Boron neutron capture therapy of a murine mammary carcinoma using a lipophilic carboranyltetraphenylporphyrin

The first control of a malignant tumor in vivo by porphyrin-mediated boron neutron capture therapy (BNCT) is described, In mice bearing implanted EMT- 6 mammary carcinomas, boron uptake using a single injection of either p-bor onophenylalanine (BPA) or mercaptoundecahydrododecaborane (BSH) was compare d with either a single injection or multiple injections of the carboranylpo rphyrin CuTCPH, The BSH and BPA doses used were comparable to the highest d oses of these compounds previously administered in a single injection to ro dents, For BNCT, boron concentrations averaged 85 mug B-10/g in the tumor a nd 4 mug B-10/g in blood 2 days after the last of six injections (over 32 h ) that delivered a total of 190 mug CuTCPH/g body weight. During a single 1 5, 20, 25 or 30 MW-min exposure to the thermalized neutron beam of the Broo khaven Medical Research Reactor, a tumor received average absorbed doses of approximately 39, 52, 66 or 79 Gy, respectively. A long-term (>200 days) t umor control rate of 71% was achieved at a dose of 66 Gy with minimal damag e to the leg. Equivalent long-term tumor control by a single exposure to 42 Gy X rays was achieved, but with greater damage to the irradiated leg. (C) 2001 by Radiation Research Society.