Comparison of microwave ablation and radiofrequency ablation for hepatocellular carcinoma: a systematic review and meta-analysis

Outcomes and Complications of Image-Guided Percutaneous Tumour Ablation for Hepatocellular Carcinoma at the Irish National Liver Transplant Centre

Background: Image-guided tumour ablation is a minimally invasive treatment for early stage hepatocellular carcinoma (HCC). Our study reviews the complications and long term outcomes in patients treated at a tertiary referral centre. Methods: Retrospective study. All patients with HCC who underwent microwave ablation (MWA) or radiofrequency ablation (RFA) from 1st January 2014 to 31st December 2022 were identified. Treatment response of target lesion, complications, and survival were recorded. Results: One hundred seventy ablations were performed in 118 patients; 70% MWA, 30% RFA. Median radiological follow-up 21 months (range 3-107). Follow-up imaging was reported using LI-RADS and mRECIST. At first follow-up imaging, 94 patients had complete response (primary efficacy rate 80.3%) while 19.7% (n = 23) had residual disease. Fifteen of these had repeat ablation; 10 had complete response (secondary efficacy rate 85.6%). By end of study duration, 70.5% (n = 79) achieved sustained local complete response from single ablation without documented recurrence. 14.3% (n = 16) required more than one ablation of target lesion. Overall, 84.8% (n = 95) demonstrated long term local complete response to ablation. Complication occurred in 5.9% (n = 10); 40.0% Grade I, 40.0% Grade II, 10.0% Grade III, 10.0% Grade IV as per the CIRSE Classification. 1-, 3-, and 5-year overall survival (OS) rate was 97%, 68%, and 61% respectively. Mean OS was 5.3 years (median 4.7). No difference in OS (P = .7) or local progression free survival (P = .5) between patients treated with MWA versus RFA. Conclusion: This study demonstrates excellent long-term response to TA, with acceptable complication profile. No difference in survival between RFA versus MWA.

Combination locoregional and systemic therapies in hepatocellular carcinoma

Locoregional therapies play a fundamental role in the treatment of patients with early and intermediate and locally advanced hepatocellular carcinomas. With encouraging recent advances in immunotherapy-based systemic therapies, locoregional therapies are being both promoted and challenged by new systemic therapy options. Combined locoregional and systemic therapies might enhance treatment outcomes compared with either option alone. This Series paper summarises the existing data on locoregional and systemic therapies for hepatocellular carcinoma, and discusses evidence from studies investigating their combination with a focus on their synergistic efficacy and safety.

Evaluation of a deformable image registration algorithm for image-guided thermal ablation of liver tumors on clinically acquired MR-temperature maps

BACKGROUND

Quantitative real-time MRI-based temperature mapping techniques are hampered by abdominal motion. Intrascan motion can be reduced by rapid acquisition sequences such as 2D echo planar imaging (EPI), and inter-scan organ displacement can be compensated by image processing such as optical flow (OF) algorithms. However, motion field estimation can be seriously affected by local variation of signal intensity on magnitude images inherent to tissue heating, potentially leading to erroneous temperature estimates.

PURPOSE

This study aims to characterize, in the context of clinical MRI-guided microwave ablation (MWA), a novel deformable image registration (DIR) algorithm that enhances the generation of thermal maps aligned to a reference position, a critical step for calculating cumulative thermal dose and, consequently, for the real-time evaluation of interventional procedure progress.

METHODS

A retrospective image analysis was performed on 11 patients that underwent MWA of a liver tumor (primary or metastasis). Ablation duration was set to 9 ± 2 min with a 14-gauge large antenna. A stack of 13-20 contiguous slices was acquired dynamically (350 repetitions) at 1.5T using a single-shot EPI sequence. Evaluation was first performed on motion-free datasets (5 gated acquisitions using a cushion positioned in the patient abdomen) then with ones with motion (8 fixed-frequency acquisitions at 0.5 Hz). Temperature, thermal dose and lesion size were computed using three workflows: (i) standard phase subtraction (gold standard), (ii) conventional OF motion compensation, (iii) PCA-based OF motion compensation. The impact of flow field, temperature and lesion volume estimation were compared using averaged endpoint error (AEE), NRMSE and bland Altman plot, respectively.

RESULTS

Intensity signal decreases (close to 50%) were observed in the vicinity of the probe during MW energy delivery. Both motion correction algorithms reduce the NRMSE of magnitude images throughout the acquisition (p < 0.005) and achieve similar results between them. Gated acquisition results. Conventional OF produced erroneous vector fields compared to the PCA-based OF, leading to higher maximal EE (3 mm vs. 1 mm) and temperature errors up to 15°C-20°C. PCA-based OF algorithm significantly reduces the NRMSE of temperature (p < 0.005). The conventional OF method underestimated the final size of lesions with a bias of 0.93 cm3 while the PCA-based OF reported a bias of 0.5 cm3. Fixed frequency acquisition results. The temperature estimation without motion correction led to strong fluctuations or loss of temperature measurement while the proposed PCA-based OF recovered both a stable and precise measurement with null bias.

CONCLUSION

The deformable image registration algorithm is less sensitive to local variations of the signal. Volumetric temperature imaging without gating (20 slices/2 s) could be performed with the same accuracy, and offer trade-offs in acquisition time or volume coverage. Such a strategy is expected to increase procedure safety by monitoring large volumes more rapidly for MR-guided thermotherapy on mobile organs.

Microwave ablation for liver metastases from colorectal cancer: A comprehensive review of clinical efficacy and safety

Microwave ablation (MWA) is emerging as a highly effective treatment for colorectal liver metastases (CRLMs). This review explores the advantages of MWA compared to other ablative techniques such as radiofrequency ablation and cryoablation and highlights its clinical efficacy, safety, and technical considerations. MWA offers significant benefits, including higher intratumoral temperatures, larger ablation zones, and reduced susceptibility to the heat-sink effect, which make it particularly suitable for tumors near large blood vessels. This review details the patient selection criteria, procedural approaches, and the use of advanced imaging techniques to improve the precision and effectiveness of MWA. Clinical outcomes indicate that MWA achieves high rates of complete tumor ablation and long-term survival with a favorable safety profile. This review is significant because it provides updated insights into the expanding role of MWA in treating unresectable CRLM and its potential as an alternative to surgical resection for resectable tumors. By summarizing recent studies and clinical trials, this review highlights the comparative effectiveness, safety, and integration with systemic therapies of MWA. In conclusion, MWA is a promising treatment option for CRLM and offers outcomes comparable to or better than those of other ablative techniques. Future research should focus on optimizing technical parameters, integrating MWA with systemic therapies, and conducting large-scale randomized controlled trials to establish standardized treatment protocols. Advancing our understanding of MWA will enhance its application and improve long-term survival and quality of life for patients with CRLM.

Safety and Effectiveness of Microwave Ablation of Liver Tumors: Initial Real-World Results from the Multinational NeuWave Observational Liver Ablation (NOLA) Registry

PURPOSE

To investigate the safety and effectiveness of microwave ablation (MWA) for treating liver tumors using real-world data from a multicenter registry (NeuWave Observational Liver Ablation [NOLA]).

MATERIALS AND METHODS

NOLA is approved to enroll up to 1,500 adults treated with MWA and follow them for 5 years. Initial data for 615 patients treated across 24 tertiary healthcare centers in the United States (14), Europe (8), and Asia (2), from January 2020 to October 2022, are summarized herein. Effectiveness and safety endpoints included technical success (TS), technique efficacy (TE), local tumor progression (LTP), adverse events (AEs), and overall survival (OS). AEs were retrospectively graded according to the Society of Interventional Radiology (SIR) classification. A total of 615 patients (male, 72.7%; median age, 66 years; range, 25-89 years) underwent 721 MWA sessions to treat 760 liver tumors, with 95.6% of sessions performed percutaneously.

RESULTS

TS and TE were achieved in 98.1% (730/744) and 95.1% (615/647) of tumors, respectively. The cumulative incidence of LTP at 12 months was 11.9% (95% confidence interval [CI], 8.8%-15.5%) for patients. Within 30 days following the ablation, 408 AEs were reported, with 78.4% (320/408) classified as mild, 3.9% (16/408) as moderate, and 16.9% (69/408) as severe AEs. Procedure-related AEs and serious AEs were reported in 63.7% (392/615) and 11.7% (72/615) of the total patient cohort, respectively. The OS rate at 12 months was 95.5% (95% CI, 92.8%-97.2%).

CONCLUSIONS

MWA is a safe and effective treatment for primary and metastatic liver tumors in a large, real-world patient population.

Imaging-based prediction of hepatocellular carcinoma recurrence after microwave ablation as bridge therapy: A glimpse into the future

Liver transplantation (LT) remains the treatment of choice for early-stage hepatocellular carcinoma (HCC) and offers the best long-term oncological outcomes. However, the increasing waiting list for LT has led to a significant dropout rate as patients experience tumor progression beyond the Milan criteria. Currently, locoregional therapies, such as microwave ablation (MWA), have emerged as promising bridge treatments for patients awaiting LT. These therapies have shown promising results in preventing tumor progression, thus reducing the dropout rate of LT candidates. Despite the efficacy of MWA in treating HCC, tumoral recurrence after ablation remains a major challenge and significantly impacts the prognosis of HCC patients. Therefore, accurately diagnosing tumoral recurrence post-ablation is crucial. Recent studies have developed novel imaging features based on magnetic resonance imaging of HCC, which could provide essential information for predicting early tumoral recurrence after MWA. These advancements could address this unresolved challenge, improving the clinical outcomes of patients on the LT waiting list. This article explored the current landscape of MWA as a bridge therapy for HCC within the Milan criteria, highlighting the emerging role of novel imaging-based features aimed at improving the prediction of tumor recurrence after MWA.

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 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.

Accuracy of 3D real-time MRI temperature mapping in gel phantoms during microwave heating

BACKGROUND

Interventional magnetic resonance imaging (MRI) can provide a comprehensive setting for microwave ablation of tumors with real-time monitoring of the energy delivery using MRI-based temperature mapping. The purpose of this study was to quantify the accuracy of three-dimensional (3D) real-time MRI temperature mapping during microwave heating in vitro by comparing MRI thermometry data to reference data measured by fiber-optical thermometry.

METHODS

Nine phantom experiments were evaluated in agar-based gel phantoms using an in-room MR-conditional microwave system and MRI thermometry. MRI measurements were performed for 700 s (25 slices; temporal resolution 2 s). The temperature was monitored with two fiber-optical temperature sensors approximately 5 mm and 10 mm distant from the microwave antenna. Temperature curves of the sensors were compared to MRI temperature data of single-voxel regions of interest (ROIs) at the sensor tips; the accuracy of MRI thermometry was assessed as the root-mean-squared (RMS)-averaged temperature difference. Eighteen neighboring voxels around the original ROI were also evaluated and the voxel with the smallest temperature difference was additionally selected for further evaluation.

RESULTS

The maximum temperature changes measured by the fiber-optical sensors ranged from 7.3 K to 50.7 K. The median RMS-averaged temperature differences in the originally selected voxels ranged from 1.4 K to 3.4 K. When evaluating the minimum-difference voxel from the neighborhood, the temperature differences ranged from 0.5 K to 0.9 K. The microwave antenna and the MRI-conditional in-room microwave generator did not induce relevant radiofrequency artifacts.

CONCLUSION

Accurate 3D real-time MRI temperature mapping during microwave heating with very low RMS-averaged temperature errors below 1 K is feasible in gel phantoms.

RELEVANCE STATEMENT

Accurate MRI-based volumetric real-time monitoring of temperature distribution and thermal dose is highly relevant in clinical MRI-based interventions and can be expected to improve local tumor control, as well as procedural safety by extending the limits of thermal (e.g., microwave) ablation of tumors in the liver and in other organs.

KEY POINTS

Interventional MRI can provide a comprehensive setting for the microwave ablation of tumors. MRI can monitor the microwave ablation using real-time MRI-based temperature mapping. 3D real-time MRI temperature mapping during microwave heating is feasible. Measured temperature errors were below 1 °C in gel phantoms. The active in-room microwave generator did not induce any relevant radiofrequency artifacts.

British Society of Gastroenterology guidelines for the management of hepatocellular carcinoma in adults

Deaths from the majority of cancers are falling globally, but the incidence and mortality from hepatocellular carcinoma (HCC) is increasing in the United Kingdom and in other Western countries. HCC is a highly fatal cancer, often diagnosed late, with an incidence to mortality ratio that approaches 1. Despite there being a number of treatment options, including those associated with good medium to long-term survival, 5-year survival from HCC in the UK remains below 20%. Sex, ethnicity and deprivation are important demographics for the incidence of, and/or survival from, HCC. These clinical practice guidelines will provide evidence-based advice for the assessment and management of patients with HCC. The clinical and scientific data underpinning the recommendations we make are summarised in detail. Much of the content will have broad relevance, but the treatment algorithms are based on therapies that are available in the UK and have regulatory approval for use in the National Health Service.

Microwave Thermal Ablation for Breast Cancer in Africa: A Pioneering Case Report Utilizing TATOpro

The adoption of minimally invasive treatments for early-stage breast cancer is increasing. Microwave thermal ablation (MWA), a minimally invasive technique, has been studied for treating small breast cancer lesions. However, long-term evidence on its efficacy as a sole treatment is limited, as most studies combine MWA with other therapies and post-treatment surgical excision. This report details the case of an 83-year-old African patient who declined surgery and systemic therapies, opting for MWA using the TATOpro system as the sole treatment for contralateral breast cancer with axillary lymph node metastasis. The report includes a one-year follow-up, assessing disease recurrence with MRI and ultrasound. The findings highlight MWA's potential as an innovative and efficacious breast cancer treatment, emphasizing the need for adaptable strategies in oncology.

Long-term oral administration of Huaier granules improves survival outcomes in hepatocellular carcinoma patients within Milan criteria following microwave ablation: a propensity score matching and stabilized inverse probability weighting analysis

Objective

This study aimed to elucidate the therapeutic effects of Huaier granules on hepatocellular carcinoma (HCC) within the Milan criteria in patients who underwent microwave ablation (MWA).

Materials and methods

A total of 228 patients were included, with 97 in the Huaier group and 131 in the control group. We evaluated progression-free survival (PFS), overall survival (OS), and extrahepatic metastasis survival (EMS) using Kaplan-Meier (KM) curves with a log-rank test. Propensity Score Matching (PSM) and Stabilized Inverse Probability of Treatment Weighting (IPTW) were performed to minimize selection and confounding biases.

Results

Following PSM, the 1-, 3-, and 5-year PFS rates in the Huaier and control groups were 83.5% vs 70.7%, 57.7% vs 42.6%, and 43.6% vs 31.9% (p = 0.030), respectively. The 1-, 3-, and 5-year OS rates were 98.9% vs 95.6%, 83.9% vs 72.3%, and 72.2% vs 53.7% (p = 0.023), respectively. The corresponding 1-, 3-, and 5-year EMS rates were 98.9% vs 93.4%, 91.7% vs 83.7%, and 91.7% vs 78.5% (p = 0.039), respectively. Stabilized IPTW analysis of KM curves yielded results similar to those of the PSM analysis. Additionally, administering Huaier granules for at least 6 months significantly improved PFS and OS.

Conclusion

Huaier granules can reduce the risk of recurrence and improve the OS of patients with HCC within the Milan criteria following MWA. Administering Huaier granules for over 6 months proved beneficial.

Complication Rates and Risk of Recurrence After Percutaneous Radiofrequency Ablation and Microwave Ablation for the Treatment of Liver Tumors: a Meta-analysis

RATIONALE AND OBJECTIVES

The rate of complications and risk of local recurrence following percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for liver tumors varies significantly between investigations. This meta-analysis aimed to assess complication rates and risk of local recurrence after percutaneous RFA and MWA.

MATERIALS AND METHODS

PubMed, Medline, Web of Science, the Cochrane Library, Embase, Google Scholar, and CINAHL were systematically searched from database inception until August 2022 to retrieve articles reporting the complication rates and risk of recurrence after percutaneous RFA and MWA for the treatment of liver tumors. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated and displayed by forest plots. To measure heterogeneity, Cochran Q and I2 statistics were also applied. Egger's test and funnel plots were also performed to assess any potential publication bias. Additionally, subgroup analysis was done to investigate the source of heterogeneity.

RESULTS

26 studies including 2026 and 1974 patients for RFA and MWA, respectively, were included. The rate of minor complications was significantly higher after MWA compared to RFA, yielding an overall OR of 0.688 (95% CI: 0.549-0.862, P = 0.001). Similarly, the rate of major complications was significantly higher after MWA than RFA (P = 0.012), yielding an overall OR of 0.639 (95% CI: 0.450-0.907). No significant difference was found between RFA and MWA in terms of local recurrence after ablation (P > 0.05). In addition, there was no statistical evidence of publication bias.

CONCLUSION

When most factors are considered equally, percutaneous RFA and MWA can be considered safe modalities for the treatment of liver tumors, with RFA superior in terms of the incidence of minor and major complications.

Thermal ablation versus liver resection for hepatocellular carcinoma in patients with cirrhosis: a systematic review and meta-analysis of propensity-score matched studies

The outcomes of cirrhotic patients with hepatocellular carcinoma (HCC) after thermal ablation (TA) versus liver resection (LR) are debated. We aimed to compare the overall survival (OS), disease-free survival (DFS), and operative outcomes after TA and LR for HCC in patients with cirrhosis. Until November 15, 2022, we searched PubMed, Embase, and Cochrane databases by using Medical Subject Heading terms and other terms, and used the Newcastle-Ottawa literature evaluation scale to assess the quality of selected studies. OS, DFS, and operative outcomes were extracted and analyzed. The meta-analysis showed that 5 propensity-score matched (PSM) studies including 933 patients (463 TA vs. 470 LR) were included. After analysis, TA and LR had similar results at 1-year OS (odds ratio [OR] 1.68; 95% confidence interval [CI] 1.01-2.78; P = 0.05) and 3-year OS (OR 0.76; 95% CI 0.56-1.04; P = 0.08), whereas LR increased 5-years OS (OR 0.37; 95% CI 0.18-0.74; P = 0.005). In addition to the DFS, the 1-year DFS was significantly higher in patients with LR. However, there were no obvious differences in 3-year and 5-year DFS when comparing TA and LR. The length of operative time and hospital stay were longer in the LR group. Besides, the LR group had significantly higher rate of perioperative blood transfusions and major complications. Our research proved that LR took advantage of OS and DFS for HCC patients with cirrhosis. Additional well-designed randomized controlled trials are needed.

Big data and RCT's in surgical oncology: Impact on improving hepatopancreatobiliary cancer surgical care on the global stage

Randomized controlled clinical trials (RCTs) are at the heart of "evidence-based" medicine. Conducting well-designed RCTs for surgical procedures is often challenged by inadequate recruitment accrual, blinding, or standardization of the surgical procedure, as well as lack of funding and evolution of the treatment strategy during the many years over which such trials are conducted. In addition, most clinical trials are performed in academic high-volume centers with highly selected patients, which may not necessarily reflect a "real-world" practice setting. Large databases provide easy and inexpensive access to data on a large and diverse patient population at a variety of treatment centers. Furthermore, large database studies provide the opportunity to answer questions that would be impossible or very arduous to answer using RCTs, including questions regarding health policy efficacy, trends in surgical practice, access to health care, the impact of hospital volume, and adherence to practice guidelines, as well as research questions regarding rare disease, infrequent surgical outcomes, and specific subpopulations. Prospective data registries may also allow for quality benchmarking and auditing. There are several high-quality RCTs providing evidence to support current practices in hepatopancreatobiliary (HPB) oncology. Evidence from big data bridges the gap in several instances where RCTs are lacking. In this article, we review the evidence from RCTs and big data in HPB oncology identify the existing lacunae, and discuss the future directions of research in HPB oncology.

The current landscape of therapies for hepatocellular carcinoma

Globally, primary liver cancer is the third leading cause of cancer-related deaths, with approximately 830 000 deaths worldwide in 2020, accounting for 8.3% of total deaths from all cancer types (1). This disease disproportionately affects those in countries with low or medium Human Development Index scores in Eastern Asia, South-Eastern Asia, and Northern and Western Africa (2). Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, often develops in the background of chronic liver disease, caused by hepatitis B or C virus, non-alcoholic steatohepatitis (NASH), or other diseases that cause cirrhosis. Prognosis can vary dramatically based on number, size, and location of tumors. Hepatic synthetic dysfunction and performance status (PS) also impact survival. The Barcelona Clinic Liver Cancer (BCLC) staging system best accounts for these variations, providing a reliable prognostic stratification. Therapeutic considerations of this complex disease necessitate a multidisciplinary approach and can range from curative-intent surgical resection, liver transplantation or image-guided ablation to more complex liver-directed therapies like transarterial chemoembolization (TACE) and systemic therapy. Recent advances in the understanding of the tumor biology and microenvironment have brought new advances and approvals for systemic therapeutic agents, often utilizing immunotherapy or VEGF-targeted agents to modulate the immune response. This review will discuss the current landscape in the treatments available for early, intermediate, and advanced stage HCC.

Guidelines for the Diagnosis and Treatment of Primary Liver Cancer (2022 Edition)

Background

Primary liver cancer, of which around 75-85% is hepatocellular carcinoma in China, is the fourth most common malignancy and the second leading cause of tumor-related death, thereby posing a significant threat to the life and health of the Chinese people.

Summary

Since the publication of Guidelines for Diagnosis and Treatment of Primary Liver Cancer in China in June 2017, which were updated by the National Health Commission in December 2019, additional high-quality evidence has emerged from researchers worldwide regarding the diagnosis, staging, and treatment of liver cancer, that requires the guidelines to be updated again. The new edition (2022 Edition) was written by more than 100 experts in the field of liver cancer in China, which not only reflects the real-world situation in China but also may reshape the nationwide diagnosis and treatment of liver cancer.

Key Messages

The new guideline aims to encourage the implementation of evidence-based practice and improve the national average 5-year survival rate for patients with liver cancer, as proposed in the "Health China 2030 Blueprint."

Management of early-stage hepatocellular carcinoma: challenges and strategies for optimal outcomes

Although hepatocellular carcinoma (HCC) is associated with a poor prognosis, management of early-stage HCC is often successful with highly efficacious treatment modalities such as liver transplantation, surgical resection, and radiofrequency ablation. However, unfavorable clinical outcomes have been observed under certain circumstances, even after efficient treatment. Factors that predict unsuitable results after treatment include tumor markers, inflammatory markers, imaging findings reflecting tumor biology, specific outcome indicators for each treatment modality, liver functional reserve, and the technical feasibility of the treatment modalities. Various strategies may overcome these challenges, including the application of reinforced treatment indication criteria with predictive markers reflecting tumor biology, compensation for technical issues with up-to-date technologies, modification of treatment modalities, downstaging with locoregional therapies (such as transarterial chemotherapy or radiotherapy), and recently introduced combination immunotherapies. In this review, we discuss the challenges to achieving optimal outcomes in the management of early-stage HCC and suggest strategies to overcome these obstacles.

Efficacy and safety of MWA versus RFA and CA for renal tumors: A systematic review and meta-analysis of comparison studies

PURPOSE

Thermal ablation procedures represent an alternative treatment option for patients with T1a renal tumors. Radiofrequency ablation (RFA) and cryoablation (CA) are the most used and studied techniques, while microwave ablation (MWA) has progressively emerged in recent years. Our aim was to assess the effectiveness and safety of MWA in comparison to RFA and CA for the treatment of primary renal tumors.

METHOD

Pubmed, CENTRAL, Web of Science and Scopus were searched until March 2023 to identify studies aimed at comparing the efficacy and safety of MWA with those of RFA and CA for the treatment of patients with primary renal tumors. We compared MWA and RFA/CA primary technique efficacy, local recurrences, overall and cancer-specific survival, major and overall complications, and eGFR changes. Moreover, subgroup analyses were conducted (MWA vs RFA; MWA vs CA; MWA vs RFA/CA in T1a renal tumors).

RESULTS

Ten retrospective studies with 2258 thermal ablations were included (508 MWA and 1750 RFA /CA). MWA had fewer local recurrences (OR = 0.31; 95% CI, 0.16, 0.62; p = 0.0008) than RFA/CA; the other outcomes were not significantly different. In subgroup analyses, MWA resulted to have fewer overall complications than RFA (OR = 0.60; 95% CI, 0.38, 0.97; p = 0.04) and CA (OR = 0.49; 95% CI, 0.28, 0.85; p = 0.01); moreover, MWA was associated with fewer recurrences than CA (OR = 0.30; 95% CI, 0.11, 0.84; p = 0.02). In T1a renal tumors subgroup analysis, the outcomes were not significantly different.

CONCLUSIONS

MWA is an ablative procedure as effective and safe as RFA or CA for the treatment of renal tumors.

Preliminary study of 3D printing technology for extracorporeal positioning guide assisted ultrasound-guided microwave ablation of the liver

BACKGROUND

We designed a 3D-printed extracorporeal positioning guide for assisting ultrasound-guided microwave ablation of the liver and observed its effectiveness.

RESEARCH DESIGN AND METHODS

13 patients with liver cancer were selected, and their CT data were obtained. The CT data is reconstructed in 3D by computer software Mimics to create a 3D model. The 3D-printed in vitro positioning guides were designed by 3-Matic and fabricated using 3D printing technology. Finally, it is applied to the clinic, and its effect is observed.

RESULTS

The preliminary design of a 3D printed extracorporeal positioning guide was applied to the clinic, and the efficiency of assisted ultrasound positioning was 76.92% (10/13), with three patients requiring repositioning. The efficiency of the 3D printed extracorporeal positioning guide technique was 76.92%, a CT examination was performed one month after surgery, and three patients had residual lesions.

CONCLUSIONS

3D-printed extracorporeal positioning guides can assist ultrasound in localizing tumors during liver microwave ablation and reduce repeated punctures. It makes percutaneous microwave ablation of the liver more precise and safe. However, the current study sample is small, there are still apparent shortcomings, and long-term clinical studies are needed to prove its effectiveness.

Ablative margins in percutaneous thermal ablation of hepatic tumors: a systematic review

INTRODUCTION

This study aims to systematically review current evidence on ablative margins and correlation to local tumor progression (LTP) after thermal ablation of hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM).

METHODS

A systematic search was performed in PubMed (MEDLINE) and Web of Science to identify all studies that reported on ablative margins (AM) and related LTP rates. Studies were assessed for risk of bias and synthesized separately per tumor type. Where possible, results were pooled to calculate risk differences (RD) as function of AM.

RESULTS

In total, 2910 articles were identified of which 43 articles were eligible for final analysis. There was high variability in AM measurement methodology across studies in terms of measurement technique, imaging modalities, and timing. Most common margin stratification was < 5 mm and > 5 mm, for which data were available in 25/43 studies (58%). Of these, all studies favored AM > 5 mm to reduce the risk of LTP, with absolute RD of 16% points for HCC and 47% points for CRLM as compared to AM < 5 mm.

CONCLUSIONS

Current evidence supports AM > 5 mm to reduce the risk of LTP after thermal ablation of HCC and CRLM. However, standardization of AM measurement and reporting is critical to allow future meta-analyses and improved identification of optimal threshold value for clinical use.

Targeting Non-Coding RNAs for the Development of Novel Hepatocellular Carcinoma Therapeutic Approaches

Hepatocellular carcinoma (HCC) remains a global health challenge, representing the third leading cause of cancer deaths worldwide. Although therapeutic advances have been made in the few last years, the prognosis remains poor. Thus, there is a dire need to develop novel therapeutic strategies. In this regard, two approaches can be considered: (1) the identification of tumor-targeted delivery systems and (2) the targeting of molecule(s) whose aberrant expression is confined to tumor cells. In this work, we focused on the second approach. Among the different kinds of possible target molecules, we discuss the potential therapeutic value of targeting non-coding RNAs (ncRNAs), which include micro interfering RNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These molecules represent the most significant RNA transcripts in cells and can regulate many HCC features, including proliferation, apoptosis, invasion and metastasis. In the first part of the review, the main characteristics of HCC and ncRNAs are described. The involvement of ncRNAs in HCC is then presented over five sections: (a) miRNAs, (b) lncRNAs, (c) circRNAs, (d) ncRNAs and drug resistance and (e) ncRNAs and liver fibrosis. Overall, this work provides the reader with the most recent state-of-the-art approaches in this field, highlighting key trends and opportunities for more advanced and efficacious HCC treatments.

Combined Ablation and Resection for Colorectal Liver Metastases in the Minimally Invasive Surgical Era

BACKGROUND

Thermal ablation is an accepted treatment modality for small and central liver tumors. In extensive colorectal liver metastatic disease (CRLM), hepatectomy can be combined with ablation, resulting in a parenchymal-sparing strategy. This may increase salvageability rates in case of recurrence.

METHODS

All patients with advanced CRLM that underwent combined ablation and resection between April 2012 and April 2021, were retrospectively analyzed from a prospectively maintained database. Primary endpoints include postoperative 30-day morbidity and ablation-site recurrence (ASR). The surgical approaches were compared. Ablated lesions were screened for ASR on postoperative follow-up imaging.

RESULTS

Of 54 patients that underwent combined ablation and resection, 32 (59.3%) were performed through a minimally invasive approach. Eleven (20.4%) were minor resections, 32 (59.3%) were technically major and 11 (20.4%) were anatomically major resections. Twelve complications occurred (22.2%), among which 2 (3.8%) major complications (Clavien-Dindo ≥IIIa). Ninety-day mortality rate was 1.9%. Out of 82 ablated lesions, 6 ASRs (11.1%) occurred. Median blood loss was significantly lower in the minimally invasive group, compared with open [90 mL (32.5 to 200) vs. 200 mL (100 to 400), P =0.005]. Pringle maneuver was significantly performed less in the minimally invasive group [8 (25.0%) vs. 16 (72.7%), P =0.001], but took more time [36.1 min (±15.6) vs. 21.6 (±9.9); P =0.011]. Short-term (1 y) overall and disease-free survival were respectively 81.4% and 50.0%.

CONCLUSION

Combining microwave ablation and liver resection is a feasible and safe parenchymal-sparing technique, through both minimally invasive and open approach for treating extended CRLM disease. It has a low ablation-related complication rate and acceptable ablation-site recurrence rate.

Non-Surgical Locoregional Therapies Alone or in Combination with Systemic Therapy in Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, representing the third-leading cause of cancer-related deaths worldwide. Curative intent treatment options for patients with HCC include liver transplantation, resection and ablation of small lesions. Other potentially curative therapies include cryoablation, microwave ablation and percutaneous alcohol injection. For locally advanced disease, different arterially directed therapies including transarterial chemoembolization and selective internal radiation therapy, plus external beam radiation including three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, stereotactic body radiation therapy and proton beam therapy, are available or studied. Systemic therapies based on checkpoint inhibitors and tyrosine kinase inhibitors are available for the management of metastatic HCC and sometimes for locally advanced disease. Combinations of locoregional therapies with systemic drugs are currently the subject of several clinical trials.

Clinical consensus statement: Establishing the roles of locoregional and systemic therapies for the treatment of intermediate-stage hepatocellular carcinoma in Canada

BACKGROUND

Hepatocellular carcinoma (HCC) a leading cause of cancer mortality worldwide and approximately one-third of patients present with intermediate-stage disease. The treatment landscape of intermediate-stage HCC is rapidly evolving due to developments in local, locoregional and systemic therapies. Treatment recommendations focused on this heterogenous disease stage and that take into account the Canadian reality are lacking. To address this gap, a pan-Canadian group of experts in hepatology, transplant, surgery, radiation therapy, nuclear medicine, interventional radiology, and medical oncology came together to develop consensus recommendations on management of intermediate-stage HCC relevant to the Canadian context.

METHODS

A modified Delphi framework was used to develop consensus statements with strengths of recommendation and supporting levels of evidence graded using the AHA/ACC classification system. Tentative consensus statements were drafted based on a systematic search and expert input in a series of iterative feedback cycles and were then circulated via online survey to assess the level of agreement.

RESULTS & CONCLUSION

The pre-defined ratification threshold of 80 % agreement was reached for all statements in the areas of multidisciplinary treatment (n = 4), intra-arterial therapy (n = 14), biologics (n = 5), radiation therapy (n = 3), surgical resection and transplantation (n = 7), and percutaneous ablative therapy (n = 4). These generally reflected an expansion in treatment options due to developments in previously established or emergent techniques, introduction of new and more active therapies and increased therapeutic flexibility. These developments have allowed for greater treatment tailoring and personalization as well as a paradigm shift toward strategies with curative intent in a wider range of disease settings.

2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Ablation for Benign Liver Tumors: Current Concepts and Limitations

Percutaneous ablation under imaging guidance is a curative treatment that can induce complete tumor necrosis with advantages of minimal invasiveness and a low risk of complications. Thermal ablation, which includes radiofrequency ablation and microwave ablation, is a representative technique that has sufficient antitumor effects in cases of hepatocellular carcinoma with ≤3 lesions measuring ≤3 cm and preserved liver function. The short- and long-term outcomes of patients are comparable with those achieved with surgical resection. Despite their nonmalignant nature, some benign liver tumors require treatment for symptoms caused by the presence of the tumor and/or continuous enlargement. Ablation may be the treatment of choice because it has lower burden on patients than surgical treatment. This review describes the recent concepts, progress, and limitations of ablation-based treatment for benign liver tumors.

Hyperthermia combined with immune checkpoint inhibitor therapy: Synergistic sensitization and clinical outcomes

BACKGROUND

Within the field of oncotherapy, research interest regarding immunotherapy has risen to the point that it is now seen as a key application. However, inherent disadvantages of immune checkpoint inhibitors (ICIs), such as their low response rates and immune-related adverse events (irAEs), currently restrict their clinical application. Were these disadvantages to be overcome, more patients could derive prolonged benefits from ICIs. At present, many basic experiments and clinical studies using hyperthermia combined with ICI treatment (HIT) have been performed and shown the potential to address the above challenges. Therefore, this review extensively summarizes the knowledge and progress of HIT for analysis and discusses the effect and feasibility.

METHODS

In this review, we explored the PubMed and clinicaltrials.gov databases, with regard to the searching terms "immune checkpoint inhibitor, immunotherapy, hyperthermia, ablation, photothermal therapy".

RESULTS

By reviewing the literature, we analyzed how hyperthermia influences tumor immunology and improves the efficacy of ICI. Hyperthermia can trigger a series of multifactorial molecular cascade reactions between tumors and immunization and can significantly induce cytological modifications within the tumor microenvironment (TME). The pharmacological potency of ICIs can be enhanced greatly through the immunomodulatory amelioration of immunosuppression, and the activation of immunostimulation. Emerging clinical trials outcome regarding HIT have verified and enriched the theoretical foundation of synergistic sensitization.

CONCLUSION

HIT research is now starting to transition from preclinical studies to clinical investigations. Several HIT sensitization mechanisms have been reflected and demonstrated as significant survival benefits for patients through pioneering clinical trials. Further studies into the theoretical basis and practical standards of HIT, combined with larger-scale clinical studies involving more cancer types, will be necessary for the future.

Surgical approach to microwave and radiofrequency liver ablation for hepatocellular carcinoma and colorectal liver metastases less than 5 cm: a systematic review and meta-analysis

BACKGROUND

Primary hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) represent the two most common malignant neoplasms of the liver. The objective of this study was to assess outcomes of surgical approaches to liver ablation comparing laparoscopic versus percutaneous microwave ablation (MWA), and MWA versus radiofrequency ablation (RFA) in patients with HCC or CRLM lesions smaller than 5 cm.

METHODS

A systematic review was conducted across seven databases, including PubMed, Embase, and Cochrane, to identify all comparative studies between 1937 and 2021. Two independent reviewers screened for eligibility, extracted data for selected studies, and assessed study bias using the modified Newcastle Ottawa Scale. Random effects meta-analyses were subsequently performed on all available comparative data.

RESULTS

From 1066 records screened, 11 studies were deemed relevant to the study and warranted inclusion. Eight of the 11 studies were at high or uncertain risk for bias. Our meta-analyses of two studies revealed that laparoscopic MW ablation had significantly higher complication rates compared to a percutaneous approach (risk ratio = 4.66; 95% confidence interval = [1.23, 17.22]), but otherwise similar incomplete ablation rates, local recurrence, and oncologic outcomes. The remaining nine studies demonstrated similar efficacy of MWA and RFA, as measured by incomplete ablation, complication rates, local/regional recurrence, and oncologic outcomes, for both HCC and CRLM lesions less than 5 cm (p > 0.05 for all outcomes). There was no statistical subgroup interaction in the analysis of tumors < 3 cm.

CONCLUSION

The available comparative evidence regarding both laparoscopic versus percutaneous MWA and MWA versus RFA is limited, evident by the few studies that suffer from high/uncertain risk of bias. Additional high-quality randomized trials or statistically matched cohort studies with sufficient granularity of patient variables, institutional experience, and physician specialty/training will be useful in informing clinical decision making for the ablative treatment of HCC or CRLM.

Development of Glycyrrhetinic Acid and Folate Modified Cantharidin Loaded Solid Lipid Nanoparticles for Targeting Hepatocellular Carcinoma

Cantharidin (CTD) is the major component of anticancer drugs obtained from Mylabris Cichorii and has a good inhibitory effect on several cancers, including hepatocellular carcinoma (HCC) and breast cancer. However, due to its toxicity, oral administration can cause various adverse reactions, limiting its clinical application. The aim of this work was to design glycyrrhetinic acid (GA)- and/or folate (FA)-modified solid lipid nanoparticles (SLNs) for the encapsulation of CTD to target HCC. Four CTD-loaded SLNs (cantharidin solid lipid nanoparticles (CSLNs), glycyrrhetinic acid-modified cantharidin solid lipid nanoparticles (GA-CSLNs), folate-modified cantharidin solid lipid nanoparticles (FA-CSLNs), and glycyrrhetinic acid and folate-modified cantharidin solid lipid nanoparticles (GA-FA-CSLNs)) were prepared by the emulsion ultrasonic dispersion method, and their physicochemical parameters were determined (particle size and distribution, morphology, zeta-potential, entrapment efficiency, drug loading, and hemolysis). Additionally, the antitumor activities of the four SLNs were evaluated comprehensively by tests for cytotoxicity, cell migration, cell cycle, apoptosis, cellular uptake, competition suppression assay, and in vivo tumor suppression assay. Four SLNs showed spherical shapes and mean diameters in the range of 75–110 nm with size dispersion (PDI) within the range of 0.19–0.50 and zeta-potential approximately –10 mV. The entrapment efficiency of CTD in SLNs was higher than 95% for all tested formulations, and no hemolysis was observed. Compared to GA-CSLNs or CSLNs, GA-FA-CSLNs and FA-CSLNs showed stronger cytotoxicity on hepatocellular carcinoma cells (HepG2), and the cytotoxicity of GA-FA-CSLNs on hepatocyte cells (L-02) was remarkably reduced compared with other formulations. GA-FA-CSLNs and FA-CSLNs also increased the inhibition of HepG2 cell migration, and FA-CSLNs had the highest apoptosis rate. The cell cycle results indicated that HepG2 cells were arrested mainly in the S phase and G2/M phase. Analysis of competition inhibition experiments showed that GA and FA ligands had targeted effects on HepG2 cells. The in vivo tumor inhibition experiment showed that GA-FA-CSLNs and FA-CSLNs had excellent tumor inhibition ability—their tumor inhibition rates were 96.46% and 89.92%, respectively. Our results indicate that GA-FA-CSLNs and FA-CSLNs have a promising future in the therapeutic intervention of HCC.

2022 KLCA-NCC Korea practice guidelines for the management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the fourth most common cancer among men in South Korea, where the prevalence of chronic hepatitis B infection is high in middle and old age. The current practice guidelines will provide useful and sensible advice for the clinical management of patients with HCC. A total of 49 experts in the fields of hepatology, oncology, surgery, radiology, and radiation oncology from the Korean Liver Cancer Association-National Cancer Center Korea Practice Guideline Revision Committee revised the 2018 Korean guidelines and developed new recommendations that integrate the most up-to-date research findings and expert opinions. These guidelines provide useful information and direction for all clinicians, trainees, and researchers in the diagnosis and treatment of HCC.

Outcomes of microwave versus radiofrequency ablation for hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND

Studies to date comparing outcomes of microwave ablation (MWA) with radiofrequency ablation (RFA) on patients with hepatocellular carcinoma have yielded conflicting results, with no clear superiority of one technique over the other. The aim of this systematic review and meta-analysis was to compare the efficacy and safety of MWA with RFA.

AIM

To perform a systematic review and meta-analysis comparing the efficacy and safety of MWA with RFA.

METHODS

A systematic literature search was performed using Ovid Medline, Embase, PubMed, Reference Citation Analysis, Cochrane Central and Cochrane Systematic Review databases, and Web of Science. Abstracts and full manuscripts were screened for inclusion utilising predefined inclusion and exclusion criteria comparing outcomes of MWA and RFA. A random-effects model was used for each outcome. Meta-regression analysis was performed to adjust for the difference in follow-up period between the studies. Primary outcome measures included complete ablation (CA) rate, local recurrence rate (LRR), survival [local recurrence-free survival (LRFS), overall survival (OS)] and adverse events.

RESULTS

A total of 42 published studies [34 cohort and 8 randomised controlled trials (RCT)] with 6719 patients fulfilled the selection criteria. There was no significant difference in tumour size between the treatment groups. CA rates between MWA and RFA groups were similar in prospective cohort studies [odds ratio (OR) 0.95, 95% confidence interval (CI) 0.28–3.23] and RCTs (OR 1.18, 95%CI 0.64–2.18). However, retrospective studies reported higher rates with MWA (OR 1.29, 95%CI 1.06–1.57). Retrospective cohort studies reported higher OS (OR 1.54, 95%CI 1.15–2.05 and lower LRR (OR 0.67, 95%CI 0.51–0.87). No difference in terms of LRFS or 30-d mortality was observed between both arms. MWA had an increased rate of adverse respiratory events when compared to RFA (OR 1.99, 95%CI 1.07–3.71, P = 0.03).

CONCLUSION

MWA achieves similar CA rates and as good or better longer-term outcomes in relation to LRR and OS compared to RFA. Apart from an increased rate of respiratory events post procedure, MWA is as safe as RFA.

Current Imaging Diagnosis of Hepatocellular Carcinoma

Simple Summary

The role of imaging in the management of hepatocellular carcinoma (HCC) has significantly evolved and expanded beyond the plain radiological confirmation of the tumor based on the typical appearance in a multiphase contrast-enhanced CT or MRI examination. The introduction of hepatobiliary contrast agents has enabled the diagnosis of hepatocarcinogenesis at earlier stages, while the application of ultrasound contrast agents has drastically upgraded the role of ultrasound in the diagnostic algorithms. Newer quantitative techniques assessing blood perfusion on CT and MRI not only allow earlier diagnosis and confident differentiation from other lesions, but they also provide biomarkers for the evaluation of treatment response. As distinct HCC subtypes are identified, their correlation with specific imaging features holds great promise for estimating tumor aggressiveness and prognosis. This review presents the current role of imaging and underlines its critical role in the successful management of patients with HCC.

Abstract

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer related death worldwide. Radiology has traditionally played a central role in HCC management, ranging from screening of high-risk patients to non-invasive diagnosis, as well as the evaluation of treatment response and post-treatment follow-up. From liver ultrasonography with or without contrast to dynamic multiple phased CT and dynamic MRI with diffusion protocols, great progress has been achieved in the last decade. Throughout the last few years, pathological, biological, genetic, and immune-chemical analyses have revealed several tumoral subtypes with diverse biological behavior, highlighting the need for the re-evaluation of established radiological methods. Considering these changes, novel methods that provide functional and quantitative parameters in addition to morphological information are increasingly incorporated into modern diagnostic protocols for HCC. In this way, differential diagnosis became even more challenging throughout the last few years. Use of liver specific contrast agents, as well as CT/MRI perfusion techniques, seem to not only allow earlier detection and more accurate characterization of HCC lesions, but also make it possible to predict response to treatment and survival. Nevertheless, several limitations and technical considerations still exist. This review will describe and discuss all these imaging modalities and their advances in the imaging of HCC lesions in cirrhotic and non-cirrhotic livers. Sensitivity and specificity rates, method limitations, and technical considerations will be discussed.

Radiofrequency ablation in the treatment of hepatocellular carcinoma

OBJECTIVE

The purpose of this article is to discuss the use, comparative efficacy, and research progress of radiofrequency ablation (RFA), alone or in combination with other therapies, for the treatment of hepatocellular carcinoma (HCC).

METHOD

To search and summarize the basic and clinical studies of RFA in recent years.

RESULTS

RFA is one of the radical treatment methods listed in the guidelines for the diagnosis and treatment of HCC. It has the characteristics of being minimally invasive and safe and can obtain good local tumor control, and it can improve the local immune ability, improve the tumor microenvironment and enhance the efficacy of chemotherapy drugs. It is commonly used for HCC treatment before liver transplantation and combined ALPPS and hepatectomy for HCC. In addition, the technology of RFA is constantly developing. The birth of noninvasive, no-touch RFA technology and equipment and the precise RFA concept have improved the therapeutic effect of RFA.

CONCLUSION

RFA has good local tumor control ability, is minimally invasive, is safe and has other beneficial characteristics. It plays an increasingly important role in the comprehensive treatment strategy of HCC. Whether RFA alone or combined with other technologies expands the surgical indications of patients with HCC and provides more benefits for HCC patients needs to be determined.

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

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Surgical resection is often only possible in the early stages of HCC and among those with limited cirrhosis. Radiofrequency ablation and Microwave ablation are 2 main types of percutaneous thermal ablation for the treatment of HCC. The efficacy and safety between these 2 therapy methods are still under a debate.

OBJECTIVE

To compare the efficacy and safety of Radiofrequency ablation and Microwave ablation in treating HCC.

METHODS

PubMed, EMBASE, the Cochrane databases and Web of Science were systematically searched. We included randomized controlled trials and cohort studies comparing the efficacy and safety of Radiofrequency ablation and Microwave ablation in HCC patients. Outcome measures on local tumor progression, complete ablation, disease-free survival, overall survival, or major complications were compared between the 2 groups. The random effect model was used when there was significant heterogeneity between studies, otherwise the fixed effect model was used.

RESULTS

A total of 33 studies, involving a total of 4589 patients were identified, which included studies comprised 7 RCTs, 24 retrospective observational trials, and 2 prospective observational trial. Microwave ablation had a lower local tumor progression than Radiofrequency ablation in cohort studies (OR = 0.78, 95% CI 0.64-0.96, P = .02). Complete ablation rate of Microwave ablation was higher than that of Radiofrequency ablation in cohort studies (OR = 1.54, 95% CI 1.05-2.25, P = .03). There was no significant difference in overall survival and disease-free survival between the 2 groups. Meta-analysis showed that there was no significant difference in the main complications between Microwave ablation and Radiofrequency ablation.

CONCLUSIONS

Microwave ablation has higher complete ablation and lower local tumor progression than Radiofrequency ablation in the ablation treatment of HCC nodules. There was no significant difference in overall survival between the 2 therapy methods.

Combination approaches in hepatocellular carcinoma: How systemic treatment can benefit candidates to locoregional modalities

The management of hepatocellular carcinoma (HCC) is challenging because most patients have underlying cirrhosis, and the treatment provides, historically, a limited impact on the natural history of patients with advanced-stage disease. Additionally, recurrence rates are high for those patients who receive local and locoregional modalities, such as surgical (resection and transplantation) or image-guided (ablation and intra-arterial) therapies. Translational research has led to new concepts that are reshaping the current clinical practice. Substantial advancements were achieved in the understanding of the hallmarks that drive hepatocarcinogenesis. This has primed a successful incorporation of novel agents with different targets, such as anti-angiogenic drugs, targeted-therapies, and immune-checkpoint inhibitors. Although clinical trials have proven efficacy of systemic agents in advanced stage disease, there is no conclusive evidence to support their use in combination with loco-regional therapy. While novel local modalities are being incorporated (e.g., radioembolization, microwave ablation, and irreversible electroporation), emerging data indicate that locoregional treatments may induce tumor microenvironment changes, such as hyperexpression of growth factors, release of tumor antigens, infiltration of cytotoxic lymphocytes, and modulation of adaptative and innate immune response. Past trials that evaluated the use of antiangiogenic drugs in the adjuvant setting after ablation or chemoembolization fail to demonstrate a substantial improvement. Current efforts are directed to investigate the role of immunotherapy-based regimens in this context. The present review aims to describe the current landscape of systemic and locoregional treatments for HCC, present evidence to support combination approaches, and address future perspectives.

Local and Regional Therapies for Hepatocellular Carcinoma and Future Combinations

Simple Summary

Percutaneous interventional radiological techniques offer many alternatives for treatment of Hepatocellular Carcinoma (HCC) using local anesthesia and sedation. These methods aim to destroy the malignant tumors locally without affecting the non-malignant liver. In this way, complications are kept low and patient recovery is quick. Indications depend on tumor size, type and stage, as well as patient’s condition, liver function and co-morbidities. In recent years, a lot of research has been made in combining such approaches with immune therapy, but there is still much work to be done. This manuscript tries to analyze where we stand today and explain, using a comprehensive algorithm, the treatment options for each different clinical condition.

Abstract

Background: Hepatocellular carcinoma (HCC) can be treated by local and regional methods of percutaneous interventional radiological techniques. Indications depend on tumor size, type and stage, as well as patient’s condition, liver function and co-morbidities. According to international classification systems such as Barcelona Clinic Liver Cancer (BCLC) classification, very early, early or intermediate staged tumors can be treated either with ablative methods or with transarterial chemoembolization (TACE), depending on tumor characteristics. The combination of both allows for individualized forms of treatment with the ultimate goal of improving response and survival. In recent years, a lot of research has been carried out in combining locoregional approaches with immune therapy. Although recent developments in systemic treatment, especially immunotherapy, seem quite promising and have expanded possible combined treatment options, there is still not enough evidence in their favor. The aim of this review is to provide a comprehensive up-to-date overview of all these techniques, explaining indications, contraindications, technical problems, outcomes, results and complications. Moreover, combinations of percutaneous treatment with each other or with immunotherapy and future options will be discussed. Use of all those methods as down-staging or bridging solutions until surgery or transplantation are taken into consideration will also be reviewed. Conclusion: Local and regional therapies remain a mainstay of curative and palliative treatment of patients with HCC. Currently, evidence on potential combination of the local and regional treatment options with each other as well as with other treatment modalities is growing and has the potential to further individualize HCC therapy. To identify the most suitable treatment option out of these new various options, a repeated interdisciplinary discussion of each case by the tumor board is of utmost importance.

Evaluation of short- and medium-term efficacy and complications of ultrasound-guided ablation for small liver cancer

BACKGROUND

To ensure clinical efficacy and prolong patient survival, treatments such as surgery and microwave ablation (MWA) are used for early liver cancer. MWA is preferred because it effectively preserves the normal liver tissue and causes transient coagulation necrosis of local liver tumor cells. However, due to technical limitations, the cancerous liver tissue cannot be completely ablated; therefore, the probability of local tumor recurrence is high.

AIM

To investigate the clinical efficacy and safety of ultrasound-guided percutaneous MWA in the treatment of small liver cancer.

METHODS

A total of 118 patients treated for small liver cancer in The Central Hospital of Yongzhou from January 2018 to April 2019 were selected. Sixty-six patients received ultrasound-guided percutaneous MWA (MWA group) and 52 received laparoscopic surgery (laparoscope group). The operation time, blood loss, hospital stay, and medical expenses of both groups were statistically analyzed. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), albumin (ALB), alpha fetal protein (AFP), carcinoembryonic antigen (CEA), and peripheral blood regulatory T lymphocytes (Treg) levels were evaluated pre- and post-operatively. The cross-sectional area of tumors measured before and after ablation was analyzed statistically; the therapeutic effect was compared between both groups in terms of surgical complications, 2-year progression-free survival rate, and overall survival rate.

RESULTS

The operation time, blood loss, hospital stay, and medical expenses in the MWA group were lower than those of the laparoscope group, and the differences were significant (P < 0.05); these parameters, and ALT, AST, TBIL, and ALB levels were compared preoperatively between both groups, and there was no significance (P > 0.05). The operation time, blood loss, hospital stay, and medical expenses for 2 d and 1 wk after surgery, the ALT and AST of the MWA group were lower than those of the laparoscope group, and the difference was significant (P < 0.05). The operation time, blood loss, hospital stay, and medical expenses, and serum AFP, CEA, and Treg levels were measured preoperatively and 4 and 8 wk postoperatively, and there were no significant differences between the two groups (P > 0.05). Compared with preoperative levels, serum AFP, CEA, and Treg levels in both groups were decreased (P < 0.05). The lesion in the MWA group had a maximum area of 4.86 ± 0.90 cm2, 1.24 ± 0.57 cm2, and 0.31 ± 0.11 cm2 preoperatively, 1 and 3 mo postoperatively, respectively. Fifty-eight of them achieved complete response and eight achieved a partial response. After 2 years of follow-up, the progression-free and overall survival rates in the MWA group were 37.88% and 66.67%, respectively, compared with 44.23% and 76.92% in the laparoscope group, with no significant difference (P > 0.05).

CONCLUSION

The effects of ultrasound-guided percutaneous MWA in the treatment of small liver cancer are similar to those of laparoscopic surgery. However, ablation causes less trauma and liver dysfunction.

Comparison of combined transarterial chemoembolization and ablations in patients with hepatocellular carcinoma: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis compares the efficacy of three combination therapies, including transarterial chemoembolization (TACE) with radiofrequency ablation (RFA), microwave ablation (MWA), and cryoablation (CRA) for the treatment of patients with hepatocellular carcinoma (HCC).

METHODS

Online databases, including Scopus, Web of Science, PubMed, Embase, CNKI, Google Scholar, and Cochrane Library were searched.

RESULTS

Forty-two studies with 5468 pooled patients (TACE + RFA: 21 studies with 3398 patients, TACE + MWA:14 studies with 1477 patients, and TACE + CRA: 7 studies with 593 patients) reported combination therapy versus TACE alone. The TACE + MWA subcohort had the best odds of long-term overall survival (OR 4.81, 95% CI 1.44, 16.08, P = 0.011) and objective response rate (OR 3.93, 95% CI 2.34, 6.61, P < 0.001) compared with the other two combination subcohorts. The TACE + RFA and TACE + MWA subcohorts had approximately similar odds of 1-year recurrence-free survival (OR 5.21, 95% CI 2.13, 12.75, P < 0.001 and OR 4.61, 95% CI 1.70, 12.51, P = 0.003, respectively). The disease control rate was similar between the TACE + MWA and TACE + CRA subcohorts (OR 4.01, 95% CI 2.66, 6.04, P < 0.001 and OR 4.05, 95% CI 1.68, 9.74, P = 0.002) but greater than the TACE + RFA subcohort (OR 3.23, 95% CI 2.14, 4.86, P < 0.001).

CONCLUSION

Overall, the TACE + MWA subcohort had the best efficacy and outcomes, especially for younger patients (less than 60-year-old) with tumor size of ≤ 3 cm, compared with the TACE + RFA or TACE + CRA subcohorts.

Prognostic utility of systemic inflammatory markers and chronic hepatitis C virus infection status in hepatocellular carcinoma patients treated with local ablation

Background

Hepatocellular carcinoma (HCC) has high incidence and mortality worldwide. Local ablation using radiofrequency ablation (RFA) or microwave ablation (MWA) is potentially curative for early-stage HCC with outcomes comparable to surgical resection. We explored the influence of demographic, clinical, and laboratory factors on outcomes of HCC patients receiving ablation.

Methods

This retrospective cohort study included 221 HCC patients receiving local ablation at Mayo Clinic between January 2000 and October 2018, comprising 140 RFA and 81 MWA. Prognostic factors determining overall survival (OS) and disease-free survival (DFS) were identified using multivariate analysis.

Results

There was no clinically significant difference in OS or DFS between RFA and MWA. In multivariate analysis of OS, pre-ablation lymphocyte-monocyte ratio [Hazard ratio (HR) 0.7, 95% confidence interval (CI) 0.58–0.84, P = 0.0001], MELD score [HR 1.12, 95%CI 1.068–1.17, P <  0.0001], tumor number [HR 1.23, 95%CI 1.041–1.46, P = 0.015] and tumor size [HR 1.18, 95%CI 1.015–1.37, P = 0.031] were clinically-significant prognostic factors. Among HCC patients with chronic hepatitis C (HCV) infection, positive HCV PCR at HCC diagnosis was associated with 1.4-fold higher hazard of death, with 5-year survival of 32.8% vs 53.6% in HCV PCR-negative patients. Regarding DFS, pre-ablation lymphocyte-monocyte ratio [HR 0.77, 95%CI 0.66–0.9, P = 0.001], MELD score [HR 1.06, 95%CI 1.022–1.11, P = 0.002], Log² AFP [HR 1.11, 95%CI 1.033–1.2, P = 0.005], tumor number [HR 1.29, 95%CI 1.078–1.53, P = 0.005] and tumor size [HR 1.25, 95%CI 1.043–1.51 P = 0.016] were independently prognostic.

Conclusions

Pre-ablation systemic inflammation represented by lymphocyte-monocyte ratio is significantly associated with OS and DFS in HCC patients treated with local ablation. HCV viremia is associated with poor OS. Tumor biology represented by tumor number and size are strongly prognostic for OS and DFS while AFP is significantly associated with DFS only.

Risk factors for the recurrence of early hepatocellular carcinoma treated by percutaneous radiofrequency ablation with a multiple-electrode switching system: a multicenter prospective study

PURPOSE

To investigate the long-term efficacy of radiofrequency ablation (RFA) with a multiple-electrode switching system (MESS) in the treatment of early hepatocellular carcinoma (HCC) and evaluate the patterns and risk factors of intrahepatic recurrence of HCC after RFA.

METHODS

In total, 139 patients with early HCC who underwent RFA with MESS as primary treatment at multiple centers were prospectively enrolled according to the inclusion criteria. We evaluated the local tumor progression (LTP), intrahepatic distant recurrence (IDR), the incidence of cumulative disease-free survival (DFS), LTP-free survival, IDR-free survival, and overall survival. We also analyzed the associated risk factors.

RESULTS

A total of 139 patients were included in the study and the median follow-up time was 64 months, ranging from 11 to 72 months. The complete ablation rate was 98.56%. Sixty-nine (49.64%) were found to have intrahepatic recurrence (LTP, n = 15; IDR, n = 55) during follow-up. The 1-year, 3-year and 5-year cumulative DFS, LTP-free survival, and IDR-free survival rates were 74.82, 94.46 and 78.75%; 54.68, 88.03 and 61.79%; and 51.80, 85.67 and 60.17%, respectively. In the multivariable analysis, tumor size > 4 cm was the only important risk factor for LTP. The alkaline phosphatase (ALP) level and the number of tumors were independent risk factors for IDR; α-fetoprotein (AFP) level > 400 µg/L and recurrence interval were risk factors for the overall survival period.

CONCLUSIONS

The MESS-RFA is an effective method for local control of tumors in early HCC. Early HCC with multiple high-ALP tumors has a higher rate of recurrence, which mainly occurs in an IDR pattern. Early HCC with high AFP levels and a shorter initial recurrence interval resulted in a poorer prognosis. Thus, treatments such as liver transplantation or surgical resection may be a good strategy in those cases.

CLINICALTRIALS.GOV ID

NCT02046356.

OUP accepted manuscript

Background

The efficacy of repeat hepatic resection (rHR) in the treatment of recurrent hepatocellular carcinoma compared with radiofrequency or microwave ablation after resection of the primary tumour remains controversial. A systematic review and meta-analysis were performed to compare the safety and efficacy of these procedures.

Methods

PubMed, Embase, Scopus, Cochrane Library, and China National Knowledge Infrastructure databases were systematically searched to identify related studies published before 10 October 2021. Overall and recurrence-free survival after different treatments were compared based on pooled hazard ratios with a random-effects model.

Results

Two randomized clinical trials and 28 observational studies were included, involving 1961 and 2787 patients who underwent rHR and ablation respectively. Median perioperative mortality in both groups was zero but patients in the rHR group had higher median morbidity rates (17.0 per cent) than those in the ablation group (3.3 per cent). rHR achieved significantly longer recurrence-free survival than ablation (HR 0.79, 95 per cent c.i. 0.70 to 0.89, P < 0.001), while both groups had similar overall survival (HR 0.93, 95 per cent c.i. 0.83 to 1.04, P = 0.18).

Conclusion

rHR and ablation based on radio- or microwaves are associated with similar overall survival in patients with recurrent hepatocellular carcinoma after resection of the primary tumour.

New era of electrochemotherapy in treatment of liver tumors in conjunction with immunotherapies

Electrochemotherapy is a local ablative therapy that increases the cytotoxicity of either bleomycin or cisplatin by applying electric pulses (electroporation) to tumors. It has already been widely used throughout Europe for the treatment of various types of human and veterinary cutaneous tumors, with an objective response rate ranging from 70%-90%, depending on the tumor histotype. Recently, electrochemotherapy was introduced for the treatment of primary liver tumors, such as hepatocellular carcinoma (HCC). The complete response rate was 85% per treated lesion, with a durable response. Therefore, electrochemotherapy could become a treatment of choice for HCC, especially after achieving a transition from an open surgery approach to a percutaneous approach that uses dedicated electrodes. Electrochemotherapy elicits a local immune response and can be considered an in situ vaccination. HCC, among others, is a potentially immunogenic tumor; thus, electrochemotherapy could boost adjuvant immunotherapy to achieve a better and longer-lasting antitumor response. Therefore, therapeutic strategies that combine electrochemotherapy with immune checkpoint inhibitors or adjuvant treatment with cytokines are indicated for HCC. Immunogene therapy using electroporation as a delivery system for plasmid DNA coding for interleukin-12 is a highly promising approach. This electroporation approach has shown efficacy in preclinical settings and veterinary oncology and is awaiting translation for the treatment of liver tumors, i.e., HCC.

Efficacy and safety of various primary treatment strategies for very early and early hepatocellular carcinoma: a network meta-analysis

BACKGROUND

Several treatments are available for treatment of early and very early-stage Hepatocellular Carcinoma, also known as small Hepatocellular Carcinoma (SHCC). However, there is no consensus with regards to the efficacies of these methods. We aimed at identifying the most effective initial treatment strategy for SHCC through Bayesian network meta-analyses.

METHODS

Studies published between January, 2010, and February, 2021 were searched in EMBASE, Cochrane Library, PubMed and Web of science databases, and conference proceedings for trials. The included studies reported the survival outcomes of very early and early Hepatocellular Carcinoma patients subjected to radiofrequency ablation (RFA), microwave ablation (MWA), surgical resection (SR), transarterial chemoembolization (TACE), percutaneous ethanol injection (PEI), minimally invasive liver surgery (MIS), stereotactic body radiotherapy (SBRT) and cryoablation (CA). Then, data were extracted from studies that met the inclusion criteria. Patient survival data were retrieved from the published Kaplan-Meier curves and pooled. A Bayesian random-effects model was used to combine direct and indirect evidence.

RESULTS

A total of 2058 articles were retrieved and screened, from which 45 studies assessing the efficacies of 8 different treatments in 11,364 patients were selected. The included studies had high methodological quality. Recurrence free survival* (progression/recurrence/relapse/disease/tumor-free survival were combined and redefined as RFS*) and overall survival (OS) outcomes were highest in MIS-treated patients (HR 0·57, 95% confidence intervals [CI] 0·38-0·85; HR 0.48,95% CI 0.36-0.64, respectively), followed by SR-treated patients (HR 0.60, 95% CI 0.50-0.74; HR 0.62, 95% CI 0.55-0.72, respectively). TACE was highly efficacious (58.9%) at decreasing the rates of major complications. Similar findings were obtained through sensitivity analysis, and in most of the prognostic subgroups.

CONCLUSIONS

MIS and SR exhibited the highest clinical efficacies, however, they were associated with higher rates of complications. Ablation is effective in small tumors, whereas SBRT is a relatively promising treatment option for SHCC. More well-designed, large-scale randomized controlled trials should be performed to validate our findings.

Hyperthermia ablation combined with transarterial chemoembolization versus monotherapy for hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND AND AIMS

The existing evidence has indicated that hyperthermia ablation (HA) and HA combined with transarterial chemoembolization (HATACE) are the optimal alternative to surgical resection for patients with hepatocellular carcinoma (HCC) in the COVID-19 crisis. However, the evidence for decision-making is lacking in terms of comparison between HA and HATACE. Herein, a comprehensive evaluation was performed to compare the efficacy and safety of HATACE with monotherapy.

MATERIALS AND METHODS

Worldwide studies were collected to evaluate the HATACE regimen for HCC due to the practical need for global extrapolation of applicative population. Meta-analyses were performed using the RevMan 5.3 software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark).

RESULTS

Thirty-six studies involving a large sample of 5036 patients were included finally. Compared with HA alone, HATACE produced the advantage of 5-year overall survival (OS) rate (OR:1.90; 95%CI:1.46,2.46; p < 0.05) without increasing toxicity (p ≥ 0.05). Compared with TACE alone, HATACE was associated with superior 5-year OS rate (OR:3.54; 95%CI:1.96,6.37; p < 0.05) and significantly reduced the incidences of severe liver damage (OR:0.32; 95%CI:0.11,0.96; p < 0.05) and ascites (OR:0.42; 95%CI:0.20,0.88; p < 0.05). Subgroup analysis results of small (≤3 cm) HCC revealed that there were no significant differences between the HATACE group and HA monotherapy group in regard to the OS rates (p ≥ 0.05).

CONCLUSIONS

Compared with TACE alone, HATACE was more effective and safe for HCC. Compared with HA alone, HATACE was more effective for non-small-sized (>3 cm) HCC with comparable safety. However, the survival benefit of adjuvant TACE in HATACE regimen was not found for the patients with small (≤3 cm) HCC.

Hepatocellular Carcinoma in 2021: An Exhaustive Update

Primary liver cancer is a challenging global health concern with an estimated more than a million persons to be affected annually by the year 2025. The commonest type is hepatocellular carcinoma (HCC), which has been increasing in incidence the world over, mostly due to chronic viral hepatitis B infection. In the last decade, paradigm changes in the etiology, understanding of molecular biology, and pathogenesis, including the role of gut microbiota; medical and surgical treatments, and outcome trends are notable. The application of omics-based technology has helped us unlock the molecular and immune landscape of HCC, through which novel targets for drug treatment such as immune-checkpoint inhibitors have been identified. Novel tools for the surveillance and diagnosis of HCC include protein-, genomics-, and composite algorithm-based clinical/biomarker panels. Magnetic resonance imaging-based novel techniques have improved HCC diagnosis through ancillary features that enhance classical criteria while positron emission tomography has shown value in prognostication. Identification of the role of gut microbiota in the causation and progression of HCC has opened areas for novel therapeutic research. A select group of patients still benefit from modified surgical and early interventional radiology treatments. Improvements in radiotherapy protocols, identification of parameters of futility among radiological interventions, and the emergence of novel first-line systemic therapies that include a combination of antiangiogenic and immune-checkpoint inhibitors have seen a paradigm change in progression-free and overall survival. The current review is aimed at providing exhaustive updates on the etiology, molecular biology, biomarker diagnosis, imaging, and recommended treatment options in patients with HCC.

Recent Advances in Local Thermal Ablation Therapy for Hepatocellular Carcinoma

Image-guided local thermal ablation (LTA) plays an important role in the treatment of hepatocellular carcinoma (HCC), especially in patients with HCC who are not suitable for hepatectomy. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most widely used LTA clinically. Radiofrequency ablation can achieve the best result; that is, a similar therapeutic effect as hepatectomy if the tumor ≤3 cm, while MWA can effectively ablate tumors ≤5 cm. Local thermal ablation has an advantage over liver resection in terms of minimally invasive surgery and can achieve a comparable prognosis and efficacy to liver resection. For borderline liver function, selecting LTA as the first-line therapy may bring more benefits to patients with cirrhosis background. In addition, a combination of multiple therapies for HCC is a good choice, such as LTA combined with transcatheter arterial chemoembolization (TACE), which can achieve a better prognosis than single therapy for larger tumors. For patients who are awaiting liver transplantation, LTA is a good choice. The main problem of LTA needed to be solved is to prevent the local tumor recurrence after ablation in patients with HCC.

Recent Advances in Local Thermal Ablation Therapy for Hepatocellular Carcinoma

Image-guided local thermal ablation (LTA) plays an important role in the treatment of hepatocellular carcinoma (HCC), especially in patients with HCC who are not suitable for hepatectomy. Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most widely used LTA clinically. Radiofrequency ablation can achieve the best result; that is, a similar therapeutic effect as hepatectomy if the tumor ≤3 cm, while MWA can effectively ablate tumors ≤5 cm. Local thermal ablation has an advantage over liver resection in terms of minimally invasive surgery and can achieve a comparable prognosis and efficacy to liver resection. For borderline liver function, selecting LTA as the first-line therapy may bring more benefits to patients with cirrhosis background. In addition, a combination of multiple therapies for HCC is a good choice, such as LTA combined with transcatheter arterial chemoembolization (TACE), which can achieve a better prognosis than single therapy for larger tumors. For patients who are awaiting liver transplantation, LTA is a good choice. The main problem of LTA needed to be solved is to prevent the local tumor recurrence after ablation in patients with HCC.

Hepatocellular Carcinoma and the Role of Liver Transplantation: A Review

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths worldwide and liver transplantation (LT) is the only potentially curative treatment. Over the years, Milan criteria has been used for patient selection. There is ongoing research in this field with introduction of new biomarkers for HCC that can help guide future treatment. Furthermore, newer therapies for downstaging of the tumor are being implemented to prevent dropout from the transplant list. In addition, combination therapies for better outcome are under investigation. Interestingly, the concept of living-donor LT and possible use of hepatitis C virus-positive donors has been implemented as an attempt to expand the organ pool. However, there is a conflict of opinion between different centers regarding its efficacy and data is scarce. The aim of this review article is to outline the various selection criteria for LT, discuss the outcomes of LT in HCC patients, and explore future directions of LT for HCC. Therefore, a comprehensive PubMed/MEDLINE review was conducted. To expand our search, references of the retrieved articles were also screened for additional data. After selecting the studies, the authors independently reviewed them to identify the relevant studies. After careful evaluation 120 studies relevant to out topic are cited in the manuscript. Three tables and two figures are also included. In conclusion LT for HCC has evolved over the years. With the introduction of several expanded criteria beyond Milan, the introduction of bridging therapies, such as transcatheter arterial chemoembolization and radiofrequency ablation, and the approval of newer systemic therapies, it is evident that there will be more LT recipients in the future. It is promising to see ongoing trials and the continuous evolution of protocols. Prospective studies are needed to guide the development of a pre-LT criteria that can ensure low HCC recurrence risk and is not overly stringent, clarify the role of LDLT, and determine the optimal bridging therapies to LT.

Percutaneous microwave ablation versus radiofrequency ablation of hepatocellular carcinoma: a meta-analysis of randomized controlled trials

PURPOSE

Percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) are well-validated interventions for hepatocellular carcinoma (HCC). The purpose of this study was to compare their safety and efficacy through a meta-analysis of randomized controlled trials (RCT).

METHODS

MEDLINE, Pubmed, and the Cochrane Library were queried up to September 2020 using the terms "microwave", "radiofrequency", "hepatocellular", and "randomized". Only RCTs investigating MWA versus RFA for HCC were included. Baseline study characteristics, complete ablation rate, ablation time, overall survival, local recurrence, and complication rates were investigated.

RESULTS

Among the five original studies included, a total of 413 and 431 patients were treated with RFA and MWA, respectively. All studies focused on very early and early-stage HCC only (Barcelona Clinic Liver Cancer Stage 0 and A). No statistical significance was observed in terms of complete ablation rate (96.7 vs 96.9%, p = 0.882), overall survival (6 month: 95.7 vs 100%, p = 0.492; 1 year: 91.9 vs 94.1%, p = 0.264; 3 year: 77.5 vs 78.4%, p = 0.905), recurrence-free survival (6 month: 99.1 vs 99.7%, p = 0.717; 1 year: 94.6 vs 93.9%, p = 0.675; 3 year: 76.8 vs 77.1%, p = 0.935), and complication rates (p > 0.05 in all types). The mean ablation time of MWA was significantly shorter than RFA (26.9 vs 14.1 min, p < 0.001).

CONCLUSION

For very early and early-stage HCC, RFA and MWA are equally safe and effective, though the former is associated with a longer ablation time.