P09.13.B RE-IRRADIATION FOR RECURRENT GLIOBLASTOMA

Abstract BACKGROUND Glioblastoma multiforme (GBM) is one of the most aggressive primary brain tumors, characterized by rapid progression, resistance to conventional treatments, and poor prognosis. 90% of glioblastomas (GBM) relapse within two years of diagnosis. This study aims to evaluate the efficacy of intensity modulated radiation therapy (IMRT) in patients with recurrent GBM and assess its role in prolonging survival and improving clinical outcomes. METHODS A retrospective analysis was conducted on a cohort of patients diagnosed with recurrent GBM who received re-irradiation. Data were collected from clinical records, including radiation doses, timing of recurrence, overall survival (OS), progression-free survival (PFS), and treatment-related side effects. The primary endpoints were OS and PFS, while secondary endpoints included the evaluation of toxicities related to re-irradiation. Patients were stratified based on tumor location, initial treatment protocols, and the number of previous treatments received. RESULTS The analysis included 17 patients who underwent re-irradiation following tumor recurrence. The median OS after re-irradiation was 11.1 months, and the median PFS was 5.2 months. A subgroup of patients with limited previous treatments showed a higher response rate to re-irradiation, with a median OS of 14.3 months. However, patients with extensive prior therapies had a significantly shorter OS and PFS. Treatment-related toxicities were manageable, with the most common being mild cognitive decline and fatigue. Severe toxicities, including radionecrosis, were observed in 12% of patients. DISCUSSION Our findings suggest that radiotherapy remains a valuable option for recurrent GBM, providing symptom control and some degree of disease stabilization. However, its impact on long-term survival is limited, particularly in patients with heavily pre-treated tumors. The data emphasize the importance of early intervention and personalized treatment planning. Future studies should explore combination therapies and more precise radiation delivery techniques to maximize the therapeutic benefit of radiotherapy for recurrent GBM. Additionally, continued investigation into alternative treatment strategies is necessary to improve the overall prognosis of GBM patients.