Beyond radiation: immunological potentials of boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a targeted radiotherapeutic modality that employs boron-10 (¹⁰B) to capture thermal neutrons, thereby releasing high-linear energy transfer α-particles and lithium ions that selectively eradicate tumor cells while sparing the surrounding normal tissues. Immune checkpoint inhibitors (ICIs), including inhibitors of PD-1/PD-L1 and CTLA-4, enhance antitumor immunity by alleviating immunosuppression within the tumor microenvironment. As immunotherapy continues to expand across multiple tumor types and becomes integral to systemic cancer treatment, attention has increasingly focused on combining systemic immunomodulation with localized therapies. BNCT functions primarily as a local therapeutic approach, whereas ICIs elicit systemic immune activation. Whether the two modalities can produce synergistic therapeutic effects remains an important question.

In this narrative review, we summarize current mechanistic insights, preclinical and clinical developments, and ongoing challenges associated with the combination of BNCT and ICIs, highlighting the potential of this strategy to achieve durable, synergistic antitumor responses.