Biological Basis for Rational Design of Clinical Treatment with Combined Hyperthermia and Radiation

Among the different aspects of hyperthermic cancer therapy, the potential use of hyperthermia as an adjuvant to radiation therapy has been the most widely studied. The current role of hyperthermia in clinical cancer treatment appears most attractive with such a combined treatment. However, numerous problems are related to the optimal application of hyperthermia as an adjuvant to radiation, both because it is still a modality which is technically difficult to apply, and because several biological problems must be solved before we can define the optimal treatment regime for the combined therapy. The aim of the present paper is to analyze the most pertinent of these problems. A series of experiments performed in a C3H mammary carcinoma and its surrounding normal skin will be discussed in order to ease the understanding of the biological rationale. The use of our own data for this purpose should not be considered a case of scientific chauvinism but has simply been chosen in order to simplify the presentation. This series of experiments represents the most comprehensive set of data in an individual tumour model. Furthermore, it should be noted that there is a general consistency in different experimental data, and a wider insight into the literature can be achieved from several recent reviews (3,4,8,10,11,13,33,37,47).