Gastrointestinal stromal tumor (GIST) is a type of cancer that develops in the digestive tract. It is a rare type of cancer that affects the cells of the digestive tract, most commonly the stomach and small intestine. GISTs can be benign (non-cancerous) or malignant (cancerous). Symptoms of GIST can include abdominal pain, nausea, vomiting, and weight loss. Treatment for GIST typically involves surgery to remove the tumor, as well as chemotherapy and/or radiation therapy.