The current status and future perspectives of clinical boron neutron capture therapy trials

Abstract Purpose Several hundreds of patients have been so far treated in clinical trials with boron neutron capture therapy (BNCT). Methods This is a non-systematic review of clinical trials with BNCT, with special emphasis on the more recent trials. Results The conducted trials have been relatively small single-arm studies and included mostly the patients with head and neck carcinomas resistant to traditional treatment modalities and glioblastomas. In general, the efficacy results have been promising and BNCT has been relatively well tolerated, even in the patients who have already been treated with conventional radiotherapy or chemoradiation. The most frequent adverse events have been similar to those associated with the conventional radiotherapy. At present, there is no evidence how the efficacy of BNCT would compare to the standard treatment modalities in earlier treatment lines. Conclusions Most of the existing studies have been performed with reactor-based facilities, but there is now a rapidly increasing number of linear accelerator-based BNCT sites, and the clinical research is apparently activating again. This, combined with the increased knowledge on cancer biology and novel types of oncological therapies, opens possibilities to study innovative boron carriers and to combine BNCT with modern oncological therapies in the future clinical trials. To conduct larger phase III trials, multicenter approaches are encouraged to be applied, keeping in mind the importance of joint instructions and quality control measurements.