Percutaneous Radiofrequency Ablation with Multiple Electrodes for Medium-Sized Hepatocellular Carcinomas

OBJECTIVE: To prospectively evaluate the safety and short-term therapeutic efficacy of switching monopolar radiofrequency ablation (RFA) with multiple electrodes to treat medium-sized (3.1-5.0 cm), hepatocellular carcinomas (HCC). MATERIALS AND METHODS: In this prospective study, 30 patients with single medium-sized HCCs (mean, 3.5 cm; range, 3.1-4.4 cm) were enrolled. The patients were treated under ultrasonographic guidance by percutaneous switching monopolar RFA with a multichannel RF generator and two or three internally cooled electrodes. Contrast-enhanced CT scans were obtained immediately after RFA, and the diameters and volume of the ablation zones were then measured. Follow-up CT scans were performed at the first month after ablation and every three months thereafter. Technical effectiveness, local progression and remote recurrence of HCCs were determined. RESULTS: There were no major immediate or periprocedural complications. However, there was one bile duct stricture during the follow-up period. Technical effectiveness was achieved in 29 of 30 patients (97%). The total ablation time of the procedures was 25.4 +/- 8.9 minutes. The mean ablation volume was 73.8 +/- 56.4 cm3 and the minimum diameter was 4.1 +/- 7.3 cm. During the follow-up period (mean, 12.5 months), local tumor progression occurred in three of 29 patients (10%) with technical effectiveness, while new HCCs were detected in six of 29 patients (21%). CONCLUSION: Switching monopolar RFA with multiple electrodes in order to achieve a sufficient ablation volume is safe and efficient. This method also showed relatively successful therapeutic effectiveness on short-term follow up for the treatment of medium-sized HCCs.

Radiofrequency Ablation for Treating Liver Metastases from a Non-Colorectal Origin

OBJECTIVE: We wanted to assess the safety and efficacy of performing radiofrequency ablation (RFA) in patients with non-colorectal liver metastases. MATERIALS AND METHODS: In this retrospective study, 25 patients with 40 hepatic metastases (M:F = 17:8; mean age, 57 years; tumor size, 0.5-5.0 cm) from a non-colorectal origin (stomach, biliary, breast, pancreas, kidney and skin) were treated with RFA. The RFA procedures were performed using either an internally cooled electrode or a clustered electrode under ultrasound or CT guidance. Contrast-enhanced CT scans were obtained immediately after RFA and follow-up CT scans were performed within three months after ablation and subsequently at least every six months. The intrahepatic disease-free interval was estimated and the overall survival from the time of the initial RFA was analyzed using the Kaplan-Meier method. RESULTS: No intraprocedural deaths occurred, but four major complications developed, including abscesses (n = 3) and pneumothorax (n = 1). Technical effectiveness was determined on the initial follow-up images. During the follow-up period (range, 5.9-68.6 months; median time, 18.8 months) for 37 tumors in 22 patients where technical effectiveness was achieved, 12 lesions (32%, 12 of 37) showed local tumor progression and new intrahepatic metastases occurred in 13 patients (59%, 13 of 22). The median intrahepatic disease-free interval was 10.1 months. The 1-year, 3-year and 5-year overall survival rates after RFA were 86%, 39% and 19%, respectively. CONCLUSION: RFA showed intermediate therapeutic effectiveness for the treatment of non-colorectal origin liver metastases.