ACRIN 6684 assessment of tumor hypoxia in glioblastoma using 18F-fluoromisonidazole with PET and MRI.

TPS10635 Background: Glioblastoma (GBM) is an aggressive type of primary malignant brain tumor and despite treatment with surgery, radiation, and temozolomide (TMZ) chemotherapy, median overall survival (OS) remains poor. A pathologic hallmark of GBM is tumor necrosis, a suspected result from endogenous tumor hypoxia. Angiogenesis is stimulated by hypoxia-driven signaling cascades and is required for tumor proliferation. The inefficient blood supply of these hypoxic tumors also limits the efficacy of chemotherapy and radiotherapy. Surviving hypoxic tumor cells may be selected out and proliferate as a more aggressive tumor subtype, therefore hindering OS. 18F-Fluoromisonidazole (FMISO) is a PET radiotracer whose uptake in hypoxic tissues can be measured radiographically. The degree of tumor hypoxia has been negatively associated with time to tumor progression and survival (Spence et al, 2008). Knowledge of the degree/distribution of tumor hypoxia by PET uptake and perfusion MRI parameters may provide progn...