Boron neuron capture therapy using epithermal neutrons for recurrent cancer in the oral cavity and cervical lymph node metastasis

The purpose of this clinical trial was to evaluate the utility of boron neutron capture therapy (BNCT) using epithermal neutrons for cases of recurrent cancer in the oral cavity, which are not indicated for a conventional treatment modality. We enrolled four patients with local recurrence or metastasis to the regional lymph nodes after completion of initial treatments, including surgery, chemotherapy and radiotherapy. Before receiving BNCT, patients underwent 18F-p-bononophenylalanine (BPA) positron emission tomography (PET) examinations to assess the BPA accumulation ratios in tumors and normal tissues. All patients showed at least a tentative partial response, while a marked improvement in quality of life was seen in one patient. Before BNCT, that patient could not be discharged from the hospital because of eating difficulties and malaise; after treatment, he was comfortably discharged. Mild malaise, oral mucositis and alopecia were seen as mild adverse effects; however, no life-threatening systemic symptoms were observed in any of the cases. Our results suggested that BNCT is a useful treatment modality for recurrent or regionally metastasized oral cancer.