Brain Tumours

Where most brain tumours start

In adults, most brain tumours grow in the

• Forebrain
• Thin layers of body tissue covering the brain (the meninges) or
• Nerves entering or leaving the brain

In children, the picture is slightly different. 6 out of 10 (60%) childhood brain tumours are in the hindbrain or brain stem. Only 4 out of 10 (40%) are in the forebrain.

Secondary brain tumours

In adults, most cancers found in the brain are not tumours that started in brain cells. They are other types of cancer that have spread to the brain. These are called secondary brain tumours.
If you or your relative have cancer in the brain, but have had another cancer diagnosed (for example in the lung, breast or bowel) then it is most likely that the cancer in your brain is a secondary cancer that has spread and not a primary brain tumour.

Where brain tumours start

Cancer in the brain can start in the brain or spread from another cancer somewhere else in the body. Cancers that start in the brain are called primary brain tumours. Most of the information in this section of the website is about primary brain tumours. Some of it will be useful for both types. For example, the living with a brain tumour section.

Cancers that have spread to the brain from somewhere else are called secondary brain tumours. Cancers of the lung, breast, kidney, stomach, bowel (colon), and melanoma skin cancer can all spread to the brain.

How cancers spread to the brain
Cancer cells break away from the main tumour and travel through the bloodstream to lodge in the brain and begin to grow into new tumours. There is information about the treatment of secondary brain tumours in this section of the website.

If you are looking for information, it is important to understand which of these types of brain cancer you have. The treatment and outlook may be very different for each.

What secondary brain tumours are
Secondary brain tumours are cancers that have spread to the brain from somewhere else in the body. The commonest cancers that spread to the brain are

• Lung cancer
• Breast cancer
• Bowel cancer (colorectal cancer)
• Melanoma
• Kidney cancer

Other types of cancer can spread to the brain, but these are the most common. When a cancer spreads, first some cells break away from the primary cancer (in the lung or breast, for example). These cells then travel through the bloodstream and lodge somewhere else in the body, in this case, the brain. After some time, they can begin to grow into new tumours. These secondary tumours can cause:

• Headaches
• Feeling sick
• Weakness of an arm or leg
• Fits (seizures)
• Personality or mood changes

The exact symptoms will depend on where in your brain the secondary tumours are. They can cause pressure on the surrounding brain tissue and the symptoms will depend on what this part of the brain does.

Fits (seizures) can mean a number of different things. The most well known type of fit affects the whole body, with jerking of the arms and legs and unconsciousness during the fit and for a short time afterwards. These are sometimes called grand mal fits. There are other less severe types of fit - just affecting one arm or leg, for example. It is also possible to have petit mal fits. These are when you just forget where you are for a few moments or don't seem to make sense to the people around you. When you come to, you will not know what happened or remember anything you said.

Your doctor can only be certain that your brain tumour is secondary to another cancer by taking a biopsy and looking at the cells under a microscope. It is usually clear that the cells are cancerous breast or lung cells, for example, and were not originally brain cells. But having a biopsy of a brain tumour is a major medical procedure. And, taking your medical history into account, it will usually be clear from looking at brain scans what has happened, without doing a biopsy. Secondary brain tumours usually look quite different to primary brain tumours on a scan. They are usually rounder and less likely to grow into the surrounding brain tissue.

Secondary brain tumours can be treated with

• Radiotherapy
• Surgery
• Chemotherapy

Radiotherapy
Radiotherapy is the commonest treatment for secondary brain tumours. The amount of radiotherapy you have will depend on the size of the area of your brain affected by cancer. The specialist may suggest treating your whole brain if there is a risk that other secondary tumours will develop in the future. For whole brain radiotherapy, or for larger areas, you will usually have conventional external beam radiotherapy over 1 or 2 weeks.

Your doctor may recommend targeted radiotherapy (stereotactic radiotherapy) if you have only one or two small secondary brain tumours. Or they may recommend cyberknife treatment if you have several tumours. There is more about stereotactic treatment in this section of the website and a page about cyberknife treatment in our question and answer section.

Surgery

It is sometimes possible to remove secondary brain tumours with surgery. This is most likely to be done if you have a single secondary brain tumour. Secondary cancers are often too widely spread within the brain for surgery to be possible.

If it is possible to remove your secondary brain tumours,the procedure for removing a secondary tumour is much the same as that for removing a primary tumour.

Your specialist may suggest radiotherapy after you have had your secondary tumours removed. There may be cancer cells left in your brain that could grow into new tumours. The aim of the radiotherapy is to try to kill off these cells and stop any other secondary cancers from starting to grow.

Chemotherapy
Depending on the type of cancer you have, your specialist may suggest chemotherapy for a secondary brain tumour. For chemotherapy to be the best treatment, it will have to be a type of primary cancer that

• Responds well to chemotherapy
• Can be treated with drugs that cross the blood-brain barrier

What stereotactic radiotherapy is
Stereotactic radiotherapy is a way of targeting radiotherapy very precisely at the tumour. You have the treatment aimed at the tumour from many different points around your head. This type of treatment is not available at all hospitals because it needs specialist equipment and skills.
The radiotherapy beam is targeted very accurately with this type of treatment. So it is vitally important that your head is in exactly the same position each time and does not move while you are being treated.
You have the treatment with a linear accelerator (LINAC). This is the same type of radiotherapy machine used for regular external beam radiotherapy. Stereotactic radiotherapy treatment is usually divided into between 6 and 25 daily doses called fractions. A single fraction of stereotactic radiotherapy is called radiosurgery.

What stereotactic radiotherapy is used for

This type of treatment can be used for

• Secondary brain tumours
• Gliomas that have come back since they were first treated

You can't have this type of treatment as your main treatment for high grade brain tumours. High grade tumours tend to send finger like growths into the normal brain tissue. This would mean that you would need to have too large an area of the brain treated.

The head frame
To have stereotactic radiotherapy you need to have a head frame made. This can take up to a week to do and must be very accurate. The frame is made very carefully and specifically for you using the information from your scans.
Another way of fixing the frame is to have a thermoplastic mask made. The frame fixes to the mask. The mask in turn attaches to the scanner or radiotherapy machine bed while you are wearing it. This means you cannot move, but there is nothing actually attached to you directly.

Planning stereotactic radiotherapy
Stereotactic radiotherapy planning is similar to having planning for normal external radiotherapy. The specialist uses a CT scanner or MRI scanner. You have to wear your mask and head frame while your treatment is being planned.

During planning, your specialist uses the scans to work out how to shape the radiotherapy beam so that it exactly fits your tumour. This means that the normal brain tissue surrounding the tumour gets a very low dose of radiation. So you will have fewer side effects than with conventional radiotherapy.

The planning session is the most important part of your treatment. Your specialist has to do this very carefully and precisely and it can take up to 2 ½ hours.

Having your treatment
You go to the hospital a number of times to have treatment. The treatment itself does not take very long. But it takes a little while for the radiographer to fit the mask and head frame and position you on the radiotherapy table. You can go home as soon as each treatment is over.

Side effects
Stereotactic radiotherapy treatment has fewer side effects than the usual type of radiotherapy. This is because less healthy brain tissue is exposed to radiation. You will not normally have hair loss, feel sick, or have any reddening of your skin. All these are common side effects of regular external beam radiotherapy to the brain. But you may feel very tired for a while afterwards.