Introducing GIST

Gastrointestinal stromal tumour usually forms on the stomach or the upper intestine. Occasionally it is found lower down the GI system. It is a cancer of the cells which form the structure of the stomach and intestine, not a cancer of the linings of the organ itself (that would be a carcinoma). This means that it is usually painless and until it causes a swelling, or discomfort by pressing on other organs, or ruptures causing blood loss and anaemia, it may remain undetected.

Many low grade GISTs are found during other forms of GI surgery and may be removed, often identified as a benign tumour. This happened more frequently prior to the discovery of Glivec and GI surgeons are more cautious today. It does mean however that there are people who have had a GIST removed and remain unaware of the fact.

Because of the difficulty of identifying GIST early, many patients first present with advanced disease. High grade GIST metastasises readily - usually to the liver - so although a surgeon may be able to successfully remove the primary tumour it is not unusual for more advanced disease to set in quite quickly. About 80% of patients with high grade tumours have advanced GIST.

The disease is resistant to radiotherapy and traditional chemotherapies. Until Glivec was first made available to advanced and metastatic GIST patients in 2000 the prospect of long-term survival for this group of patients was very poor indeed.

It is calculated that about 50% of all GIST patients are cured by surgery. Calculating the numbers is problematical because GIST is not separately identified in cancer statistics, being reported as both a sarcoma and as a GI cancer quite separately, depending on which speciality the consultant treating the patient belongs to.

When a GIST is diagnosed early the consultant may seek to treat the patient with Glivec prior to surgery. This is not a licensed use of the drug but may be permitted under certain trial conditions. There is some evidence that in this case surgery can be less radical and patients can recover quicker and more completely.