Treatment Of Hypoxic Tumours With Plasma Jets

A challenge in cancer therapy is the destruction of tumours, where there is the potential issue of cancer cells residing within hypoxic tissue. The concept of hypoxic regions within tumours dates back to 1909 and it has long been suspected that under low oxygen tension, cells are “afforded” radiation protection. It has been shown many decades ago, that raising the concentration of oxygen in tissues can significantly improve the outcomes in radiotherapy. For example, in 1953, a meta-analysis of 83 randomised trials showed a clear benefit from raising tissue oxygen tension during radiation therapy, with the clearest benefits seen in cancers of neck and head [1]. However, there are only a limited number of ways to raise oxygen tension in tissues, which include breathing pure oxygen at or above standard temperature and pressure, or hypoxic modification by the means of an administered drug (e.g. nimorazole) [2, 3, 4]. Recently, we (and other research groups) have shown that cold atmospheric plasma jets not only readily deliver reactive oxygen and nitrogen species (RONS) into tissue, but concomitantly raise the oxygen tension in tissue. Combined RONS and oxygen delivery, may significantly elevate oxidative stress in cancer cells, resulting in destruction of these cells within hypoxic tumours. In this presentation, I will provide a brief historical overview of research on the modification of hypoxia in cancers; I will then discuss results that have shown how plasma jets can be used to treat hypoxia in tumours (through delivery of RONS and oxygen into tissues). I will also discuss the potential opportunities, challenges and limitations of the plasma technology for treatment of hypoxic cancer tumours.