THE INFLUENCE OF ICRF-159 AND LEVAMISOLE ON THE INCIDENCE OF METASTASES FOLLOWING LOCAL IRRADIATION OF A SOLID TUMOR

Irradiation of 6000 rad in 10 equal fractions over 12 days delivered to KHT sarcomas in mice controlled 55% of the local tumors but 83% of the mice died from metastases. Three strategies to reduce the risk of metastatic spread were tested. The fractionation scheme was changed to deliver the same total dose using a large initial fraction followed by 7 equal portions with the same overall time. ICRF-159 was used with the intention of partially synchronizing the tumor growth fraction in a radiosensitive state of the growth cycle and of promoting normalization of the tumor vasculature. Levamisole was used to stimulate the immune system. The combination of ICRF-159 with the 8-fraction radiation course proved to be effective for increasing local control and decreasing the incidence of metastases. The addition of levamisole did not improve the results obtained with a combination of ICRF-159 and irradiation.