The treatment for gastrointestinal stroma tumours (GISTs) depends on a number of factors, including your general health and the size and position of the tumour. The results of your tests will help your doctors decide on the best treatment for you.

Surgery is usually the first choice of treatment for a GIST, although the decision to operate depends on the size and location of the tumour. The surgeon will remove the tumour, along with some surrounding healthy tissue. If the tumour has begun to grow into other tissues close by, these are also removed. The aim is to make sure that all the GIST cells have been taken away.

If the GIST has begun to spread, it is sometimes possible to remove the secondary tumours. Surgery may also be used to treat GISTs that come back after treatment.

If the GIST is in your small bowel, you may have an operation to remove part of the small bowel.

If you have GIST in your stomach, you may need to have part or most of your stomach removed. This may mean making changes to your diet, particularly the size and frequency of your meals. Our specialist dietitians will give you advice and support around this.

Your surgeon will tell you about any possible effects of the surgery that is planned for you. The possible effects will depend on the size and location on the tumour.

If the GIST is very large or in a difficult position, or if there are several other tumours, you will usually be treated with targeted therapy. This works by blocking signals within the cancer cells that make them grow and divide.

In about 85 per cent of people with a GIST, the tumour cells have a change (mutation) in a protein called KIT. This change means the GIST cells constantly get signals telling them to grow and multiply.

Treatment with growth inhibitors can block these signals. This may make the cancer shrink or stop it from growing. Growth inhibitors may be used to treat GISTs that can't be completely removed with an operation. There are two therapies that can be used to treat a GIST: imatinib (Glivec™) and sunitinib.

The side effects of imatinib are usually mild or moderate and include: tiredness, feeling sick (nausea), diarrhoea, swollen ankles and puffy eyes, and an itchy rash. Common side effects of sunitinib include: a skin rash and soreness, tiredness, mouth ulcers and high blood pressure. These side effects can usually be well controlled with medicines. Always tell your doctor if they continue or are troublesome.

The National Institute for Health and Care Excellence (NICE) advises doctors on the use of new drugs and treatments in the NHS. It recommends that imatinib is used as the first treatment for people with a GIST that can't be completely removed with surgery or has begun to spread. Treatment with imatinib should be continued for as long as it is working.

Imatinib may sometimes be given to people who have had surgery to completely remove a GIST, but who have a high risk of the cancer coming back. Treatment that is given to reduce the risk of cancer returning is called adjuvant therapy. This treatment has not been approved by NICE, which means that imatinib may not be widely available as adjuvant therapy for GIST in the NHS.

Sunitinib may be used if imatinib doesn't work or if it stops working. NICE has recommended sunitinib as a treatment option for people with GIST.