Effect of breathing carbogen on the oxygen tension of murine and human tumours measured using an Eppendorf pO2 histograph.

Abstract

For decades the presence of hypoxic cells within solid tumours has been regarded as an impediment to the efficacy of radiotherapy (Thomlinson and Gray, 1955). Several treatment modalities have been developed with the aim of overcoming the problem posed by hypoxic cells though, so far, they have had minimal clinical impact (Hall, 1994). Most efforts have centred around either supplying more oxygen to tumour tissue, with the aim of increasing the oxygen tension in the hypoxic cells and thus increasing their sensitivity to radiation or administering drugs which selectively increase the sensitivity of hypoxic cells to radiation (Dische, 1991). More recently drugs have been developed which exhibit selective toxicity to cells at lower than normal oxygen tension (Brown, 1993). The aim of treatment with these “bioreductive cytotoxins” is to kill the hypoxic cells whilst conventional radiation / chemotherapy eradicates the more oxygenated tumour cells.