TREATMENT OF RESIDUAL METASTASES WITH NA[TRANS-RUCL4(DMSO)IM] AND RUTHENIUM UPTAKE BY TUMOR-CELLS

Treatment of MCa mammary carcinoma metastases by i.p. administration o f a total dose of 450 mg/kg Na[trans-RuCl4(DMSO)lm], after successful surgical removal of primary tumor mass, causes a significant prolongat ion of the host's life-time expectancy, This effect, related to lung m etastasis inhibition, seems not attributable to a direct inhibition of tumor cells since antimetastatic effects can be achieved also when dr ug treatment occurs before tumor cell injection into the host, Also, t he activity of Na[trans-RuCl4(DMSO)lm] seems independent of its concen tration in tumor cells, Rather it must be stressed that the fate of th is compound in the blood, following i.v. administration, is fast and o nly a very low percent of the total dose reaches the tumor target in t he lungs, These data emphasize the possibility that Na[trans-RuCl4(DMS O)Im] increases the resistance of the host against metastasis formatio n, possibly by the already shown mechanism of potentiation of the extr acellular matrix and reduction of blood stream invasion by tumor cells .