Abstract SY02-03: Imaging cancer metabolism in patients: FDG PET and beyond

Abstract

Abstract The identification of altered energy metabolism as a hallmark of cancer (1) leads to opportunities to exploit cancer metabolism as a target for diagnosis. This has been most widely exploited using the elevated rate of glycolysis observed in most tumors as a target for imaging (2)–in particular, positron emission tomography (PET) imaging of the glucose analog 18F-fluorodeoxyglucose (FDG). FDG PET, now combined with anatomic imaging in the form of PET/CT, has become an important tool for cancer detection, staging, and response assessment, widely used in oncologic clinical practices around the world (3,4). Clinical use of FDG PET has increased our appreciation of aberrant glycolysis as a feature of more aggressive, less differentiated tumors (5,6). At the same time, the variability of tumor FDG uptake seen in clinical imaging has highlighted some of the limitations of imaging tumor glycolysis and has spurred the development of new imaging probes and novel imaging modalities designed to image other facets of cancer energy metabolism. In addition, the use of therapeutics that are targeted to and/or influenced by cancer metabolic phenotype (7) drives applications of cancer metabolic imaging to clinical challenges beyond detection to predicting and and monitoring response to targeted therapy (8). This talk highlights current uses of FDG PET/CT for cancer staging and response evaluation, as well as alternative PET probes targeted to other metabolic substrates such as amino acids, lipids, and TCA intermediates (9). It also highlights other methods for imaging cancer metabolism in patients, including magnetic resonance spectroscopy, optical imaging, chemical exchange saturation transfer (CEST), MR metabolomics, and MR imaging of hyperpolarized 13C-labeled metabolic substrates such as pyruvate (10-14). Unique features and advantages of each modality are highlighted, as are approaches to image analysis common across modalities, including quantitative imaging and kinetic analysis. Finally, the talk emphasizes the benefit of multimodality imaging as an approach to fully characterize cancer metabolism, using glutaminolysis imaging as an example of active investigation. Supported in part by Komen SAC130060, DOE DE-SE0012476, NIH P30-CA016520, and NIH R01-CA211337.