Patterns of failure for patients with glioblastoma following O-(2-[18F]fluoroethyl)-L-tyrosine PET- and MRI-guided radiotherapy

Publication date: Available online 19 January 2017
Source:Radiotherapy and Oncology
Author(s): Michael Lundemann, Junia Cardoso Costa, Ian Law, Svend Aage Engelholm, Aida Muhic, Hans Skovgaard Poulsen, Per Munck af Rosenschold
Background and purposeTo evaluate the patterns of failure following clinical introduction of amino-acid O-(2-[¹⁸F]fluoroethyl)-L-tyrosine (FET)-PET-guided target definition for radiotherapy (RT) of glioblastoma patients.Materials and methodsThe first 66 consecutive patients with confirmed histology, scanned using FET-PET/CT and MRI were selected for evaluation. Chemo-radiotherapy was delivered to a volume based on both MRI and FET-PET (PETvol). The volume of recurrence (RV) was defined on MRI data collected at the time of progression according to RANO criteria.ResultsFifty patients were evaluable, with median follow-up of 45months. Central, in-field, marginal and distant recurrences were observed for 82%, 10%, 2%, and 6% of the patients, respectively. We found a volumetric overlap of 26%, 31% and 39% of the RV with the contrast-enhancing MR volume, PETvol and the composite MRPETvol, respectively. MGMT-methylation (p=0.03), larger PETvol (p<0.001), and less extensive surgery (p<0.001), were associated with larger PETvol overlap.ConclusionThe combined MRPETvol had a stronger association with the recurrence volume than either of the modalities alone. Larger overlap of PETvol and RV was observed for patients with MGMT-methylation, less extensive surgery, and large PETvol on the RT-planning scans.



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