New Topics in Embolization Effects of Central, Peripheral, or Capillary Type of Occlusion in Animal Models Simulating Tumor Embolization

Embolization is one of the new therapeutic methods in radiology. It has found acceptance for special indications such as emergency treatment of intractable bleeding (Athanasoulis 1980; Kauffmann et al. 1979; Rosch et al. 1972). However, tumor embolization is still controversial, since long-term results are so disappointing that few indications for palliative treatment are left. Even in a case with hematuria caused by renal cell carcinoma, recurrent hemorrhage is reported following Gianturco-Anderson-Wallace coil occlusion (Flamm et al. 1981). Failure of tumor embolization is caused by collaterals and recanalization of occluded arteries. Therefore only temporary reduction of tumor size is achieved: collaterals provide continuing growth in the periphery of the tumor. Clearly the possibilities of tumor embolization are not exhausted so long as the tumor periphery is not primarily occluded. Up to now there has been no medium that reaches the periphery but avoids venous propagation. All media especially developed for embolization, like the Gianturco-Anderson-Wallace coil, detachable balloons, etc., allow occlusion only of the main renal arteries. Ethibloc is the first substance especially developed for peripheral transport (besides occlusion of the pancreatic duct). Its special properties for reducing efficiency of collateral supply were examined and compared with the effect of Gelfoam powder, Butyl cyanoacrylate/Lipiodol and ligation of the renal artery.