FDG-PET to Measure Response to Targeted Therapy: The Example of Gastrointestinal Stromal Tumor and Imatinib Mesylate (Gleevec)

Imaging has played a major role in the evaluation of molecular targeted therapies in patients with gastrointestinal stromal tumors. FDG-PET has been instrumental in the evaluation of the tyrosine kinase inhibitors used to treat this disease. Imaging findings on FDG-PET and CT have illustrated the need to re-evaluate traditional response assessment criteria. Because most PET studies are now performed on hybrid PET/CT scanners, there is an opportunity to test and validate existing and new PET tracers and to provide anatomic and functional information in one setting. The inclusion of imaging in the testing and implementation of targeted therapies is helping to define the concept of personalized medicine.