Optimizing Boron Neutron Capture Therapy (BNCT) to Treat Cancer: An Updated Review on the Latest Developments on Boron Compounds and Strategies

Abstract

Boron neutron capture therapy (BNCT) is a tumor-selective particle radiotherapy. It combines preferential boron accumulation in tumors and neutron irradiation. The recent initiation of BNCT clinical trials employing hospital-based accelerators rather than nuclear reactors as the neutron source will conceivably pave the way for new and more numerous clinical trials, leading up to much-needed randomized trials. In this context, it would be interesting to consider the implementation of new boron compounds and strategies that will significantly optimize BNCT. With this aim in mind, we analyzed, in this review, those articles published between 2020 and 2023 reporting new boron compounds and strategies that were proved therapeutically useful in in vitro and/or in vivo radiobiological studies, a critical step for translation to a clinical setting. We also explored new pathologies that could potentially be treated with BNCT and newly developed theranostic boron agents. All these radiobiological advances intend to solve those limitations and questions that arise during patient treatment in the clinical field, with BNCT and other therapies. In this sense, active communication between clinicians, radiobiologists, and all disciplines will improve BNCT for cancer patients, in a cost- and time-effective way.

Keywords: BNCT; boron neutron capture therapy; new boron compounds; radiobiological studies; strategies; targeted therapy; theranostic compounds.

Figure 1

Schematic of the nuclear reaction between ¹⁰B atom and a thermal neutron. Epithermal neutrons are thermalized when they travel through the tissue. The high-LET particles deposit their energy within the cell where the reaction took place.

Figure 2

Chemical structures of BPA, BSH, GB-10, boric acid, and fructose–BPA.

Figure 3

Chemical structure of ¹⁸F-labeled 2-borono-4-fluoro-L-phenylalanine (¹⁸F-BPA) marker.