FET PET in Differentiating Tumour Progression From Pseudoprogression in High Grade Glioma

18F-FET (O-(2-[18F]Fluoroethyl)-L-tyrosine) PET in Differentiating Tumour Progression From Pseudoprogression in High Grade Gliomas

The goal of this clinical trial is to evaluate the performance characteristics of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET in differentiating pseudoprogression from tumour progression in patients with equivocal conventional imaging and determine the sensitivity and specificity of [18F]FET-PET in delineating disease. The main question[s] it aims to answer are:

• whether 18F-FET-PET will demonstrate high diagnostic accuracy to detect true tumour progression
• whether we can optimise the threshold cut-offs for TBRmax and other relevant parameters in discriminating pseudoprogression and disease progression Participants will undergo a limited 18F-FET PET/CT of the brain in SGH.

Inclusion Criteria:

• Men or Women, aged 21 years or older at time of screening
• Histologically confirmed diagnosis of malignant glioma (defined as WHO grade III or IV) with previous RT to tumour
• With enlarging contrast-enhancing and/or T2W/FLAIR-hyperintense lesion(s) on MRI within the previous RT field
• Gliomas with Isocitrate dehydrogenase (IDH) wild-type status, as defined on immunohistochemistry
• Subject must consent to undergo all study procedures

Exclusion Criteria:

• Low-grade gliomas (histology grade 1 or 2 by WHO classification)16,17
• Previous bevacizumab or other vascular endothelial growth factor (VEGF) targeting agents or anti-angiogenic treatments.
• Proven cerebral metastases
• IDH-mutated gliomas
• Pregnancy/ breast-feeding