Gastrointestinal Stromal Tumor - GIST: Overview

This section has been reviewed and approved by the Cancer.Net Editorial Board, 11/2013

ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Gastrointestinal Stromal Tumor. To see other pages, use the menu on the side of your screen. Think of that menu as a roadmap to this full guide.

About the gastrointestinal tract

The gastrointestinal (GI or digestive) tract includes the esophagus, stomach, gallbladder, liver, small intestine, colon, rectum, and lining of the gut. The GI tract plays a central role in digesting food and liquid, and processing waste.

When food is swallowed, it is pushed down a muscular tube called the esophagus and enters the stomach. The muscles in the stomach mix the food and release gastric juices that help break down and digest the food. The food then moves into the small intestine (or small bowel) for further digestion and then into the large intestine.

The colon and rectum make up the large intestine, which helps remove waste from the body. The colon makes up the first five to six feet of the large intestine, and the rectum makes up the last six inches, ending at the anus.

A tumor begins when normal cells change and grow uncontrollably. A tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). A tumor can start in any part of the GI tract, and there are several different types of GI tumors.

About GIST

A gastrointestinal stromal tumor (GIST) is a type of GI tumor. GISTs are different than other, more common types of GI tumors because of the type of tissue in which they start. Originally, GISTs were thought to be either muscle or nerve tumors, but modern research shows that GISTs start 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. Soft tissue sarcomas are a group of cancers that develop in the tissues that support and connect the body, and the sarcoma cells resemble the cells that hold the body together, including fat cells, muscles, nerves, tendons, joints, blood vessels, or lymph vessels.

It is important to note that all GISTs can become cancerous. Sometimes it may be hard for the doctor to tell immediately whether a GIST is likely to come back after its surgical removal. As a result, the doctor will look at many factors to determine the best treatment, including the size of the tumor, whether it has already spread, how many dividing cells there are, its genetic makeup, and the tumor’s location.

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