Clinical Scorecard: Boron Neutron Capture Therapy for Recurrent Meningiomas: An Evaluation of Dosimetric Parameters and Clinical Outcomes
At a Glance
Category
Detail
Condition
Recurrent meningiomas including benign, atypical (WHO Grade 2), and anaplastic (WHO Grade 3) subtypes
Key Mechanisms
Selective tumor cell destruction via boron-10 neutron capture reaction producing high-LET alpha particles and lithium nuclei with short path lengths, sparing normal tissue
Target Population
Patients with recurrent meningiomas after initial treatment, eligible based on PET imaging tumor-to-normal tissue uptake ratio
Care Setting
Salvage therapy delivered at specialized nuclear reactor facility (Tsing-Hua Open-Pool Reactor) with epithermal neutron source
Key Highlights
BNCT exploits selective uptake of boronated compounds (e.g., boronophenylalanine) by tumor cells for targeted radiotherapy
Treatment eligibility requires PET imaging demonstrating tumor-to-normal tissue ratio ≥2.0 (¹⁸F-BPA PET) or fixed TNR of 2.5 (¹⁸F-Fluciclovine PET)
Dose constraints prioritize limiting brain exposure (max 13 GyE or mean 3 GyE) without specific tumor dose limits
Guideline-Based Recommendations
Diagnosis
Classify meningiomas by WHO grading (benign, atypical, anaplastic) via pathology
Use PET imaging (¹⁸F-BPA or ¹⁸F-Fluciclovine) to assess boron uptake and eligibility for BNCT
Management
Consider BNCT as salvage treatment for recurrent meningiomas when re-irradiation is limited by prior dose constraints
Administer BNCT at facilities with appropriate epithermal neutron sources following IAEA guidelines
Plan irradiation time and dose based on brain dose constraints rather than tumor dose
Monitoring & Follow-up
Perform MRI before and 3 months post-BNCT to evaluate tumor response using RANO criteria
Classify response as complete or partial response (responders) versus stable or progressive disease (non-responders)
Follow patients for at least 6 months post-treatment for progression-free survival assessment
Risks
Potential neurological impairment from treatment-related brain radiation exposure
Limitations in re-irradiation due to prior radiotherapy dose constraints
Uncertainty in boron uptake quantification when using ¹⁸F-Fluciclovine PET
Patient & Prescribing Data
13 patients with recurrent meningiomas treated with salvage BNCT after excluding second BNCT courses and short follow-up
BNCT delivered with epithermal neutron flux of 1.69 × 10⁹ n/cm²·s at 2 MW power; treatment planning incorporates PET-derived tumor-to-normal tissue ratios; brain dose constraints guide irradiation duration
Clinical Best Practices
Ensure pre-treatment PET imaging to confirm adequate boron uptake ratio for treatment eligibility
Adhere to brain dose constraints (max 13 GyE or mean 3 GyE) to minimize neurological toxicity
Use RANO criteria for standardized tumor response assessment post-BNCT
Obtain informed consent and IRB approval for BNCT salvage therapy in recurrent meningioma patients
Consider BNCT particularly when conventional re-irradiation options are limited or contraindicated
