Radiobiological effects of AB-BNCT on tongue squamous cell carcinoma: An in vitro and in vivo study

This study systematically investigated the radiobiological effects of an accelerator-based boron neutron capture therapy (AB-BNCT) system on SAS cells, a human tongue squamous cell carcinoma (TSCC) cell line. In vitro experimental results showed that L-¹⁰B-BPA incubation within 12 h had no significant effect on cell viability. At 24 and 48 h post-irradiation, the 26N20 group exhibited 11 % and 31.91 % reductions in cell viability, accompanied by 82.15 % and 68.34 % decreases in proliferation rates, respectively, compared to controls. In the 26N10 group, 48-h post-irradiation analysis revealed 49.05 % G2/M phase cell cycle arrest and a 40.17 % apoptosis rate (p < 0.05).

In vivo experiments revealed that 1 h after L-¹⁰B-BPA administration, the boron concentration in tumor tissue reached 59.36 ppm with tumor-to-normal tissue (T/N) ratio reached a maximum value of 8.48. Thirteen days after treatment, a complete tumor response was observed in 33 % of cases, while the objective response rate reached 100 %. Median survival time was significantly prolonged to 68 days from 27days for control (p < 0.05). Notably, at advantage depth, the L-¹⁰B-BPA combined with neutron irradiation failed to confer survival benefit. Neutron irradiation alone demonstrated tumor growth-promoting effects at identical fluence levels. These findings underscore the critical need to address dose cold spots in deep-seated tumors during clinical applications.

These results indicate that the AB-BNCT system effectively suppresses the progression of TSCC, likely through the induction of DNA damage and apoptosis. Further studies will explore the underlying molecular mechanisms of BNCT-induced apoptosis, providing a scientific basis for its precise clinical application.