Abstract
Boron neutron capture therapy （BNCT） is a radiotherapeutic modality that enables highly localized, high-dose irradiation within cancer cells through the combination of tumor-selective accumulation of boron-containing compounds and neutron irradiation. In Japan, the clinical application of BNCT has expanded as a novel salvage treatment for recurrent head and neck cancer after radiotherapy, following the clinical introduction of accelerator-based BNCT systems and regulatory approval of the boron compound borofalan （10B） （Steboronine®）.
Oral cancer is a disease in which local control is directly associated with prognosis; however, treatment options for post-irradiation recurrence remain limited. This review summarizes the current status of BNCT for recurrent oral cancer and presents the results of a retrospective analysis of patients with recurrent oral squamous cell carcinoma treated with BNCT at our institution.
Thirty patients who underwent BNCT after June 2020 and for whom at least 3 years had elapsed since treatment were included in the analysis. The objective response rate was 76.7％. The 2-year overall survival, local control, and progression-free survival rates were 53.3％, 31.6％, and 20.0％, respectively. Patients who achieved a complete response showed significantly better survival outcomes than those without a complete response （p＜0.01）. Severe adverse events included oral mucositis, osteonecrosis of the jaw, and carotid artery rupture.
These findings suggest that BNCT may be a promising treatment option for recurrent oral cancer after radiotherapy. However, strict patient selection, adequate supportive care, and appropriate differentiation from other treatment modalities are essential for its safe and effective clinical application.
