Stimulation of resistance against local tumor growth, of hosts pretreated by combined local hyperthermia and X-irradiation.

The relationships involved in host resistance to tumor development were studied. Animals were pretreated by local hyperthermia, local irradiation and combined local hyperthermia and x-irradiation. After treatment, the animals were inoculated with tumor cells 0--96 or 0--120 hours post treatment. (BALB/c X C57B1/6)F1 mice were inoculated with the SV40 local fibrosarcoma, and (C3H/eB/B1)F1 mice were inoculated with the metastatic Lewis lung carcinoma. The results show an enhanced resistance to tumor development in animals pretreated by the combined simultaneous local heat and x-irradiation, as compared to animals only preirradiated, only preheated, or to control untreated tumor-bearing animals.