Blockage of the hepatic-artery blood flow by biodegradable microspheres (Spherex) combined with local hyperthermia in the treatment of experimental liver tumors in rats.

The effect of local hyperthermia and a simultaneous blockage of the hepatic-artery blood flow by degradable starch microspheres (Spherex) was studied in a model of liver cancer in Wistar rats. Six days after each rat was inoculated with a cell suspension (NGW) in the central liver lobe, the rats were randomly allocated into four groups. The first group served as control, the second was treated with hyperthermia, the third by degradable starch microspheres (DSM) intraarterially, and the fourth with a combination of hyperthermia and DSM intraarterially. Tumor volumes were measured at laparotomy on days 0, 7, and 14. Temperature fluctuations in the tumor correlated well with those in the liver tissue, but were 2 degrees-4 degrees higher. The infusion of DSM did not change the pattern significantly. The tumor volumes were homogeneous between the groups at the start of treatment. The tumor growth was significantly reduced compared with the control group at day 7 in group III (P less than 0.05) and group IV (P less than 0.01) but only in group IV at day 14 (P less than 0.05). No differences in survival were found. Local hyperthermia concurrent with a blockage of the nutritional tumor blood flow seems to offer a more prominent and lasting tumor-growth inhibition.