A GIST is a rare type of sarcoma found in the digestive system, most often in the wall of the stomach. A soft tissue sarcoma is a type of cancer.
Who gets GIST
GIST is most common in older people.
People with a genetic condition called neurofibromatosis (NF), have an increased risk of developing a GIST.
GIST in children is rare.
People with an early stage GIST often do not have any symptoms. So an 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 an advanced GIST are likely to include:
- pain or discomfort in the tummy (abdomen)
- a feeling of fullness
- being sick
- blood in your stools or vomit
- feeling very tired
- a low red blood cell count (anaemia)
Your treatment depends on the size and position of the cancer, and your general health. Your specialist will discuss this with you.
Surgery is usually the main treatment for GIST. Your surgeon aims to remove as much of the cancer as possible with a border of healthy tissue (clear margin) around it. Having a border of healthy tissue without any cancer cells is important as it lowers the risk of the cancer coming back.
Surgery might cure a smaller GIST. But it might not be possible for a surgeon to remove a larger GIST completely.
GIST can sometimes spread to other parts of the body. This spread is called a secondary or metastases. In some situations, it might be possible for a surgeon to remove these secondaries.
GIST in the stomach means your surgeon might need to remove all or part of your stomach. They may also need to remove your spleen. Surgery to the stomach is a big operation and it will take some time to adjust your eating afterwards. You will probably have to eat small, frequent meals (about two hourly) for quite a long time after the operation.
Targeted cancer drugs
Cancer cells have changes in their genes (DNA) that make them different from normal cells. These changes mean that they behave differently. Cancer cells can grow faster than normal cells and sometimes spread. Targeted cancer drugs work by ‘targeting’ those differences that a cancer cell has.
A type of targeted cancer drug used for GIST is called a tyrosine kinase inhibitor (TKI). They block chemical messengers (enzymes) called tyrosine kinases. Tyrosine kinases help to send growth signals in cells, so blocking them stops the cell growing and dividing.
Examples of TKIs used to treat GIST include:
- imatinib (Glivec)
- sunitinib (Sutent)
- regorafenib (Stivarga)
You might have imatinib to treat a GIST that can’t be completely removed with surgery, or which has spread before surgery.
Some people with GIST have a higher risk of their cancer coming back after surgery. This is called a high risk GIST. Imatinib can help to reduce the chances of the GIST coming back. So in this situation, your doctor may recommend you take imatinib for up to 3 years after your operation.
You may also have imatinib 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 imatinib.
Protein testing for imatinib
Your doctor needs a sample of your GIST to carry our protein testing. This sample might be from when you had a biopsy to diagnose GIST, or an operation to remove the GIST. The cells are tested to see if they 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, imatinib is likely to work very well. But it can work even for GISTs that are CD117 negative.
Your doctor might recommend that you have sunitinib (Sutent) in one of the following situations:
- imatinib has stopped working
- you have had severe side effects with imatinib treatment
You must have GIST that cannot be completely removed or has spread.
Regorafenib (Stivarga) is used to treat advanced GIST. Your doctor might recommend regorafenib if you have had treatment with imatinib and sunitinib and these drugs:
- have not worked
- or caused bad side effects
Advanced GIST means you cannot have surgery to remove the GIST, or it has spread. You must be fairly fit and well to have this drug.
Coping with a diagnosis of a rare cancer can be especially difficult, both practically and emotionally. Being well informed about your cancer and its treatment can make it easier to make decisions and cope with what happens.
Talking to other people
Talking to other people who have the same thing can also help.
Our discussion forum Cancer Chat is a place for anyone affected by cancer. You can share experiences, stories and information with other people who know what you are going through.
Some sarcoma organisations offer information and support, especially GIST Support UK. This is an organisation of people with GIST and their families
What is a GIST?
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, that may or may not be cancer.
Some GISTs behave in a non cancerous (benign) way. Generally, a tumour that behaves in a benign way tends to be relatively slow growing and is less likely to come back.
A tumour that behaves in a cancerous (malignant) way is faster growing, and is more likely to come back or spread.
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 cancer. Most of these tumours start in the stromal tissue of 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.