Brain Cancer
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A tumor that begins in the brain is called a primary brain
tumor. In children, most brain tumors are primary tumors. In adults, most
tumors in the brain have spread there from the lung, breast, or other parts
of the body. When this happens, the disease is not brain cancer. The tumor
in the brain is a secondary tumor. It is named for the organ or the tissue in which it began.
Treatment for secondary brain tumors depends on where the cancer started
and the extent of the disease.
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The brain is a soft, spongy mass of tissue. It is protected by the
bones of the skull and three thin membranes called meninges. Watery fluid
called cerebrospinal fluid cushions the brain. This fluid flows through spaces
between the meninges and through spaces within the brain called ventricles.
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The brain and nearby structures
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A network of nerves carries messages back and forth between the brain
and the rest of the body. Some nerves go directly from the brain to the eyes,
ears, and other parts of the head. Other nerves run through the spinal cord
to connect the brain with the other parts of the body. Within the brain and
spinal cord, glial cells surround nerve cells and hold them in place.
The brain directs the things we choose to do (like walking and talking)
and the things our body does without thinking (like breathing). The brain
is also in charge of our senses (sight, hearing, touch, taste, and smell),
memory, emotions, and personality.
The three major parts of the brain control different activities:
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Cerebrum—The cerebrum is the largest
part of the brain. It is at the top of the brain. It uses information
from our senses to tell us what is going on around us and tells our body
how to respond. It controls reading, thinking, learning, speech, and
emotions.
The cerebrum is divided into the left and right cerebral hemispheres,
which control separate activities. The right hemisphere controls the
muscles on the left side of the body. The left hemisphere controls the
muscles on the right side of the body.
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Cerebellum—The cerebellum is under
the cerebrum at the back of the brain. The cerebellum controls balance
and complex actions like walking and talking.
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Brain Stem—The brain stem connects
the brain with the spinal cord. It controls hunger and thirst. It also
controls breathing, body temperature, blood pressure, and other basic
body functions.
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Major parts of the
brain
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Cancer begins in cells, the building blocks that make up tissues.
Tissues make up the organs of the body.
Normally, cells grow and divide to form new cells as the body needs
them. When cells grow old, they die, and new cells take their place.
Sometimes this orderly process goes wrong. New cells form when the
body does not need them, and old cells do not die when they should. These
extra cells can form a mass of tissue called a growth or tumor.
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Brain tumors can be benign or malignant:
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Doctors sometimes group brain tumors by grade—from low grade
(grade I) to high grade (grade IV). The grade of a tumor refers to the
way the cells look under a microscope. Cells from high-grade tumors look
more abnormal and generally grow faster than cells from low-grade tumors.
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Tumors that begin in brain tissue are known as primary tumors
of the brain. (Information about secondary brain tumors appears in the
following section.) Primary brain tumors are named according to the type
of cells or the part of the brain in which they begin.
The most common primary brain tumors are gliomas. They begin
in glial cells. There are many types of gliomas:
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Astrocytoma—The tumor arises from star-shaped glial
cells called astrocytes. In adults, astrocytomas most often arise
in the cerebrum. In children, they occur in the brain stem, the cerebrum,
and the cerebellum. A grade III astrocytoma is sometimes called an
anaplastic astrocytoma. A grade IV astrocytoma is usually called
a glioblastoma multiforme.
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Brain stem glioma—The tumor occurs in the lowest part
of the brain. Brain stem gliomas most often are diagnosed in young
children and middle-aged adults.
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Ependymoma—The tumor arises from cells that line the
ventricles or the central canal of the spinal cord. They are most
commonly found in children and young adults.
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Oligodendroglioma—This rare tumor arises from cells
that make the fatty substance that covers and protects nerves. These
tumors usually occur in the cerebrum. They grow slowly and usually
do not spread into surrounding brain tissue. They are most common
in middle-aged adults.
Some types of brain tumors do not begin in glial cells. The
most common of these are:
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Medulloblastoma—This tumor usually arises in the cerebellum.
It is the most common brain tumor in children. It is sometimes called
a primitive neuroectodermal tumor.
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Meningioma—This tumor arises in the meninges. It usually
grows slowly.
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Schwannoma—A tumor that arises from a Schwann cell.
These cells line the nerve that controls balance and hearing. This
nerve is in the inner ear. The tumor is also called an acoustic neuroma.
It occurs most often in adults.
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Craniopharyngioma—The tumor grows at the base of the
brain, near the pituitary gland. This type of tumor most often occurs
in children.
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Germ cell tumor of the brain—The tumor arises from
a germ cell. Most germ cell tumors that arise in the brain occur
in people younger than 30. The most common type of germ cell tumor
of the brain is a germinoma.
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Pineal region tumor—This rare brain tumor arises in
or near the pineal gland. The pineal gland is located between the
cerebrum and the cerebellum.
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When cancer spreads from its original place to another part
of the body, the new tumor has the same kind of abnormal cells and the
same name as the primary tumor. Cancer that spreads to the brain from
another part of the body is different from a primary brain tumor. When
cancer cells spread to the brain from another organ (such as the lung
or breast), doctors may call the tumor in the brain a secondary tumor
or metastatic tumor. Secondary tumors in the brain are far more common
than primary brain tumors.
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No one knows the exact causes of brain tumors. Doctors can
seldom explain why one person develops a brain tumor and another does
not. However, it is clear that brain tumors are not contagious. No one
can "catch" the disease from another person.
Research has shown that people with certain risk factors are
more likely than others to develop a brain tumor. A risk factor is anything
that increases a person's chance of developing a disease.
The following risk factors are associated with an increased
chance of developing a primary brain tumor:
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Being male—In general, brain tumors are more common
in males than females. However, meningiomas are more common in females.
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Race—Brain tumors occur more often among white people
than among people of other races.
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Age—Most brain tumors are detected in people who are
70 years old or older. However, brain tumors are the second most
common cancer in children. (Leukemia is the most common childhood
cancer.) Brain tumors are more common in children younger than 8
years old than in older children.
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Family history—People with family members who have
gliomas may be more likely to develop this disease.
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Being exposed to radiation or certain chemicals at
work:
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Radiation—Workers in the nuclear industry
have an increased risk of developing a brain tumor.
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Formaldehyde—Pathologists and embalmers who
work with formaldehyde have an increased risk of developing brain
cancer. Scientists have not found an increased risk of brain
cancer among other types of workers exposed to formaldehyde.
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Vinyl chloride—Workers who make plastics may
be exposed to vinyl chloride. This chemical may increase the
risk of brain tumors.
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Acrylonitrile—People who make textiles and
plastics may be exposed to acrylonitrile. This exposure may increase
the risk of brain cancer.
Scientists are investigating whether cell phones may cause
brain tumors. Studies thus far have not found an increased risk of brain
tumors among people who use cell phones.
Scientists also continue to study whether head injuries are
a risk factor for brain tumors. So far, these studies have not found
an increased risk among people who have had head injuries.
Most people who have known risk factors do not get brain cancer.
On the other hand, many who do get the disease have none of these risk
factors. People who think they may be at risk should discuss this concern
with their doctor. The doctor may be able to suggest ways to reduce the
risk and can plan an appropriate schedule for checkups.
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The symptoms of brain tumors depend on tumor size, type, and
location. Symptoms may be caused when a tumor presses on a nerve or damages
a certain area of the brain. They also may be caused when the brain swells
or fluid builds up within the skull.
These are the most common symptoms of brain tumors:
- Headaches (usually worse in the morning)
- Nausea or vomiting
- Changes in speech, vision, or hearing
- Problems balancing or walking
- Changes in mood, personality, or ability to concentrate
- Problems with memory
- Muscle jerking or twitching (seizures or convulsions)
- Numbness or tingling in the arms or legs
These symptoms are not sure signs of a brain tumor. Other
conditions also could cause these problems. Anyone with these symptoms
should see a doctor as soon as possible. Only a doctor can diagnose and
treat the problem.
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If a person has symptoms that suggest a brain tumor, the doctor
may perform one or more of the following procedures:
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Physical exam—The doctor checks general signs of health.
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Neurologic exam—The doctor checks for alertness, muscle
strength, coordination, reflexes, and response to pain. The doctor
also examines the eyes to look for swelling caused by a tumor pressing
on the nerve that connects the eye and brain.
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CT scan—An x-ray machine linked to a computer takes
a series of detailed pictures of the head. The patient may receive
an injection of a special dye so the brain shows up clearly in the
pictures. The pictures can show tumors in the brain.
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MRI—A powerful magnet linked to a computer makes detailed
pictures of areas inside the body. These pictures are viewed on a
monitor and can also be printed. Sometimes a special dye is injected
to help show differences in the tissues of the brain. The pictures
can show a tumor or other problem in the brain.
The doctor may ask for other tests:
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Angiogram—Dye injected into the bloodstream flows
into the blood vessels in the brain to make them show up on an x-ray.
If a tumor is present, the doctor may be able to see it on the x-ray.
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Skull x-ray—Some types of brain tumors cause calcium
deposits in the brain or changes in the bones of the skull. With
an x-ray, the doctor can check for these changes.
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Spinal tap—The doctor may remove a sample of cerebrospinal
fluid (the fluid that fills the spaces in and around the brain and
spinal cord). This procedure is performed with local anesthesia.
The doctor uses a long, thin needle to remove fluid from the spinal
column. A spinal tap takes about 30 minutes. The patient must lie
flat for several hours afterward to keep from getting a headache.
A laboratory checks the fluid for cancer cells or other signs of
problems.
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Myelogram—This is an x-ray of the spine. A spinal
tap is performed to inject a special dye into the cerebrospinal fluid.
The patient is tilted to allow the dye to mix with the fluid. This
test helps the doctor detect a tumor in the spinal cord.
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Biopsy—The removal of tissue to look for tumor cells
is called a biopsy. A pathologist looks at the cells under a microscope
to check for abnormal cells. A biopsy can show cancer, tissue changes
that may lead to cancer, and other conditions. A biopsy is the only
sure way to diagnose a brain tumor.
Surgeons can obtain tissue to look for tumor cells in three
ways:
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Needle biopsy—The surgeon makes a small incision in
the scalp and drills a small hole into the skull. This is called
a burr hole. The doctor passes a needle through the burr hole and
removes a sample of tissue from the brain tumor.
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Stereotactic biopsy—An imaging device, such as CT
or MRI, guides the needle through the burr hole to the location of
the tumor. The surgeon withdraws a sample of tissue with the needle.
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Biopsy at the same time as treatment—Sometimes the
surgeon takes a tissue sample when the patient has surgery to remove
the tumor.
Sometimes a biopsy is not possible. If the tumor is in the brain stem
or certain other areas, the surgeon may not be able to remove tissue from
the tumor without damaging normal brain tissue. The doctor uses MRI, CT,
or other imaging tests instead.
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A person who needs a biopsy may want to ask the doctor
the following questions:
- Why do I need a biopsy? How will the biopsy
affect my treatment plan?
- What kind of biopsy will I have?
- How long will it take? Will I be awake? Will it hurt?
- What are the chances of infection or bleeding after the biopsy? Are there any
other risks?
- How soon will I know the results?
- If I do have a brain tumor, who will talk to me about treatment? When?
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Many people with brain tumors want to take an active part in making
decisions about their medical care. They want to learn all they can about
their disease and their treatment choices. However, shock and stress after
a diagnosis of a brain tumor can make it hard to think of everything to ask
the doctor. It often helps to make a list of questions before an appointment.
To help remember what the doctor says, patients may take notes or ask whether
they may use a tape recorder. Some also want to have a family member or friend
with them when they talk to the doctor—to take part in the discussion, to
take notes, or just to listen.
The doctor may refer the patient to a specialist, or the patient may
ask for a referral. Specialists who treat brain tumors include neurosurgeons,
neurooncologists, medical oncologists, and radiation oncologists. The patient
may be referred to other health care professionals who work together as a
team. The medical team may include a nurse, dietitian, mental health counselor,
social worker, physical therapist, occupational therapist, and speech therapist.
Children may need tutors to help with schoolwork.
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Treatment depends on a number of factors, including the type, location, size,
and grade of the tumor. For some types of brain cancer, the doctor also needs
to know whether cancer cells were found in the cerebrospinal fluid.
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These are some questions a person may want to ask
the doctor before treatment begins:
- What type of brain tumor do I have?
- Is it benign or malignant?
- What is the grade of the tumor?
- What are my treatment choices? Which do you recommend for me? Why?
- What are the benefits of each kind of treatment?
- What are the risks and possible side effects of each treatment?
- What is the treatment likely to cost?
- How will treatment affect my normal activities?
- Would a clinical trial (research study) be appropriate for me? Can you help
me find one?
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People do not need to ask all of their questions or understand all
of the answers at one time. They will have other chances to ask the doctor
to explain things that are not clear and to ask for more information.
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People with brain tumors have several treatment options. Depending
on the tumor type and stage, patients may be treated with surgery, radiation
therapy, or chemotherapy. Some patients receive a combination of treatments.
In addition, at any stage of disease, patients may have treatment
to control pain and other symptoms of the cancer, to relieve the side effects
of therapy, and to ease emotional problems. This kind of treatment is called
symptom management, supportive care, or palliative care.
The doctor is the best person to describe the treatment choices and
discuss the expected results.
A patient may want to talk to the doctor about taking part in a clinical
trial, which is a research study of new treatment methods. The section on "The Promise of Cancer Research" has more information about clinical trials.
Surgery is the usual treatment for most brain tumors. Surgery to open
the skull is called a craniotomy. It is performed under general anesthesia.
Before surgery begins, the scalp is shaved. The surgeon then makes an incision
in the scalp and uses a special type of saw to remove a piece of bone from
the skull. After removing part or all of the tumor, the surgeon covers the
opening in the skull with that piece of bone or with a piece of metal or
fabric. The surgeon then closes the incision in the scalp.
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These are some questions a person may want to ask
the doctor before having surgery:
- How will I feel after the operation?
- What will you do for me if I have pain?
- How long will I be in the hospital?
- Will I have any long-term effects? Will my hair grow back? Are there any side
effects from using metal or fabric to replace the bone in the skull?
- When can I get back to my normal activities?
- What is my chance of a full recovery?
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Sometimes surgery is not possible. If the tumor is in the brain stem
or certain other areas, the surgeon may not be able to remove the tumor without
damaging normal brain tissue. Patients who cannot have surgery may receive
radiation or other treatment.
Radiation therapy (also called radiotherapy) uses high-energy rays
to kill tumor cells. The radiation may come from x-rays, gamma rays, or protons.
A large machine aims radiation at the tumor and the tissue close to it. Sometimes
the radiation may be directed to the entire brain or to the spinal cord.
Radiation therapy usually follows surgery. The radiation kills tumor
cells that may remain in the area. Sometimes, patients who cannot have surgery
have radiation therapy instead.
The patient goes to a hospital or clinic for radiation therapy. The
treatment schedule depends on the type and size of the tumor and the age
of the patient. Each treatment lasts only a few minutes.
Doctors take steps to protect the healthy tissue around the brain
tumor:
Fractionation—Radiation therapy usually is given five days a week for several
weeks. Giving the total dose of radiation over an extended period helps to
protect healthy tissue in the area of the tumor. Hyperfractionation—The patient
gets smaller doses of radiation two or three times a day instead of a larger
amount once a day.
Stereotactic
radiation therapy—Narrow beams of radiation are directed at the tumor from
different angles. For this procedure, the patient wears a rigid head frame.
An MRI or CT scan creates pictures of the tumor's exact location. The doctor
uses a computer to decide on the dose of radiation needed, as well as the
sizes and angles of the radiation beams. The therapy may be given during
a single visit or over several visits.
3-dimensional conformal radiation therapy—A computer creates a 3-dimensional
image of the tumor and nearby brain tissue. The doctor aims multiple radiation
beams to the exact shape of the tumor. The precise focus of the radiation beams
protects normal brain tissue.
Proton
beam radiation therapy—The source of radiation is protons rather than x-rays. The doctor aims the proton beams at the tumor. Protons can pass through healthy
tissue without damaging it.
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These are some questions a person may want to ask
the doctor before having radiation therapy:
- Why do I need this treatment?
- When will the treatments begin? When will they end?
- How will I feel during therapy? Are there side effects?
- What can I do to take care of myself during therapy?
- How will we know if the radiation is working?
- Will I be able to continue my normal activities during treatment?
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Chemotherapy, the use of drugs to kill cancer cells, is sometimes
used to treat brain tumors. The drugs may be given by mouth or by injection.
Either way, the drugs enter the bloodstream and travel throughout the body.
The drugs are usually given in cycles so that a recovery period follows each
treatment period.
Chemotherapy may be given in an outpatient part of the hospital, at
the doctor's office, or at home. Rarely, the patient may need to stay in
the hospital.
Children are more likely than adults to have chemotherapy. However,
adults may have chemotherapy after surgery and radiation therapy.
For some patients with recurrent cancer of the brain, the surgeon
removes the tumor and implants several wafers that contain chemotherapy.
Each wafer is about the size of a dime. Over several weeks, the wafers dissolve,
releasing the drug into the brain. The drug kills cancer cells.
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Patients may want to ask these questions about chemotherapy:
- Why do I need this treatment?
- What will it do?
- Will I have side effects? What can I do about them?
- When will treatment start? When will it end?
- How often will I need checkups?
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Because treatment may damage healthy cells and tissues, unwanted side
effects are common. These side effects depend on many factors, including
the location of the tumor and the type and extent of the treatment. Side
effects may not be the same for each person, and they may even change from
one treatment session to the next. Before treatment starts, the health care
team will explain possible side effects and suggest ways to help the patient
manage them.
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Patients often have a headache or are uncomfortable for the first
few days after surgery. However, medicine can usually control their pain.
Patients should feel free to discuss pain relief with the doctor or nurse.
It is also common for patients to feel tired or weak. The length of
time it takes to recover from an operation varies for each patient.
Other, less common, problems may occur. Cerebrospinal fluid or blood
may build up in the brain. This swelling is called edema. The health care
team monitors the patient for signs of these problems. The patient may receive
steroids to help relieve swelling. A second surgery may be needed to drain
the fluid. The surgeon may place a long, thin tube (shunt) in a ventricle
of the brain. The tube is threaded under the skin to another part of the
body, usually the abdomen. Excess fluid is carried from the brain and drained
into the abdomen. Sometimes the fluid is drained into the heart instead.
Infection is another problem that may develop after surgery. If this
happens, the health care team gives the patient an antibiotic.
Brain surgery may damage normal tissue. Brain damage can be a serious
problem. The patient may have problems thinking, seeing, or speaking. The
patient also may have personality changes or seizures. Most of these problems
lessen or disappear with time. But sometimes damage to the brain is permanent.
The patient may need physical therapy, speech therapy, or occupational therapy.
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Some patients have nausea for several hours after treatment. The health
care team can suggest ways to help patients cope with this problem. Radiation
therapy also may cause patients to become very tired as treatment continues.
Resting is important, but doctors usually advise patients to try to stay
as active as they can.
In addition, radiation therapy commonly causes hair loss. Hair usually
grows back within a few months. Radiation therapy also may affect the skin
in the treated area. The scalp and ears may become red, dry, and tender.
The health care team can suggest ways to relieve these problems.
Sometimes radiation therapy causes brain tissue to swell. Patients
may get a headache or feel pressure. The health care team watches for signs
of this problem. They can provide medicine to reduce the discomfort.
Radiation sometimes kills healthy brain tissue. This side effect is
called radiation necrosis. Necrosis can cause headaches, seizures, or even
the patient's death.
In children, radiation may damage the pituitary gland and other areas
of the brain. This could cause learning problems or slow down growth and
development. In addition, radiation during childhood increases the risk of
secondary tumors later in life. Researchers are studying whether chemotherapy
may be used instead of radiation therapy in young children with brain tumors.
Side effects may be worse if chemotherapy and radiation therapy are
given at the same time. The doctor can suggest ways to ease these problems.
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The side effects of chemotherapy depend mainly on the drugs that are
used. The most common side effects include fever and chills, nausea and vomiting,
loss of appetite, and weakness. Some side effects may be relieved with medicine.
Patients who receive an implant (a wafer) that contains a drug are
monitored by the health care team for signs of infection after surgery. An
infection can be treated with an antibiotic.
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At any stage of disease, people with brain tumors receive supportive
care to prevent or control problems and to improve their comfort and quality
of life during treatment. Patients may have treatment to control pain and
other symptoms of a brain tumor, to relieve the side effects of therapy,
and to ease emotional problems.
These are common types of supportive care for people with brain tumors:
- Steroids—Most patients with brain tumors need steroids to help
relieve swelling of the brain.
- Anticonvulsant medicine—Brain tumors can cause seizures. Patients may take an
anticonvulsant medicine to prevent or control seizures.
- Shunt—If fluid builds up in the brain, the surgeon may place a shunt to drain
the fluid. Information about shunts is under "Surgery" in the "Side Effects" section.
Many people with brain tumors receive supportive care along with treatments
intended to slow the progress of the disease. Some decide not to have antitumor
treatment and receive only supportive care to manage their symptoms.
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Rehabilitation can be a very important part of the treatment plan.
The goals of rehabilitation depend on the person's needs and how the tumor
has affected daily activities. The health care team makes every effort to
help the patient return to normal activities as soon as possible. Several
types of therapists can help:
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Physical therapists—Brain tumors and their treatment may cause
paralysis. They may also cause weakness and problems with balance. Physical
therapists help patients regain strength and balance.
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Speech therapists—Speech therapists help patients who have
trouble speaking, expressing thoughts, or swallowing.
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Occupational therapists—Occupational therapists help patients
learn to manage activities of daily living, such as eating, using the
toilet, bathing, and dressing.
Children with brain tumors may have special needs. Sometimes children
have tutors in the hospital or at home. Children who have problems learning
or remembering what they learn may need tutors or special classes when they
return to school.
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Regular followup is very important after treatment for a brain tumor.
The doctor checks closely to make sure that the tumor has not returned. Checkups
may include careful physical and neurologic exams. From time to time, the
patient may have MRI or CT scans. If the patient has a shunt, the doctor
checks to see that it is working well. The doctor can explain the followup
plan—how often the patient must visit the doctor and what tests will be needed.
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Living with a serious disease such as a brain tumor is not easy. Some
people find they need help coping with the emotional and practical aspects
of their disease. Support groups can help. In these groups, patients or their
family members get together to share what they have learned about coping
with the disease and the effects of treatment. Patients may want to talk
with a member of their health care team about finding a support group. Groups
may offer support in person, over the telephone, or on the Internet.
People living with a brain tumor may worry about caring for their
families, keeping their jobs, or continuing daily activities. Concerns about
treatments and managing side effects, hospital stays, and medical bills are
also common. Doctors, nurses, and other members of the health care team can
answer questions about treatment, working, or other activities. Meeting with
a social worker, counselor, or member of the clergy can be helpful to those
who want to talk about their feelings or discuss their concerns. Often, a
social worker can suggest resources for financial aid, transportation, home
care, or emotional support.
The Cancer Information Service can provide information to help patients
and their families locate programs, services, and publications.
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