The effect of combination treatment with cis-platinum and low dose rate 125I radiation in a murine brachytherapy model.

Overview

We studied the effect of combination treatment with cis-platinum during low dose rate irradiation from 125I sources in the RIF-1 murine flank tumor model. Cell survival measured with a colony forming efficiency assay was used as the experimental endpoint. Sources implanted into tumors delivered 25 Gy of radiation to isodosed annuli of tissue at a dose rate of 1.3 Gy/hr. When 3 mg/kg of cis-platinum was administered 24, 12, and 1 hr before or 0, 12 and 24 hr after irradiation, the effect on cell kill was additive. Thus in the RIF-1 model there is no particular advantage gained by treatment with the combinations of cis-platinum and 125I radiation used in these studies.