ESTRO 2024 - Abstract Book

S772

Clinical - CNS

ESTRO 2024

655

Digital Poster

FET-PET and MRI integration in the planning process of HGG treated with adjuvant radiochemotherapy

Camilla Delli Paoli 1 , Marco Esposito 2 , Iashar Laghai 3 , Margherita Betti 4 , Linda Poggesi 5 , Fiammetta Meacci 1 , Paolo Alpi 1 , Raffaella Barca 1 , Simona Fondelli 1 , Barbara Grilli Leonulli 1 , Lisa Paoletti 1 , Andrea Bruschi 6 , Anna Maria Buccoliero 7 , Giovanni Muscas 8 , Andrea Pratesi 9 , Valentina Baldazzi 10 , Marco Perna 10 , Angela Konze 11 , Maurizio Bartolucci 9 , Alessandro Della Puppa 8 , Serenella Russo 6 , Stelvio Sestini 3 , Silvia Scoccianti 1 1 Santa Maria Annunziata Hospital, Radiation Oncology Unit, Firenze, Italy. 2 The Abdus Salam International Centre for Theoretical Physics, Medical Physics Unit, Trieste, Italy. 3 S. Stefano Hospital, Nuclear Medicine Unit, Prato, Italy. 4 S. Stefano Hospital, Medical Physics Unit, Prato, Italy. 5 Santa Maria Annunziata Hospital, Diagnostic Imaging Unit, Firenze, Italy. 6 Santa Maria Annunziata Hospital, Medical Physics Unit, Firenze, Italy. 7 Meyer Children's Hospital, Pathology Unit, Firenze, Italy. 8 University Hospital of Careggi, Neurosurgery Unit, Department of NEUROFARBA, Firenze, Italy. 9 S. Stefano Hospital, Diagnostic Imaging Unit, Prato, Italy. 10 Santa Maria Annunziata Hospital, Medical Oncology Unit, Firenze, Italy. 11 Santa Maria Nuova Hospital, Diagnostic Imaging Unit, Firenze, Italy

Purpose/Objective:

To evaluate prognostic value of morfological, metabolic and dosimetric parameters in a cohort of patients (pts) with high grade glioma (HGG) treated with adjuvant radiotherapy (RT) and Temozolomide Chemotherapy (TMZ), in which the morphological imaging of postoperative MRI was integrated with FluorEthyl-l-Tyrosine (FET) PET during the radiation therapy treatment planning process

Material/Methods:

In the planning process, MRI and FETPET were co-registered on the CT scan using the registration algorithms of MIM (version 7.2.5). CTV was delineated according to ESTRO-ACROP guidelines based on the postoperative post-contrast T1w MR images but it also encompassed the postoperative metabolic abnormalities on the FET-PET images. Maximum tumour-to-brain ratios (TBRmax), SUVmax, Volume-Based PET Parameters, and dosimetrics data were calculated. Survival analysis was performed by Kaplan-Meier method. We used log rank test and Cox proportional hazards model in evaluating the prognostic value of analyzed parameters

Results:

We retrospectively assessed 32 pts (15 males and 17 females, median age 54 y) with histopathologically confirmed HGG (18,7% WHO grade 3; 81,3% WHO grade 4) treated with postoperative RT-TMZ, from November 2020 to April 2022. Clinical and pathological characteristics were collected. Median follow-up was 13.4 months (m), median OS and PFS were 16,2 m and 12.15 m, respectively. In the univariate analysis, WHO grade 4 (p .005), age >50 y (p .039), IDH-wildtype status (p .034), TBRmax >4.02 (p .0001), Metabolic Tumor Volume (MTV) > 40245 mm3 (p .0003), MTVmax > 12963.5 mm3 ( p .0001), and VGTV57 Gy <99% (p .0001) were independent prognostic factors of poor OS.