CLINICAL INVESTIGATION Dose-Escalated Radiation Therapy Is Associated With Improved Outcomes for High

Purpose: The optimal modern radiation therapy (RT) approach after surgery for atypical and malignant meningioma isunclear. We present results of dose escalation in a single-institution cohort spanning 2000 to 2021. Methods and Materials: Consecutive patients with histopathologic grade 2 or 3 meningioma treated with RT were reviewed.A dose-escalation cohort (>= 66 Gy equivalent dose in 2-Gy fractions using ana/b= 10) was compared with a standard-dosecohort (<66 Gy). Outcomes were progression-free survival (PFS), cause-specific survival, overall survival (OS), local failure(LF), and radiation necrosis. Results: One hundred eighteen patients (111 grade 2, 94.1%) were identified; 54 (45.8%) received dose escalation and 64(54.2%) standard dose. Median follow-up was 45.4 months (IQR, 24.0-80.0 months) and median OS was 9.7 years (Q1:4.6 years, Q3: not reached). All dose-escalated patients had residual disease versus 65.6% in the standard-dose cohort (P<.001). PFS at 3, 4, and 5 years in the dose-escalated versus standard-dose cohort was 78.9%, 72.2%, and 64.6% versus 57.2%,49.1%, and 40.8%, respectively, (P= .030). On multivariable analysis, dose escalation (hazard ratio [HR], 0.544;P= .042) wasassociated with improved PFS, whereas >= 2 surgeries (HR, 1.989;P= .035) and older age (HR, 1.035;P<.001) were associatedwith worse PFS. The cumulative risk of LF was reduced with dose escalation (P= .016). Multivariable analysis confirmed thatdose escalation was protective for LF (HR, 0.483;P= .019), whereas >= 2 surgeries before RT predicted for LF (HR, 2.145;P= .008). A trend was observed for improved cause-specific survival and OS in the dose-escalation cohort (P<.1). Sevenpatients (5.9%) developed symptomatic radiation necrosis with no significant difference between the 2 cohorts Conclusions: Dose-escalated RT with >= 66 Gy for high-grade meningioma is associated with improved local control and PFSwith an acceptable risk of radiation necrosis. (c) 2023 Elsevier Inc. All rights reserved