[Combined effects of local hyperthermia, bleomycin, and x-ray on Ehrlich ascites tumor in mice]

The combined effects of local hyperthermia at 42.5 degrees C for 30 minutes (HTM), 1/10 LD50 Bleomycin iv(BLM) and 200 rad-irradiation (200R) were studied in DDD strain male mice with Ehrlich ascites tumor. The objective was to acquire data on the optimum regimen for a combined administration of these 3 modalities. The treatments were carried out 10 days after the inoculation of 2 X 10(6) of the cells into the right hind-limb. HTM was applied by water bath heating. Concomitant application of the 3 modalities led to the best effect with a 80% complete regression. A single modality produced no significant effect and a 30-50% regression occurred when 2 modalities were combined. To assess the influence of timing and sequence, HTM was applied at 1,2,4 and 6 hours before, after or simultaneously with the combination of BLM and 200R. A significant effect was obtained in case of simultaneous application of the 3 modalities and the effectiveness of HTM remained as long as the time interval between HTM and BLM plus 200R was 2 hours. This enhancement disappeared in case of 4 hour intervals.