The use of oxygen in the treatment of cancer has been around as a concept for a long time in numerous guises and for a variety of different reasons. It is now widely accepted that oxygen is a potential anti-cancer therapy.
All mammalian cells require oxygen to proliferate, and under certain conditions cells also need oxygen to undergo programmed cell death. A way of thinking of cancer is that the balance between cell proliferation and cell death is not in equilibrium.
A useful way to visualise this is to imagine it as a population explosion based on increased longevity and fertility outpacing the supply of accommodation in a large city. Continuing with this metaphor, the accelerated growth and proliferation outstrips the city’s infrastructure and the ability to supply and nourish the new occupants.
In social terms these would become areas of ill health and malignancy; this is what happens to the cells in the body. The limited angiogenesis (development of new blood vessels) in solid tumours results in areas where oxygen concentrations are very low. While hypoxia probably slows tumour growth, it also causes these tumours to be resistant to the effects of radiation.
Hyperbaric oxygen therapy (HBOT) was used successfully over 30 years ago to enhance the cell sensitivity to radiotherapy in clinical trials of head, neck and cervical cancer. These trials were performed by the British Medical Research Council.
Laboratory based studies1 have demonstrated that HBOT can also increase the effects of chemotherapeutic agents. Back to our city analogy; think of oxygen as outreach workers, social services and the local government reaching into the damaged community to allow policing to reduce the crime rate, build new roads (blood vessels) thereby increasing supplies and improving the refuse collection of the by-products of those living there (natural cell balance).
1 Al-Waili NS, Butler GJ, Beale J, et al. Hyperbaric oxygen and malignancies: a potential role in radiotherapy, chemotherapy, tumour surgery and phototherapy. Med Sci Monit 2005;11(9):RA279–89.
Further reading https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510426/