This information is about brain tumours in children. It is helpful to read it alongside our general information on children's cancer, which contains more information about cancers in children, their diagnosis and treatment, and the support services available.

Brain tumours are the most common solid tumours that occur in children. Children of any age may be affected. Each year, about 350 children in the UK develop brain tumours. Boys are affected more often than girls.

Brain tumours can be either primary or secondary. Primary brain tumours are tumours which develop in the brain. Secondary brain tumours (more commonly called cerebral metastases) occur when cancer cells from other parts of the body spread to the brain. This section is about primary brain tumours.

The brain, together with the spinal cord, makes up the central nervous system (CNS), which controls all of our body’s functions. Between the brain and the skull are three layers of membrane called meninges, which completely cover the brain and spinal cord, giving them protection. A fluid called cerebrospinal fluid (CSF) is contained between two of these layers and cushions the brain.

Like every other organ in the body, the brain is made up of cells. There are about 40 billion nerve cells, known as neurons, in the brain. These cells communicate with each other and with other parts of the body by sending messages (nerve impulses) through a system of nerve pathways or networks.

The main parts of the brain are:

• the cerebrum (the forebrain)
• the cerebellum (the hindbrain)
• the brain stem

Cerebrum This is the largest area of the brain and is made up of two halves or hemispheres. The right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body. Each hemisphere is divided into four areas or lobes: frontal, parietal, temporal and occipital. Each lobe controls a different range of activities. The cerebrum is mainly concerned with mental functions such as thinking, memory, speech, hearing and vision. It also deals with motor function and sensation.

Cerebellum This is the back part of the brain and is concerned with balance and coordination.

Brain stem The brain stem controls the basic functions that are essential for maintaining life, including blood pressure, breathing, heart beat and eye movement. It is at the bottom (base) of the brain and connects to the spinal cord.

The structures and functions of the brain are described in more detail in our general information about brain tumours.

Primary brain tumours can develop from any of the different types of cells found in the brain. They can be either non-cancerous (benign) or cancerous (malignant).

Most primary brain tumours are benign, which means they remain in the part of the brain in which they started and do not spread into and destroy other areas of the brain.

Malignant primary brain tumours are most likely to cause problems by spreading to the normal brain tissue which surrounds them. This can cause pressure and damage to the surrounding areas.

The two main types of brain tumours that affect children are gliomas and medulloblastomas.

Gliomas develop from the supporting cells of the brain (which hold the nerve cells in place). They can be subdivided into two main types in children: astrocytomas and ependymomas.

Medulloblastomas usually develop in the cerebellum at the back of the brain. They may spread to other parts of the brain or into the spinal cord.

Although the cause of brain tumours is unknown, research is ongoing to try to find the cause.

Brain tumours may cause a wide variety of symptoms. These are usually caused by a rise in pressure within the brain (raised intracranial pressure). This happens when the tumour blocks the flow of the cerebrospinal fluid (CSF) around the brain (this is called hydrocephalus). There are many varied symptoms, including headaches, feeling and/or being sick, drowsiness, irritability, fits (seizures) or moments of unconsciousness.

If hydrocephalus occurs in a young baby, the soft spot on the top of their head may bulge and their head may increase in size.

Other symptoms depend on the position of the tumour within the brain. For example, a tumour in the cerebellum may cause weakness and unsteadiness when walking. These symptoms are described in more detail in our information about brain tumours.

A variety of tests and investigations may be needed to diagnose a brain tumour. The specialist will select the most suitable tests for the situation. These may include: a CT scan or MRI scan which give a detailed image of the inside of the brain. A brain angiogram (which shows up the structure of the blood vessels in the brain) is sometimes used to help plan surgery.

Careful examination of the eyes is important as this can show if there is any raised intracranial pressure. Hearing tests may also be done. A sample of cells from the tumour (a biopsy) is often taken.

A chest x-ray and blood tests may be needed to check your child’s general health. Any tests and investigations that your child needs will be explained to you. Our general information on children’s cancers, gives details of what the tests and scans involve.

A biopsy is the removal of a small sample of the tumour to find out exactly which type of tumour it is. Having a biopsy is likely to mean you have to spend a few days in hospital as it involves an operation under a general anaesthetic.

During the operation, a small hole, called a burr hole, is made in the skull. A fine needle is then passed down through the burr hole to remove a sample of the tumour. This is examined in the laboratory by a pathologist. In some situations, the exact type of tumour is not identified until the whole tumour, or part of it, is removed during surgery (an excision biopsy).

Close examination of tumour cells under the microscope helps doctors identify the specific type of brain tumour (classification) and how fast, or slow-growing it is likely to be (its grade).

Brain tumours arise from different types of brain cells; they are classified and named according to the cells in which they began.

Many brain tumours start in glial cells (supporting cells) and are known as gliomas. They include astrocytomas, ependymomas and oligodendrogliomas. Gliomas are graded according to how potentially slow-growing (low-grade) or fast-growing (high-grade) they are. Grade 1 is slow-growing, and grade 4 is the fastest-growing type.

Other types of brain tumour may not be given a numerical grade, but may be classified as being high-grade or low-grade.

Surgery, radiotherapy or chemotherapy may be used alone, or in combination, to treat brain tumours. Your child’s doctor will plan the treatment, taking into consideration the size, position and type of brain tumour. In most cases, a doctor specialising in brain tumours (neurosurgeon) will operate to remove as much of the tumour as possible.

A fine tube (shunt) may be inserted to drain excess fluid from the brain and into the lining of the abdominal cavity (peritoneum). This will stop any further rise in intracranial pressure. The shunt is not visible outside of the body. After brain surgery, a child will usually spend a few days in an intensive care ward.

If a tumour cannot be completely removed, or if there is a chance that some cancer cells have been left behind, radiotherapy may be given after the surgery. Radiotherapy treats cancer by using high-energy rays that destroy the cancer cells. It may also be used as the main treatment if surgery is not possible.

Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is used routinely to treat medulloblastoma and is increasingly being used to treat other types of brain tumours. Chemotherapy may also be used in situations where the tumour cannot be removed completely with surgery. It can be given in the form of tablets, or by injection into a vein (intravenously).

Steroids may also be given, as they can help to reduce the swelling that often surrounds brain tumours. The steroids do not treat the tumour but can improve symptoms. They may be given before or after surgery, or during or after radiotherapy.

Drugs to prevent fits (known as anticonvulsants) may also be given. There are many different types of anticonvulsants. Commonly used drugs are carbamazepine and phenytoin.

Treatment often causes side effects, and your child’s doctor will discuss this with you before treatment starts. Possible side effects include:

• hair loss
• tiredness
• feeling sick (nausea) and vomiting
• lowered resistance to infection
• bruising and anaemia due to a temporary reduction in the number of blood cells made in the bone marrow.

Late side effects

Any disease of the brain, or its treatment by surgery, radiotherapy or chemotherapy, may affect your child’s physical and intellectual development. This is especially important if the child is very young, when the brain is growing quickly. Different treatments may be recommended at different ages. The possible risks of any treatment given will be explained to you.

More detailed information about the possible late side effects of treatment can be found in our general information on children's cancer.

Many children have their treatment as part of a clinical research trial. Trials aim to improve our understanding of the best way to treat an illness (usually by comparing the standard treatment with a new or modified version of the standard treatment). Specialist doctors carry out trials for brain tumours. Your child's medical team will talk to you about taking part in a clinical trial (if appropriate) and will answer any questions you may have. Written information is often provided to help explain things. Taking part in a research trial is completely voluntary, and you'll be given plenty of time to decide if it is right for your child.

After treatment is completed, your child will be seen regularly by specialists, who will look for signs of the cancer coming back and any side effects of treatment. If you have specific concerns about your child’s condition and treatment, it is best to discuss them with your child’s doctor, who knows the situation in detail.

As a parent, the fact that your child has cancer is one of the worst situations you can be faced with. You may have many different emotions, such as fear, guilt, sadness, anger and uncertainty. These are all normal reactions, and are part of the process that many parents go through at such a difficult time.

Your child may have a range of powerful emotions throughout their experience of cancer. Our booklet, Peppermint Ward, is a storybook for younger children with cancer. It looks at the issues that they and their family may face, and helps them to explore their feelings.

This section has been compiled using information from a number of reliable sources, including:

• Cancer in Children: Clinical Management (5th ed). Eds PA Voute et al. Oxford University Press, 2005.

For further references, please see the general bibliography.