Overview

A gastrointestinal stromal tumor (GIST) is a type of tumor that occurs in the gastrointestinal (GI or digestive) tract, including the esophagus, stomach, gallbladder, liver, small intestine, colon, and rectum. GIST is a rare tumor that differs from other types of gastrointestinal tumors because of the type of tissues in which it starts. Originally, GISTs were thought to be either muscle or nerve tumors, but recent research points to GISTs starting in cells found in the walls of the GI tract, called interstitial cells of Cajal (ICC); these cells send signals to the GI tract to help move food and liquid through the system. GISTs belong to a group of cancers called soft tissue sarcoma. Sarcoma occurs in connective tissues such as muscle, fat, nerves, blood vessels, cartilage, and bone.

It is important to note that GISTs can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). Sometimes it may be hard for the doctor to tell immediately whether a GIST is cancerous. As a result, the doctor will look at many factors to determine the best treatment, including the size of the tumor, whether it is spreading, how many dividing cells there are, and the tumor’s location.

Statistics

In 2009, approximately 4,500 to 6,000 adults in the United States will be diagnosed with GISTs. They occur most commonly in the stomach (50% to 70%) and small intestine (20% to 30%). The remaining types of GISTs affect the large intestine and esophagus. Most GISTs occur in people older than 50, and GIST is more common in men than in women.

Cancer statistics should be interpreted with caution. Estimates are based on data from thousands of cases of this type of cancer in the United States each year, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with a gastrointestinal stromal tumor. Because the survival statistics are measured in five-year intervals, they may not represent advances made in the treatment or diagnosis of this cancer.

Source: American Cancer Society

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