O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) PET as a potential selection tool for second surgery in glioblastoma patients

BACKGROUND: Treatment-related changes still represent a diagnostic challenge in the management of patients with suspect of recurrent glioblastoma. The specificity of conventional MRI in detecting recurrence remains limited. Brain PET imaging provides information on tumor metabolism and can contribute to improving the diagnostic accuracy of cerebral neoplasms. We performed a retrospective analysis to evaluate the clinical value of O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) PET in the diagnosis of glioblastoma recurrence. METHODS: A retrospective analysis on patients considered suitable for salvage surgery for recurrence glioblastoma was performed. 18F-FET-PET was performed to investigate gadolinium enhancement suspected for recurrence. Static and kinetic 18F-FET parameters were analyzed and related to O-6-methylguanine-DNA methyltransferase (MGMT) status.RESULTS: Forty-two of the 51 patients who underwent 18F-FET-PET were re-operated. In each case, neuropathological diagnosis of tumor recurrence was confirmed. pMGMT hypermethylation was detected in 21 patients. Mean tumor-to-brain ratios (TBR) max was 3.87 (range 2.6-6.0). Static and kinetic 18F-FET parameters were similar according to MGMT status.CONCLUSIONS: 18FET-PET can be a reliable tool to improve the selection of patients suitable for salvage surgery for glioblastoma recurrence.