Key Facts
There are many different types of brain tumour. Tumours that develop from cells in the brain are usually referred to as primary brain tumours. A short description of each of these is given in the Cancer Types section below.
The brain is also a common site for secondary cancers (metastases) that have spread from other parts of the body (in particular the lung, breast and gastrointestinal tract).
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Key Figures
The expected incidence of 74,000 new cases is based on an incidence rate of 14.8 per 100,000 people with a total population of 500 million in all European states.
Brain tumours are:
- The leading cause of death from childhood cancers among people up to 19 years of age.
- The second leading cause of cancer related deaths in males ages 20-39
- The fifth leading cause of cancer related deaths in women ages 20-39
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Cancer Types
Gliomas
Gliomas are the most common form of brain tumour. There are four main types of glioma:
Astrocytomas are the most common type of glioma and occur in both adults and children. Astrocytomas can be subdivided as follows:
Ependymomas are tumours that can affect children and young adults. They develop from cells called ependymal cells which repair damaged nerve tissue. On rare occasions, ependymomas will spread though the cerebrospinal fluid within the brain and spinal cord.
Oligodendrogliomas are tumours found in adults and develop from oligodendrocytes, which make myelin (the substance that covers the long nerve axons). Oligodendrogliomas vary in how fast they grow and whether or not they spread to other parts of the nervous system.
Mixed Gliomas are a mixture of the different types of glioma. For this reason, they vary in how they grow and whether or not they spread to other areas. In general these tumours behave very much like astrocytomas.
Acoustic Neuroma
Acoustic neuromas grow in the auditory nerve that connects the ear to the brain, controlling hearing and balance. They often cause deafness on the affected side. They are slow growing and do not spread to other parts of the brain or elsewhere in the body. They are most often found in middle aged and older people, however, younger people with neurofibromatosis also develop these tumours.
Craniopharyngioma
Craniopharyngiomas are tumours that tend to affect children, teenagers and young adults. They do not usually spread but can affect vision and hormone balance resulting in weight gain and growth problems in children.
Haemangioblastoma
Haemangioblastomas grow from blood vessels. They tend to be slowly growing and do not spread to other parts of the brain.
Lymphoma
Lymphomas can start in the brain, particularly in people who have had an organ transplant or have AIDS because their immune systems are suppressed. Lymphomas in the brain and spinal cord are not the same as lymphomas found in the rest of the body and tend to be more difficult to treat.
Meningioma
Meningiomas are the second most frequent form of brain tumour and account for approximately 25% of all brain tumours in adults. They usually affect older people and, more commonly, women. Meningiomas are tumours that grow from the meninges, the tissues that cover the brain. They are not usually cancerous but depending on their location in the brain they can cause significant symptoms, usually due to pressure that they apply on the surrounding structures.
Pineal Gland Tumours
Pineal gland tumours are rare. They start in the pineal gland, which makes melatonin.
Pituitary Tumours
Pituitary gland tumours are usually benign and curable. The pituitary gland produces a number of hormones and so controls a wide range of body functions. Tumours can cause too much or too little of these hormones to be produced as well as having other effects by pressing on nearby structures (most importantly the optic nerves connecting the eyes to the brain). Pituitary tumours include:
Primitive Neuroectodermal Tumour (PNET)
Medulloblastoma is the most common form of primitive neuroectodermal tumour. The tumours tend to grow in the cerebellum (responsible for balance and coordination) and are the most common brain tumour in children, but they can also affect young adults. Medulloblastomas can grow very quickly and may spread to other parts of the brain and spinal cord through the cerebrospinal fluid.
Secondary Brain Tumours (Metastases)
Other forms of cancer can spread to the brain through the blood stream. Often there will be just one, two or three of these tumours present. If these are detected at an early stage using a CT or MRI scan, some can be treated using surgery or various forms of radiotherapy.
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Causes of Brain Tumour
The cause of most brain tumours remains unknown.
Exposure to electromagnetic fields from power lines and electronic devices such as mobile and cordless phones has not yet been proven to be a risk factor.
Two proven risks are:
- high doses of radiation to the head (for example in people previously treated with radiotherapy)
- rare genetic conditions, including neurofibromatosis, which make those affected more likely to develop acoustic neuromas and meningiomas.
In the vast majority of cases, however, there is no identifiable cause for the tumour to have developed.
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Prevention of Brain Tumours
There is no proof that the development of brain tumours is related to exposure to electromagnetic fields but some pressure groups argue that mobile (cell) phones should be used as infrequently as possible. There are no known risk factors for the majority of brain tunours so there are no practical steps that can be taken to reduce the risk of developing a brain tumour.
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Common Symptoms
The effect of anything interfering with brain function will vary according to the part of the brain which is affected. Usually, symptoms will occur in the part of the body that the affected area controls.
General symptoms include:
- Headaches – which are worse in the morning.
- Nausea and vomiting
- Convulsions (fits)
- Visual problems
- Depression and confusion.
Specific symptoms (which can also indicate which part of the brain is affected) include:
- Numbness
- Sensory changes or weakness
- Loss of coordination
- Personality changes
- Speech problems
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Diagnostic Tests
MRI Scans are the most sensitive test for the detection of brain tumours.
A biopsy is essential to obtain a specific diagnosis.
Examination of the cerebrospinal fluid (CSF) is necessary for tumours which spread through the CSF.
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Treatment
Available treatments include:
- surgery
- radiotherapy
- chemotherapy
- chemoradiation – combined radiotherapy and chemotherapy
- Targeted therapies
Surgery
Brain surgery is the preferred treatment option for many brain tumours.
If removing the tumour is not possible without damaging normal brain tissue, radiotherapy may be the better option. However, surgery might still be required in these cases if a biopsy needs to be obtained for accurate diagnosis or to relieve the symptoms caused by raised pressure within the brain.
External Beam Radiotherapy
External beam radiotherapy uses high energy X-ray beams generated from machines (normally alinear accelerator) to kill cancer cells.
Before any treatment can be given there is a careful planning phase. This involves:
- obtaining an exact diagnosis
- being sure about the exact location size and shape of the tumour
- determining the best treatment option
Radiotherapy is frequently used in conjunction with chemotherapy (chemoradiation).
There are a number of new very sophisticated forms of radiotherapy whih may be used in the treatment of localised brain tumours. These are:
- Sterotactic RadioTherapy (SRT) is a form of high precision radiotherapy that focuses on the whole tumour with very little effect to surrounding normal tissues.
- Radiosurgery is a form of stereotactic radiotherapy where the treatment is given in one long session instead of a number of shorter sessions.
- Tomotherapy delivers radiation to tumours with extreme precision using thousands of small beams. Daily CT scans are then used to plan the treatment precisely allowing for the smallest of changes in tumour size.
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. Treating brain tumours with drugs can be difficult as many drugs do not cross from the blood vessels into the brain. This is called the blood-brain barrier, which is usually very helpful in keeping harmful substances out of the brain. If drugs that do not cross the blood-brain barrier are required in the treatment of a tumour, they can be given directly into the cerebrospinal fluid.
Chemotherapy may be given to try to prevent a brain tumour from recurring after surgery, or to treat recurrences if they occur, to treat a brain tumour where surgery is not possible or to shrink a tumour so that surgery is easier.
But not all brain tumours respond to chemotherapy - for more details see the treatment for specific brain tumours below.
Chemotherapy is often given instead of raadiotherapy in young children. This is to avoid the long term side effects of radiotherapy in children under three years of age.
Chemoradiation
Radiotherapy and chemotherapy are used as combined treatment for glioblastoma multiforme.
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Key Trends
- High-grade (anaplastic) gliomas are occurring more often. They are becoming more common in older people.
- Chemoradiation is being used more and is becoming the standard treatment in many forms of brain tumour.
- Secondary brain tumours (metastases) from cancers of the lung, breast gastrointestinal tract and other sites are now being treated in many centres.
- Sophisticated forms of radiotherapy (including stereotactic radiotherapy, radiosurgery and tomotherapy) are now being used to treat a wide range of brain tumours.
- New forms of imaging (functional imaging) allow more precise diagnosis and treatment planning.
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Important Research Areas
- The use of gene profiling to determine which patients are best suited to particular treatments, thus avoiding giving the toxic side effects of treatment to patients where overall the treatment is unlikely to succeed.
- New ‘molecular targeted agents’ and their use in the treatment of various forms of brain tumour. These include monoclonal antibodies and small molecules which target cell growth pathways and may be investigated for their ability to enhance the effectiveness of radiotherapy as well.
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