Combined hyperthermia and radiation suggest an alternative to heavy particle therapy for reduced oxygen enhancement ratios

Abstract

THE American Cancer Society estimates that 250,000 people in the United States will die from cancer in 1974 and it has been speculated that 100,000 of them will die because of failure to control the primary tumour site¹. In the report of a 1972 conference on particle accelerators in radiation therapy Bagshaw said: “… perhaps the most critical factor in determining success or failure in the sterilisation of a localised neoplasm with standard megavoltage radiation is the state of oxygenation of the cells being irradiated …”². Cells which are poorly oxygenated when irradiated are more resistant to conventional X radiation than those which are well oxygenated. Many tumours are hypoxic and thus may be more resistant to radiation than the well oxygenated surrounding normal tissue. Considerable time and effort have been expended during the past decade in attempts to circumvent this problem. Efforts are currently focused on the use of heavy particles. We now have data suggesting that hyperthermia in conjunction with standard megavoltage radiation may present an alternative for circumventing the oxygen problem.