Boron neutron capture therapy for glioblastoma. Yamamoto T, Nakai K,
Matsumura A. Cancer Lett.
2008 Apr 18;262(2):143-52.
Boron neutron capture therapy (BNCT) theoretically allows
the preferential destruction of tumor cells while sparing the normal tissue,
even if the cells have microscopically spread to the surrounding normal brain.
The tumor cell-selective irradiation used in this method is dependent on the
nuclear reaction between the stable isotope of boron ((10)B) and thermal
neutrons, which release alpha and (7)Li particles within a limited path length
(-9 microm) through the boron neutron capture reaction, (10)B(n,alpha)(7)Li.
Recent clinical studies of BNCT have focused on high-grade glioma and
cutaneous melanoma; however, cerebral metastasis of melanoma, anaplastic
meningioma, head and neck tumor, and lung and liver metastasis have been
investigated as potential candidates for BNCT. To date, more than 350
high-grade gliomas have been treated in BNCT facilities worldwide. Current
clinical BNCT trials for glioblastoma (GBM) have used the epithermal beam at a
medically optimized research reactor, and p-dihydroxyboryl-phenylalanine (BPA)
and/or sulfhydryl borane Na(2)B(12)H(11)SH (BSH) as the boron delivery
agent(s). The results from these rather small phase I/II trials for GBM appear
to be encouraging, but prospective randomized clinical trials will be needed
to confirm the efficacy of this theoretically promising modality. Improved
tumor-targeting boron compounds and optimized administration methods, improved
boron drug delivery systems, development of a hospital-based neutron source,
and/or other combination modalities will enhance the therapeutic effectiveness
of BNCT in the future.