Gastrointestinal Stromal Tumours

Gastrointestinal stromal tumours (GISTs) are rare tumours involving the digestive tract and account for about 1% of primary gastrointestinal cancers. They occur predominantly in middle-age or older age groups, and are extremely rare in individuals under 30 years of age. The most common tumour locations are the:

• stomach (60%)
• small intestines (30%)
• Other less common locations include the duodenum (5%), large intestine (<5%), appendix and oesophagus (<1%)

These tumours arise from within the walls of the digestive tract, unlike the more common types of digestive cancers such as stomach or colon cancer which arise from the glandular cells in the inner lining. GISTs have varying malignant potential and are treated differently.

The majority of GIST cases are asymptomatic and are discovered either during an endoscopy or from a computed tomography (CT) scan. For cases that are symptomatic, the symptoms vary depending on their location and size. The main symptoms that one may present with are:

• Gastrointestinal bleeding
• Symptoms of anaemia such as fatigue, chest discomfort, giddiness and shortness of breath on exertion
• Abdominal pain and discomfort (especially in a large tumour)
• Abdominal mass

​GIST are caused by genetic mutations so there are no known methods of prevention. However early detection though early diagnosis via radiological scans or endoscopy for abdominal symptoms can result in curative treatment.

​GIST are caused by genetic mutations, occur predominantly in middle-aged and older people. There are some hereditary syndromes associated with GIST such as primary familial GIST syndrome, neurofibromatosis type 1 (NG1) and Carney-Stratakis syndrome.

Depending on the symptoms (e.g. gastrointestinal bleeding or an abdominal mass), your doctor may use any of the following procedures to assess and diagnose a GIST tumour.

1. CT scan
This is usually the imaging method of choice to evaluate an abdominal mass to see where it arises from, the extent of the tumour, and to see if there is presence of disease spread. However, it may be difficult to determine the organ of origin when the mass is very large.


2. Endoscopy
This is usually the procedure of choice in patients who present with gastrointestinal bleeding. - This is a day surgery procedure performed under sedation whereby a long, thin flexible video camera is inserted into your digestive tract. A standard biopsy (obtaining tissue samples) may be inconclusive as the GIST originates from a deeper layer of the wall of the digestive tract and regular biopsies may be too superficial.


3. Endoscopic ultrasound
This is used to further characterise a GIST by identifying its layer of origin within the walls of the digestive tract. It also enables targeted, deeper tissue biopsies of the tumour. A diagnostic biopsy may not always necessary in the treatment of a GIST.

Your doctor may also order other investigations if deemed appropriate.

Treatment for GISTs depends on their size and symptoms. The recommended treatment for symptomatic GISTs or GISTS larger than 2cm is removal with surgery. This can be done via minimally invasive means such as laparoscopy (key-hole) surgery.

In large tumours or those that involve other organs, an immunotherapy drug may be given prior to surgery to ‘shrink’ the tumour, and reduce the need to remove more tissue than necessary.

For asymptomatic GISTs less than 2cm in size, an option of regular surveillance may also be considered.

Our team of doctors will discuss the potential risks and effectiveness of each investigative procedure and the available treatment options with you.

​Ensuring adequate nutrition, stop smoking and maintain fitness before surgery.

​Depending on location of tumor, size, and extent of surgery, stay in hospital may be 2-7 days.