engleski

The antitumour effect of etoposide is potentiated by heat

In last two decades the use of hyperthermia in cancer treatment has been more studied because of its potential clinical application as a single agent or in combination with radiation and/or cytostatics. In clinical practise hyperthermia is rarely used as a single agent and is more frequently combined with irradiation and/or chemotherapeutic agents. The aim of this work is to investigate the antitumour effect of hyperthermia and some cytostatics on the growth of mouse mammary carcinoma. Tumour tissue is implanted into mouse footpad. When tumour volume was about 200 mm3 in size animals were treated with hyperthermia alone and with hyperthermia and cyitostatics. From the cytostytics we have used etoposide, ifosfamide and cyclophosphamide. These drugs were used as a single agent and in combination with hyperthermia. All drugs were dissolved in physiological saline and given intraperitonealy. Heat was applied locally by immersing footpad of tumour bearing leg into water bath where temperature was set up to 43.5 C. The end point was observation of tumour growth time, i.e. the time needed for treated tumour to increase its volume fivefold. Obtained data have shown that hyperthermia per se increase tumour growth time three times over control. The drugs per se increase tumour growth time from twice to thrice, while combined treatment (heat plus drug) increase much more tumour growth time than single treatment which sometimes is additive and sometimes synergistic. Ifosfamide and cyclophosphamide gives the best antitumour effect when given simultaneously with hyperthermia while etoposide is the most active when given 72 hours before hyperthermia. These effects are synergistic. When three treatment regimens (hyperthermia, ifosfamide, etoposide) were given the antitumour effect was just additive. If radiation and hyperthermia were combined the best antitumour effect was achieved when radiation was given 4 hours before heat. When all three treatment were applied antitumour effect was additive.

hiperthermia; etoposide; iphosphamide; mouse tumour; tumour growth delay

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