[Gastrointestinal stromal tumors]

Abstract

Gastro-intestinal stromal tumors (GIST), an abdominal sarcoma entity are characterized by a gain-of-function mutation in c-kit proto-oncogen (CD117). Initial treatment should aim at complete removal of the primary tumor (R0 resection) which almost never develops lymphatic metastases. Distant metastatic spread involves mainly the peritoneal cavity and the liver. In patients with metastatic disease, treatment with tyrosinkinase inhibitor imatinib mesylate (Glivec) is indicated and very effective. Systemic chemotherapy and external beam radiation must be considered ineffective. Patients requiring multivisceral resection to remove their primary tumor rapidly develop tumor recurrence and could potentially benefit from preoperative treatment with imatinib. Primary tumors are classified into four risk categories according to their size and mitotic activity. Whether there is an advantage of adjuvant treatment is currently under investigation within international randomized trials. Patients who develop an extensive remission of metastatic disease should be evaluated individually for resection of the tumor remnants. Even resection of single progressive lesions (with newly developed mutations) should be considered in carefully selected patients, if the remaining tumor can be controlled by continued imatinib treatment.