Recent Study Of Boron Neutron Capture Therapy For Malignant Brain Tumor In Japan

Since 1968, we have treated 145 patients and performed boron-neutron capture therapy (BNCT) on 160 occasions using 5 reactors in Japan. There were 85 patients with glioblastoma (including anaplastic astrocytoma and grade 4 astrocytoma), 37 patients with astrocytoma grade 2 or 3. Six patients had meningioma, six had PNET and four had metastatic brain tumors and 3 had a large AVM. Out of 87 patients operated on before May 1987, 18 lived or have lived longer than 5 years. Nine of these 18 lived or have lived longer than 10 years out of 53 patients operated on before May 1982. The survival rate of the patients with grade 3 -4 suppratentorial glioma treated between 1968 and 1985 was 19%. The five years survival rate was 58% in cases with small tumors within 6 cm of less in depth or size. On the other hand, the five year survival rates in the recent cases including recurrent cases treated between 1986-1994 was 29.3 %. The recent advancement of diagnostic procedure (CT scan and MRI) made it possible to detect the size and the depth of the tumor with greater accuracy. The induction of prompt gamma ray spectrometry gave us data of boron concentration in the tumor tissue and blood. These data have enabled more accurate dosimetry and radiation planning with boron neutron capture therapy. We also report on a new concept of BNCT.