RESPONSE OF MOUSE SARCOMA-180 TO CISPLATIN IN COMBINATION WITH RADIATION AND HYPERTHERMIA

The in vivo response of a transplantable mouse tumour, sarcoma-180, to cis-piatin (cDDP, 1.0, 2.5 or 5.0 mg/kg b.wt), local hyperthermia (HT , 42 degrees C, 30' or 60' acid 43 degrees C, 30') and irradiation (RT , 10 Cy) was assessed on the basis of tumour cure (complete response, CR), volume doubling time (VDT) and regrowth delay (RD) as well as ani mal survival up to 120 days. Each agent was given as a single modality or in different combination regimens. A single injection of cDDP prod uced a dose dependent increase in all the parameters. Of all the singl e treatments, HT at 43 degrees C, 30' gave the maximum tumour cure. Co mbination of any of the two treatments resulted in a better response t han all the single treatments. The chemosensitizing effect of beat was more pronounced than its radiosensitizing effect. Combination of all the three modalities, cDDP (2.5 mg/kg) + RT + HT (43 degrees C, 30') r esulted in 100 per cent CR, without any local recurrence. This treatme nt also resulted in a significant increase in 120 day tumour free surv ival compared to ail single modality treatments and bimodality treatme nts, except cDDP + 43 degrees C, 30'. This study indicates a potential advantage of the trimodality approach over single and bimodality trea tments in the local control of solid tumours.