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. However, if left untreated, a benign behaving tumour can also 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.
Symptoms of GIST
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.
Treatment for GIST
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. For tumours in the stomach the surgeon will remove part or all of your stomach and may need to remove your spleen.
You may have a biological therapy called Gleevec (imatinib) to treat GIST that can’t be completely removed with surgery, or which has spread. Gleevec 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, Gleevec is likely to work well. But it can work even for GISTs that are CD117 negative.
Sunitinib (Sutent) has been licensed to treat GIST if Gleevec doesn’t work, or stops working. You can have sunitinib for GIST if you either can’t take Gleevec because of side effects or have GIST that has become resistant to it.
Regorafenjb (Stivarga) is licensed to treat people with advanced GIST who have had treatment with imatinib (Gleevec) 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.
Is GIST curable?
If GIST can be completely removed with surgery, then it may be cured. But 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 Gleevec, 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, Gleevec stops GIST from growing for around 2 years. Even if the GIST comes back, Gleevec may still help to slow down the growth of the tumour and may help to control it for another few years.
GIST is so rare that doctors outside the GIST centers come too little or rarely into contact with GIST. Ask therefore your doctor always for a referral to one of the GIST centers, at least for a second opinion.