Radiation Therapy for Brain Tumors
About
Brain Tumors
The brain is the center
of thought, memory, emotion, speech, sensation and motor function.
The spinal cord and special nerves in the head called cranial nerves
carry and receive messages between the brain and the rest of the
body.
- There are two types of brain tumors:
- Primary — a tumor that starts in the brain. Primary brain
tumors can be benign (noncancerous) or malignant.
- Metastatic — a tumor caused by cancer elsewhere in the body
that spreads to the brain. Metastatic brain tumors are always
cancerous.
- Primary tumors in the brain or spinal cord rarely spread to
distant organs.
- Brain tumors cause damage because as they grow they can interfere
with surrounding cells that serve vital roles in our everyday
life.
General
Risk Factors for Brain Tumors
Most brain and spinal cord
tumors have no known risk factors and occur for no apparent reason.
There are no known proven ways to prevent these tumors.
Facts
about Brain Tumors
- The Central Brain Tumor Registry of the United States estimates
that more than 40,000 Americans will be diagnosed with a primary
brain tumor this year.
- This year, an estimated 170,000 Americans will be diagnosed
with a brain or spinal cord tumor that has spread from another
part of the body.
Signs
of Brain Tumors
No blood test or other screening
exam can detect brain tumors, but there are often some outward signs.
While tumors in different parts of the central nervous system disrupt
different functions, some symptoms include:
- Headaches.
- Nausea/vomiting.
- Seizures.
- Weakness or numbness on one side of the body.
- Changes in vision, hearing or sensation.
- Difficulty with speech.
- Lack of coordination.
- A change in mood or personality.
- Memory loss.
Diagnosing
Brain Tumors
If you suffer from any of
the initial signs of a brain tumor, your doctor will likely conduct
some or all of the following tests:
- A physical exam to determine your overall health.
- A neurologic exam to evaluate brain and spinal cord function.
- Imaging studies, such as CT, MRI or PET scans, to look for signs
of a brain tumor.
- If studies or scans indicate you might have a brain tumor, some
tissue may be taken from the tumor to make an exact diagnosis.
This test is called a biopsy.
- A spinal tap may also be performed to look for tumor cells.
During this test, a needle is placed in the lower back to obtain
a sample of cerebrospinal fluid. This fluid is then examined to
see if tumor cells are present.
Treating
Brain Tumors
If doctors determine that
you have a tumor, the treatment options and prognosis are based
on the following factors:
- Tumor type.
- Location and size of tumor.
- Tumor grade (how abnormal the cells are).
- Your age, medical history and general health.
Understanding
Radiation Therapy
Radiation therapy, sometimes
called radiotherapy, is the careful use of radiation to safely and
effectively treat many different kinds of tumors.
- Doctors called radiation oncologists use radiation therapy to
try to kill tumors, to control tumor growth or to relieve symptoms.
- Radiation therapy works within tumor cells by damaging their
ability to multiply. When these cells die, the body naturally
eliminates them.
- Healthy cells near the tumor may be affected by radiation, but
they are able to repair themselves in a way tumor cells cannot.
Radiation
Therapy Options for Brain Tumors
People with brain tumors
should discuss treatment options with several cancer specialists,
including a radiation oncologist. A radiation oncologist is a doctor
who will help you understand the types of radiation therapy available
to treat your tumor. Conventional radiation therapy treatment options
for brain tumors include:
- External beam radiation therapy.
- Brachytherapy or internal radiation therapy.
External
Beam Radiation Therapy
External beam radiation therapy
involves a series of daily outpatient treatments over several weeks
to accurately deliver radiation to the brain. Radiation is often
given after surgery, and sometimes it is used instead of surgery.
- 3-dimensional conformal radiotherapy (3D-CRT) combines multiple
radiation treatment fields to deliver precise doses of radiation
to the brain. Tailoring each of the radiation beams to the patient's
tumor allows coverage of the brain tumor while keeping radiation
away from nearby organs, such as the eyes.
- Intensity modulated radiation therapy (IMRT) is the most recent
advance in the delivery of radiation. IMRT differs from 3D-CRT
by modifying the intensity of the radiation within each of the
radiation beams.
- Stereotactic radiotherapy, sometimes called radiosurgery, is
a type of external beam radiation therapy that pinpoints high
doses directly on the tumor, in some cases in only one treatment.
- Proton therapy is given much the same way as external beam therapy,
but it uses proton particles rather than X-rays to kill brain
tumor cells. This treatment is only available in a few regions
of the country.
Internal
Radiation Therapy
Internal radiation therapy,
or brachytherapy, works by placing radioactive sources in or just
next to a tumor.
- During brachytherapy, a tube or balloon called a catheter will
be inserted into the brain. The radiation will then be carried
to the tumor using this catheter.
- The radioactive source will then be left in place from several
hours to several days to kill the tumor cells.
- In some cases, the radiation is permanently placed directly
into the tumor or the area where the tumor was before surgery.
Newer
Techniques
Doctors are constantly exploring
new and better ways to treat primary brain tumors.
- Drugs that make tumor cells more sens itive to radiation are
called radiosensitizers. Combining radiation with radiosensitizers
may allow doctors to kill more tumor cells.
- Chemotherapy is used with radiation to treat some brain tumors.
Your doctor may recommend that you consult with a medical oncologist
(chemotherapy doctor) before starting radiation.
Potential
Side Effects
The effects of brain radiation
can vary depending on your tumor and the technique used to treat
it.
- Before treatment, your radiation oncologist will discuss any
side effects — however rare — you may experience.
- Possible side effects can include fatigue, change in appetite,
headaches, visual changes, hair loss, skin irritation, nausea,
vomiting and/or unsteadiness.
Some side effects can be
treated with steroids or other medications. Talk to your doctor
about any problems you experience.
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