Repeated dearterializations of an experimental liver tumor: short- and long-term results

Intermittent dearterialization, as compared to permanent dearterialization, is preferably used in palliative ischemic treatment of liver tumors because collaterals seem to be avoidable. In this study the most efficient time period of hepatic arterial occlusion was assessed and short- and long-term effects of repeated daily dearterializations on the growth of a transplanted liver tumor was evaluated. In five groups of inbred Wistar/Furth rats bearing metastatic liver tumors the hepatic arterial circulation was repeatedly and transiently blocked for 0 (n = 8), 30 (n = 8), 60 (n = 8), 120 (n = 8), and 180 (n = 8) min daily for 5 days, respectively, with an implanted minioccluder. Another group (n = 6) was permanently dearterialized for 5 days. In addition, one group (n = 6) was intermittently dearterialized 120 min/day for 18 days and compared to the no treatment (n = 6) and permanent dearterialization (n = 6) groups. We found that repeated arterial occlusions for 120 and 180 min as well as permanent dearterialization for 5 days almost retarded the liver tumor growth completely. Collaterals developed in all rats subjected to permanent dearterialization and in one of the rats that were dearterialized repeatedly for 180 min. However, prolonged intermittent dearterializations for 180 days significantly delayed the tumor growth compared to permanent dearterialization (P < 0.05) yet collaterals did not develop. Therefore, we conclude that repeated arterial occlusions for 120 min are the optimal method of dearterialization that effectively retards the growth and prevents collateral circulation of this liver tumor. It may have implications in the palliative treatment of human liver tumor when dearterialization is considered.