What is Brain Stem Glioma?
Brain stem gliomas are a group of tumours located in the area of
the brain called the brainstem. These account for 10-20% of brain
tumours in childhood, and commonly affect children between the ages
of 5 to 10. They can be of a low or high-grade, however a larger
number (approximately 70%) are high-grade.
The brainstem is the area at the lower back portion of the neck,
which connects the spinal cord with the brain. It is the area of
the brain and spinal cord that is responsible for many vital body
functions, including vision, swallowing, gagging, balance and
strength. Because of the location of these tumours, they are more
difficult to treat than gliomas in other parts of the brain.
Low-grade brain stem gliomas are focal, or confined to one area
of the brain stem. High-grade brain stem gliomas tend to be
diffuse, or infiltrate and spread throughout the brain stem.
Signs & Symptoms
Children with a low-grade brain stem glioma commonly present
with a long history (greater than 6 months) of symptoms, including
headaches, vomiting and visual disturbances.
Children presenting with a high-grade tumour experience similar
symptoms, however the onset of symptoms is generally more sudden or
acute.
Treatment
Low-grade brain stem gliomas
Although these tumours arise in a vital area of the brain, the
Neurosurgeon may partially or incompletely remove them. This is
because they are generally contained to one area of the brainstem,
and when surgically approached, is not life threatening. Additional
treatment (ie, chemotherapy and/or radiotherapy) following surgery
is often not required. Chemotherapy may be necessary in children
whose tumour progress following surgery, or whose tumours were not
surgically accessible.
High-grade brain stem gliomas
A surgical resection is not usually an option for treatment of a
high-grade brain stem glioma. This is because of the tumour's
location within the brain stem, which is diffuse and infiltrating.
This can lead to damage to the nerves within the brain stem that
are vital for breathing, swallowing, consciousness, arm, leg and
eye movement. A biopsy is rarely performed for similar reasons,
therefore diagnosis is often made on clinical presentation of the
child and neuro-imaging (CT scans and MRI scans).
Radiation treatment to the area of the tumour is the current
standard of treatment for this tumour type. A large percentage of
children will clinically improve with radiation treatment, but
their condition will decline rapidly within 6-9 months after
completing therapy. There is currently no clear role for
chemotherapy in the treatment of these tumours.
Other issues
Approximately 50% of children with brain stem gliomas will
develop hydrocephalus at some stage during the course of their
illness. Hydrocephalus is a build up of fluid within the brain,
caused by obstruction of the normal cerebrospinal fluid (fluid that
surrounds the brain and spine) pathway by the tumour. Insertion a
shunt system (ventriculo-peritoneal shunt) is necessary to treat
this condition. Children with brain stem gliomas are often
prescribed steroids because of the swelling and tightness the
tumour causes at the base of the skull. Because of the side effects
of steroids, including mood changes, weight gain and fluid
retention, steroids are used sparingly.
Follow Up Care
After treatment has finished, children visit clinic on a regular
basis, and undergo MRI scans to monitor the state of their
disease