[Ultrasonically controlled percutaneous high frequency thermotherapy of liver tumors with perfused needle electrodes].

Percutaneous radiofrequency ablation (HFTT) is a new therapeutic technique for the treatment of inoperable primary and secondary liver tumors. We report our initial experience using a newly developed perfusion electrode. Twelve liver tumors (11 metastases of colorectal tumors, 1 hepatocellular carcinoma) were treated in 5 inoperable patients. The patients had 1 to 3 liver tumors. All lesions were cytologically confirmed and measured 12-47 mm. The technique was approved by the institutional review board and informed consent was obtained from all patients. A 12-mm-needle electrode with a 15-mm-active tip was introduced into the liver tumors under ultrasound guidance and tumors were coagulated with radiofrequency energy of 350 kHz. The needle electrodes were perfused with 0.9% saline during coagulation to increase the volume of coagulation necrosis without tissue vaporization. The serial changes in tumor size after therapy were evaluated with spiral CT imaging. Dynamic CT showed that unenhanced areas indicative of coagulation necrosis developed in all tumors. In 8 of 12 tumors no signs of recurrence appeared during the observation period of 7 (5-12) months. No major complications were observed. Our preliminary experience suggests that percutaneous radiofrequency coagulation can be a simple, safe and potentially effective treatment for selected patients with inoperable liver tumors. The results justify further studies to investigate the possible role in clinical practice.