Recent Advances in Tumor Ablation for Hepatocellular Carcinoma

Abstract

Image-guided tumor ablation for early stage hepatocellular carcinoma (HCC) is an accepted non-surgical treatment that provides excellent local tumor control and favorable survival benefit. This review summarizes the recent advances in tumor ablation for HCC. Diagnostic imaging and molecular biology of HCC has recently undergone marked improvements. Second-generation ultrasonography (US) contrast agents, new computed tomography (CT) techniques, and liver-specific contrast agents for magnetic resonance imaging (MRI) have enabled the early detection of smaller and inconspicuous HCC lesions. Various imaging-guidance tools that incorporate imaging-fusion between real-time US and CT/MRI, that are now common for percutaneous tumor ablation, have increased operator confidence in the accurate targeting of technically difficult tumors. In addition to radiofrequency ablation (RFA), various therapeutic modalities including microwave ablation, irreversible electroporation, and high-intensity focused ultrasound ablation have attracted attention as alternative energy sources for effective locoregional treatment of HCC. In addition, combined treatment with RFA and chemoembolization or molecular agents may be able to overcome the limitation of advanced or large tumors. Finally, understanding of the biological mechanisms and advances in therapy associated with tumor ablation will be important for successful tumor control. All these advances in tumor ablation for HCC will result in significant improvement in the prognosis of HCC patients. In this review, we primarily focus on recent advances in molecular tumor biology, diagnosis, imaging-guidance tools, and therapeutic modalities, and refer to the current status and future perspectives for tumor ablation for HCC.

Keywords: Diagnosis; Hepatocellular carcinoma; Image-guided tumor ablation; Treatment outcome.

Fig. 1

Recent advances in HCC ablation treatment.

Fig. 2

Double contrast US using Sonazoid® and imaging fusion US/MRI in RFA for HCC. a Arterial phase on MRI with Gd-EOB-DTPA enhancement shows a 1.1 cm sized-small HCC (white arrow) in segment 5 of the liver. b A contrast-enhance US with Sonazoid® shows the defect (white arrow) in the postvascular phase at 10 minutes after the injection of the contrast medium. c By defect-reperfusion US imaging, reinjection of an additional dose of Sonazoid® can confirm the tumor's hyper-vascularity (white arrow) before needle insertion. d RFA is performed using a 15-gauge electrode with a 2-cm active tip (white arrow heads) for the target tumor (white arrow). e ACT scan obtained immediately following RFA reveals complete tumor ablation with a sufficient tumor ablative margin (asterisk) without immediate major complications.