What are brain tumours?
A brain tumour
is an abnormal growth of cells within the brain. It arises from glial cells of
the brain, lymphatic tissues, nerves and meninges. Benign brain tumours grow slowly
but they can compress adjacent parts of the brain. Malignant tumours grow rapidly
and they invade adjacent structures of the brain. Brain tumours are graded according
to the nature of cell growth. Grade I and II tumours are grouped as low-grade,
whereas grade III and IV are grouped as high-grade tumours. Prognosis
is better in
low-grade or benign tumours.
The following types of brain
tumours are seen commonly:
In children:
Juvenile pilocytic astrocytoma, craniopharyngioma, medulloblastoma, brainstem
glioma and germ cell tumours.
In adults:
Astrocytoma, oligodendroglioma, ependymoma, meningioma, vestibular schwannoma
and lymphoma. Cancers from other parts of the body can also spread to brain.
What are the common symptoms
of brain tumours?
* Headaches,
usually in the morning
* Vomiting
* Convulsions or
seizures
* Weakness in
limbs
* Loss of
balance while walking
* Altered speech
or vision
* Altered
behaviour
* Loss of
orientation
* Memory lapses
How are brain tumours diagnosed?
* Imaging: CT
scan or MRI scan of brain is commonly performed.
* Biopsy: A
piece of tumour is removed for examination by open surgery or in stereotactic
fashion using rigid frame to fix skull and localizing tumour under guidance of
CT scan or MRI.
How is brain tumours treated?
Brain tumours are treated
by surgery, radiation therapy or chemotherapy, or a combination of these. The
choice of treatment depends upon the age of the patient, type of tumour, its
location, size and grade.
* Surgery:
Maximum safe resection of the tumour or at least a biopsy is the standard goal
of surgery.
* Radiation
therapy: Radiation kills tumour cells with high energy X-rays, gamma rays or
protons. It is usually started after surgery and given over 5-6 weeks.
* Chemotherapy:
Chemotherapy is the use of drugs to kill cancer cells. It is given orally or
through veins. It is given concomitantly with radiation therapy in high-grade
tumours. It is also given in recurrent brain tumours after failure of initial
treatment.
What are the advances in radiation
therapy of brain tumours?
* 3-Dimensional
Conformal Radiation Therapy (3D-CRT) and Intensity Modulated Radiation Therapy
(IMRT):
CT scan and MRI
are used to delineate the tumour and computers are used for radiation planning.
Only the tumour and the high-risk region surrounding the tumour is radiated,
avoiding radiation to
the normal
structures in the brain.
* Stereotactic
Radio-surgery (SRS) and Stereotactic Radiotherapy (SRT): Highly precise
immobilization and image guidance system is used for treatment of selected brain
tumours. High dose of radiation is delivered only to the tumour with very minimal
spillage of dose to the rest of the sensitive brain structures. Stereotactic radiotherapy
is preferred in children. Stereotactic radio-surgery delivering high-dose of
radiation in single or a very few sessions is performed in adults with tumours
such as metastatic residual glioma, meningioma and schwannoma. Novalis-Tx and
Cyberknife are advanced machines to deliver such high-precision therapy.
*
High-definition Rapid Arc: This is the latest software advancement in radiation
planning technology. Radiation is delivered in continuous fashion moving the machine
head and its small components simultaneously around the patient's head targeting
the tumour by infinite small radiation beams. Radiation treatment with such a
technique is highly precise and fast. This is preferred in children and elderly
patients who cannot lie on treatment couches for long periods.
* Proton beam
therapy: Proton therapy avoids spillage of radiation dose to the surrounding
brain. It is preferred in children as well as in patients with recurrent tumours
who have received radiation therapy earlier.
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