Irreversible electroporation versus radiofrequency ablation for hepatocellular carcinoma: a single centre propensity-matched comparison

Clinical and safety outcomes in unresectable, very early and early-stage hepatocellular carcinoma following Irreversible Electroporation (IRE) and Transarterial Chemoembolization (TACE): A systematic literature review and meta-analysis

BACKGROUND

Locoregional treatments for early-stage unresectable hepatocellular carcinoma (HCC) are widely used, with irreversible electroporation (IRE) and transarterial chemoembolization (TACE) representing two non-thermal treatment options. However, to date, no systematic evaluations of these technologies have been conducted. This study sought to comparatively assess the safety and effectiveness of IRE and TACE for the treatment of very early and early-stage, inoperable HCC via systematic literature reviews (SLRs) and meta-analyses.

METHODOLOGY

Searches were conducted targeting English-language publications and congress proceedings of clinical trials and observational studies from January 1, 2012 to December 21, 2023 that reported effectiveness and safety outcomes (tumor response, progression-free survival (PFS), adverse events (AE)) for IRE and TACE. Two reviewers independently assessed eligibility and abstracted data. For each procedure, meta-analyses were conducted to assess tumor response by follow-up time point, as data permitted, and other outcomes were descriptively analyzed; Quality and risk of bias assessments were performed.

RESULTS

12 IRE publications (195 patients) and 33 TACE publications (6,899 patients) met eligibility criteria. During 0 to < 3 month follow-up, complete response was achieved in 84% of IRE patients vs. 68% for TACE (all results at 1-month); a proportion that increased at 3 to < 6 months (91% IRE vs. 41% TACE). Median PFS was 10.4 months for IRE and 19-30 months for TACE. Serious AEs (SAEs) were experienced by 4% vs. 5% of IRE and TACE patients, respectively.

CONCLUSION

Both IRE and TACE are safe and effective non-thermal treatments for unresectable, very early and early-stage HCC. The high rate of short-term complete response observed for IRE, coupled with a low SAE rate, may support the broader adoption of this procedure in this patient population.

Assessment of efficacy and safety of irreversible electroporation versus TACE for treatment of difficult location hepatocellular carcinoma

Introduction

Radiofrequency ablation (RFA) and microwave ablation (MWA) are widely accepted as the established treatment options for patients diagnosed with early-stage hepatocellular carcinoma (HCC) who are deemed unfit for surgical procedures. However, the effective implementation of these techniques is hindered by various challenges, primarily associated with the precise targeting of tumors within the liver. The utilization of thermal ablative methods is not recommended for hepatocellular carcinoma (HCC) that is located near intestinal loops, bile ducts, or in eccentric positions. The unmet need for non-thermal methods in the treatment of hepatocellular carcinoma (HCC) was addressed following the introduction of irreversible electroporation (IRE) as an innovative approach.

Aim of the work

To assess the efficacy, safety, and outcomes of IRE in the treatment of difficult-located HCC compared to transarterial chemoembolization (TACE).

Methods

This is a prospective study that included 24 patients with HCC who presented to the National Hepatology and Tropical Medicine Research Institute (NHTMRI) during the period from January 2017 to January 2020. Ten patients underwent IRE, while 14 patients underwent TACE.

Results

Sixteen patients (66.7%) were males; eight patients were females (33.3%). Their median age was 60.5 years (48–70 years). Seventeen patients (70.8%) were Child–Pugh class A, while seven patients (29.2%) were Child–Pugh class B. All the study population had a single focal lesion; the mean size of the focal lesions was 2.94 ± 0.59 cm. The most frequent difficult locations of HCC were segment V focal lesions adjacent to both the common bile duct and portal vein in eight patients (33.3%) followed by lesions adjacent to the inferior vena cava in five patients (20%) followed by the subcapsular lesions in three patients (12.5%) and lesions adjacent to the right kidney in two patients (8.3%). Complete response (CR) was higher in the IRE group (80%) compared to the TACE group (50%). Clinical decompensation occurred in six patients in the IRE group (60%) and eight patients in the TACE group (57.1%) (P value 1). Recurrence occurred in five patients (50%) treated with IRE and in seven patients (50%) treated with TACE (P value 1). Within the IRE group, two patients (20%) remained alive; on the other hand, within the TACE group six patients (42.9%) remained alive by the end of the study (P value 0.388).

Conclusion

Our data suggest that IRE is an effective procedure in the treatment of difficult-located HCC in terms of complete response, fewer sessions, and fewer side effects as compared to TACE.

Irreversible electroporation: Beyond the limits of tumor ablation

Irreversible Electroporation (IRE) is a non-thermal tumor ablation technique. High-voltage electrical pulses are applied between pairs of electrodes inserted around and/or inside a tumor. The generated electric current induces the creation of nanopores in the cell membrane, triggering apoptosis. As a result, IRE can be safely used in areas near delicate vascular structures where other thermal ablation methods are contraindicated. Currently, IRE has demonstrated to be a successful ablation technique for pancreatic, renal, and liver tumors and is widely used as a focal therapeutic option for prostate cancer. The need for specific anesthetic management and accurate parallel placement of multiple electrodes entails a high level of complexity and great expertise from the interventional team is required. Nevertheless, IRE is a very promising technique with a remarkable systemic immunological capability and may impact on distant metastases (abscopal effect).

Ablative and non-surgical therapies for early and very early hepatocellular carcinoma: a systematic review and network meta-analysis

Background

A wide range of ablative and non-surgical therapies are available for treating small hepatocellular carcinoma in patients with very early or early-stage disease and preserved liver function.

Objective

To review and compare the effectiveness of all current ablative and non-surgical therapies for patients with small hepatocellular carcinoma (≤ 3 cm).

Design

Systematic review and network meta-analysis.

Data sources

Nine databases (March 2021), two trial registries (April 2021) and reference lists of relevant systematic reviews.

Review methods

Eligible studies were randomised controlled trials of ablative and non-surgical therapies, versus any comparator, for small hepatocellular carcinoma. Randomised controlled trials were quality assessed using the Cochrane Risk of Bias 2 tool and mapped. The comparative effectiveness of therapies was assessed using network meta-analysis. A threshold analysis was used to identify which comparisons were sensitive to potential changes in the evidence. Where comparisons based on randomised controlled trial evidence were not robust or no randomised controlled trials were identified, a targeted systematic review of non-randomised, prospective comparative studies provided additional data for repeat network meta-analysis and threshold analysis. The feasibility of undertaking economic modelling was explored. A workshop with patients and clinicians was held to discuss the findings and identify key priorities for future research.

Results

Thirty-seven randomised controlled trials (with over 3700 relevant patients) were included in the review. The majority were conducted in China or Japan and most had a high risk of bias or some risk of bias concerns. The results of the network meta-analysis were uncertain for most comparisons. There was evidence that percutaneous ethanol injection is inferior to radiofrequency ablation for overall survival (hazard ratio 1.45, 95% credible interval 1.16 to 1.82), progression-free survival (hazard ratio 1.36, 95% credible interval 1.11 to 1.67), overall recurrence (relative risk 1.19, 95% credible interval 1.02 to 1.39) and local recurrence (relative risk 1.80, 95% credible interval 1.19 to 2.71). Percutaneous acid injection was also inferior to radiofrequency ablation for progression-free survival (hazard ratio 1.63, 95% credible interval 1.05 to 2.51). Threshold analysis showed that further evidence could plausibly change the result for some comparisons. Fourteen eligible non-randomised studies were identified (n ≥ 2316); twelve had a high risk of bias so were not included in updated network meta-analyses. Additional non-randomised data, made available by a clinical advisor, were also included (n = 303). There remained a high level of uncertainty in treatment rankings after the network meta-analyses were updated. However, the updated analyses suggested that microwave ablation and resection are superior to percutaneous ethanol injection and percutaneous acid injection for some outcomes. Further research on stereotactic ablative radiotherapy was recommended at the workshop, although it is only appropriate for certain patient subgroups, limiting opportunities for adequately powered trials.

Limitations

Many studies were small and of poor quality. No comparative studies were found for some therapies.

Conclusions

The existing evidence base has limitations; the uptake of specific ablative therapies in the United Kingdom appears to be based more on technological advancements and ease of use than strong evidence of clinical effectiveness. However, there is evidence that percutaneous ethanol injection and percutaneous acid injection are inferior to radiofrequency ablation, microwave ablation and resection.

Study registration

PROSPERO CRD42020221357.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment (HTA) programme (NIHR award ref: NIHR131224) and is published in full in Health Technology Assessment; Vol. 27, No. 29. See the NIHR Funding and Awards website for further award information.

Irreversible electroporation of hepatocellular carcinoma and colorectal cancer liver metastases: A nationwide multicenter study with short- and long-term follow-up

INTRODUCTION

A nationwide multicenter study was performed to examine short- and long-term effects of irreversible electroporation (IRE) for hepatocellular carcinoma (HCC) and colorectal cancer liver metastases (CRCLM). IRE is an alternative method when thermal ablation is contraindicated because of risk for serious thermal complications.

METHODS

All consecutive patients in Sweden treated with IRE because of HCC or CRCLM, were included between 2011 and 2018. We evaluated medical records and radiological imaging to obtain information regarding patient-, tumor-, and treatment characteristics. We also assessed local tumor progression, and survival.

RESULTS

In total 206 tumors in 149 patients were treated with IRE. Eighty-seven patients (58.4%) had colorectal cancer liver metastases, and 62 patients (41.6%) had hepatocellular carcinoma. Median tumor size was 20 mm (i.q.r. 14-26 mm). Median overall survival for CRCLM and HCC, were 27.0 months (95% CI 22.2-31.8 months), and 35.0 months (95% CI 13.8-56.2 months), respectively. Median follow-up time was 58 months (95% CI 50.6-65.4). Local ablation success at six and twelve months for HCC was 58.3% and 40.3%, and for CRCLM 37.7% and 25.4%. The median time to local tumor progression (LTP) for HCC was 21.0 months (95% CI: 9.5-32.5 months), and for CRCLM 6.0 months (95% CI: 4.5-7.5 months). At 30-day follow-up, 15.4% (n = 23) of patients suffered from a complication rated as Clavien-Dindo grade 1-3a. Three patients (2.0%) had grade 3b-5 with one death in a thromboembolic event.

CONCLUSION

IRE is a safe ablation modality for patients with liver tumors that are located in such a way that other treatment options are unsuitable.

The Role of Ablative Techniques in the Management of Hepatocellular Carcinoma: Indications and Outcomes

The management of hepatocellular carcinoma (HCC) remains complex and will continue to rely on the multidisciplinary input of hepatologists, surgeons, radiologists, oncologists and radiotherapists. With the appropriate staging of patients and selection of suitable treatments, the outcomes for HCC are improving. Surgical treatments encompassing both liver resection and orthotopic liver transplantation (OLT) are the definitive curative-intent options. However, patient suitability, as well as organ availability, pose essential limitations. Consequently, non-surgical options, such as ablative techniques, play an increasingly important role, especially in small HCCs, where overall and disease-free survival can be comparable to surgical resection. Ablative techniques are globally recommended in recognised classification systems, showing increasingly promising results. Recent technical refinements, as well as the emerging use of robotic assistance, may expand the treatment paradigm to achieve improved oncological results. At present, in very early stage and early stage unresectable disease, percutaneous thermal ablation is considered the treatment of choice. Owing to their different features, various ablative techniques, including radiofrequency ablation, microwave ablation, cryotherapy ablation and irreversible electroporation, have been shown to confer different comparative advantages and applicability. We herein review the role of available ablative techniques in the current complex multidisciplinary management of HCC, with a main focus on the indications and outcomes, and discuss future perspectives.

Local-Regional Treatment of Hepatocellular Carcinoma: A Primer for Radiologists

The treatment planning for patients with hepatocellular carcinoma (HCC) relies predominantly on tumor burden, clinical performance, and liver function test results. Curative treatments such as resection, liver transplantation, and ablative therapies of small lesions should be considered for all patients with HCC. However, many patients are ineligible for these treatments owing to advanced disease stage and comorbidities. Despite efforts to increase screening, early-stage HCC remains difficult to diagnose, which decreases the possibility of curative therapies. In this context, local-regional treatment of HCC is accepted as a form of curative therapy in selected patients with early-stage disease, as a therapeutic option in patients who are not eligible to undergo curative therapies, as a downstaging approach to decrease tumor size toward meeting the criteria for liver transplantation, and as a bridging therapy to avoid tumor growth while the patient is on the waiting list for liver transplantation. The authors review the indications, types, mechanism of action, and possible complications of local-regional treatment, as well as the expected postprocedural imaging features of HCC. Furthermore, they discuss the role of imaging in pre- and postprocedural settings, provide guidance on how to assess treatment response, and review the current limitations of imaging assessment. Finally, the authors summarize the potential future directions with imaging tools that may add value to contemporary practice at response assessment and imaging biomarkers for patient selection, treatment response, and prognosis. ©RSNA, 2022.

Biliary complications and efficacy after ablation of peribiliary tumors using irreversible electroporation (IRE) or radiofrequency ablation (RFA)

OBJECTIVE

To evaluate the biliary complication rates and efficacy of peribiliary tumor ablation using irreversible electroporation (IRE) or radiofrequency ablation (RFA).

MATERIAL AND METHODS

This is a retrospective study of 42 consecutive patients with 44 peribiliary tumors (≤5 mm distance between the tumor margin and the primary or secondary bile duct). Data were collected between January 2014 and September 2020 from patients who underwent percutaneous liver ablation using IRE (n = 13) or RFA (n = 31).

RESULTS

The median length of follow-up was 23.1 months. The mean tumor size was 17.2 ± 5.2 mm in IRE vs. 18.4 ± 7.0 mm in RFA (p= .56). Complete tumor ablation was achieved in 100% with a significantly larger ablation zone in the IRE group (3.8 ± 0.3 cm vs. 2.6 ± 0.6 cm, p<.001). Significant biliary complications occurred in one patient (7.7%) of the IRE group and in five patients (16.1%) of the RFA group. Significant risk factors for biliary complications included the RFA procedure (HR 9.71, p=.032) and proximity of the tumor to the bile duct (HR 0.63, p=.048). The local tumor progression (LTP) rates were 7.7% (IRE) vs. 21.5% (RFA) at 1 year, 23.1% (IRE) vs. 32.7% (RFA) at 2 years and 23.1% (IRE) vs. 44% (RFA) at 3 years, respectively (p=.289).

CONCLUSIONS

The IRE and RFA procedures are safe and effective to treat peribiliary liver tumors. However, the RFA may have a higher risk of significant bile duct injury than IRE. The shorter distance between the bile duct and the tumor is a strong risk factor for biliary complications.