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Glioblastoma is a malignant brain tumour that forms from glial cells (cells that surround neurons in the brain and the spinal cord). Also referred to as 'Glioblastoma Multiforme' (abbreviated to GBM), it is a rapidly growing primary brain tumour and is the most aggressive type (Grade IV) within the family of astrocytomas. It occurs in roughly 15% of all brain tumours, and the incidence of glioblastoma in the general population is around 3 people in every 100,000 (0.00003%) every year.


In the majority of cases of glioblastoma, it is not possible to determine a specific cause. However, glioblastoma is linked with a number of risk factors:

Hereditary conditions.

  • Neurofibramatosis (Type 1 and Type 2).
  • Li-Fraumeni Syndrome.
  • Turcot Syndrome.
  • Radiation*.
  • Exposure to radiation during previous radiation therapy or X rays.
  • Age / Sex - glioblastoma is more common in older people (average age of onset is 64) and more common in men than women.

* non-ionising electromagnetic radiation, for example UV and infrared radiation, microwaves and radio waves have been considered possible causes of brain tumours, however this has not been borne out by research.


Glioblastoma shares many of the same symptoms of other brain tumours. The combination of symptoms may vary depending on the location of the tumour. These are:

  • Headaches.
  • Stroke-like symptoms – may include weakness on one side of the face or body, or blindness.
  • Cognitive impairment – may include confusion, issues with memory, reasoning and thinking.
  • Change in personality – this can be subtle.
  • Nausea / vomiting.
  • Seizures / epilepsy.
  • Reduced level of consciousness.

Of these, new onset of headaches is the most common symptom, with half of all people with a brain tumour experiencing headaches. In some instances, brain tumours may not have symptoms and are found on brain scans done for other reasons.

Tests / Diagnosis

Where a brain tumour is suspected, a brain scan either using CT (computed tomography) or MRI (magnetic resonance imaging) is performed. Generally, a CT scan is the first test, followed by an MRI scan. The scans may be performed with intravenous contrast, a dye that is injected through the veins to highlight the tumour on CT or MRI scans. These scans are also useful for navigation during operations, similar to a GPS system.

Once a brain tumour is diagnosed, surgery may be necessary to:

  • Determine the nature of the tumour; This is done by taking a tissue sample (biopsy) and sending the sample for laboratory for analysis.
  • Reduce the pressure (or mass effect) of the tumour on surrounding brain structures.
  • Reduce the volume of tumour to improve the effectiveness of other treatments, such as chemotherapy and radiotherapy.


Three main treatment options for glioblastoma are offered, often as combined treatment. These include surgery (biopsy or removal of brain tumour), radiotherapy (usually delivered in multiple sessions) and chemotherapy (which can be given as oral tablets or intravenous injections). Treatment is provided by a team of specialists in different areas (Neurosurgery, Radiation Oncology and Medical Oncology).

Related Information

Craniotomy – Basic Facts Minimally-Invasive Surgery for Brain Tumours