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

Patients with recurrent meningiomas treated with prior radiation therapy have limited treatment options. This study aims to evaluate the efficacy and tolerability of reirradiation with temporally-modulated pulsed radiation therapy (TMPRT) in a cohort of patients with recurrent meningioma.

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 radiation therapy, and were retreated with temporally-modulated pulsed radiation therapy. Radiographic progression was assessed using Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Acute and late toxicities were graded based on Common Terminology Criteria for Adverse Events (CTCAE) 5.0. Overall survival and progression-free survival (PFS) were estimated using the Kaplan-Meier method.

Median follow-up was 61.9 months. Median TMPRT dose was 54 Gy in 2 Gy fractions. Median planning treatment volume was 193 cm³. 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 overall survival 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.

TMPRT was effective and generally well-tolerated in a cohort of patients with recurrent meningioma previously treated with radiation therapy. 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.