Abstract
We report on preclinical study and clinical pilot study for applying boron neutron capture therapy (BNCT) to malignant liver tumors. In the preclinical study, rat liver tumors were developed by direct injection of Walker 256 cells into the liver parenchyma. Borocaptate sodium (BSH) (75 mg/kg)/lipiodol (0.3 ml/kg) emulsion was administered via the hepatic artery. Boron concentrations in the tumors, liver, and blood were measured at 1, 6, and 12 h after administration. Neutron capture radiography (NCR) was taken to confirm the selective accumulation of 10B in the liver tumors. In the pilot study, we applied BSH-lipiodol BNCT to two cases of liver tumors, a 63-year-old man with multiple hepatocellular carcinomas (HCCs) and a 60-year-old man with chorangiocellular carcinoma. Boron concentrations in the liver tumors and the tumor/liver (T/L) boron concentration ratio at 1, 6 and 12 h after administration of BSH/lipiodol emulsion (concentration: T/L ratio) were 479.2 ppm: 4.0, 197.3 ppm: 14.9, and 96.5 ppm: 6.6, respectively. Highly selective irradiation was clearly demonstrated by the NCR images. In the clinical study, no acute side effect was observed in two cases treated with BNCT. In the case of HCCs, the multiple tumors in the right lobe treated with BNCT showed no growth in one month after the treatment. Intra-arterial administration of BSH/lipiodol emulsion is effective method for delivering high concentration of 10B selectively to the liver tumors. The feasibility of our protocol for treating multiple liver tumors with BNCT was confirmed.
