The Effect of Local Hyperthermia on the Tissue Oxygen Tension of Melanoma in the Hamster

Abstract

The cytotoxic effect of hyperthermia in malignant tumors varies with the heat distribution in the tumor and in the surrounding tissue. Therefore, nutritive tumor circulation and morphologic changes in the microvasculature after the temperature increase are important variables in reaching a complete destruction of tumor cells under in vivo conditions [1–4, 11]. Hyperthermia not only induces environmental changes in the interstitial space, but also affects the thermosensitivity and the development of thermotolerance [11]. Nevertheless, since devices for noninvasive temperature measurements have not yet become available for routine use in clinical practice, hyperthermia is still being induced without knowledge of the actual temperature in the tumor. Moreover, to date, theoretical calculations of the heat distribution within a tumor have not been acceptable as an approximation of the temperature variations. If, however, a detailed quantitative analysis of tissue oxygenation and microhemodynamics under local hyperthermia of malignant tumors became available, a theoretical basis could be provided for mathematical models.