Surgery and Imatinib in the Management of GIST: Emerging Approaches to Adjuvant and Neoadjuvant Therapy

Abstract

Gastrointestinal stromal tumor (GIST) is a neoplasm of the gastrointestinal tract, mesentery, or omentum that expresses the protein-tyrosine kinase KIT (CD117) and is the most common mesenchymal tumor arising at these sites. Surgical resection is the first-line intervention for operable GISTs, particularly localized primary tumors, and it was historically the only effective treatment. However, more than half of all GIST patients present with locally advanced, recurrent, or metastatic disease. The 5-year survival rate ranges from 50% to 65% after complete resection of a localized primary GIST and decreases to approximately 35% for patients with advanced disease who undergo complete surgical resection. A total of 40% to 90% of all GIST surgical patients subsequently have postoperative recurrence or metastasis. Imatinib is a potent, specific inhibitor of KIT that has demonstrated significant activity and tolerability in the treatment of malignant unresectable or metastatic GIST, inducing tumor shrinkage of 50% or more or stabilizing disease in most patients. A key strategy for prolonging the survival of patients with GIST is to improve the outcome of surgery. It is possible that the adjuvant and neoadjuvant use of imatinib (e.g., rendering initially inoperable tumors resectable) in the overall management approach to advanced GIST may contribute to surgeons’ success in attaining this objective.