Recurrent meningioma treated with boron neutron capture therapy: a feasibility study with dosimetric and clinical correlates.

Background: Boron neutron capture therapy (BNCT) is a targeted radiotherapy modality that has shown promise in the treatment of recurrent gliomas and head and neck cancers. Although meningiomas are generally slow-growing, recent studies have demonstrated favorable uptake of boron-containing compounds, particularly boronophenylalanine (BPA), suggesting a potential role for BNCT in recurrent meningioma.

Methods: We retrospectively analyzed 13 patients with recurrent meningiomas treated with salvage BNCT at the Tsing Hua Open-Pool Reactor between August 2020 and May 2024. Tumor uptake was assessed using either ¹⁸F-BPA or ¹⁸F-Fluciclovine PET. Treatment response was evaluated using RANO criteria, and outcomes were analyzed in relation to dosimetric and clinical factors.

Results: Of the 13 patients (1 WHO grade 3, 6 grade 2, and 6 grade 1), 5 (38%) responded to BNCT. Responders had significantly higher tumor mean dose (45.10 vs. 25.85 GyE, p = 0.003). Tumor location influenced dosimetry; non-skull base tumors received higher doses and showed a trend toward better response. TNR and tumor size were not predictive of response. No severe adverse events were observed.

Conclusions: Salvage BNCT is a feasible and well-tolerated treatment for recurrent meningioma, with dose distribution and tumor location significantly influencing treatment response. Further studies are warranted to refine imaging and planning strategies, particularly for skull base lesions and in the context of Fluciclovine PET.