Gastrointestinal Stromal Tumor - GIST: Introduction

Approved by the Cancer.Net Editorial Board, 03/2017

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. Use the menu to see other pages. Think of that menu as a roadmap for this complete guide.

About the gastrointestinal tract

The gastrointestinal (GI or digestive) tract includes the:

  • Esophagus

  • Stomach

  • Gallbladder and bile ducts

  • Liver

  • Pancreas

  • Small intestine

  • Colon

  • Rectum

  • Anus

  • Lining of the gut

The GI tract plays a central role in digesting food and liquid and in processing waste.  When you swallow food, 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 before entering the large intestine. The large intestine helps remove waste from the body. The colon makes up the first 5 to 6 feet of the large intestine. The rectum makes up the last 6 inches, ending at the anus.

About gastrointestinal stromal tumor (GIST)

A tumor begins when healthy cells change and grow out of control, forming a mass called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread. A tumor can start in any part of the GI tract. There are several different types of GI tumors, including gastrointestinal stromal tumor (GIST).

GISTs are different from more common types of GI tumors because of the type of tissue in which they start. GISTs belong to a group of cancers called soft-tissue sarcomas. Soft-tissue sarcomas develop in the tissues that support and connect the body. The sarcoma cells resemble the cells that hold the body together, including fat cells, muscles, nerves, tendons, joints, blood vessels, and lymph vessels.

Doctors used to think that GISTs were muscle or nerve tumors. However, research shows that GIST begins in “pacemaker” cells found in the walls of the GI tract. These pacemaker cells are called interstitial cells of Cajal (ICCs), and they send signals to the GI tract to help move food and liquid through the digestive system.

Looking for More of an Introduction?

If you would like more of an introduction, watch this short video led by an ASCO expert in sarcoma. The video provides basic information and areas of research. Please note that this link will take you to another section on Cancer.Net.

The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with this disease and general survival rates. You may use the menu to choose a different section to read in this guide.