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

Ultrasound-Guided Percutaneous Microwave Coagulation Studies on VX2 Rabbit Models for Breast Cancer Treatment and Ultrasound Imaging Assessment

Background

The study aimed to explore the tissue morphology and hemodynamics of rabbit VX2 breast carcinoma by high-frequency ultrasound (US) and the effectiveness and safety of US-guided percutaneous microwave coagulation (PMC) therapy on rabbit VX2 breast tumors.

Methods

Twenty VX2 tumor-bearing rabbits were assessed using color Doppler ultrasound for tumor growth characteristics including echo, size, blood supply and hemodynamic parameters once a week for six weeks. Subsequently, US-guided PMC was performed in randomly assigned ten VX2 tumor-bearing rabbits (the other ten as controls). US images after ablation were obtained and analyzed. Three rabbits with double VX2 tumors were used as pathological observation at weeks 0, 1, and 4 of ablation. The therapeutic efficacy was evaluated by tumor growth, physical examinations, survival time, survival rate and metastasis of tumors and histopathology.

Results

Ultrasound monitoring indicated that the tumor growth rate was 463.09% at the 2nd to 3rd weeks, and PMC was performed during this period under real-time US guidance. After microwave ablation, some tumors were greatly reduced or undetectable at week 8. Moreover, no flow signals were detected by US. The survival rates at 2 and 3 months in the treatment group and control group were 100%, 70% and 10%, 0%, respectively, while the metastatic rates were 10%, 30% and 90%, 100%, respectively (P<0.05).

Conclusion

The proliferation and metastasis of rabbit VX2 breast carcinoma were monitored by US imaging, and US-guided percutaneous microwave ablation was proven to be a safe, effective and minimally invasive therapeutic option for treating breast cancer in rabbits, showing potential clinical applicability.

Anatomic sub-segmentectomy with single-session combined transcatheter arterial embolization/microwave ablation for the treatment of hepatocellular carcinoma: preliminary results

PURPOSE

This retrospective study aimed to confirm the safety and long-term efficacy of a single-session combined treatment approach with transcatheter arterial embolization (TAE) and microwave ablation (MWA) for inoperable small-to intermediate-sized hepatocellular carcinomas (HCC), focusing on their combined benefits for improving local control.

MATERIALS AND METHODS

All consecutive patients with up to 2 small-to-intermediate HCC lesions (≤ 5 cm) treated with a combined single-session MWA-TAE approach were enrolled between April 2020 and October 2023. All procedures were performed in two stages: TAE and MWA. Clinical and radiological follow-up was performed 3, 6, and 12 months after treatment.

RESULTS

In the 21 enrolled patients (15 males, mean age 75.9 years), post-procedural contrast-enhanced CT scans confirmed a satisfactory ablation zone in all patients (100%), with minor peri-procedural complications reported in three patients (14%). At the last 12-month follow-up, one patient (8%) displayed local tumor progression, previously classified as LR-TR equivocal at the 6-month follow-up, and half of the patients (6 patients, 50%) exhibited distant tumor progression, predominantly in the form of intra-hepatic recurrence.

CONCLUSION

The combined approach of TAE and MWA is a promising method to enhance the percutaneous treatment of small to intermediate-sized HCCs with a resulting anatomic ablation area resembling a surgical sub-segmentectomy. This technique can potentially reduce the gap between percutaneous treatment and liver resection outcomes, allowing for a safe and effective option for oncological control in patients with > 3 cm lesions.

Embolic and Ablative Therapy for Hepatocellular Carcinoma

Embolic and ablative locoregional therapies (LRTs) for hepatocellular carcinoma are widely used to cure, bridge, or downstage patients for more definitive therapies. Common ablative therapies include microwave ablation and radiofrequency ablation, while embolic options include transarterial chemoembolization and 90Y transarterial radioembolization. While these therapies can be highly effective for the appropriate stage of disease, LRTs can suffer from a high rate of posttreatment recurrences. Considerations for administration of specific therapies include disease burden and underlying liver function. Recent data on concomitant or adjuvant systemic therapy, with LRT, have the potential to improve disease control and improve outcomes in this high-risk patient population.

Variations in Microwave Ablation Zones as a Function of Probe Spacing, Angulation, and Geometry

Despite advancements in precision and effectiveness of microwave ablation for tumor management, accurately predicting ablation zone geometry and minimum ablation margin remains a major challenge. This pilot study aimed to elucidate the influence of probe configuration on the morphometry of resulting ablation zones using tissue-mimicking thermochromic phantoms. In vitro results from 12 ablations were analyzed: (a) a single-probe ablation (n = 1) and (b) dual-probe ablations (n = 11). Angles and separations greatly influenced ablation zone morphometry. In dual-probe ablations, probe tip separation and angle of offset were positively correlated with ablation zone volume, length, and cross-sectional circularity. Interventional radiology ablation planning is currently suboptimal as it often relies on cognitive registration. Even treatment planning software creates virtual composite ablation volumes based on data from theoretical ablations in single, idealized configurations and settings. These findings draw attention to a need for improved ablation zone prediction and planning, which might impact efficiency, safety, cost, and outcomes.

Local Ablation for Hepatocellular Carcinoma: 2024 Expert Consensus-Based Practical Recommendations of the Korean Liver Cancer Association

Local ablation for hepatocellular carcinoma, a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the first-line treatment for early-stage hepatocellular carcinoma. The lack of organized evidence and expert opinions regarding patient selection, preprocedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-Guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and post-treatment management of patients.

Local Ablation for Hepatocellular Carcinoma: 2024 Expert Consensus-Based Practical Recommendations of the Korean Liver Cancer Association

Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the first-line treatment for early-stage HCC. The lack of organized evidence and expert opinions regarding patient selection, pre-procedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and post-treatment management of patients.

Local ablation for hepatocellular carcinoma: 2024 expert consensus-based practical recommendation of the Korean Liver Cancer Association

Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the firstline treatment for early-stage HCC. The lack of organized evidence and expert opinions regarding patient selection, pre-procedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and posttreatment management of patients.

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.