Temporally-Modulated Pulsed Radiation Therapy for Large-Volume Reirradiation of Recurrent Meningioma

Background Patients with recurrent meningiomas treated with prior radiotherapy have limited treatment options. This study aims to evaluate the efficacy and tolerability of re-irradiation with temporally-modulated pulsed radiation therapy (TMPRT) in a cohort of patients with recurrent meningioma. Methods We retrospectively identified 26 patients with recurrent meningioma treated with TMPRT from 2003 to 2025 at a single institution. All patients had radiographic or pathologic evidence of progression, were not candidates for radiosurgery or surgery, had previously received conventionally fractioned radiotherapy, and were re-treated with temporally modulated pulsed radiotherapy. Radiographic progression was assessed using RECIST criteria. Acute and late toxicities were graded based on CTCAE 5.0. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method. Results Median follow-up was 61.9 months. Median TMPRT dose was 54 Gy in 2 Gy fractions. Median planning treatment volume was 193 cm 3 . PFS at 6 months was 77% (95% CI 56% - 89%) and median PFS was 27.2 months (95% CI 7.5 – 46.5 months). Median OS was 27.2 months (95% CI 16.4 – 73.9 months). Three patients (12%) experienced grade ≥3 acute toxicity, 3 patients (12%) experienced grade ≥3 late toxicity. Conclusions TMPRT was effective and generally well-tolerated in a cohort of patients with recurrent meningioma previously treated with radiotherapy. This represents the largest-volume reported reirradiation meningioma cohort, and suggests that TMPRT may safely expand the role of photon reirradiation to a patient population with limited local treatment options.