Percutaneous saline-enhanced radiofrequency ablation of unresectable hepatic tumors:: Initial experience in 26 patients

Objective. The purpose of our study was to evaluate the safety and efficacy of percutaneous saline-enhanced radiofrequency ablation for unresectable primary or metastatic hepatic tumors. Subjects and Methods. Twenty-six patients with 15 hepatocellular carcinomas and 33 hepatic metastases (maximum diameter less than or equal to8.6 cm) were treated; of these, seven tumors in five patients were treated twice. Thus, 44 radiofrequency treatments were performed. Saline-enhanced and impedance-controlled radiofrequency ablation (0.5-1.1 mL/min of saline, 15-mm conductive portion of the electrode tip, 25-60 W, 5-43 min) was performed using MR imaging guidance. Coagulation necrosis, volume indexes, morbidity, and complications were assessed. Results. The volume of coagulation necrosis 1-7 days after radiofrequency ablation was 1.6-126.6 cm(3) (median, 18.9 cm(3)), corresponding to coagulation diameters of 1.5-6.2 cm (median, 3.2 cm). The coagulation volume was significantly larger if there were more than four radiofrequency applications (p=0.006). Tumors of 3 cm or less in diameter were eight times as likely to be successfully completely ablated (p=0.01) and volume indexes of lesions treated with the patient under general anesthesia were significantly larger than those treated with the patient under conscious sedation (p<0.001). Major complications occurred in four patients (15%). Incomplete ablation in 19 (35%) of 54 radiofrequency lesions was due to cooling by a large vessel nearby (n=2) or to low power applied in painful (n=11) or critical (n=6) locations. Residual tumor was observed in 14 (58%) of 24 tumors evaluated 6-8 months after radiofrequency ablation. Conclusion. Percutaneous saline-enhanced and impedance-controlled radiofrequency ablation can be effective in the treatment of unresectable hepatic tumors and minimizes potential carbonization. A greater number of radiofrequency applications, general anesthesia, and increasing experience provide significantly better results.