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Jargon buster

A comprehensive list of the terms and words you will come across in relation to brain tumours.


Occipital lobe

The part of each cerebral hemisphere of the brain located towards the very rear of the skull. Its main role is the control of vision.


An excess build-up of fluid in the tissues or cavities in the body, causing swelling and other symptoms. Cerebral oedema: build-up of fluid in the cells in the brain or in the spaces outside the cells. Symptoms include nausea and vomiting, blurred vision and, in severe cases, seizures, coma or death.

Off-label access

The use of medicines outside the terms of their licence (i.e. 'off-label'), if it is judged to be in the best interest of the patient. For example, it could be used with a different dose or route of administration, or for a different disease.


A type of brain cell which produces a protective sheath around the brain's nerve cells ('neurons'), known as the myelin sheath. An oligodendrocyte is a type of glial cell.


Doctor who specialises in treating people who have cancer

Optic disc

A circular area at the back of the inside of the eye connecting to the optic nerve.

Optic nerve

The nerve connecting the eye to the brain.

Oral candidiasis

Another name for oral thrush - a fungal/yeast infection of the mouth.

Oral mucositis

Inflammation of the inside of the mouth, that can cause soreness and mouth ulcers. It is a common side-effect of treatments, such as chemotherapy and radiotherapy.

Oral thrush

A fungal/yeast infection of the mouth. Also known as oral candidiasis, it can occur when treatments, such as radiotherapy or chemotherapy, upset the normal balance of bacteria and yeast within the mouth, allowing the yeast to grow.


Taken through the mouth.


A disease of decreased bone strength. The bones become more fragile and likely to break due to loss of tissue. It is usually caused by hormonal changes or lack of calcium or Vitamin D.

Overall survival

Overall survival means how long someone will live, which is different progression-free survival (PFS).