Local hyperthermia enhances cyclophosphamide, ifosfamide and cis-diamminedichloroplatinum cytotoxicity on human-derived breast carcinoma and sarcoma xenografts in nude mice.

Antitumour response and toxicity of locally applied hyperthermia with or without cyclophosphamide, ifosfamide, and cis-diamminedichloroplatinum (cisplatin) have been compared. The model systems were human breast carcinoma (MX1/3) and human sarcoma (S117) grown in nude mice. In order to detect changes of tumour oxygenation intratumoral PO2 and pH were measured before, during and following hyperthermia. In both human tumour lines a monotherapy with one of the cytotoxic drugs or with hyperthermia caused a transient growth delay, while the combination of the same dose of the drugs with hyperthermia (at 43 degrees C for 1 h) resulted in complete tumour remissions. During hyperthermia, in both tumour types oxygenation was improved. Intratumoral pH remained practically unchanged.