therapy

for physical aftereffects and supportive therapy to help the patient

manage pain and the side effects of cancer treatment.

Prognosis

The prognosis of a brain tumor depends on whether the tumor is benign

or malignant, its location and grade, and the patient

health. Patients with Grade I tumors that can be entirely removed may

recover completely. The prognosis is poorer in very young children and

in elderly patients.

The five-year survival rate for patients with malignant primary

tumors is less than 10 percent even when these cancers are treated aggressively.

Most patients with metastatic brain cancer die as a result of the

primary cancer rather than from the metastases in the brain.

’s age and overall

Prevention

Primary brain tumors are not preventable. Some metastatic brain

tumors may be prevented by not smoking, which lowers the risk of lung

cancer, or by avoiding overexposure to the sun, which lowers the risk of

melanoma.

The Future

The number of brain tumors diagnosed each year in both adults and children

in the United States has been gradually increasing since the 1960s.

The reasons for this increase are not yet clear. Theories include toxins in

the environment, viruses that have not yet been identified, and heavy

long-term use of cell phones.

Some newer treatments for brain tumors that are currently considered

experimental include drugs that block the growth of blood vessels

in tumors, thus starving them of nutrients. Other new drugs are intended

to make radiation therapy more effective by sensitizing the tumor cells to

radiation. Gene therapy and biological therapy (which works by stimulating

the patient

of research in treating brain tumors.

’s immune system) are other rapidly expanding areas

SEE ALSO

cancer; Skin cancer

Alcoholism; Breast cancer; Colorectal cancer; Headache; Lung

For more information

BOOKS

Clark, Arda Darakjian.

Hains, Bryan C.

PERIODICALS

Parker-Pope, Tara.

York Times

fullpage.html?res=9802E1D61438F930A35755C0A96E9C8B63 (accessed

on September 6, 2008).

“Experts Revive Debate over Cell Phones and Cancer.” New, June 3, 2008. Available online at http://query.nytimes.com/gst/

WEB SITES

American Brain Tumor Association (ABTA).

online at http://www.abta.org/index.cfm?contentid=146 (accessed on

September 5, 2008). Page contains links to eight diagrams of the various

parts of the brain as well as several videos and audio recordings about brain

tumors.

American Brain Tumor Association (ABTA).

Available online at http://www.abta.org/index.cfm?contentid=12 (accessed

on September 5, 2008). Detailed information about specific types of brain

tumors can be found on the menu at the right.

Mayo Clinic.

health/brain-tumor/DS00281 (updated May 15, 2008; accessed on

September 5, 2008).

National Brain Tumor Foundation (NBTF).

online at http://www.braintumor.org/BrainTumorFAQ/ (accessed on

September 6, 2008).

National Institute of Neurological Disorders and Stroke (NINDS).

Diagrams and Videos. AvailableTumor and Treatment Info.Brain Tumor. Available online at http://www.mayoclinic.com/Brain Tumor FAQ. AvailableBrain and Spinal Cord Tumors: Hope through Research

online at http://www.ninds.nih.gov/disorders/brainandspinaltumors/

detail_brainandspinaltumors.htm (updated August 11, 2008; accessed

on September 5, 2008).

Neurosurgery Today.

org/what/patient_e/brain2.asp (updated March 2006; accessed on

September 6, 2008). This is the patient education website of the American

Association of Neurological Surgeons (AANS).
WORDS TO KNOW
Benign: Not cancerous.
Brain stem: The lowest part of the brain that connects
directly to the spinal cord. It controls such
basic life functions as breathing, blood pressure,
and heart beat.
Cerebellum: The part of the brain at the lower
back of the head just above the brain stem.
Glial cells: Cells in brain tissue that hold nerve cells
in place, supply them with oxygen and nutrients,
and remove dead nerve cells.
Glioma: A type of brain tumor that starts in the
glial cells.
Hydrocephalus: Abnormal buildup of cerebrospinal
fluid within the brain.
Malignant: Cancerous.
Medulloblastoma: A type of malignant brain
tumor that develops in the cerebellum. It is the
cancer.
Meninges (singular, meninx): The protective
membranes that cover the brain and
spinal cord.
Meningioma: A type of brain tumor that starts in
the meninges.
Metastasis (plural, metastases): The spread of a
cancer from its original location to other organs
or parts of the body.
Tumor: An abnormal mass or growth of tissue that
may be either cancerous or noncancerous.Brain Tumors. Available online at http://www.neurosurgerytoday.. AvailableBrain Tumors. Detroit, MI: Thomson Gale, 2006.Brain Disorders. Philadelphia: Chelsea House Publishers, 2006.—particularly if the headaches are unusuallyGrade II. These tumors are also relatively slow-growing. They can,

is based on the tumor

it grows.

Brain Tumors

Definition

Brain tumors are abnormal growths of tissue within the brain; about

150 different types have been identified. Brain tumors can be primary or

secondary. Primary tumors are tumors that start to grow within the brain.

Some are benign, meaning that they are not cancerous. Other primary

tumors are malignant, or cancerous. Primary brain tumors are less common

than secondary tumors, with most occurring in adults rather than children.

Secondary or metastatic tumors are cancers that start in other

organs

then spread to the brain. Most brain tumors are metastatic cancers

rather than primary tumors; about a quarter of all adults being treated

for cancer in the United States eventually develop metastatic brain

tumors. It is rare, however, for primary tumors of the brain to spread

to other parts of the body.