Gastrointestinal Stromal Tumors

What are Gastrointestinal Stromal Tumors (GISTs)?

Gastrointestinal stromal tumors (GISTs) are the most common type of sarcoma in the gastrointestinal (GI) tract. They are usually found in the stomach or small intestine. GISTs are rare and begin in cells of the GI tract wall that help control muscle activity, such as peristalsis – the wave-like muscle contractions that move food through the intestines.

What Causes Gastrointestinal Stromal Tumors?

It is not known what causes GISTs. It is believed that GISTs may begin from genetic defects in the KIT gene or in the PDGFRA gene. Both of these genes provide instructions for making proteins that control the growth and development of cells, especially muscle cells and connective tissue cells. Most GISTs are caused by a KIT gene defect. This means that the gene has been changed, which leads to a protein that signals uncontrolled cell growth and division. In some cases, the KIT gene defect is inherited, but most GISTs are not.

Symptoms of Gastrointestinal Stromal Tumors

Common symptoms of GISTs can be vague. The most common symptom is feeling full after eating only a small amount of food. Other symptoms may include:

  • Pain or a feeling of pressure in the abdomen
  • Nausea and vomiting
  • Blood in the stool or blackened stool
  • Weight loss
  • Weakness, fatigue, or anemia

Diagnosis & Treatment of Gastrointestinal Stromal Tumors

Diagnosing GISTs is not easy. The doctor will ask about symptoms and conduct tests to determine the cause. Diagnostic tests may include imaging tests (such as CT or MRI scans) or endoscopy. A biopsy – removing a small sample of tissue for laboratory testing – is also done to make a definitive diagnosis. Treatment for GISTs depends on a number of factors, including the size and location of the tumor, and how it affects the patient’s general health. Surgery is the most common treatment for GISTs, either to remove the tumor or to relieve symptoms. In some cases, chemotherapy or targeted therapy drugs may be used to shrink the tumor.