[Percutaneous cryosurgery for liver tumors].

A new cryoprobe developed in our department makes it possible to perform percutaneous cryoablation for small liver tumors. This cryoprobe is placed into each lesion using an ultrasonic guidance technique. In this study there were 10 patients with hepatocellular carcinoma and 5 patients with liver metastases from colorectal carcinoma. In 6 cases the tumor size was below 2 cm, in 6 cases between 2 and 3 cm, and in 3 cases over 3 cm. Using a cryoprobe of 3 mm in diameter, each lesion was frozen using liquid nitrogen for 15 or 20 minutes then thawed for 10 minutes, and repeated. The ice ball was found to enlarge to 3 cm in 20 minutes and 5 cm in 60 minutes experimentally. Six cases were CR, 5 PR, 2 NC and 2 PD. After cryoablation, liver function did not change and there were no complications. However, as the size of the ice ball was small (about 3 cm), this method was insufficiently effective in some cases. Percutaneous cryoablation using this probe should be performed for tumors smaller than 3 cm.

[Basic studies of intra-arterial hyperthermic treatment].

Basic studies on intra-arterial hyperthermic treatment (1AHT) were conducted in rabbits implanted with VX2 tumor inside the thigh. For the purpose of determining the best temperature, saline added Adriamycin (ADM) (2 mg/body) that heated up to a predetermined objective temperature was injected. At 3 days after administration, the intratumor concentration of ADM (ITCA) and blood laboratory data were obtained. ITCA of the 53 degrees C group (1.13 +/- 0.41 micrograms/g) was significantly higher than those in the 23 degrees C group. In the 58 degrees C group, BUN, CPK, and creatinine were elevated. These data suggested that the best temperature of IAHT was about 53 degrees C. The treated rabbits were divided into 4 groups (heated saline added ADM, heated saline, non-heated saline added ADM, control) and the tumor growth rates after IAHT were investigated. The tumor size of the groups treated by heated saline was inhibited compared with that in the other two groups. There was no elevation of intratumor temperature in spite of IAHT. At 2 days after the IAHT, patho logically there were vacuolar degeneration in the arterial endothelial cells near the tumor, and narrowing of involved artery. These results suggest that the antitumor effect by IAHT is related with blood supply without hyperthermic effect.