Gastrointestinal stromal tumour (GIST)
GIST is a rare type of sarcoma found in the digestive system, most often in the wall of the stomach. Some GISTS behave in a non cancerous (benign) way. Or they can behave in a cancerous (malignant) way. Generally, a tumour that behaves in a benign way tends to be relatively slow growing and less likely to come back. A tumour that behaves in a malignant way is faster growing, and is more likely to come back or spread. Generally speaking, the larger the GIST, the more likely it is to behave like cancer. And if left untreated, a benign behaving tumour can start to act like a cancerous tumour.
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.
GIST is most common in people between 50 and 70 years old. We don't really know the cause. If you have the genetic condition neurofibromatosis (NF), it can increase your risk of developing GIST. Rarely, GIST can develop in children - there are about 20 cases a year in the UK.
People with early stage GIST often do not have any symptoms. So early stage GIST may be found when people are having 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. GIST is rare so they are more likely to be caused by something less serious, but it is always best to check.
The most common treatment for GIST is surgery. This alone may cure small tumours. But it is less likely that a surgeon can completely remove a larger tumour. If GIST has spread to other parts of your body, your surgeon may be able to remove these secondary tumours too.
Your surgeon removes the tumour and some tissue around it that doesn't contain any cancer cells. It depends on where your tumour is and how big it is, as to what surgery you'll need. To find information about surgery for where your cancer is go to our cancer types section and choose the part of the body the cancer is affecting. Then choose the surgery section for that type of cancer.
For tumours in the stomach the surgeon will remove part or all of your stomach and may need to remove your spleen. There is information about stomach surgery in the stomach cancer section. After surgery you will need to adjust the amount you can eat at one time. You will probably have to eat small, frequent meals (about two hourly) for quite a long time after the operation. There is information about diet after stomach surgery in the coping with stomach cancer section. If your tumour is in your bowel you can find information about surgery in the bowel cancer section.
Chemotherapy and radiotherapy don't work well for GIST, so researchers have been looking for other types of treatment. You may have a biological therapy called Glivec (imatinib) to treat GIST that can not be completely removed with surgery, or which has spread. Glivec is 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. This CD117 protein is made by a gene called c-kit. A fault in this gene causes the c-kit gene to make too much CD117 protein. Most GISTs have c-kit gene mutations.
If the GIST 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 Care 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.
You may also have Glivec to shrink a GIST before surgery, so that your surgeon can remove it more easily. Sometimes a surgeon can completely remove a GIST after treatment with Glivec. It may even be possible to remove GIST tumours that have spread to another part of the body, such as the liver.
Glivec can help reduce the chance of high risk tumours coming back after surgery. So, if your tumour is at high risk of coming back after your operation your doctor may recommend you take it for up to 3 years.
If your GIST has grown or your symptoms have got worse, your specialist may recommend stopping Glivec because it isn't helping. 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 drug, called sunitinib (Sutent) has been licensed in Europe to treat GIST if Glivec doesn't work, or stops working. You can have sunitinib for GIST if you either cannot take Glivec because of side effects or have GIST that has become resistant to it. You must have GIST that cannot be completely removed or has spread.
A drug called regorafenib (Stivarga) is licensed to treat people with advanced GIST who have had treatment with imatinib (Glivec) and sunitinib that has not worked or has caused bad side effects. Advanced GIST means you cannot have surgery to remove the GIST, or it has spread. Regorafenib has not been assessed by the National Institute for Health and Care Excellence (NICE). The All Wales Medicines Strategy Group (AWMSG) have approved regorafenib to treat people with a GIST in Wales. And the Scottish Medicines Consortium have approved regorafenib for treating GIST in Scotland.
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.
We have a whole section 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.
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