What is GIST?
GastroIntestinal Stromal Tumour, or GIST for short, is a very rare cancer, a kind of sarcoma (cancer of the soft/connective tissues, rather than a carcinoma). About 0.2% of tumours in the gastrointestinal area are GIST's.
- Gastrointestinal means that it occurs in the digestive tract, anywhere from the oesophagus to the rectum i.e. the gullet, stomach, intestines.
- Stromal indicates that the tumours occur, not in the "functioning" part of the organ but in the tissues (the stromal cells) that hold the organ in place in the body. So, for example, a GIST in or near the colon is not "cancer of the colon" because it does not occur in the functioning part of the colon but in the tissues which support the colon. (For reference, the functioning parts of any organ are made up of so-called parenchymal cells).
- Tumour simply means that the GIST condition is producing a solid(ish) lump unlike, e.g. leukaemia.
GISTs are malignant tumours of soft tissues in the gastro-intestinal tract (the stomach and intestines).
How common is GIST?
There are probably around 900 new cases each year in the UK. GISTs mostly affect people between 55 and 65, but there are GIST patients both younger and older. It has only been possible to diagnose GISTs unambiguously since 2000, and because of their rarity many GPs will never see a case in the whole of their career.
GIST in children and young adults is even rarer. There is now a UK group gathering data on this super-rare paediatric GIST, which does behave differently in some ways from GIST in adults. (See our section on PAWS GIST).
- Discomfort or pain in the stomach or intestines
- Bleeding from the stomach or intestines
- Weight gain
- Weight loss
- Night sweats
Because GISTs do not interfere directly with the workings of an organ, they often grow for some time without producing any symptoms. Even when they do produce symptoms, these are very varied, and all of them can be caused by other things. It is the presence of one or more of these symptoms, which cannot be explained in any other way, which should lead to a possible diagnosis of GIST.
If a tumour is found which could be a GIST, current opinion is that it is probably best to remove the tumour, if possible, without doing a biopsy. Many GISTs are only firmly diagnosed after surgery. They are sometimes found when the patient is being operated on for something else. If it is not possible to remove the tumour, then a biopsy may be done endoscopically. (Using an instrument passed into the stomach or intestines through the mouth, or anus.)
A firm diagnosis of GIST can only be made by a pathologist looking at the tumour tissue with a microscope. There are two main definitive criteria for diagnosis: finding the location of the tumour, and finding a positive c-KIT (CD 117) or PDGFRA enzyme receptor abnormality.
Today the diagnosis of GIST has different implications from those it had even a few years ago.
- GIST can now be diagnosed unambiguously
- Scientists' understanding of GIST is increasing daily
- An operation and/or drugs (Glivec® is the first option) offer genuine treatment options
Other drugs have been developed.
(See the pages on Treatments and Clinical Trials.)
Things to Read
Visit our Publications page for a list of literature which will help you understand GIST and its treatment. We would recommend that you start with GIST for Beginners. This is published by GCUK and gives a good explanation of GIST and the methods of treatment currently available under the NHS.
GIST Patient Booklet
We are grateful to Peter Greenwood for producing this convenient pocket-sized booklet in which you can note details about your GIST and any medication you are on. It is intended for use in the event of a medical emergency. It has spaces for your name, the name of your oncologist, the drugs you are on, etc, and lists the drugs to be avoided if you are on Glivec or Sutent. The booklet is based on a translation from the German of an equivalent booklet produced by Das Lebenshaus. For your own copy of the booklet please contact firstname.lastname@example.org (A donation would be welcome to cover costs and postage!)