With the variance in survival rates so dependent on type, insurers underwriting clients with brain tumours must stay informed on all the relevant statistics. Angela Kidd provides the details.
There were around 4,300 tumours of the brain and central nervous system (CNS) diagnosed in the UK in 2003.
Brain tumours include those that develop within the brain, namely primary tumours and those that metastasise from other parts of the body, so called secondary tumours.
Primary brain tumours develop from brain cells and can be either benign or malignant. Benign tumours remain in the part of the brain in which they started and do not spread into and destroy other areas of the brain tissue or other parts of the body.
Malignant primary brain tumours are most likely to cause problems by spreading into the normal brain tissue surrounding them. These tumours rarely spread outside the brain to other parts of the body.
Secondary brain tumours are more common than primary tumours and occur when cancer cells from other parts of the body, like the lung, breast, kidney and colon, spread to the brain.
TYPES OF TUMOUR
The majority of malignant primary brain tumours arise from stromal glial cells and are known collectively as gliomas, a term that includes astrocytomas, pligodendrogliomas and ependymomas. Gliomas most commonly grow in the main part of the brain, the cerebrum. However, they can occur in most parts of the brain or the spinal cord.
Gliomas are graded from one to four depending on how abnormal the cells are and how quickly they grow. Grade one is the least malignant and grade four is the most malignant. Grades one and two may be referred to as low-grade tumours and grades three and four as high-grade tumours. Other distinct malignant primary tumours include:
n Medulloblastoma
Medulloblastomas develop in the cerebellum, in a part of the brain called the posterior fossa. They can spread to other parts of the brain or the spinal cord and this is usually through the fluid that surrounds and protects the brain and spinal cord.
n CNS lymphoma
CNS lymphomas are most commonly found in the cerebrum but often spread to other parts of the brain. It is common for more than one tumour to be present.
Examples of benign primary tumours are:
n Meningiomas
The majority of these are benign. Malignant meningiomas are very rare. Meningiomas are a tumour of the meninges, which are the protective membranes that surround the brain and spinal cord.
n Acoustic neuromas
These usually develop in the internal auditory canal. This is a slow-growing tumour and does not spread from its original site.
SIGNS AND SYMPTOMS
Brain tumours can cause almost any symptom depending on which part of the brain is affected. The warning signs are caused by raised intracranial pressure caused by the tumour growing.
Brain tumours most commonly cause headaches and vomiting. Mental symptoms may follow and can sometimes cause changes in personality, behaviour and loss of intellect.
Tumours can also cause changes in sight, confusion and may affect co-ordination. Certain types may also cause seizures.
DIAGNOSIS
Diagnosis of a brain tumour is usually confirmed by using a brain computerised tomography scan or brain magnetic resonance imaging scan.
Other investigations may include:
n Chest x-ray - this can help determine whether the tumour is a primary tumour or if it has metastasised.
n Skull x-ray - may be used when looking for intracranial pressure.
n Angiography - helps differentiate different types of tumour and may show the position of the tumour in the brain.
n Biopsy - this investigation is often necessary to determine the type of tumour.
CAUSE
The cause of most brain tumours is unknown but research is continuous.
Brain tumours, like other cancers are not infectious and cannot be passed to other people.
A known risk is to those who have received doses of radiation to the head, most likely as a result of treatment for another illness.
A small number of tumours are linked to certain genetic conditions such as neurofibromatosis and tuberous sclerosis.
TREATMENT
Treatment for brain tumours depends upon a number of factors including the size, grade and location of the tumour. As with many other types of cancer, the three main types of treatment are surgery, radiotherapy and chemotherapy. Steroid drugs can also be used to reduce swelling/pressure within the skull.
For malignant tumours, surgery is normally the main treatment. Due to size, location and spread of the tumour it may be impossible to remove the tumour completely. Follow up treatment will then be required. Some tumours cannot be surgically removed, as the risk to the rest of the brain may be too high.
Radiotherapy treatment is the use of high-energy rays to destroy cancer cells. Radiotherapy may be used after surgery to destroy any remaining cells. If surgery is not possible, it can be used alone or with chemotherapy.
Chemotherapy is the use of anti-cancer drugs, which destroy cancer cells.
For meningioma's surgery is, again, the main treatment and in many cases the tumour can be completely removed without any complications. If surgery is not possible, radiotherapy or chemotherapy may be used.
For acoustic neuroma's surgery is normally successful. There is, however, a chance of permanent hearing loss or some facial paralysis.
PROGNOSIS
Brain tumour prognosis varies widely. High-grade tumours can be fatal within a year while low-grade tumours can have many years of survival. In children, about two thirds of medulloblastomas are cured by radiotherapy. For meningiomas and acoustic neuromas there is a high cure rate with surgery alone. n
Angela Kidd is life and disability underwriter at Aegon Scottish Equitable
Links
www.cancerbackup.org.uk
www.bbc.co.uk
www.cancerhelp.org.uk
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