Thermal dose-response of magnetic-induction thermoradiotherapy

Sixty-three patients with advanced cancer underwent greater than or equal to 5,000 cGy combined with Concentric Coil magnetic-induction localized hyperthermia. Tumor regression (CR + PR) was compared to thermal dose received, incorporating the premise that hyperthermia response is a function of time as well as temperature. A computer program was developed (after Sapareto and Dewey [2]) which stored minimum tumor temperatures recorded spatially and temporally during treatment and correlated response with T43 (equivalent minutes at 43 degrees C during the first treatment) and CT43 (cumulative T43, computed by multiplying T43 by the actual number of identical subsequent treatments received during the course of therapy). Those who responded--N = 46 (73%)--had significantly higher median thermal doses than those who did not respond. Comparison of T43 and CT43 thermal dose values between responders and nonresponders was significantly different at p values of 0.05 and 0.04, respectively. The data indicate that magnetic-induction hyperthermia and high-dose XRT was an effective treatment combination in advanced disease and that tumor response improved as thermal dose increased.