Gastrointestinal stromal tumors (GISTs) are not common, but the exact number of people diagnosed with this tumor each year is not known. Based on various studies, estimates for the total number of GIST cases each year in the United States have ranged from about 4,500 to about 6,000. Of these, about 1,500 have already spread to distant sites (metastasized) when they are initially found.

Although these tumors can start anywhere in the GI tract, they occur most often in the stomach (50% to 70%) or the small intestine (20% to 30%). The rest are found in the esophagus, large intestine (colon and rectum), and anus.

Most people diagnosed with GIST are older than 50, but these tumors can occur in people of any age. They are slightly more common in men. African Americans are more likely to develop GISTs than whites.

Last Medical Review: 05/11/2009
Last Revised: 05/11/2009