Boron Neutron Capture Therapy for Squamous Cell Carcinoma of the Skull Base

Abstract

Objective: 1) Describe the first case of inoperative squamous cell carcinoma (SCC) in the skull base recurring after surgery, conventional radiotherapy, and chemotherapy, which was treated using 2-stage boron neutron capture therapy (BNCT). 2) Determine the effectiveness of BNCT for head and neck cancer. Method: We present a case of inoperative recurrent SCC in the right temporal bone involving the occipital condyle. The patient underwent BNCT twice in 1 month in 2007 at Research Reactor No. 4 of the Japan Atomic Energy Research Institute to ensure neutron capture in the deep lesion. Results: An epithermal neutron beam was used as the neutron source. The total estimated radiation dose of the BNCT to the tumor beneath the skin, at the deepest point of the tumor, and in the skin around the right auricle was 41.8, 36.9, and 15.8 Gy-Eq, respectively. After the BNCT, the tumor became necrotic and shrank immediately and disappeared 6 months after the first BNCT. Radiological studies performed 5 years after the first BNCT showed no evidence of residual or recurrent tumors. Conclusion: Total resection of SCC deeply invading the skull base is difficult. Surgical complications can leave patients in critical condition. Two-stage BNCT might be an effective treatment for patients with SCC deep in the skull base.