Early prediction of response to sunitinib after imatinib failure by 18F-Fluorodeoxyglucose Positron emission tomography in patients with gastrointestinal stromal tumor

Abstract

Purpose Positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) was used to evaluate treatment response in patients with gastrointestinal stromal tumors (GIST) after administration of sunitinib, a multitargeted tyrosine kinase inhibitor, after imatinib failure. Patients and Methods Tumor metabolism was assessed with FDG-PET before and after the first 4 weeks of sunitinib therapy in 23 patients who received one to 12 cycles of sunitinib therapy (4 weeks of 50 mg/d, 2 weeks off). Treatment response was expressed as the percent change in maximal standardized uptake values (SUV). The primary end point of time to tumor progression was compared with early PET results on the basis of traditional Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Results Progression-free survival (PFS) was correlated with early FDG-PET metabolic response (P