Get the Gist on GIST
GASTRO-INTESTINAL STROMAL TUMORS (GIST)
Gastro-Intestinal Stromal Tumors (GIST) may randomly occur anywhere along the gastrointestinal tract. Common sites for GISTs are the stomach, small intestine, esophagus, rectum, and colon.
Cancer threatens life when it metastasizes or spreads to additional locations beyond the primary tumor site. With GIST, the most common sites for metastasis are the liver and the abdominal membranes. GIST rarely spreads to lymph nodes but it may occasionally affect local abdominal lymph nodes. Unusual sites of metastasis include lung and bone tissue, as well as pelvic sites.
WHY DOES GIST DEVELOP?
Scientists are beginning to unravel some of the processes that go on inside cells that cause them to develop into GISTs. Normally these cells, like other cells in the body, grow and divide in a controlled fashion. But sometimes things can go wrong, allowing these cells to grow out of control and ultimately become cancerous.
Scientists have discovered that cells may grow in an uncontrolled manner as the result of a defect in their DNA. In most GISTs, a specific gene defect causes the cells to make too much of an enzyme known as KIT. KIT is an enzyme (called a “tyrosine kinase”) responsible for sending growth and survival signals inside the cell. If the gene to make KIT is ON, the cell stays alive and grows or proliferates. The overactive, uncontrolled mutant KIT gene triggers the runaway growth of GIST cells. Much less often, GIST cells make too much of a different protein, called PDGFRA, which can also cause the cells to grow. This insight into the way GISTs develop has already helped to identify new treatments.
HOW IS GIST DIAGNOSED?
After a careful physical exam, the doctor may do an endoscopy, X-ray tests, CT scan, or MRI. These may be done to gain more information about whether there is an abnormal growth, where the growth is located, and whether it has spread.
Once a GIST has been identified, it is important to determine the best way to treat it. Ideally, surgery should be considered, to be done by an expert surgeon who has experience in GIST management. GISTs grow differently in each person. The size and location of the tumor and the rate at which they grow are important in determining the risk the tumor presents.
HOW IS GIST TREATED?
Surgery
Until recently, the only treatment for GIST was surgery. The goal of surgery is to remove the tumor completely. However, surgery alone for larger GISTs, or for GISTs that have spread, has yielded disappointing results.
New treatments are now available thanks to generous donors like you!
Targeted Therapy Drugs
Targeted therapy is the use of medicines that target parts of cancer cells that make them different from normal cells. The targeted therapy medicines used to treat GIST include:
- Imatinib (Gleevec) This drug may be used to treat either early or advanced-stage GIST. It can be given before surgery to try to shrink the tumor, or after surgery to help lower the risk of the cancer coming back. It may not cure advanced GIST, but it can often help people live longer and feel better. The medicine is taken by mouth as a pill. Side effects are mostly mild to moderate. The most common side effect is mild nausea. Other side effects, usually mild as well, include diarrhea, fluid retention and swelling (often around the eyes), indigestion, muscle cramps, bleeding from the GIST tumor, fatigue, and a skin rash.
- Sunitinib (Sutent) This medicine is often used when imatinib doesn’t work or if the side effects of imatinib are a problem. Sunitinib can often shrink tumors or stop them from growing for a time. It may help people with GIST live longer. It is taken by mouth as a pill. The most common side effects are diarrhea, mouth irritation, and changes in skin and hair color. More serious side effects can include high blood pressure, increased risk of bleeding, and swelling.
- Regorafenib (Stivarga) This drug is often used if other medicines are no longer working. It can often shrink tumors or slow their growth for a time. It is taken by mouth as a pill. Side effects can include diarrhea, feeling tired, high blood pressure, mouth sores, hair loss, loss of appetite, and problems with redness and pain in the palms of the hands and soles of the feet.
SOURCE: gistinfo.org
Memorial Sloan Kettering Cancer Center
The primary treatment for a GIST is surgery to remove the tumor. The surgery that’s right for you depends on the exact size and location of the tumor. CONTINUE READING
SOURCE: mskcc.org
