PET for Therapy Response Assessment in Glioblastoma

Abstract

Glioblastoma (GB) is the most malignant and the most common type of glioma in adults, accounting for 60-70% of all malignant gliomas. Despite the current therapy, the clinical course of GB is usually rapid, with a mean survival time of approximately 1 year. For therapy response assessment in GB, magnetic resonance imaging (MRI) is the method of choice. In 2010, the Response Assessment in Neuro-Oncology (RANO) was introduced, including the tumor size (in 2D) as measured on T2-weighted and Fluid Attenuated Inversion Recovery (FLAIR)-weighted images, in addition to the contrast-enhancing tumor part. Although the RANO criteria addressed some of the limitations of the previous MacDonald criteria for therapy evaluation in high-grade glioma, treatment-related side effects hamper correct response assessment. To address the above-mentioned drawbacks in the follow-up of GB, incorporating changes in tumor biology measured by advanced MRI and positron emission tomography (PET) imaging, which may precede anatomical changes of the tumor volume, is promising. Imaging biomarkers capable of predicting response at an early time point after treatment initiation are the premise of personalized treatment enabling change or GB Treatment Response Using PET 176 discontinuation of therapy to prevent ineffective treatment or adverse events of treatment. In this chapter, an overview of applicable PET tracers for the therapy response assessment in GB and the determination of tumor recurrence versus treatment-related effects is given.

Therapeutic Efficiency of Multiple Applications of Magnetic Hyperthermia Technique in Glioblastoma Using Aminosilane Coated Iron Oxide Nanoparticles: In Vitro and In Vivo Study

“…This radiotracer (half-life of 109.7 min) is the most widely used for detecting the glucose uptake by tumor cells [86,87]. The main objective of using PET analysis in GBM cases is to differentiate tumor recurrence from radiation necrosis [61]. There is a linear relationship in PET signals between GBM cell number and 18 F-FDG uptake levels by these cells, that is significantly higher in small cell lung cancer with activity [88].…”

“…Another important technique for therapeutic follow up analysis in glioma models is the PET that display functional and biological information, such as metastatic lesion and tumor level staging of III and IV [49,[58][59][60][61][62]. PET has high diagnostic, prognostic, and therapeutic evaluation value when integrating with CT or MRI informations [61,62] for drug metabolism and PET radiotracers as 18 F-2-fluoro-2-deoxy-D-glucose ( 18 F-FDG) which evaluates glucose metabolism. High-grade gliomas, such as GBM, are known to consume high glucose levels.…”

The Added Value of Diagnostic and Theranostic PET Imaging for the Treatment of CNS Tumors

“…To reduce uptake in healthy brain, complete fasting for a minimum of 6 h before the scan is recommended, and patients should be kept blindfolded in a quiet room during the uptake phase, or scanning times should be delayed [23]. With applying these procedures, [ 18 F]FDG has shown acceptable sensitivity for the identification of anaplastic abnormalities in patients with low-grade glioma (LGG), high-grade glioma (HGG; Figure 1a [24]), CNS lymphoma, brain metastases, and meningioma [25][26][27]. Moreover, higher [ 18 F]FDG uptake has shown a positive correlation with higher histologic grade and worse prognosis [26,28], making [ 18 F]FDG PET a suitable tool for the prediction of progression-free survival (PFS) and overall survival (OS) [29].…”

“…In addition, [ 18 F]FDG cannot distinguish between radiation-induced necrosis, changes in the tissue due to surgery, inflammation, or (remnant/recurrent) disease, making [ 18 F]FDG not valuable for follow-up studies of CNS tumor therapies [21,22]. (a) [24]. This research was originally published in Glioblastoma Table 1) [21,22,[31][32][33][34][35][36][37][38].…”

The Path Toward PET-Guided Radiation Therapy for Glioblastoma in Laboratory Animals: A Mini Review

“…However, localization and delineation of (primary) brain tumors is often difficult due to the high background glucose metabolism of normal brain parenchyma. Only coregistration of [ 18 F]FDG PET with MRI allows accurate assessment of glucose metabolism in specific areas of the tumor (5, 36, 39). Despite this phenomenon, it is worth mentioning that it has been demonstrated that delayed [ 18 F]FDG imaging (3–8 h after tracer injection) improves the distinction between tumor and normal gray matter because the washout of glucose is higher in normal brain tissue than in tumor tissue (39, 40).…”