Ultrasonography-Guided Radiofrequency Ablation in Hepatocellular Carcinoma: Current Status and Future Perspectives

Radiofrequency ablation (RFA) is one of the curative treatment modalities for small (diameter, ≤3 cm) or early stage (single tumor ≤5 cm in diameter or up to three tumors of ≤3 cm diameter each) hepatocellular carcinoma (HCC). RFA is more commonly used than other local ablative modalities because the technique is highly effective, minimally invasive, and requires fewer sessions. RFA is advocated as the first-line curative therapy for unresectable or even resectable very early stage or early stage HCC based on a survival rate comparable to that seen with resection. Although RFA is highly effective for local ablation of small HCC tumors, current RFA procedures are less effective against tumors that are in high-risk or difficult-to-ablate locations, are poorly visualized on ultrasonography (US), are associated with major complications, and are large (>3 cm in diameter). Recent advances can overcome these issues by creation of artificial ascites or pleural effusion, application of real-time virtual US assistance, incorporation of contrast-enhanced US before or after RFA, use of combination therapy before RFA, or switching RF controller with multiple electrodes. This review article provides updates on the clinical outcomes and advances in RFA in the treatment of HCC, particularly the aforementioned issues.