EP15.02 PATIENTS WITH OLIGODENDROGLIOMAS CNS WHO GRADE 2 AND 3 - PROGRESSION PATTERNS AND FUNCTIONAL OUTCOME IN LONG-TERM FOLLOW-UP

Abstract BACKGROUND Oligodendrogliomas are brain tumors typically associated with longer life expectancy and a more favorable prognosis than other gliomas. According to the current WHO classification, molecular testing for co-deletions of chromosomes 1p and 19q is essential to identify patients with CNS WHO grade 2 and 3 oligodendrogliomas who are more likely to benefit from radio-chemotherapy. However, given the relatively young age of these patients, the risk of impairment in somatic and neurocognitive function, quality of life, and social and occupational reintegration is significant, due both to the tumor and multimodal treatments. MATERIAL AND METHODS Clinical data of patients with a histologically confirmed diagnosis of oligodendroglioma, IDH mutant (CNS WHO grade 2 and 3), who were diagnosed and treated at the University Hospital of Regensburg until July 2023, were collected using a non-interventional, mixed retrospective-prospective study approach. Data include demographics (age, gender), prognostic factors (KPS at initial diagnosis, extent of resection), treatment modalities, as well as outcome data (PFS, OS). In addition, data on symptoms (NANO), cognition (NeuroCoq Fx), quality of life (EORTC QLQ-C30 and BN20), and social and occupational reintegration (specific questionnaire) were collected in a cross-sectional approach at elective scheduled follow-up appointments. Key endpoints are treatment patterns, symptoms, cognition, quality of life, social and occupational reintegration and outcomes in a real-world setting. In addition, correlations of treatment patterns and outcomes with symptoms, cognition, quality of life, and social and occupational reintegration will be investigated. A total of 105 patients were identified through the local clinical cancer registry. Of these, 4 could not be assigned to a local patient ID, 7 had a histology other than oligodendroglioma, and 15 were excluded due to missing data. Therefore, 79 patients were included, of whom 48 are still in follow up. Of these, 46 patients completed quality of life questionnaires, and 44 of them underwent neuropsychological testing during their follow-up appointments. RESULTS The data collection phase has been completed in March 2025. We started with data analysis, that will be completed by the time of the EANO meeting. After a descriptive analysis, significant factors identified in univariable analyses will be further evaluated by correlation analyses and multivariable analyses. CONCLUSION Our study will provide unprecedented data on long-term follow-ups in a homogenous cohort of patients with oligodendroglioma, IDH mutant (CNS WHO grade 2 and 3), with a specific focus on long-term quality-of-life, cognitive and social outcomes. It will therefore provide a starting point for the development of prospective supportive measures for this specific patient population.