Potentials and Limitations for the Use of Radiation Sensitizers of Resistant Hypoxic Cells in Tumors

Abstract

Abnormal vascularization often associated with tumor growth may result in the presence of significant numbers of radiation resistant hypoxic cells in some solid tumors, thereby limiting the effectiveness of radiotherapy in cancer treatment. Sufficiently low levels of oxygen have been well-documented as causing radiation resistance of mammalian cells in culture and in tumors in animals. There is also a significant amount of data available suggesting the presence of hypoxic resistant cells in human tumors. Hypoxic cells in tumors are not abnormally oxygenated because of the large diffusion distances from blood vessels and intervening consumption of oxygen by other tumor cells. One area of major research emphasis in the past ten years has been the search for compounds which sensitize hypoxic cells to ionizing radiation but are not readily consumed by the tumor cells and with pharmacological properties which result in sensitizing concentrations in regions of hypoxic cells in poorly vascularized tumor tissue.KeywordsHypoxic CellRadiation SensitizerCancer Clin TrialHigh Frequency Hearing LossClonogenic Cell SurvivalThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.