P12.62.a Second Surgery for Recurrent Glioblastoma: Does It Prolong Survival? A Propensity Scored Matched Analysis

BACKGROUND Glioblastoma is the most aggressive primary brain tumor in adults, comprising 49% of malignant brain tumors. Standard treatment includes surgical resection, radiation, and chemotherapy, yet prognosis remains poor with a median overall survival (OS) of 12-15 months and a 5-10% five-year survival rate. Recurrence, inevitable within 7-10 months, shows aggressive behavior and therapy resistance. Re-resection may improve overall survival (OS) and quality of life in selected patients, but existing evidence is limited by small sample sizes and selection bias. This study aimed to evaluate the added value of re-resection as part of adjuvant therapy for recurrent Glioblastoma and identify patient subgroups benefiting most in terms of survival and functional outcomes. MATERIAL AND METHODS This propensity scored matched analysis compared re-resection in patients with recurrent Glioblastoma followed by adjuvant treatment versus no re-resection and only adjuvant therapy at Erasmus Medical Center (2010-2022). The matched cohort included 200 patients, matched on patient characteristics, functional outcomes, pathological tumor characteristics and radiological characteristics. Primary outcomes was OS. Secondary outcomes were OS in specific subgroups and functional deterioration (KPS and NIHSS) at 6 weeks, 3 months, and 6 months, analyzed using Kaplan-Meier estimates, Cox regression, and logistic regression. RESULTS In the propensity scored matched cohort (n=200), re-resection was associated with a median overall survival of 11.5 months compared to 8.8 months in the no recurrent surgery group, representing a survival benefit of 2.7 months (hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.51-0.96, p=0.002). Subgroup analysis demonstrated the greatest survival advantage in patients with a KPS of 80-100, with a median survival benefit of 2.5 months (HR 0.66, 95% CI 0.44-0.98, p=0.041), and in those with non-multifocal tumors, who showed an increase of 2.6 months (HR 0.63, 95% CI 0.43-0.92, p=0.021). Functional outcomes, assessed via performance status and neurological impairment scores, remained stable at 6 weeks, 3 months, and 6 months post-treatment, with no significant further deterioration observed (p>0.05 across all time points) in the re-resection group compared to the no recurrent surgery group. CONCLUSION Re-resection offers a modest survival benefit, particularly in select patient groups, with stable functional outcomes, supporting its role in personalized treatment. Further research is needed to optimize its application.