EP-262 Neoadjuvant imatinib for Resectable Gastrointestinal Stromal Tumors. A State-of-the-art

Abstract

Abstract Aims Surgical removal remains the cornerstone of primary GIST treatment and complete surgical resection offers prognostic value toward risk of relapse. However, primary tumors, particularly of the stomach, are of advanced size when detected, and multivisceral resection seems to be the treatment of choice. Existing results of recent clinical trials have established the feasibility of neoadjuvant imatinib therapy mainly in unresectable GISTs. Yet, proof of the survival effectiveness of neoadjuvant imatinib therapy in borderline resectable tumors has not been sufficiently demonstrated. Methods A review of the literature was performed to identify the current evidence for preoperative treatment of large GISTs with Imatinib regarding R0 resection and oncological outcome. Results Data supporting benefit of neoadjuvant imatinib are available from several case reports and small retrospective series, most of which include a mix of patients with borderline resectable and unresectable primary disease. In addition, a single-phase II United States Intergroup trial and an Asian phase II trial of neoadjuvant therapy in large stomach tumors, concluded that Neoadjuvant imatinib therapy is preferred for marginally resectable tumors. Progressive disease after neoadjuvant treatment was a rare event, and partial response was achieved in 40–80% of all patients. Conclusion Neoadjuvant therapy with imatinib is safe and recommended for patients with resectable, locally advanced GIST. It may also enable less invasive and organ-sparing surgery, increase the complete resection rate, and avoid the surgical rupture by decreasing the tumor size. Clinical questions still remain about the most appropriate period of pre- and post-operative imatinib administration in the neoadjuvant protocol.