Efficacy and safety of microwave ablation and radiofrequency ablation in the treatment of hepatocellular carcinoma: A systematic review and meta-analysis

Threatment Strategies for Recurrent Hepatocellular Carcinoma Patients: Ablation and its Combination Patterns

With the development of guidance technology and ablation equipment, ablative procedures have emerged as important loco-regional alternatives to surgical resection for recurrent hepatocellular carcinoma (rHCC) patients. Currently, ablation modalities used in clinical practice mainly include radiofrequency ablation (RFA), microwave ablation (MWA), laser ablation (LA), cryoablation (CRA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE). Accumulated comparative data of ablation versus surgical resection reveal noninferior responses and outcomes but superior adverse effects. Moreover, studies demonstrate that ablation may serve as an excellent procedure for rHCC given its exact minimal invasiveness and immune modulation. We focus on the current status of ablation in clinical practice for rHCC and discuss new research in the field, including ablation combined with these other modalities, such as targeted therapy and immunotherapy.

Thermal ablation of hepatocellular carcinoma

Percutaneous treatment of hepatocellular carcinoma (HCC) by means of thermal ablation (TA) has been introduced in clinical guidelines as a potentially curative treatment for the early stages of the disease since the early 2000s. Due to its safety profile and cost-effectiveness, TA can be offered as a first-line treatment for patients with HCC smaller than 3 cm. Thermal ablative techniques are in fact widely available at many centres worldwide and include radiofrequency (RF) and microwave (MW) ablation, with the latter increasingly applied in clinical practice in the last decade. Pre-clinical studies highlighted, as potential advantages of MW-based ablation, the ability to achieve higher temperatures (>100°C) and larger ablation zones in shorter times, with less susceptibility to blood flow-induced heat sink effects. Despite these advantages, there is no evidence of superior overall survival in patients treated with MW as compared to those treated with RF ablation. Local control has been proven to be superior to MW ablation with a similar complication rate. It is expected that further improvement of TA results in the treatment of HCC will result from the refinement of guidance and monitoring tools and the careful assessment of ablation margins. Thermal ablative treatments may also be performed on nodules larger than 3 cm by applying multiple devices or combining percutaneous and intra-arterial approaches. The role of novel immunotherapy regimens in combination with ablation is also currently under evaluation in clinical trials, with several potential benefits. In this review, indications, technical principles, results, and future prospects of TA for the treatment of HCC will be examined.

In Vivo Thermal Ablation of Deep Intrahepatic Targets Using a Super-Convergent MRgHIFU Applicator and a Pseudo-Tumor Model

BACKGROUND

HIFU ablation of liver malignancies is particularly challenging due to respiratory motion, high tissue perfusion and the presence of the rib cage. Based on our previous development of a super-convergent phased-array transducer, we aimed to further investigate, in vivo, its applicability to deep intrahepatic targets.

METHODS

In a series of six pigs, a pseudo-tumor model was used as target, visible both on intra-operatory MRI and post-mortem gross pathology. The transcostal MRgHIFU ablation was prescribed coplanar with the pseudo-tumor, either axial or sagittal, but deliberately shifted 7 to 18 mm to the side. No specific means of protection of the ribs were implemented. Post-treatment MRI follow-up was performed at D7, followed by animal necropsy and gross pathology of the liver.

RESULTS

The pseudo-tumor was clearly identified on T1w MR imaging and subsequently allowed the MRgHIFU planning. The peak temperature at the focal point ranged from 58-87 °C. Gross pathology confirmed the presence of the pseudo-tumor and the well-delineated MRgHIFU ablation at the expected locations.

CONCLUSIONS

The specific design of the transducer enabled a reliable workflow. It demonstrated a good safety profile for in vivo transcostal MRgHIFU ablation of deep-liver targets, graded as challenging for standard surgery.

The management of hepatocellular carcinoma. Current expert opinion and recommendations derived from the 24th ESMO/World Congress on Gastrointestinal Cancer, Barcelona, 2022

This article summarises expert discussion on the management of patients with hepatocellular carcinoma (HCC), which took place during the 24th World Gastrointestinal Cancer Congress (WGICC) in Barcelona, July 2022. A multidisciplinary approach is mandatory to ensure an optimal diagnosis and staging of HCC, planning of curative and therapeutic options, including surgical, embolisation, ablative strategies, or systemic therapy. Furthermore, in many patients with HCC, underlying liver cirrhosis represents a challenge and influences the therapeutic options.