BRAIN CANCER: Causes, symptoms and treatment.

The Facts on Brain Cancer
Brain cancer is a tumour or cancerous growth in
the brain. A tumour, whether in your brain or
elsewhere, is a mass of cells that reproduce
themselves in an uncontrolled way. Tumours can be
either benign or malignant.
Benign brain tumours are abnormal collections of
cells that reproduce slowly and usually remain
separate from the surrounding normal brain. They
grow slowly, do not spread to other parts of the
brain and can usually be removed more easily than
malignant tumours. Malignant tumours reproduce
and grow quickly. Their borders are hard to
distinguish from the normal brain around them. That
is why it is hard to remove them completely without
damaging the surrounding brain.
Both benign and malignant tumours are further
broken up into different types according to the kind
of cell from which the tumour develops.
Benign tumours can be divided into the following:
chordomas: starting in embryonic cells in the spine
or base of the skull nerve
hemangioblastomas: starting in the blood vessels
meningiomas: starting in the membrane covering
the brain
osteomas: in the skull bones
pinealomas: in the pineal gland
pituitary adenomas: in the pituitary gland
schwannomas: in the cells that wrap around nerves
There are also some tumour types that can be
benign in some cases or malignant in others, such
as meningiomas or germ cell tumours.
This article focuses on the malignant (cancerous)
brain tumours.
Brain cancers are relatively rare, but they are often
deadly. The most common malignant types are
called gliomas, where cells called glia (cells which
help support the nerve cells) become cancerous.
Glioblastoma multiforme is the most common of the
gliomas. Glioblastoma multiforme and anaplastic
astrocytoma are fast-growing gliomas.
Oligodendroglioma, another type of glioma, is also
rare, but is most often found in adults. Gliomas
make up between 50% to 60% of all brain tumours
(malignant and benign) in both children and adults
combined.
Medullablastoma, which grows from the cells of the
medulla at the base of the brain, is the most
common type of brain cancer in children. It usually
affects children before puberty.
Finally, sarcoma and adenocarcinoma are
extremely uncommon types of brain tumour.
Causes of Brain Cancer
The exact cause of cancer is unknown. Brain
cancer that originates in the brain is called a
primary brain tumour. It can spread and destroy
nearby parts of the brain. Cancers of the breast,
lung, skin, or blood cells (leukemia or lymphoma)
can also spread ( metastasize) to the brain, causing
metastatic brain cancer. These groups of cancer
cells can then grow in a single area or in different
parts of the brain.
Risk factors include:
previous radiation to the head
immunosuppression (e.g., taking medication to
suppress the immune system, HIV/AIDS)
exposure to vinyl chloride (a chemical used in
making plastic)
Symptoms and Complications of Brain Cancer
Brain cancer causes symptoms when it pushes on
the brain or destroys brain tissue. Symptoms
depend on the size and location of the tumour as
well as how quickly it grows.
Although headaches are often a symptom of brain
cancer, it is important to remember that most
headaches are due to less serious conditions such
as migraine or tension, not cancer. Headaches
caused by a brain tumour are often severe,
associated with nausea and vomiting and are
usually worse in the morning. They can last for
extended periods of time or may "come and go."
Other symptoms include:
dizziness
vision changes (such as double vision)
coordination problems
weakness or numbness on one side of the body
seizures
changes in mood, senses, personality, or feelings
memory problems
confusion or trouble concentrating
Diagnosing Brain Cancer
Based on the above symptoms, your doctor may
suspect brain cancer. The first step in correctly
diagnosing any type of brain cancer is to undergo a
computerized tomography (CT) or magnetic
resonance imaging (MRI) scan. These specialized
scans can detect many types of brain tumours and
determine their exact location and size. However,
they can't tell if the tumour is cancerous or not.
A biopsy must be done to find out whether the
tumour is cancerous. In order to do this, a piece of
the tumour is removed during surgery. If the tumour
is too deep inside the brain, surgeons can use a
technique called stereotactic biopsy or three-
dimensional needle placement.
An MRI scan is used to create a 3D image of the
brain, which is then used to guide a needle held in a
special frame to the proper spot in the brain.
Tumour cells are then drawn into the needle and
collected for examination. After the biopsy sample
is removed, it is analyzed using microscopes and
special chemicals to determine the type of tumour.
It usually takes a few days to get the results of a
biopsy.
Brain tumour cells can sometimes be drawn from
the cerebrospinal fluid (CSF), which is a special
fluid that surrounds the brain and spinal cord. The
CSF is drawn out through a thin needle inserted in
the lower back under local anaesthetic - this is
called a lumbar puncture.
This procedure can't be done if there's any buildup
of pressure in the brain. The change in brain
pressure caused by a puncture could suck some of
the brain tissue down into the base of the skull,
causing serious complications.
Treating and Preventing Brain Cancer
Brain cancers are usually treated with a
combination of surgery, chemotherapy (anticancer
medications), and radiation as well as medications
that control symptoms.
High doses of steroids are frequently used any time
or around the time of radiation to reduce any
swelling caused by the tumour. These will often
relieve some or all of the symptoms but have no
effect on the tumour itself. Anticonvulsant
medications may be used to prevent seizures.
Surgery is done to remove as much of the cancer
as possible. Some brain cancers are located in
areas that surgeons can't reach without damaging
other important portions of the brain. It's often
better not to operate in those cases. Even when
surgery can't completely remove all of the cancer, it
can make the tumour smaller, which helps relieve
some of the symptoms and can make other
treatments more effective.
Radiation and chemotherapy are usually started
after surgery. They often don't cure brain cancer,
but can keep the tumour under control for months.
If you have seizures from the brain tumour, your
doctor may prescribe antiseizure medications as
well.
Treatment of metastatic cancers (those that have
spread) largely depends on the location where they
started. For example, a lung cancer that
metastasized to the brain would be treated the
same way as other lung cancers. The part of the
cancer that has spread to the brain may be treated
by radiation. If the cancer has metastasized but is
limited to one area in the brain, it is sometimes
removed surgically.
Advances in technology are providing new
treatment options such as lasers and ultrasound for
removing tumours. An alternative to surgery is a
technique called Gamma knife stereotactic
radiosurgery, where radiation beams are accurately
focused directly on the tumour. These newer
techniques may leave fewer cancer cells behind
and minimize the damage to the healthy brain tissue
around the tumour, resulting in fewer neurological
complications.
It is usually not possible to get rid of all the brain
cancer cells. If even a few are left behind, the
cancer can grow back.