Gliomas are primary brain tumours i.e. they arise from the brain itself rather than spreading to the brain from elsewhere. Brain tissue is composed of neurons (nerve cells) and glia (supporting cells). Gliomas arise from the glia. They are classified according to the exact glial cell type, molecular genetics, grade and location. The World Health Organisation (WHO) classification is the most recognised and ubiquitously used.
Classification of glioma by cell type includes:
- Astrocytic tumours – these tumours develop from astrocytes (cells which support neurons in the brain and spinal cord).
- Oliodendroglial tumours – these tumours develop from oligodendroglia (cells which insulate nerve fibres in the brain and spinal cord)
- Ependymal tumours – these are tumours that develop from ependymal cells which line the fluid filled areas of the brain (ventricles) and the spinal cord.
Classification by grade is a means of predicting biological behaviour by cellular pathology.
- Grade I tumours are biologically benign, slow growing and can potentially be cured by surgical excision.
- Grade II tumours are infiltrative and, despite slow growth, almost always recur. Grade II gliomas (known as low grade gliomas) tend to progress to higher grades of malignancy, e.g. low-grade diffuse astrocytoma that transform to anaplastic astrocytoma and glioblastoma.
- Grade III / IV tumours are malignant and fast growing and have a worse prognosis. Grade III / IV gliomas include anaplastic astrocytoma, anaplastic oligodendroglioma and glioblastoma (collectively known as high grade gliomas). Glioblastoma is the fastest growing and most aggressive brain tumour.
Symptoms will vary depending on where the tumour is in the brain; however, there are several symptoms commonly associated with gliomas including:
- headaches (these may be more severe in the morning or wake you at night);
- nausea and vomiting;
- limb weakness and poor coordination;
- confusion and disorientation;
- personality changes;
- difficulty with speech;
- visual loss and double vision.
Treatment of glioma will depend on many factors including:
- the location;
- the type and grade of the tumour;
- your general health and level of fitness.
Initial diagnosis of a brain tumour is usually by CT or MRI scan. These tests can usually help identify the precise location and size of the tumour as well as indicate the most likely type of tumour. Sometimes further imaging (such as MR spectroscopy or PET scan) is indicated. Surgery is needed to confirm the exact type of tumour, e.g. cell type, whether it is fast or slow growing, benign or malignant. Treatment for gliomas is often multimodal and includes surgery, chemotherapy and radiotherapy. Steroids are often used to reduce swelling caused by the tumour. Anti-epileptic medication may be used for seizures. There are also multiple clinical trials for more experimental treatments which you may be eligible for should you wish.