Researchers at Okayama University and Kinki University in Japan have found that effective and targeted uptake among malignant cells demonstrates the promise of a simplified boron compound for neutron radiation therapy.
"Glioblastoma multiforme is the most common malignant central nervous system primary tumor that has been incurable for decades," explained Hideki Matsui and colleagues at Okayama University Graduate School of Medicine and Kinki University in their recent report. "Treatment with ‘boron neutron capture therapy' (BNCT) has been found to double the duration of patient survival, but finding effective compounds for it has been challenging. Now Michiue and colleagues claim that they have demonstrated - both in cell lines and mice - a readily made boron compound that targets and penetrates tumor cells for effective BNCT," said Matsui.
The compound BSH is high in boron content and has the advantage of accumulating primarily in tumor tissue rather than healthy tissue. However BSH does not penetrate inside the tumor cells limiting the therapeutic effects of BNCT using it.
One of the challenges with treating glioblastoma multiforme is removing all cancer cells without causing damage to the brain. The destruction of nearby healthy cells is a significant side effect for traditional radiation therapy.
BCNT has attracted particular interest because the radiation caused is highly localized. When boron is delivered to malignant cancer cells, irradiation with low-energy thermal neutrons then triggers boron fission into a high energy alpha particle and lithium atom. While lethal to cells in their direct path the high-energy alpha particle and lithium atom produced cannot travel further than roughly a cell length before their energy is absorbed leaving nearby healthy cells intact.
BNCT has already been used clinically for treating brain tumors, malignant melanoma, head and neck cancers, and hepatoma. Hospital sources for low-thermal-energy neutrons to trigger the fission are in continued development. However clinical use so far has highlighted shortcomings in the boron delivery drugs currently available.
