IRRADIATION OF CEREBRAL ASTROCYTOMATA UNDER WHOLE-BODY HYPOTHERMIA

Abstract

Fourteen cases of cerebral glioblagtoma multiforme (astrocytoma grades III and IV) were treated by irradiation under mild hypothermia (30 to 33 deg C). It is shown that under hypothermia, cerebral tissues become more sensitive to x rays. A differential sensitivity, favorable to treatment, may exist between tumor and normal tissue cells. Because irradiation under hypothermia is followed by signs of acute cerebral edema, the totai incident dose to each hemisphere, in any single course of treatment, had to be limited to 300 to 450 r (given as 150 r daily). With these doses it was not possible to prolong life beyond what would be expected from surgery alone, Experiments on mice support the view that mild hypothermia increases tissue radiosensitlvity. Welloxygenated tissues are considered to be practically at their maximum sensitivity, and no appreciable increase in response to irradiation is expected to follow a further rise in oxygen tension. Because of some more generalized cerebral reactions, and the rise in mortality in mice after wholebody irradiation under hypothermia, it appears likely that the increased response to irradiation during mild hypothermia is not entirely due to an increase in oxygenation of the tissues. It is advised that low doses be usedmore » in commencing any course of treatment invoiving irradiation under hypothermia. (P.C.H.)« less