What is the treatment for GIST - gastrointestinal stromal tumour?

This page tells you about GIST. There is information about

• What GIST is
• Symptoms of GIST
• Treatment for GIST

• Is GIST curable?
• Where to find more information

GIST is a rare type of sarcoma found in the digestive system, most often in the wall of the stomach. Some GISTS are benign (not cancerous) but they can become cancerous if not treated. Generally speaking, the larger the GIST, the more likely it is to be cancerous.

These tumours have a rather complicated name. Gastrointestinal means they start in the digestive system (the gastrointestinal tract). Stromal means they develop from tissues that support the connective tissues controlling the movements of the gut. Tumour means a lump or growth in the body.

About 6 out of 10 (60%) of these tumours start in the stomach, but they can begin anywhere in the digestive system, for example in the bowel or food pipe (oesophagus). Very rarely, they develop outside the gastrointestinal tract.

These tumours are most common occur in people between 50 and 70 years old. We don't really know the cause but if you have the genetic condition called neurofibromatosis (NF) it can increase the risk of developing a GIST. Rarely, GIST can develop in children and there are about 20 cases a year in the UK.

People with early stage GIST often do not have any symptoms. They may be found when doing tests for other medical conditions. Most GISTs are diagnosed in later stages of the disease. The symptoms of advanced GIST are likely to include

• Pain or discomfort in the tummy (abdomen)
• A feeling of fullness
• Being sick
• Blood in stools or vomit
• Feeling very tired
• A low red blood cell count (anaemia)

Other medical conditions apart from GIST can cause these symptoms. If you have these symptoms you should see your doctor. It may be nothing serious but it is always best to check.

The most common treatment used is surgery and this alone may be a cure for people with small tumours. But larger tumours are less likely to be completely removed. If the GIST has spread to other parts of the body, it is sometimes possible to remove these secondary tumours too. Chemotherapy and radiotherapy don't work well for GIST, so researchers have been looking for other types of treatment.

Glivec (imatinib) is often used to treat GIST that can't be completely removed with surgery. Glivec is a type of biological therapy called a tyrosine kinase inhibitor. This means it blocks a chemical (an enzyme) that the cancer needs in order to grow.

Your surgeon removes a sample of your tumour during your operation and sends it to the laboratory. A specialist tests the cells to confirm the diagnosis of GIST, and to see if the cells have a receptor on their surface called CD117. If the cells are CD117 positive, Glivec is likely to work very well. But it can work even for GISTs that are CD117 negative.

Glivec is a tablet. So you can have treatment at home. The National Institute for Health and Clinical Excellence (NICE) recommend that people have a dose of 400mg a day of imatinib (Glivec) for 12 weeks. After that, your specialist will arrange a CT scan to see if your GIST has responded to the treatment. In some cases, the GIST will disappear altogether. But to show a response to treatment, the GIST may not necessarily have shrunk. It may have become less dense. Your doctor may say it has become cystic. This means that there is fluid inside it, instead of solid tumour. Improvement in your symptoms is another way of telling that the treatment is working.

If the Glivec appears to be helping, you carry on treatment for another 12 weeks. Then your specialist checks again to see how the GIST has responded. You carry on having treatment until your GIST comes back, or shows signs of growing again.

Glivec may also be used to shrink a GIST before surgery so that it can be removed more easily. If your GIST responds to treatment with Glivec, it may become possible for you to have surgery to remove it completely. Sometimes it is even possible to remove GIST tumours that have spread to another part of the body, such as the liver.

If your GIST has grown or your symptoms have got worse, your specialist will know that Glivec is not helping and may recommend stopping treatment. NICE do not currently approve increasing the dose of Glivec, but this has been tested and there is some evidence that it may help.

A European trial is looking at whether Glivec (imatinib) can stop GISTs coming back when they have been completely removed by surgery. Having a treatment in addition to your main treatment is called adjuvant treatment. An American trial also looked into this and found that for 98 out of 100 people (98%) taking Glivec, the GIST stayed under control for at least 1 year, compared to 83 out of 100 people (83%) for those not taking Glivec. In August 2010 NICE decided not to recommend imatinib after surgery. The recommendations say that people need to be followed up for longer to work out how well it works. NICE will look at it again once the results of the European trial are available. In August 2010, the Scottish Medicines Consortium (SMC) assessed Glivec as an adjuvant treatment and said it should be available within the NHS in Scotland for people who have CD117 positive GIST at high risk of coming back after surgery.

There is an international trial comparing a new type of biological therapy called nilotinib (Tasigna) with imatinib for gastrointestinal stromal tumours that cannot be completely removed with surgery, or have spread to other parts of the body. The trial aims to find out if nilotinib helps people with a GIST more than imatinib. It also aims to learn more about the side effects of nilotinib.

A drug, called sunitinib (Sutent) was recently licensed in Europe to treat GIST if Glivec does not work, or stops working. The SMC (Scottish Medicines Consortium) recommends sunitinib for GIST that cannot be operated on. And for GIST that has spread after treatment with imatinib that has not worked because of drug resistance or because the side effects are too bad. In February 2008, the AWMSG (All Wales Medicines Strategy Group) made the same decision covering the NHS in Wales. In September 2009 NICE said sunitinib could be used on the NHS in England for people with advanced cancer, who are not suitable for surgery when Glivec is not working. They also say that the manufacturers have to agree to pay for the first cycle of treatment.

If GIST can be completely removed with surgery, then it may be cured. As with any cancer, there is a chance that the tumour could come back. Because of this risk, you will have regular check ups with your specialist for some time after your surgery. It is best that you talk to your own specialist about whether there is a risk of GIST returning, as the circumstances will be different for each person.

Since the discovery of Glivec, people with GIST that cannot be completely removed are doing much better. Unfortunately, specialists don't think it is a complete cure. How people respond to particular drugs will always vary, depending on all their individual circumstances. But generally, Glivec stops GIST from growing for around 2 years. Even if the GIST comes back, Glivec may still help to slow down the growth of the tumour and may help to control it for another few years. As Glivec is a relatively new treatment, we don't have the full picture as yet. According to our specialist advisors, the longest survivors are approaching 8 years of Glivec treatment, with no sign of their GIST returning. There is research to find out the best treatment for people to have after Glivec stops working.

There is a whole section of CancerHelp UK on soft tissue sarcomas and some of that information may be useful to you. There are other useful organisations listed on our sarcoma organisations and sarcoma links pages. In particular, you are likely to find GIST Support UK of help. This is an organisation of people with GIST and their families. Their website has lots of useful information.