Hyperthermia: Healing and Hazard in Tumor Bearing Rats

We have treated a metatasizing tumor in the rat with hyperthermia, as welI as the contralateral normal Iimb by immersion in a 43 C bath. Whole body (rectal) temperatures were allowed to reach 40.5 - 41.0 C for one hour, and possible harmful effects on the host immune system investigated. Treatment which caused regression of the primary tumor also significantly reduced extent of retroperitoneal metastases. Lymphocytotoxicity against tumor target celIs in vitro assayed one and two days after hyperthermia revealed no reduction in celI mediated immunity.