If the biopsy result shows that you have cancer, your doctor may want to do some further tests to find out more about the extent (stage) of your cancer. The results of all these tests help the doctor gather as much information as possible, so they can decide which is the best type of treatment for you.

Your doctor will decide which particular tests are necessary in your case. These may include some of the following:

The doctor may want to take x-rays of your face or neck to see whether any bones have been affected. An x-ray known as an orthopantomogram (OPG) may be taken to look at your jaw and to check your teeth.

You may have a chest x-ray to check your general health and to see whether the cancer has spread to the lungs. It is very rare for head and neck cancers to spread beyond the head and neck area, but if they do it is often to the lungs.

A CT (computerised tomography) scan is a series of x-rays, which builds up a three-dimensional picture of the inside of the body. The scan is painless but takes 10–30 minutes. CT scans expose you to a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you come into contact with.

You will be asked not to eat or drink for at least four hours before the scan.

You may be given a drink or injection of a dye which allows particular areas to be seen more clearly. For a few minutes this may make you feel hot all over. Before having the injection or drink, it is important to tell your doctor and the person doing the test if you are allergic to iodine or have asthma.

You will probably be able to go home as soon as the scan is over.

An MRI (magnetic resonance imaging) scan is similar to a CT scan but uses magnetism instead of x-rays to build up a detailed picture of areas of your body.

You will need to lie very still on a couch inside a long chamber, for about 30 minutes. This can be unpleasant if you don't like enclosed spaces. If this is the case, it may help to mention this to the radiographer. The MRI scanning process is also very noisy, but you will be given earplugs or headphones to wear. You may be able to take someone with you into the room to keep you company.

The chamber is a very powerful magnet, so you should remove any metal belongings before entering the room. People who have cardiac monitors, pacemakers or some types of surgical clips cannot have an MRI because of the magnetic fields.

Positron Emission Tomography scans (PET scans) are a new type of scan and you may have to travel to a specialist centre to have one. They are not always necessary but you can discuss with your doctor whether one would be useful in your case. PET scans can be used to find whether a head and neck cancer has spread beyond the original site, or to examine any lumps that remain after treatment to see whether they are scar tissue or whether cancer cells are still present.

A PET scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. A scan is then taken a couple of hours later. Areas of cancer are usually more active than surrounding tissue and show up on the scan.

Cancers of the mouth and throat do not usually spread to other parts of the body, apart from to the lymph glands in the neck. For this reason, further tests to check whether the cancer has spread beyond the head and neck are unlikely. Occasionally, however, a bone scan may be needed to see if the cancer has spread into nearby bones such as the jawbone, but this is not common.

Bone scans are very sensitive and can detect cancer cells before they show up on x-ray. A small amount of a mildly radioactive liquid is injected into a vein, usually in the arm for this test. A scan is then taken. As abnormal bone absorbs more of the radioactive liquid than normal bone, this shows up on the scan.

After the injection you will have to wait up to three hours before the scan can be taken, so you may want to take a magazine or book with you, or a friend to keep you company.

The level of radioactivity used in these scans is very low and not harmful. It disappears from the body within a few hours.

Occasionally it is necessary to do other tests to give further information about the extent of your cancer. These may include a barium swallow or ultrasound scanning. Your doctor or nurse will explain these tests to you.

It will probably take several days for the results of your tests to be ready, and this waiting period will obviously be an anxious time for you. It may be helpful to find a close friend or relative with whom you can talk things over. You could also call our cancer support service to speak to one of the specialist cancer nurses.