The Role of Surgery in Metastatic Gastrointestinal Stromal Tumors

Emily Z. Keung, Mark Fairweather, Chandrajit P. Raut

Gastrointestinal stromal tumors (GISTs) are the most common sarcomas and mesenchymal neoplasms of the gastrointestinal tract. Macroscopically complete (R0/R1) resection is the standard treatment for localized resectable GIST with adjuvant imatinib therapy recommended for patients with intermediate or high-risk disease. In patients with advanced unresectable or metastatic GIST, imatinib has significantly improved outcomes. However, while most patients achieve partial response (PR) or stable disease (SD) on imatinib (with maximal response typically seen by 6 months on treatment), approximately half will develop secondary resistance by 2 years. Available data suggest that cytoreductive surgery may be considered in patients with metastatic GIST who respond to imatinib, particularly if a R0/R1 resection is achieved. The benefit of surgery in patients with focal tumor progression on imatinib is unclear, but may be considered. Patients with multifocal progression undergoing surgery generally have poor outcomes. Thus, surgery should be considered in patients with metastatic GIST whose disease responds to imatinib with a goal of performing R0/R1 resection. Optimal timing of surgery is unclear but should be considered between 6 months and 2 years after starting imatinib. Although surgery in patients with metastatic GIST treated with sunitinib is feasible, incomplete resections are common, complication rates are high, and survival benefit is unclear. Therefore, a careful multidisciplinary consultation is required to determine optimal treatment options on a case-by-case basis. Finally, patients with metastatic GIST should resume tyrosine kinase inhibitor treatment postoperatively.