Efficacy of Boron Neutron Capture Therapy in Primary Central Nervous System Lymphoma: In Vitro and In Vivo Evaluation

L-Boronphenylalanine Biodistribution Dynamics in the Organs of Mice with Subcutaneous Tumor Xenograft is a Model to Assess Neuron Sources Efficiency in Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT), due to its high biological efficiency, is one of the most promising methods of radiation therapy for malignant tumors. Currently, research in this area has received momentum due to the emergence of fundamentally new compact neutron sources suitable for clinical use. The aim of the investigation was to study L-boronphenylalanine (L-BPA) biodistribution in the organs of experimental animals with subcutaneous tumor xenografts, and evaluate the application of the experimental model to assess the effectiveness of new neutron sources.

MATERIALS AND METHODS

The experiments were carried out on BALB/c mice with subcutaneous xenograft of mouse adenocarcinoma CT26. L-boronphenylalanine in a molar excess of fructose was administered intravenously at a dose of 350 mg/kg, the organs under study were taken 1.5, 3, 6, and 24 h after drug administration. The content of the 10B isotope was analyzed using inductively coupled plasma mass spectroscopy (ICP-MS). The absence of toxic effects was verified pathomorphologically.

RESULTS

The maximum L-BPA content in the tumor was 142.0±4.41 μg/g 1.5 h after drug administration. The minimum therapeutic concentration of L-BPA in the tumor persists up to 5.4 h after drug administration. Among normal organs, the maximum content was observed in the kidneys, it is most likely being associated with the structural and functional features of the organ rather than the true content of L-BPA in the tissues. Histological studies revealed no structural disorders and dystrophic changes in tissues against the background of L-BPA introduction.

CONCLUSION

The results of the study demonstrate the feasibility of the studied tumor model to evaluate the efficiency of new neutron sources for BNCT. The L-borophenylalanine content in the tumor and the time of maintaining the minimum therapeutic concentration appeared to be sufficient for effective BNCT. The high contrast of 10B accumulation relative to non-pathological tissues minimizes the possible side effects of BNCT.

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

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.

Anti-tumor effect of boron neutron capture therapy in pelvic human colorectal cancer in a mouse model

Local recurrence of colorectal cancer (CRC) can occur in patients after curative resection, and additional surgical resection may therefore be required; however, this is a significant burden for patients, because additional surgical resection may necessitate the resection of other organs such as the bladder, prostate, uterus, or sacral bone. Therefore, there is a need for alternative therapeutic strategies. We focused on boron neutron capture therapy (BNCT) as a treatment modality that can selectively target tumor cells without excessive damage to normal tissues. The usefulness of BNCT to pelvic CRC remains unknown. This study investigated the anti-cancer effect of boronophenylalanine (BPA)-mediated BNCT in a previously established mouse model of pelvic recurrence of CRC. Uptake of BPA in CRC was observed both in vitro and in vivo, and the concentrations were sufficient for BNCT. Our results are the first to show that BPA-mediated BNCT prolonged the survival of experimental mice with pelvic tumors; moreover, it did not cause any obvious severe side effects in the treated animals. In conclusion, BPA-mediated BNCT could contribute to treating local recurrence of pelvic CRC.