ESTRO 2025 - Abstract Book

S738

Clinical - CNS

ESTRO 2025

4063

Digital Poster Coverage of the target volume in radiotherapy planning and FET-PET parameters as prognostic factors for patients with High Grade Glioma: GLIRARP Study Camilla Delli Paoli 1 , Lucia Pia Ciccone 1 , Iashar Laghai 2 , Giovanni Muscas 3 , Margherita Betti 4 , Marco Perna 5 , Valentina Baldazzi 6 , Angela Konze 7 , Andrea Pratesi 8 , Paolo Alpi 1 , Raffaella Barca 1 , Barbara Grilli Leonulli 1 , Alessandro Della Puppa 3 , Stelvio Sestini 2 , Maurizio Bartolucci 8 , Serenella Russo 9 , Silvia Scoccianti 1 1 Radiation Oncology Unit; Department of Oncology, Santa Maria Annunziata Hospital; Azienda USL Toscana Centro, Bagno a Ripoli, Florence, Italy. 2 Nuclear Medicine Unit, Nuovo Ospedale Santo Stefano; Azienda USL Toscana Centro, Prato, Italy. 3 Neurosurgery Unit, Azienda Ospedaliero Universitaria Careggi, Florence, Italy. 4 Medical Physics Unit, Azienda USL Toscana Centro, Prato/Pistoia, Italy. 5 Medical Oncology Unit, Department of Oncology, Santa Maria Annunziata Hospital; Azienda USL Toscana Centro, Bagno a Ripoli,, Italy. 6 Medical Oncology Unit, Department of Oncology, Santa Maria Annunziata Hospital; Azienda USL Toscana Centro, Bagno a Ripoli, Florence, Italy. 7 Neuroradiology Unit; Department of Radiology, Azienda USL Toscana Centro, Florence, Italy. 8 Department of Radiology, Azienda USL Toscana Centro, Prato, Italy. 9 Medical Physics Unit, Santa Maria Annunziata Hospital; Azienda USL Toscana Centro, Bagno a Ripoli, Florence, Italy Purpose/Objective: The aim of this monocentric retrospective study (GLIRARP ID26394) is the evaluation of prognostic value of morphological, metabolic and dosimetric parameters in patients with High Grade Glioma (HGG) treated with adjuvant radiotherapy (RT) and Temozolomide (TMZ). The RT planning process was based on the integration between the postoperative MRI and 18F-FET-PET (Figure1).

Material/Methods: We collected data about patients with a HGG histopathological diagnosis. They were staged after neurosurgery with MRIscan and FET-PET and treated with RT-TMZ. Metabolic tumor volume (MTV) was delineated on FET-PET by a nuclear radiologist, they were collected MTVtot, MTVmax, SUVmax, TBRmax. An MRIscan was scheduled 3-4 weeks after RT in order to provide a baseline imaging to monitor disease, during the maintenance TMZ. The followup was performed with an MRI every 2-3 months. All the MRI scans were reviewed with a neuroradiologist using RANO criteria [1]. If there was a MRI-evidence of suspected pseudoprogression were studied

with advanced MRI and FET-PET and evaluated according to PET-RANO criteria. [2] Primary endpoints were Overall Survival (OS) and Progression Free Survival (PFS).

Survival analysis was performed by the Kaplan-Meier method. Log-rank test and Cox proportional hazards model were used to evaluate the prognostic value of parameters at univariate and multivariate analysis, respectively. Statistical analysis was performed using MedCalc (version22.021, MedCalc Software Ltd, Ostend, Belgium).