Gastrointestinal stromal tumours (GISTs)
A GIST is a type of soft tissue sarcoma. This information is about GISTs, their symptoms, how they’re diagnosed and possible treatments. It should ideally be read with our general information about soft tissue sarcomas.
We hope this information answers your questions. If you have any further questions, you can ask your doctor or nurse at the hospital where you are having your treatment.
Gastrointestinal stromal tumours (GISTs) are rare cancers. About 900 people in the UK are diagnosed with a GIST each year. They are most common in people aged 50–60 and are rare in people younger than 40.
GISTs belong to a group of cancers called soft tissue sarcomas. Sarcomas are cancers that develop in the supporting or connective tissues of the body such as muscle, fat, nerves, blood vessels, bone and cartilage.
Most GISTs begin in the stomach or small bowel, but they can occur anywhere along the length of the digestive tract. The digestive tract is the hollow tube that runs from the gullet (oesophagus) to the anus (back passage).
The walls of the digestive tract are made up of layers of muscle. GISTs start in cells (sometimes called 'pacemaker' cells) that sit in between the muscle layers. These cells send signals to the muscles to push food and liquid through the digestive tract.
Causes and possible risk factors of GISTs
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We don't yet know what causes GISTs. Most people who have a GIST don't have a family history of the condition. But there are very rare cases where several family members have been diagnosed with a GIST.
People with a condition called neurofibromatosis (NF) have a slightly increased risk of developing a GIST.
Signs and symptoms of a GIST
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Symptoms of a GIST vary depending on the size and location of the tumour. They may include:
fatigue (tiredness and a feeling of weakness)
a high temperature (fever) and sweating at night
tummy (abdominal) discomfort or pain
a painless lump in the abdomen
being sick (vomiting)
blood in the stools (bowel motions) or vomit
anaemia (low level of red blood cells).
How GISTs are diagnosed
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Usually you begin by seeing your GP, who will examine you and refer you to a hospital specialist.
At the hospital, the doctor will ask you about your general health and any previous medical problems. They will examine you and take blood samples to check your general health. The following tests may also be carried out:
An ultrasound uses sound waves to produce an image of the inside of the tummy (abdomen). Once you're lying down comfortably, a gel is spread onto your abdomen. A small device like a microphone is then moved over the area. The scan is painless and takes about 15-20 minutes.
The doctor passes a thin, flexible tube called an endoscope into your mouth, down your gullet and into your stomach and small bowel. The endoscope has a light and camera at the end, which allows the doctor to see any abnormalities. You may also have samples of tissue (biopsies) taken. These are sent to a laboratory to be tested.
An endoscopy can be uncomfortable but is not usually painful. Some people have a sore throat after an endoscopy. This gets better after a couple of days.
An endoscopic ultrasound may be used to show the size and position of a GIST. It produces an image of the stomach and surrounding structures. It’s done using an endoscope with an ultrasound probe at the end.
You may have samples of tissue (biopsies) taken from the tumour. They will be examined under a microscope.
A special test is done on the biopsy to look for a protein called KIT (CD117). Most GIST cells have this protein.
If you have a tumour that can be removed by surgery, you may not have a biopsy taken before your operation. Instead, the tumour will be sent to the laboratory after the operation for tests to confirm that it’s a GIST.
CT (computerised tomography) scan
A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of the body. The scan is painless and takes 10-30 minutes. CT scans use small amounts of radiation, which are very unlikely to hurt you or anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.
You may be given a drink or injection of a dye that allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. If you’re allergic to iodine or have asthma, you could have a more serious reaction to the injection, so it's important to let your doctor know beforehand.
MRI (magnetic resonance imaging) scan
This test is similar to a CT scan but uses magnetism instead of x-rays to build up a detailed picture of areas of your body. Before the scan, you may be asked to complete and sign a checklist. This is to make sure it’s safe for you to have an MRI scan.
Before having the scan, you’ll be asked to remove any metal belongings, including jewellery. Some people are given an injection of dye into a vein in the arm. This is called a contrast medium and can help the images from the scan show up more clearly.
During the test, you'll be asked to lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It's painless but can be slightly uncomfortable, and some people feel a bit claustrophobic during the scan. It’s also noisy, but you’ll be given earplugs or headphones. You'll be able to hear and speak to the person operating the scanner.
PET (positron emission tomography) scan
A PET scan uses low-dose radioactive sugar to measure the activity of cells in different parts of the body. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. A scan is taken a few hours later. Areas of cancer are usually more active than surrounding tissue and show up on the scan.
The stage of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the particular type and the stage of the cancer helps the doctors decide on the most appropriate treatment. Generally, sarcomas are divided into four stages, from 'small and localised' (stage 1) to 'spread into surrounding structures' (stages 2 or 3) or 'spread to other parts of the body' (stage 4). If the cancer has spread to distant parts of the body this is known as secondary or metastatic cancer.
The stage of the cancer is an important factor in helping your doctors plan the best treatment for you. They also consider other factors. These include: where the cancer started, how fast the cells are dividing and if there are genetic changes (mutations) in the cells. Your doctors will be able to tell you more about this.
If a cancer comes back after initial treatment, it is known as recurrent cancer. It may come back in the tissues where it first started (local recurrence) or it may come back in another part of the body (metastasis).
The treatment for GIST depends on a number of factors, including your general health and the size and position of the tumour. The results of your tests will help your doctors decide on the best treatment for you.
Because GISTs are rare cancers, you should be referred for treatment at a specialist unit. You may have to travel to a hospital outside your area for this.
The most common treatment for GIST is surgery to remove the tumour. Drugs known as growth inhibitors are used to treat GISTs that can't be removed with surgery.
Chemotherapy and radiotherapy don't work well for this type of cancer and so are not used.
Surgery is usually the first choice of treatment for GIST. The surgeon removes the tumour along with some surrounding healthy tissue. If the tumour has begun to grow into other tissues close by, these are also removed. The aim is to make sure that all the GIST cells have been taken away.
If the GIST has begun to spread, it is sometimes possible to remove the secondary tumours. Surgery may also be used to treat GISTs that come back after treatment.
If the GIST is in your small bowel, you may have an operation to remove part of the small bowel. This doesn't usually have any long lasting side effects.
If you have GIST in your stomach you may need to have part or most of your stomach removed. This may mean making changes to your diet, particularly the size and frequency of your meals. Specialist dietitians can give you advice and support.
Your surgeon will tell you about any possible effects of the surgery that is planned for you. The possible effects will depend on the size and location on the tumour.
Growth inhibitors are drug treatments that are taken as tablets. They work by blocking signals within the cancer cells that make them grow and divide.
In about 85% of people with a GIST, the tumour cells have a change (mutation) in a protein called KIT. This change means the GIST cells constantly get signals telling them to grow and multiply.
Treatment with growth inhibitors can block these signals. This may make the cancer shrink or stop it from growing. Growth inhibitors may be used to treat GISTs that can't be completely removed with an operation. There are two that can be used to treat a GIST. These are imatinib (Glivec ®) and sunitinib (Sutent ®).
The side effects of imatinib are usually mild or moderate. Some of the common side effects include tiredness, feeling sick (nausea), diarrhoea, swollen ankles and puffy eyes, and an itchy rash. Common side effects of sunitinib include a skin rash and soreness, tiredness, mouth ulcers and high blood pressure. These side effects can usually be well controlled with medicines. Always tell your doctor if they continue or are troublesome.
The National Institute for Health and Clinical Excellence (NICE) currently advises doctors on the use of new drugs and treatments in the NHS. It recommends that imatinib is used as the first treatment for people with a GIST that can't be completely removed with surgery or has begun to spread. Treatment with imatinib is continued for as long as it is working.
Imatinib may sometimes be given to people who have had surgery to completely remove a GIST but who also have a high risk of the cancer coming back. Treatment that’s given to reduce the risk of cancer returning is called adjuvant therapy. This treatment has not been approved by NICE, which means that imatinib may not be widely available as adjuvant therapy for GIST in the NHS. Adjuvant therapy with imatinib has been approved for use in certain circumstances by The Scottish Medicines Consortium (SMC) in Scotland.
Sunitinib may be used if imatinib doesn't work or if it stops working. NICE has recommended sunitinib as a treatment option for people with GIST.
We can send you information about what you can do if a treatment isn't available.
Cancer doctors use clinical trials to assess new treatments. A recently developed growth inhibitor called regorafenib has recently been tested in trials for GIST. It has shown promising results.
You may be invited to take part in a clinical trial. If you decide to take part in a trial, your doctor will discuss the treatment with you so that you have a full understanding of the trial and what it means to take part. You may decide not to take part or to withdraw from a trial at any stage. You will then receive the best standard treatment available.
You will have regular check-ups at the hospital. Your doctor will examine you and ask about any side effects or symptoms. You will also have blood tests. You may also have a CT scan from time to time.
Let your doctor know if you have any new symptoms between appointments.
Having investigations and treatment for cancer can be a very stressful experience.
You may have many emotions including anxiety, anger and fear. These are all normal reactions and are part of the process many people go through in trying to come to terms with their condition.
Many people find it helpful to talk things over with their doctor or nurse, or with one of our cancer support specialists. Family members and close friends can also offer support.
GIST Support UK
GIST support UK offers a support network on its website, an online discussion forum and two meetings a year for patients with GIST and their families.
This information has been compiled using information from a number of reliable sources, including:
Casail P, Blay J. Gastrointestinal stromal tumours: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology. 2010. 21: 98–102.
Demetri G, et al. Local treatment for gastrointestinal stromal tumors, leiomyomas, and leiomyosarcomas of the gastrointestinal tract. UpToDate (accessed September 2012).
National Institute for Health and Clinical Excellence. Imatinib for the treatment of unresectable and/or metastatic gastrointestinal stromal tumours. November 2010.
Reid R, et al. Guidelines for the management of gastrointestinal stromal tumours (GISTs) in Scotland. 2009.
Sunitinib for the treatment of gastrointestinal stromal tumours. Technology appraisal TA179. 2009. National Institute for Health and Clinical Excellence (NICE).
With thanks to: Professor Ian Judson, Professor of Cancer Pharmacology; and the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.