Early clinical trial concept for boron neutron capture therapy: A critical assessment of the EORTC trial 11001

Charged particle radiotherapy for thyroid cancer. A systematic review

The role of external beam radiotherapy (EBRT) in thyroid cancer (TC) remains contentious due to limited data. Retrospective studies suggest adjuvant EBRT benefits high-risk differentiated thyroid cancer (DTC) and limited-stage anaplastic thyroid carcinoma (ATC), enhancing locoregional control and progression-free survival when combined with surgery and chemotherapy. Intensity-modulated radiotherapy (IMRT) and particle therapy (PT), including protons, carbon ions, and Boron Neutron Capture Therapy (BNCT), represent advances in TC treatment. Following PRISMA guidelines, we reviewed 471 studies from January 2002 to January 2024, selecting 14 articles (10 preclinical, 4 clinical). Preclinical research focused on BNCT in ATC mouse models, showing promising local control rates. Clinical studies explored proton, neutron, or photon radiotherapy, reporting favorable outcomes and manageable toxicity. While PT shows promise supported by biological rationale, further research is necessary to clarify its role and potential combination with systemic treatments in TC management.

Ultrasound Combination to Improve the Efficacy of Current Boron Neutron Capture Therapy for Head and Neck Cancer

Boron neutron capture therapy (BNCT) is radiotherapy in which a nuclear reaction between boron-10 (10B) in tumor cells and neutrons produces alpha particles and recoiling 7Li nuclei with an extremely short range, leading to the destruction of the tumor cells. Although the neutron source has traditionally been a nuclear reactor, accelerators to generate neutron beams have been developed and commercialized. Therefore, this treatment will become more widespread. Recurrent head and neck cancer (HNC) close to the body surface is considered a candidate for BNCT using the boron compound boronophenylalanine (BPA) and has been found to be highly responsive to this treatment. However, some cases recur early after the completion of the treatment, which needs to be addressed. Ultrasound is a highly safe diagnostic method. Ultrasound with microbubbles is expected to promote the uptake of BPA into tumor cells. Ultrasound also has the ability to improve the sensitivity of tumor cells to radiotherapy. In addition, high-intensity focused ultrasound may improve the efficacy of BNCT via its thermal and mechanical effects. This review is not systematic but outlines the current status of BPA-based BNCT and proposes plans to reduce the recurrence rate of HNC after BNCT in combination with ultrasound.

Strategic Clinical Trial Design for Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) involves infusion of cancer patients with a tumor-seeking, boron-loaded compound and irradiation by a beam of neutrons, with an energy range of 1 eV-10 keV. Neutron capture in the ¹⁰B atoms results in an effective lethal radiation dose to the tumor cells, while sparing the healthy tissue. Recently available accelerator-based irradiation facilities facilitate developing BNCT to a treatment modality. However, the binary principle of BNCT, together with other points, is challenging in designing clinical trials that allow a timely and safe introduction of this innovative targeted modality into clinical practice. We propose a methodological framework to work toward a systematic, coordinated, and internationally accepted and evidence-based approach.

DNA Damage Response and Repair in Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is an approach to the radiotherapy of solid tumors that was first outlined in the 1930s but has attracted considerable attention recently with the advent of a new generation of neutron sources. In BNCT, tumor cells accumulate 10B atoms that react with epithermal neutrons, producing energetic α particles and 7Li atoms that damage the cell's genome. The damage inflicted by BNCT appears not to be easily repairable and is thus lethal for the cell; however, the molecular events underlying the action of BNCT remain largely unaddressed. In this review, the chemistry of DNA damage during BNCT is outlined, the major mechanisms of DNA break sensing and repair are summarized, and the specifics of the repair of BNCT-induced DNA lesions are discussed.

Boron Neutron Capture Therapy: Current Status and Challenges

Boron neutron capture therapy (BNCT) is a re-emerging therapy with the ability to selectively kill tumor cells. After the boron delivery agents enter the tumor tissue and enrich the tumor cells, the thermal neutrons trigger the fission of the boron atoms, leading to the release of boron atoms and then leading to the release of the α particles (⁴He) and recoil lithium particles (⁷Li), along with the production of large amounts of energy in the narrow region. With the advantages of targeted therapy and low toxicity, BNCT has become a unique method in the field of radiotherapy. Since the beginning of the last century, BNCT has been emerging worldwide and gradually developed into a technology for the treatment of glioblastoma multiforme, head and neck cancer, malignant melanoma, and other cancers. At present, how to develop and innovate more efficient boron delivery agents and establish a more accurate boron-dose measurement system have become the problem faced by the development of BNCT. We discuss the use of boron delivery agents over the past several decades and the corresponding clinical trials and preclinical outcomes. Furthermore, the discussion brings recommendations on the future of boron delivery agents and this therapy.

Boron neutron capture therapy for urological cancers

Boron neutron capture therapy is based on a nuclear reaction between the nonradioactive isotope boron-10 and either low-energy thermal neutrons or high-energy epithermal neutrons, which generate high linear energy transfer α particles and a recoiled lithium nucleus (⁷ Li) that selectively destroys the DNA helix in tumor cells. Boron neutron capture therapy is an emerging procedure aimed at improving the therapeutic ratio for the traditional treatment of various malignancies, which has been studied clinically in a variety of diseases, including glioblastoma, head and neck cancer, cutaneous melanoma, hepatocellular carcinoma, lung cancer, and extramammary Paget's disease. However, boron neutron capture therapy has not been clinically performed for urological cancers, excluding genital extramammary Paget's disease that appeared at the scrotum to penis area. In this review, we aimed to provide an updated summary of the current clinical literature of patients treated with boron neutron capture therapy and to focus on the future prospects of boron neutron capture therapy for urological cancers.

Boron Neutron Capture Therapy: A Review of Clinical Applications

Boron neutron capture therapy (BNCT) is an emerging treatment modality aimed at improving the therapeutic ratio for traditionally difficult to treat tumors. BNCT utilizes boronated agents to preferentially deliver boron-10 to tumors, which, after undergoing irradiation with neutrons, yields litihium-7 and an alpha particle. The alpha particle has a short range, therefore preferentially affecting tumor tissues while sparing more distal normal tissues. To date, BNCT has been studied clinically in a variety of disease sites, including glioblastoma multiforme, meningioma, head and neck cancers, lung cancers, breast cancers, hepatocellular carcinoma, sarcomas, cutaneous malignancies, extramammary Paget's disease, recurrent cancers, pediatric cancers, and metastatic disease. We aim to provide an up-to-date and comprehensive review of the studies of each of these disease sites, as well as a review on the challenges facing adoption of BNCT.

Urinary Proteomics Profiles Are Useful for Detection of Cancer Biomarkers and Changes Induced by Therapeutic Procedures

Boron neutron capture therapy (BNCT) is a binary cancer treatment modality where two different agents (¹⁰B and thermal neutrons) have to be present to produce an effect. A dedicated trial design is necessary for early clinical trials. The concentration of ¹⁰B in tissues is an accepted surrogate to predict BNCT effects on tissues. Tissue, blood, and urines were sampled after infusion of two different boron carriers, namely BSH and BPA in the frame of the European Organisation for Research and Treatment of Cancer (EORTC) trial 11001. In this study, urine samples were used to identify protein profiles prior and after drug infusion during surgery. Here, an approach that is based on the mass spectrometry (MS)-based proteomic analysis of urine samples from head and neck squamous cell carcinoma (HNSCC) and thyroid cancer patients is presented. This method allowed the identification of several inflammation- and cancer-related proteins, which could serve as tumor biomarkers. In addition, changes in the urinary proteome during and after therapeutic interventions were detected. In particular, a reduction of three proteins that were involved in inflammation has been observed: Galectin-3 Binding Protein, CD44, and osteopontin. The present work represents a proof of principle to follow proteasome changes during complex treatments based on urine samples.

The Physiological Role of Boron on Health

Boron is an essential mineral that plays an important role in several biological processes. Boron is required for growth of plants, animals, and humans. There are increasing evidences of this nutrient showing a variety of pleiotropic effects, ranging from anti-inflammatory and antioxidant effects to the modulation of different body systems. In the past few years, the trials showed disease-related polymorphisms of boron in different species, which has drawn attention of scientists to the significance of boron to health. Low boron profile has been related with poor immune function, increased risk of mortality, osteoporosis, and cognitive deterioration. High boron status revealed injury to cell and toxicity in different animals and humans. Some studies have shown some benefits of higher boron status, but findings have been generally mixed, which perhaps accentuates the fact that dietary intake will benefit only if supplemental amount is appropriate. The health benefits of boron are numerous in animals and humans; for instance, it affects the growth at safe intake. Central nervous system shows improvement and immune organs exhibit enhanced immunity with boron supplementation. Hepatic metabolism also shows positive changes in response to dietary boron intake. Furthermore, animals and human fed diets supplemented with boron reveal improved bone density and other benefits including embryonic development, wound healing, and cancer therapy. It has also been reported that boron affects the metabolism of several enzymes and minerals. In the background of these health benefits, low or high boron status is giving cause for concern. Additionally, researches are needed to further elucidate the mechanisms of boron effects, and determine the requirements in different species.

Critical review, with an optimistic outlook, on Boron Neutron Capture Therapy (BNCT)

The first BNCT trials took place in the USA in the early 1960's, yet BNCT is still far from mainstream medicine. Nonetheless, in recent years, reported results in the treatment of head and neck cancer and recurrent glioma, coupled with the progress in developing linear accelerators specifically for BNCT applications, have given some optimism to the future of BNCT. This article provides a brief reminder on the ups and downs of the history of BNCT and supports the view that controlled and prospective clinical trials with a modern design will make BNCT an evidence-based treatment modality within the coming decade.

BPA uptake does not correlate with LAT1 and Ki67 expressions in tumor samples (results of EORTC trial 11001)

The system L-amino acid transporter (LAT1) imports p-boronophenylalanine (BPA) mainly into proliferating cells. This study investigates in three tumor entities whether the proportion of tumor cells expressing LAT1 and/or Ki67 correlates with BPA uptake. Tumors were analyzed for (10)B concentration with prompt gamma-ray spectroscopy and for Ki67 and LAT1 expressions with immunohistochemical methods. The proportion of LAT1-expressing cells was much higher (5-90%) than that of Ki67-expressing cells (0-20%) and cells expressing both Ki67 and LAT1 (0-5%). Neither LAT1 nor Ki67 expression predicted BPA uptake.

Metabolism of borono-phenylalanine-fructose complex (BPA-fr) and borocaptate sodium (BSH) in cancer patients--results from EORTC trial 11001

Within the clinical trial EORTC 11001, patients were infused with (10)B-enriched borono-phenylalanine-fructose complex (BPA-fr), or borocaptate sodium (BSH) solutions, which are used as boron carriers for boron neutron capture therapy. Urine samples were periodically collected and analyzed by (10)B NMR spectroscopy. The results revealed time-dependent metabolic changes of the administered compounds. BPA-fr dissociated to the constituents BPA and fructose, and the borate group was partly cleaved from BPA. BSH was partly aggregated to a dimer form, BSSB. These observations were previously reported for cultured cells and animal models, and are confirmed here in human cancer patients.