Boron neutron capture therapy for recurrent head and neck malignancies

Abstract

Boron neutron capture therapy (BNCT) is a tumor-cell targeted radiotherapy. When 10B absorbs thermal neutrons, the alpha and 7Li particles generated by the 10B (n, α) 7Li reaction are high LET particles, and carry high kinetic energy (2.34 MeV), and have short ranges (4-9 micron-meters) of approximately one-cell diameter, resulting in a large RBE and selective destruction of tumor cells containing 10B. We have, for the first time in the world, used BNCT to treat 11 patients with recurrent head and neck malignancies (HNM) after a standard primary therapy since 2001. The 11 patients were composed of 6 squamous cell carcinomas, 3 salivary gland tumors and 2 sarcomas. The results of BNCT were as follows. (Regression rates (volume %) were CR: 2 cases, >90%: 5 cases, 73%: 1case, 54%: 1 case, PD: 1 case, NE (not evaluated): 1 case. The response rate was 82%. (Improvement of QOL was recognized, such as disappearance of tumor ulceration and covering with normal skin: relief of severe pain, bleeding, trismus and dyspnea: improvement of PS (from 4 to allowing the patients to return to work and elongate his survival period. (3) Survival periods after BNCT were 1-38 months (mean: 8.5 months). The survival rate was 36% (4 cases). (4) There are a few side-effects such as transient mucositis and alopecia less than Grade-2. These results indicate that BNCT represents a new and promising treatment approach even for a huge or far-advanced HNM. © 2005, Japan Society for Head and Neck Cancer. All rights reserved.