Site dependent response of tumours to combined heat and radiation

Abstract

In previous experiments, large differences in thermal sensitization were observed for tumors grown on the tails or the chests of mice. The results of experiments comparing the response of tumors [mouse Sarcoma F cells] in 4 different sites [in mice] to the radiosensitizing effects of heat and misonidazole are reported. Factors influencing tumor response, e.g., tumor growth rate, blood flow, temperature uniformity, temperature increase during heating and drug availability, were also studied. Tumor response and most of the parameters measured varied according to the site of tumor implantation. Growth rate, blood flow and natural tumor temperature are all likely to be important. However, there appears to be no simple relationship by which tumor response could be predicted, although heat dose, the product of temperature elevation above the natural level and treatment time, may be the most relevant parameter. Clearly, the choice of implant site does influence response to treatment. Tumors grown on the extremities may be poor models for human tumors because of their low natural temperatures.