Glioblastoma Multiforme (GBM)
About This Condition
These tumours are malignant Grade IV (highest cancer grade) tumours where a large portion of tumour cells are reproducing and dividing at any given time. They are nourished by an ample and abnormal tumour vessel blood supply.
The tumour is predominantly made up of abnormal astrocytic cells but also contact a mix of different cell types and areas of dead cells. GBMs are infiltrative and invade nearby regions of the brain. Sometimes they can also spread to the opposite of the brain through connection fibres called corpus callosum. It is exceedingly rare for GBMs to spread outside of the brain.
GBMs may begin as a Grade IV tumour with no evidence of a lower grade precursor. De novo (primary) tumours are the most common form of GBM and tend to be more aggressive, particularly affecting older patients. Secondary GBMs may progress from a lower-grade astrocytic tumour and evolve into Grade IV tumours over time. In general, these tumours tend to be slower growing initially but can progressively become aggressive.
GBMs are generally found in the cerebral hemispheres of the brain but can be found anywhere. IDH (isocitrate dehydrogenase) mutant GBMs tend to arise preferentially in the frontal lobe. Patients with GBMs develop symptoms rapidly due to mass effect from the tumour itself or from the fluid surrounding the tumour that causes further brain swelling.
Common symptoms include nausea, vomiting and severe headaches, which are typically worse in the worse, and are related to increased pressure in the brain. Depending on the location of the tumour, patients can also present with neurological symptoms such as balance difficulties, memory issues or weakness or sensory changes of the face, arm or leg, or seizures.