Effect of systemic hyperthermia of different intensity which was used in combination with a chemical agent (CDDP) and BRM (OK-432) for the treatment of murine ascites tumor was comparatively investigated.
Animals used were adult male mice of F1 hybrid between C57L and A/HeMs. Tumor cells were of a syngeneic cloned cell line FMA3 which was derived from Furth's mastocytoma. Number of cells transplanted into the abdominal cavity was at 105. Single uses of systemic hyperthermia of 39, 40, 41 and 42°C for 10 min or OK-432 which was given at a dose of 5 KE/kg did not cause a significant extension of mean survival fime (M. S. T.). CDDP, administered singly at a dose of 4 mg/kg, 1, 2, 3 or 4 times, caused the M. S. T. to extend 1.85, 3.96, 4.15 or 3.87 times longer than that in the control group, respectively. Additional use of the OK-432 to the CDDP of 4 mg/kg extended M. S. T. 1.47 times more than that achieved with the single use of CDDP (P < 0.01). Further addition of the systemic hyperthermia of 39°C to the combination of the CDDP and OK-432 further extended 1.82 times longer than the level attained with the combination of CDDP and OK-432 (P < 0.01). The magnitude of the extension of M. S. T. was comparable to that achieved with a single use of CDDP given more than twice, whereas the extent of irreparable renal disturbance was much slighter.
However, such beneficial effects on M. S. T. as well as on nephrotoxicity were not observed with the hyperthermia of temperatures examined higher than 39°C.