Hyperglycemia as a means of increasing the efficacy of hyperthermia in radiotherapy of tumors

: In experiments on mice with Ehrlich carcinoma transplanted into the thigh the authors determined a gain in tumor heating from the use of induced hyperglycemia (IH) during thermoradiotherapy. Tumors were irradiated at a dose of 20 Gy followed in 3 h by local hyperthermia (HT) by emerging a tumor into water at 40-45 degrees C for 30 min. IH followed irradiation (i.e. 3 h before HT) in the form of 5-time ip administration of glucose at a total dose of 10.4 g/kg for 2 h. Isoeffective tumor damage was achieved in irradiation combined with HT (45 degrees C) only and in irradiation with subsequent IH and HT (40 degrees C), i.e. a gain in the temperature of heated water as a result of glucose use was 5 degrees C. In the independent use (without irradiation) of HT this value was equal approximately 2.5 degrees C. Thermometric investigations have shown that these effects are partially accounted for by better heating (by 0.2-0.4 degrees C) of tumor tissue in IH. However glucose action was mainly connected with resultant physiological changes in tumors like a noticeable decrease in pH and stable disorder of the blood flow.