Gastrointestinal Stromal Tumor (GIST)
GIST is rare form of sarcoma that arises most commonly in the stomach or small intestine. Sarcomas are tumors that grow from muscle, fat, nerve, or other specialized cell types. GIST can be detected during an evaluation for symptoms such as abdominal pain, fatigue, weight loss, or nausea. With increasing frequency, we are detecting GIST during the course of examinations, such as CT scans or endoscopies, done for other reasons. GIST typically occurs in adults in their 40s-60s who have no significant family history. A rare form of GIST can occur in children, typically in teenage girls.
When a tumor is seen in the stomach or small intestine on CT scan or during an endoscopic procedure, the suspicion level for GIST is often high enough to proceed with therapy without doing a biopsy. Rarely, a GIST will take on an unusual appearance or arise in an unusual location which may make a biopsy necessary.
General Treatment Principles
The treatment of GIST centers around both surgical removal when feasible and a drug, called Gleevec (imatinib mesylate), that specifically inhibits the growth of GIST cells. Imatinib is available in a tablet form, and patients typically have minimal side effects with the drug. When the tumor is isolated to the stomach or small intestine, surgical removal is the treatment of choice. For patients with large or aggressive tumors, we often recommend imatinib after surgery, based on a large clinical trial. When GIST has spread from the stomach or small intestine to other organs, such as the liver, then we use a combination of therapies which include imatinib, surgery, and minimally invasive tumor ablation. The Roger Williams Medical Center is proud to be one of 31 sites participating in a national clinical trial to determine how long patients should receive imatinib after surgical removal of high-risk GIST.