# Long-term outcomes and toxicity of radiotherapy for WHO Grade II and III meningiomas: a retrospective analysis of 98 patients

## TL;DR

This study shows that modern radiotherapy effectively controls high-grade meningiomas with mostly mild side effects, and particle therapy may reduce certain late toxicities.

## Contribution

The study provides long-term outcomes and toxicity data for high-grade meningiomas treated with modern radiotherapy, comparing skull base and non-skull base tumors.

## Key findings

- High-precision radiotherapy achieved 99% survival at 8 years with mostly mild early toxicities.
- Particle therapy was associated with lower rates of vertigo and headache compared to photon therapy.
- Late toxicities were rare and mostly non-severe, with radiation-induced cerebral contrast enhancement observed.

## Abstract

This retrospective study evaluated outcomes and toxicity in patients with WHO Grade II and III meningiomas treated with modern photon or particle radiotherapy, with emphasis on skull base versus non-skull base tumors.

Ninety-seven patients received photon (58.2%) or particle therapy (41.8%). Median age was 61 years (range, 15–88). Tumor location was non-skull base in 69.1% and skull base in 30.9%. All patients underwent fractionated radiotherapy with a median dose of 59.4 Gy (range, 34–68). Follow-up included MRI and assessment of local control (LC), progression-free survival (PFS), overall survival (OS), and toxicity (CTCAE v5).

At last follow-up, 94 patients (96.9%) were alive. Median OS was not reached, with survival rates of 100% at 2 and 5 years and 99% at 8 years. Median PFS was 32.0 months, with 2- and 5-year rates of 88.7% and 66.0%. Median LC was 33.0 months, with 2- and 5-year rates of 91.8% and 72.2%. Disease progression occurred in 40 patients (41.2%), including 30 in-field and 22 outside the irradiated volume. Early toxicities were mainly Grade I–II, most commonly alopecia, fatigue, and headache. Late toxicities were less frequent, including headache, seizures, vertigo, and radiation-induced cerebral contrast enhancement (RICE). Severe late toxicity (Grade III) was rare (n = 3). Particle therapy was associated with lower rates of vertigo and headache.

High-precision photon and particle radiotherapy achieved effective long-term control with favorable safety in high-grade meningiomas. Most adverse effects were mild and manageable, supporting the role of particle therapy in reducing selected late toxicities.