Vitamin C may enhance radiation therapy for aggressive brain tumours, University of Otago researchers have found.
The study, carried out in association with the Malaghan Institute, was recently published in the journal Free Radical Biology and Medicine.
Lead author Dr Patries Herst and Dr Melanie McConnell investigated how combining high dose vitamin C with radiation affected survival of cancer cells isolated from glioblastoma multiforme (GBM) brain tumours, and compared this with the survival of normal cells.
They found that high dose vitamin C by itself caused DNA damage and cell death which was much more pronounced when high dose vitamin C was given just prior to radiation.
Dr Herst said GBM patients had a poor prognosis because the aggressive GBM tumours were very resistant to radiation therapy.
"We found that high dose vitamin C makes it easier to kill these GBM cells by radiation therapy".
She said there had long been debate about the use of high dose vitamin C in the treatment of cancer.
High dose vitamin C specifically kills a range of cancer cells in the laboratory and in animal models. It produces aggressive free radicals in the tumour environment but not in the environment of healthy cells. The free radicals damage DNA, which kills the cells, but the high concentration necessary to kill cancer cells can only be achieved by intravenous injection.
However, these promising findings have so far not been validated in clinical studies.
"If carefully designed clinical trials show that combining high dose vitamin C with radiation therapy improves patient survival, there may be merit in combining both treatments for radiation-resistant cancers, such as glioblastoma multiforme," Dr Herst said.
This study was funded by the Wallace Family Estate, Genesis Oncology Trust and a University of Otago Research Grant.