What is a Brain Tumour?
A brain tumour is a form of cancer arising from the brain itself, from the membranes around the brain or from the hormone producing gland at the base of the skull called the pituitary gland. Membranes around the brain are called meninges and tumours that arise from them are called meningiomas. Tumours affecting the pituitary gland are called pituitary adenomas. Over 90% of tumours affecting the brain are actually secondary cancers from other malignancies such as lung cancer and breast cancer. This guidance is about the 10% of brain tumours that have arisen as a primary tumour within the brain.
Different parts of the brain control different functions and therefore the location of a tumour will determine the possible disabling effects. For example there is an area which controls speech and paired areas that control motor nerves and sensory nerves on the right and left side of the body respectively – these are responsible for movement and sensation for each side of the body. Other areas are responsible for vision, memory, the ability to balance when walking, the production of hormones, control of unconscious processes in the body like breathing and vomiting reflexes. One or more of these areas may be affected.
There are many different names for brain tumours depending on cell type involved and grade of tumour. Many of these can occur anywhere in the brain tissue and will cause symptoms depending on location of the tumour in the brain. Whether a tumour is treatable or not will depend both on what cell type and grade the tumour is (see link at bottom of page) and how accessible it is for treatment. This guidance covers both benign and malignant primary brain tumours, this is because benign brain tumours can be fatal and may cause severe disability particularly if they arise in a functionally important part of the brain and cannot be removed by surgery.
This guidance will describe disabling effects of tumours in different parts of the brain, the treatments for brain tumours and the possible disabling effects of those treatments. A list of brain tumour names and their likely outcome in terms of survival is also provided. This has been done separately as outcomes for brain tumours are too variable to generalise about. Specific disabling effects and outcome of treatment can be predicted if the area of the brain affected and the type of tumour is known. Other effects such as fatigue and somnolence may be more general and non-specific.
Medical evidence is likely to give the name of the tumour concerned and describe either the location and/or disabling effects. Brain tumours virtually never spread to other organs like other cancers; they tend to stay within the central nervous system. This means that people with primary CNS or brain tumours have a different pattern of disabling effects compared to people with other kinds of advanced cancer. In general when brain tumours progress they affect larger areas of the brain over time and new neurological disabling effects appear.
Brain tumours affect just over 4000 people each year in the UK and around 3500 die of the disease each year. Outcome is best in young people - about 50% of people under 40 who develop brain tumours can survive 5 years. In older people survival rates are significantly lower, partly because the majority of newly diagnosed tumours are glioblastoma multiforme (GBM) which carries a very poor prognosis. Brain tumours are rare malignancies and are more commonly diagnosed in people over the age of 50 years. They are more common in men than women. They can run in families usually due to one of a number of rare genetic syndromes. The risk of developing a primary brain tumour is increased for people who have had previous radiation treatment to the head for example as part of treatment for leukaemia as a child. They are also increased for people who are immunosuppressed either because they have AIDS or are taking immunosuppressant drugs.
- Click here for detailed information on prognosis of individual types of brain tumour.
- WHO classification of brain tumours
Amended November 2009