P25.03.B RWD OF IDH MUTANT GLIOMAS IN SPAIN, A RETSINE - GEINO STUDY
Authors: M Mazariegos, R Girones, S Del Barco, A Garcia, G Velilla, A Hernandez, M Alonso, L Ferreira, N Luque, I Fernández, T Quintanar, S Peralta, I Ceballos, E Iza, M Sanchez, E Pablo Martín, E Almagro Casado, J Mazarico, G Duran, P Álvarez, P Ayala, O Gallego, R Sarabia, R De las Peñas, I Nuñez, I Morilla, A Cunquero, N Cheverria, I Moya, M Vaz, R Luque, A Esteve, E Pineda
Journal: Neuro-Oncology (2024)

Abstract BACKGROUND IDH mutant gliomas are brain tumors with a high impact in quality of life and morbidity in the AYA (young adults and adolescents) population. It is a very heterogeneous disease with different treatment options and a new effective targeted therapy (vorasidenib) very well tolerated. More RWD is needed to advance faster in the best management of this population. METHODS A retrospective cohort study of all IDH mutant gliomas diagnosed from 2019 to 2023 in 21 Spanish centers, a total of 485 cases. This study includes data from a GEINO questionnaire (21 centers) and from the RETSINE (Spanish registry of CNS tumors). GEINO questionnaire includes 2021 WHO diagnosis, treatment strategy decision and how many remain in watch and wait (WW) strategy in 2024. RESULTS From 2019 to 2023, 485 cases of IDH mutant glioma were diagnosed in 21 centers, 67% astrocytomas (A) (326/485) and 33% oligodendrogliomas (O) (159/485). WW strategy was relatively frequent in low grade gliomas (LGG) 33% (75/226), and slightly more frequent in O grade 2 40% (41/103) than in A grade 2 28% (34/123). WW strategy was decided in only 3% of grade (gr) 3 IDH mutant gliomas (5/172). Despite this, with a very short follow-up, 24% (19/80) of WW population have ended up receiving treatment, radiotherapy (RT) or chemotherapy (CT). We have collected all data from 241 cases in RETSINE. Median age was 46 years old and 56% were male. Nearly half were glioma grade 2, 46% (67 A, 45 O), 32% grade 3 (49 A, 28 O) and 21% grade 4 (52). Complete resection was achieved in 35%, Karnofksy index (KPS) was superior to 80% in 70% and neurologic deficit at diagnosis was present in 35%. Almost 50% had epileptic seizures at diagnosis. Overall survival (OS) at 2 years is 94% (O gr2), 96% (O gr3), 91% (A gr2), 82% (A gr3) and 55% (A gr4) and progression-free survival at 2 years is 80% (O gr2), 91% (O gr3), 74% (A gr2), 51% (A gr3) and 27% (A gr4), with a median follow up of 1,8 years. Univariate analyses for OS in astrocytomas confirm the prognostic role of various factors: histologic grade 3-4 (HR 4.07; 1.56-10.6; p=0.004), KPS &amp;gt;80% (HR 0.19; 0.09-0.42; p&amp;lt;0.001); tumor size ≥ 6 cm (HR 2.53; 1.1-5.85; p=0.03) and previous neurologic deficit (HR 2.64; 1.27-5.49; p=0.01). WW population was enriched with complete resection and younger age (&amp;lt;40 years old). All detailed data of almost 600 patients or more will be presented at the congress, more centers will be included in this project. CONCLUSIONS RWD of IDH mutant gliomas in Spain demonstrates that WW is a strategy decision in 33% of LGG, 40% in oligodendrogliomas grade 2. Despite this, in short follow-up, 24% of these end up receiving RT and/or CT. RWD can help to better understanding the disease and optimize patient care strategies in the new era of IDH inhibitors. We should work on better quality data on registries, including quality of life parameters as capacity for work in this long-term disease with a high impact on morbidity.