Radiobiology of BNCT mediated by GB-10 and GB-10+BPA in experimental oral cancer

We previously reported biodistribution and pharmacokinetic data for GB-10 (Na210B10H10) and the combined administration of GB-10 and boronophenylalanine (BPA) as boron delivery agents for boron neutron capture therapy (BNCT) in the hamster cheek pouch oral cancer model. The aim of the present study was to assess, for the first time, the response of hamster cheek pouch tumors, precancerous tissue and normal tissue to BNCT mediated by GB-10 and BNCT mediated by GB-10 and BPA administered jointly using the thermalized epithermal beam of the RA-6 Reactor at the Bariloche Atomic Center. GB-10 exerted 75.5% tumor control (partial+complete remission) with no damage to precancerous tissue around tumor or to normal tissue. Thus, GB-10 proved to be a therapeutically efficient boron agent in this model despite the fact that it is not taken up selectively by oral tumor tissue. GB-10 exerted a selective effect on tumor blood vessels leading to significant tumor control with a sparing effect on normal tissue. BNCT mediated by the combined administration of GB-10 and BPA resulted in a reduction in the dose to normal tissue and would thus allow for significant escalation of dose to tumor without exceeding normal tissue tolerance.