NCOG-20. RADIATION-RELATED MORBIDITY OUTCOMES IN ATYPICAL MENINGIOMA PATIENTS: A RETROSPECTIVE COHORT STUDY

Abstract Atypical meningiomas present with unique challenges in management and prognosis. Given their tendency to recur, adjuvant radiation therapy (ART) is frequently utilized, however there are few reports on radiation-related morbidity in this patient population. The study aims to investigate the radiation-related complications in atypical meningioma patients treated with or without ART. The primary outcomes were the incidence and severity of RT-related morbidity. All patients treated for atypical meningiomas at our institution between January 1, 2014 and January 1, 2024 were retrospectively analyzed. Patients were grouped into two cohorts, those who were initially treated with surgical resection only and those who also received adjuvant RT. Radiation morbidity grading was assigned for all patients that received radiation treatments during their clinical course based on established grading systems. Fisher’s Exact and Kruskal-Wallis tests were used to determine associations between the two groups. There were 76 patients who were initially treated with surgery only and 23 patients who had surgery and ART. Mean length of follow-up among all patients was 55.6 months. Significantly lower rates of RT-related morbidity in the surgery only group were observed compared to the surgery and RT cohort (15.8% vs. 60.9%, p < 0.0001). Among patients in the surgery only cohort, 23 patients received RT at recurrence or progression. When comparing this subgroup to those who underwent ART, there was no significant difference in the severity of RT-related morbidity (p=0.2724). In this series, patients receiving ART experienced a higher incidence of radiation-related morbidity. When comparing only those who received RT, there was no difference in the incidence or severity of radiation-related morbidity between the two cohorts.