Changes in the clonogenic ability of solid tumor cells during combined exposure to hyperthermia and irradiation

A study was made of the clonogenic capacity of cells from central and peripheral zones of NKLy solid tumors of mice after heating up to 42 degrees C and after the combined effect of hyperthermia and local irradiation of the tumor. Hyperthermia markedly increased the rate of radiation death of cell populations from central tumor zones, having low oxygen tension, and had no effect on radiosensitivity of cells from peripheral well oxygenated zones. In heated tumors, the repair of potentially lethal radiation damages to cells from the peripheral zones was inhibited while in conventional irradiation conditions these damages could be restored.