Gastrointestinal Stromal Tumors (GIST)

GIST is often diagnosed during routine tests for other, more common, conditions. To obtain more knowledge about the cause of a patient's symptoms, a doctor might conduct the following tests:

• Upper endoscopy (inspection of organs or cavities using a device called endoscope)
• Laparoscopy (abdominal exploration using a device called a laparoscope)
• Ultrasound (using sound waves to take images of internal organs)
• Computed tomography (CT or CAT) scan (a radiographic technique that produces a film that represents a detailed cross section of tissue structure)
• Magnetic resonance imaging (MRI) (another medical imaging technique)

These tests help determine whether patients have a tumor or tumors, where the tumor or tumors are located, how big they are, and whether or not the cancer has spread outside of the GI system (metastasized).

If a tumor is present, a tissue sample, or biopsy, is needed for the doctor to determine whether it is malignant (cancerous) or benign (non-cancerous), and to determine what type of cancer it is. If the tumor is a sarcoma, further testing of the tissue will determine the type of sarcoma and how rapidly the disease is likely to spread.

After the biopsy, the tumor sample is sent to a specialist called a pathologist who examines the cells and tissues. The pathologist will also test the tumor sample for the presence of Kit/CD117 - the enzyme thought to be responsible for most GISTs.

If a GIST is identified, it is important that the patient be referred to an oncologist. The size of the GIST, and other characteristics of the tumor cells, indicate how likely the tumor is to spread to other parts of the body and whether it may be treated by surgery. GIST is now recognized as a very aggressive cancer and experts now understand that all GISTs, despite their size, are at risk for eventually spreading to other parts of the body. Therefore, patients who have been diagnosed with GIST should seek treatment as soon as possible.

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