The Chemotherapy of Intracerebral vs Subcutaneous Murine Gliomas

An anticancer drug, epipodophyllotoxin (VM 26), was administered to mice bearing intracerebral and subcutaneous ependymoblastomas in order to compare the two sites of implantation as models for chemotherapy of brain tumors. VM 26 increased survival of intracerebral tumorbearing animals only about 20% despite a marked inhibition of both intracerebral and subcutaneous tumor growth. The drug depressed the uptake and incorporation of tritiated thymidine into the DNA of tumor implanted in either site, excluding the blood-brain barrier as a cause of the poor results in the survival studies. VM 26 delayed subcutaneous tumor growth by 21 days. The results suggest very little difference in drug effect on tumor itself relative to the implantation site, but considerable difference in the effect on the tumor-bearing animals. Comparison with randomized clinical studies suggest that human response to anticancer drugs is predicted better by the intracerebral survival model than by the subcutaneous model.