Assessment of the results from the phase I/II boron neutron capture therapy trials at the Brookhaven National Laboratory from a clinician's point of view.

Boron neutron capture therapy (BNCT) represents a promising modality for a relatively selective radiation dose delivery to the tumor tissue. The key to effective BNCT of tumors such as glioblastoma multiforme (GBM) is the homogeneous preferential accumulation of 10B in the tumor, including the infiltrating GBM cells, as compared to that in the vital structures of the normal brain. Provided that sufficiently high tumor 10B concentration (approximately 10(9) boron-10 atoms/cell) and an adequate thermal neutron fluence (approximately 10(9) neutrons/cm2) are achieved, it is the ratio of the 10B concentration in tumor cells to that in the normal brain cells and the blood that will largely determine the therapeutic gain of BNCT.