Treatment of VX2 liver tumor in rabbits with "wet" electrode mediated radio-frequency ablation

Radio-frequency ablation (RFA) has been considered as an alternative therap y for liver tumors. A "wet" electrode with interstitial infusion of hyperto nic saline was tested for the RFA of liver tumor in rabbits. Seventy-eight liver tumors (circle divide 1.5 to 3.0 cm) were induced in 41 rabbits by VX 2 carcinoma implantation. Fifty-one tumors in 27 rabbits were treated with RFA. Under Laparotomy, the RF energy was delivered while 5% saline was infu sed through the electrode into the tumor at 1 ml/min. Six rabbits with 12 t umors were treated with only intratumoral 5% saline infusion without RFA. A nother 8 rabbits with 15 tumors received sham operation as untreated contro ls. The efficacy of the therapy was evaluated with survival rate, MRI, micr oangiography, and histopathology, In the RFA group, 6 rabbits survived long er than 6 months (absolute eradication rate 22.2 %); 12 rabbits were found free of viable tumor at the moment when they were sacrificed (relative erad ication rate 44.4%); 9 rabbits showed local tumor relapse and/or lung metas tasis 2-10 weeks after ablation (re-current current rate 33.3 %). In contro l groups of saline infusion and sham operation, all 14 rabbits died within 3 months (mortality rate 100%). Three-month survival rates between RFA grou p and control groups were significantly different (p < 0.05). Findings of M RI, microangiography, and histology supported these outcomes. Radical treat ment of liver malignancy in rabbits is possible with the present modified R FA technique. Its clinical usefulness has to be further proven.