GIST Learning Center

Symptoms of GIST

GIST almost always grow within the wall of the gastrointestinal tract. Often they cause few or no symptoms at all and are identified because an imaging study like a CT scan or MRI has been performed for other reasons. When GIST do cause symptoms it can be in the form of:

 

  • Intestinal bleeding due to the erosion of the tumor into the inside of the intestine.
  • Occasionally GIST cause abdominal pain or bloating as a result of blockage of the intestine.
  • Blockage of the intestine progresses and can manifest as nausea and vomiting or even abdominal pain.
  • Rarely an abdominal mass or lump can be felt.
Symptoms of Gastrointestinal Stromal Tumors

How are GIST Diagnosed?

Symptoms of Gastrointestinal Stromal Tumors
GIST are usually identified on the CT scan or a PET/CT scan or an upper GI endoscopy. In some cases the characteristic appearance of the GIST may be enough to suggest the diagnosis and no initial biopsy is needed. Other times of biopsy or sampling of the GIST is necessary to confirm the diagnosis. Biopsy can sometimes be performed by endoscopy or colonoscopy. Because GIST form within the wall of the intestine they may not be on the inner surface of the intestine, which is seen by endoscopy. In this case, diagnosis may require a specialized endoscopy called an endoscopic ultrasound or EUS which allows for biopsy of deeper lesions within the intestinal wall that are not right on the surface.

How are GIST Treated?

How are GIST Treated?

Treatment of GIST depends on the location and size of the tumor. Some small GIST, particularly those within the stomach, can be managed with ‘watchful waiting’ without removal. When tumors are larger or when there is concern that they might have a more aggressive course surgical resection will be necessary. If surgical resection is difficult to perform without excessive side effects or if the tumor has spread at the time of diagnosis, medical therapy is used before surgery.

Where do GIST come from and why is this important for treatment?
GIST derived from specialized pacemaker cells within the intestinal tract called the Interstitial cells of Cajal (ICC). Mutations in the gene for C-KIT within these cells results in an aggressive “ON” switch for tyrosine kinase receptors on the cell. This results in aggressive overgrowth of the ICC and formation of a tumor. There are a number of medications such as imatinib, sunitinib and regorafenib which are tyrosine kinase inhibitors and can limit and reverse the growth of GIST. These medications can be used before surgery for very large GIST to make them easier to surgically remove. We also use these medications for GIST that have spread, particularly to the liver, before surgical treatment. Unfortunately tyrosine kinase inhibitor medications will not cure most GIST and surgical removal will eventually be necessary after the medications have reduce the size and extent of the tumor.
What does surgical treatment of GIST involve?
Most GIST will require surgical removal. Smaller GIST within the stomach can be removed with minimally invasive laparoscopic or robotic surgery as an outpatient with a very short hospital stay. Larger tumors can often be removed with laparoscopy or may require open surgery with removal of a portion of the intestine. When tumors have spread to organs like the liver, surgical removal or surgical destruction of the tumor in the liver may be necessary.
Laparoscopic Resection Gastric GIST
Laparoscopic Resection of Gastric GIST: A Simplified Approach
Robotic Resection of a Duodenal GIST

Prognosis

The prognosis for smaller tumors, particularly those within the stomach is excellent. When tumors are larger or involve other organs surgical removal may need to be followed by medical treatment with tyrosine kinase inhibitors. The prognosis following surgery for GIST can be estimated using a simple
nomogram which takes into account tumor size, location and mitotic index which is a measure of how actively the cells within the tumor are dividing. The nomograms can be accessed using the link below.

Access Nomograms

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