No-touch ablation in hepatocellular carcinoma has the potential to prevent intrasubsegmental recurrence to the same degree as surgical resection

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.

Magnetic resonance imaging for treatment response evaluation and prognostication of hepatocellular carcinoma after thermal ablation

Hepatocellular carcinoma (HCC) accounts for the vast majority of primary liver cancer and constitutes a major global health challenge. Tumor ablation with either radiofrequency ablation (RFA) or microwave ablation (MWA) is recommended as a curative-intent treatment for early-stage HCC. Given the widespread use of thermal ablation in routine clinical practice, accurate evaluation of treatment response and patient outcomes has become crucial in optimizing individualized management strategies. Noninvasive imaging occupies the central role in the routine management of patients with HCC. Magnetic resonance imaging (MRI) could provide full wealth of information with respect to tumor morphology, hemodynamics, function and metabolism. With accumulation of liver MR imaging data, radiomics analysis has been increasingly applied to capture tumor heterogeneity and provide prognostication by extracting high-throughput quantitative imaging features from digital medical images. Emerging evidence suggests the potential role of several qualitative, quantitative and radiomic MRI features in prediction of treatment response and patient prognosis after ablation of HCC. Understanding the advancements of MRI in the evaluation of ablated HCCs may facilitate optimal patient care and improved outcomes. This review provides an overview of the emerging role of MRI in treatment response evaluation and prognostication of HCC patients undergoing ablation. CLINICAL RELEVANCE STATEMENT: MRI-based parameters can help predict treatment response and patient prognosis after HCC ablation and thus guide treatment planning. KEY POINTS: 1. ECA-MRI provides morphological and hemodynamic assessment of ablated HCC. 2. EOB-MRI provides more information for tumor response prediction after ablation. 3. DWI improve the characterization of HCC and optimize treatment decision. 4. Radiomics analysis enables characterization of tumor heterogeneity guidance of clinical decision-making. 5. Further studies with multiple radiologists and sufficient follow-up period are needed.

Clinical feasibility of radiofrequency ablation using novel adjustable separable electrodes with a multipurpose needle for treating small hepatocellular carcinomas: a prospective single center study

BACKGROUND

The novel separable clustered electrode system with two adjustable active tips (ICAEs) and a fine multipurpose needle (MPN) for in situ temperature monitoring and adjuvant agent injection was developed and validated in an animal study. The purpose of this study was to evaluate the technical efficacy and complication of the novel electrode system for patients who have small HCC.

METHODS

In this prospective, single-center clinical trial, ten participants with 14 small (≤ 2 cm, BCLC 0-A) HCCs referred for RFA were enrolled. A novel electrode system consisting of two ICAEs and one MPN with a thermometer and side holes was used for RFA. The RF energy was delivered using a multichannel RF system combining bipolar and switching monopolar modes. Technical success, efficacy, and complications were evaluated on immediate and one-month follow-up CT.

RESULTS

Technical success was achieved in 92.9% (13/14) of tumors. One participant withdrew consent after RFA, and technical efficacy was achieved in 91.7% (11/12) of tumors. None showed thermal injury to nontarget organs. All patients were discharged the day after RFA without major complications. The active electrode lengths were adjusted in 60% (6/10) of patients during the procedure to tailor the ablation zone (83.3%, n = 5) or treat two tumors with different sizes (16.7%, n = 1). MPN was capable of continuous temperature monitoring during all ablations (100%, 14/14).

CONCLUSIONS

RFA using a novel electrode system showed acceptable technical efficacy and safety in patients with small HCCs. Further comparative studies are needed for the investigation of the system's potential benefits compared to conventional electrodes.

Efficacy and safety of no-touch radiofrequency ablation for small hepatocellular carcinoma-a systematic review and single-arm meta-analysis

OBJECTIVE

The purpose of this study was to report the efficacy and safety of no-touch radiofrequency ablation (NT-RFA) in the treatment of small hepatocellular carcinoma (HCC).

METHODS

We systematically searched for eligible studies in PubMed, Embase and Cochrane library until June 1, 2022. Random effect model was applied to synthesize the pooled proportions of local tumor progression-free survival (LTP), recurrence-free survival (RFS) and overall survival (OS) respectively, as well as adverse events, for small HCC treated by NT-RFA.

RESULTS

Of the 10 included studies, 3 of them reported local tumor recurrence. One reported local tumor recurrence at 19 months (range, 12-24), and 2 studies had no tumor recurrence with 24-months of follow-up. The 1- and 2-year LTP pooled proportions were 99.3% (95%CI, 97.5-100) and 97.8% (95%CI, 94.6-99.6) respectively, and two studies reported a 3-year LTP rate of 96.4% (204/212, 36/37). The 1-yearRFS rates was 91.3% (95%CI, 84.1-98.4), 2-year was 86.4% (95%CI, 75.3-97.5). The 1-, 2- and 3- year OS rates were 92.4% (95%CI, 82.8-92.7), 84.1% (95%CI, 74.7-93.6) and 81.8% (116/181, 33/36) respectively, and only one study reported a 5-year OS rate of 47.0% (85/181). The ablative success rate of the HCC nodules was 96.6% (95%CI, 91.3-99.5) and the proportions of mild and severe adverse events following ablation were 18.3% (95%CI, 8.1-41.6) and 5.0%, respectively.

CONCLUSION

NT-RFA provides safely very high rate of sustained local control for the treatment of HCC up to 5 cm.

Imaging and histological features of tumor biopsy sample predict aggressive intrasegmental recurrence of hepatocellular carcinoma after radiofrequency ablation

Aggressive intrasegmental recurrence (AIR) is a form of local recurrence associated with a dismal prognosis and defined by multiple nodules or by an infiltrative mass with a tumor thrombus, occurring in the treated segment, after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC). We aimed to identify radiological and/or histological characteristics of tumor biopsy predictive of AIR. We retrospectively analyzed patients treated by No-Touch multi-bipolar RFA (mbpRFA) for a first HCC with a systematic per-procedural tumor biopsy positive for diagnosis of HCC. The first recurrence was classified as non-aggressive local recurrence, AIR or intrahepatic distant recurrence. 212 patients were included (168 men; mean age 67.1 years; mean tumor size 28.6 mm, 181 cirrhosis). AIR occurred in 21/212 patients (10%) and was associated with a higher risk of death (57% in patients with AIR vs 30% without AIR, p = 0.0001). Non-smooth tumor margins, observed in 21% of the patients and macro-trabecular massive histological subtype, observed in 12% of the patients were independently related to a higher risk of AIR (HR: 3.7[1.57;9.06], p = 0.002 and HR:3.8[2.47;10], p = 0.005 respectively). Non smooth margins at imaging and macro-trabecular massive histological subtype are associated with AIR and could be considered as aggressive features useful to stratify therapeutic strategy.

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.

The impact of background liver disease on the long-term prognosis of very-early-stage HCC after ablation therapy

Background and aim

The long-term prognosis of hepatocellular carcinoma (HCC) treated at a very-early-stage (the Barcelona Clinical Liver Cancer (BCLC) classification stage 0) was unclear, especially in terms of background liver disease.

Methods

This single-center, retrospective study included 302 patients with BCLC stage 0 HCC treated with radiofrequency ablation (RFA) and followed for at least six months. We examined the impact of background liver disease on overall survival and recurrence.

Results

The median age was 72 (range; 36–91) years; the median tumor diameter was 15 (range; 8–20) mm. The etiologies of background liver disease were hepatitis B virus infection (HBV) in 24 cases, hepatitis C virus infection (HCV) in 195 cases, and non-viral (NBNC) in 83 cases. Among the patients with HCV, 63 had achieved sustained virological response (SVR) by antiviral therapy (HCV SVR) before developing HCC (n = 37) or after HCC treatment (n = 26), and 132 had active HCV infection (HCV non-SVR). The median overall survival was 85 (95% CI; 72–98) months, and the median recurrence-free survival was 26 (95% CI; 20–30) months. Active infection with hepatitis C virus negatively contributed to overall survival (HR 2.91, 95% CI 1.31–3.60, p = 0.003) and recurrence-free survival (HR 1.47, 95% CI 1.06–2.05, p = 0.011).

Conclusions

The prognosis of RFA treatment for very early-stage HCC was favorable. Achieving SVR in hepatitis C was important for further prognosis improvement.

Unidirectional ablation minimizes unwanted thermal damage and promotes better thermal ablation efficacy in time-based switching bipolar radiofrequency ablation

Switching bipolar radiofrequency ablation (bRFA) is a thermal treatment modality used for liver cancer treatment that is capable of producing larger, more confluent and more regular thermal coagulation. When implemented in the no-touch mode, switching bRFA can prevent tumour track seeding; a medical phenomenon defined by the deposition of cancer cells along the insertion track. Nevertheless, the no-touch mode was found to yield significant unwanted thermal damage as a result of the electrodes' position outside the tumour. It is postulated that the unwanted thermal damage can be minimized if ablation can be directed such that it focuses only within the tumour domain. As it turns out, this can be achieved by partially insulating the active tip of the RF electrodes such that electric current flows in and out of the tissue only through the non-insulated section of the electrode. This concept is known as unidirectional ablation and has been shown to produce the desired effect in monopolar RFA. In this paper, computational models based on a well-established mathematical framework for modelling RFA was developed to investigate if unidirectional ablation can minimize unwanted thermal damage during time-based switching bRFA. From the numerical results, unidirectional ablation was shown to produce treatment efficacy of nearly 100%, while at the same time, minimizing the amount of unwanted thermal damage. Nevertheless, this effect was observed only when the switch interval of the time-based protocol was set to 50 s. An extended switch interval negated the benefits of unidirectional ablation.

Outcome of No-Touch Radiofrequency Ablation for Small Hepatocellular Carcinoma: A Multicenter Clinical Trial

Background Recently introduced no-touch radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) has the potential to improve local tumor control. Purpose To evaluate midterm clinical outcomes of monopolar no-touch RFA in single HCCs 2.5 cm or smaller. Materials and Methods In this multicenter clinical trial (ClinicalTrials.gov: NCT03375281), participants were evaluated for eligibility from November 2017 to January 2019. Patients with single HCCs 2.5 cm or smaller planning to be treated with no-touch RFA were enrolled. The rate of successful no-touch RFA, defined as performing RFA without violation of the tumor itself, was recorded. Multivariable logistic regression analysis was used to determine associated factors for failure of no-touch RFA. Development of major complication after no-touch RFA was also recorded. Cumulative incidence of local tumor progression (LTP) and recurrence-free survival were estimated by using the Kaplan-Meier method. Results A total of 140 participants (mean age, 62 years ± 9 [standard deviation]; 106 men) were evaluated. No-touch RFA was successfully performed in 128 participants (128 of 140; 91.4%), and conversion to tumor puncture RFA was undertaken in 12 participants because of the lack of a safe access route. By using either no-touch RFA or conversion to tumor puncture RFA, all participants achieved technical success of RFA, which was defined as complete coverage of target tumor by ablation zone. Insufficient peritumoral parenchyma (<5 mm width around more than half portion of tumor; odds ratio, 74; 95% CI: 18, 309; P < .001) was the only significant predictive factor for failure of the no-touch technique. Among the 140 participants, LTP developed in two participants, and the estimated 1- and 2-year cumulative incidence of LTP was 0.7% and 1.6%, respectively. The estimated 1- and 2-year recurrence-free survival was 82.8% and 74.1%, respectively. Conclusion No-touch radiofrequency ablation was an effective and safe treatment method for small hepatocellular carcinomas (≤2.5 cm), with 1.6% of cumulative incidence of local tumor progression at 2 years. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Soulen and García-Mónaco in this issue.

Perivascular vital cells in the ablation center after multibipolar radiofrequency ablation in an in vivo porcine model

Multibipolar radiofrequency ablation (RFA) is an advanced ablation technique for early stage hepatocellular carcinoma and liver metastases. Vessel cooling in multibipolar RFA has not been systematically investigated. The objective of this study was to evaluate the presence of perivascular vital cells within the ablation zone after multibipolar RFA. Multibipolar RFA were performed in domestic pigs in vivo. Three internally cooled bipolar RFA applicators were used simultaneously. Three experimental settings were planned: (1) inter-applicator-distance: 15 mm; (2) inter-applicator-distance: 20 mm; (3) inter-applicator-distance: 20 mm with hepatic inflow occlusion (Pringle maneuver). A vitality staining was used to analyze liver cell vitality around all vessels in the ablation center with a diameter > 0.5 mm histologically. 771 vessels were identified. No vital tissue was seen around 423 out of 429 vessels (98.6%) situated within the central white zone. Vital cells could be observed around major hepatic vessels situated adjacent to the ablation center. Vessel diameter (> 3.0 mm; p < 0.05) and low vessel-to-ablation-center distance (< 0.2 mm; p < 0.05) were identified as risk factors for incomplete ablation adjacent to hepatic vessels. The vast majority of vessels, which were localized in the clinically relevant white zone, showed no vital perivascular cells, regardless of vessel diameter and vessel type. However, there was a risk of incomplete ablation around major hepatic vessels situated directly within the ablation center. A Pringle maneuver could avoid incomplete ablations.

The Short-Term Efficacy of Novel No-Touch Combined Directional Perfusion Radiofrequency Ablation in the Treatment of Small Hepatocellular Carcinoma with Cirrhosis

BACKGROUND

No-touch combined directed perfusion radiofrequency ablation (NTDP-RFA) is a new technique for the treatment of hepatocellular carcinoma (HCC). The purpose of this study was to evaluate the short-term efficacy of this new technique for the treatment of small HCC with cirrhosis.

METHODS

From January 2017 to March 2018, 56 consecutive patients treated with NTDP-RFA at our center were enrolled in this retrospective study. All NTDP-RFA procedures involved the use of internally cooled wet electrodes with a directional injection function, which can perform both intraelectrode cooling and extraelectrode saline perfusion. Survival curves were analyzed using Kaplan-Meier methods, and Cox proportional hazards regression analyses were used to assess predictors of tumor progression and overall survival. Operative characteristics and complications were also assessed.

RESULTS

No technical failure occurred, and the complete ablation rate after single NTDP-RFA treatment was 98.2%. The median tumor diameter and ablation time were 26 (18.0 - 28.0) mm and 8 (6 - 8) min, respectively. Mild complications occurred in five patients (8.9%) postoperatively, and the median hospital stay was 4 (4 - 5) days. In the 18 patients (32.1%) with poor liver function reserve (indocyanine green retention rate at 15 min > 15%, their liver function returned to normal on the third day after the postoperation. The 1- and 2-year local and distant progression rates were 1.7%, 7.1%, 3.5% and 10.7%, respectively.

CONCLUSIONS

NTDP-RFA in the treatment of small HCC with cirrhosis has a low incidence of complications and provides a high survival rate without local tumor progression.

Comparisons between impedance-based and time-based switching bipolar radiofrequency ablation for the treatment of liver cancer

Switching bipolar radiofrequency ablation (bRFA) is a cancer treatment technique that activates multiple pairs of electrodes alternately based on a predefined criterion. Various criteria can be used to trigger the switch, such as time (ablation duration) and tissue impedance. In a recent study on time-based switching bRFA, it was determined that a shorter switch interval could produce better treatment outcome than when a longer switch interval was used, which reduces tissue charring and roll-off induced cooling. In this study, it was hypothesized that a more efficacious bRFA treatment can be attained by employing impedance-based switching. This is because ablation per pair can be maximized since there will be no interruption to RF energy delivery until roll-off occurs. This was investigated using a two-compartment 3D computational model. Results showed that impedance-based switching bRFA outperformed time-based switching when the switch interval of the latter is 100 s or higher. When compared to the time-based switching with switch interval of 50 s, the impedance-based model is inferior. It remains to be investigated whether the impedance-based protocol is better than the time-based protocol for a switch interval of 50 s due to the inverse relationship between ablation and treatment efficacies. It was suggested that the choice of impedance-based or time-based switching could ultimately be patient-dependent.

Bipolar radiofrequency ablation treatment of liver cancer employing monopolar needles: A comprehensive investigation on the efficacy of time-based switching

Radiofrequency ablation (RFA) is a thermal ablative treatment method that is commonly used to treat liver cancer. However, the thermal coagulation zone generated using the conventional RFA system can only successfully treat tumours up to 3 cm in diameter. Switching bipolar RFA has been proposed as a way to increase the thermal coagulation zone. Presently, the understanding of the underlying thermal processes that takes place during switching bipolar RFA remains limited. Hence, the objective of this study is to provide a comprehensive understanding on the thermal ablative effects of time-based switching bipolar RFA on liver tissue. Five switch intervals, namely 50, 100, 150, 200 and 300 s were investigated using a two-compartment 3D finite element model. The study was performed using two pairs of RF electrodes in a four-probe configuration, where the electrodes were alternated based on their respective switch interval. The physics employed in the present study were verified against experimental data from the literature. Results obtained show that using a shorter switch interval can improve the homogeneity of temperature distribution within the tissue and increase the rate of temperature rise by delaying the occurrence of roll-off. The coagulation volume obtained was the largest using switch interval of 50 s, followed by 100, 150, 200 and 300 s. The present study demonstrated that the transient thermal response of switching bipolar RFA can be improved by using shorter switch intervals.

Switching Monopolar No-Touch Radiofrequency Ablation Using Octopus Electrodes for Small Hepatocellular Carcinoma: A Randomized Clinical Trial

INTRODUCTION

A switching monopolar no-touch radiofrequency ablation (RFA) technique is used for small hepatocellular carcinoma (HCC); however, there have not been any randomized clinical trials comparing this technique to the conventional RFA technique.

OBJECTIVE

This study aims to compare the results of two RFA techniques, and to comparatively identify more effective methods to reduce the progression of local tumors associated with small HCC (≤2.5 cm).

METHODS

This prospective randomized clinical trial (NCT03375281) recruited a total of 116 participants (M:F, 93:23; 68.3 ± 8.4 years) between October 2016 and September 2017. The primary outcome was the cumulative incidence of local tumor progression (LTP) after RFA. Secondary outcomes included technical success rate, technique efficacy, and RFA procedure characteristics. Kaplan-Meier analysis and the Cox proportional hazard regression model were used.

RESULTS

The mean follow-up period was 24.1 months. A sufficient ablative margin was more frequently achieved in the no-touch RFA group (57/60 = 95%) than in the conventional RFA group (50/64 = 78.1%) on immediate follow-up CT (p = 0.01). The cumulative incidence of LTP in the no-touch RFA group was significantly lower than that in the conventional RFA group (p = 0.02). In multivariable analysis, no-touch RFA was the only predictive factor for LTP (p = 0.04, hazard ratio = 0.2, 95% confidence interval = 0.04-0.94).

CONCLUSIONS

A switching monopolar no-touch RFA technique is a favorable treatment option and provides lower LTP after RFA compared with conventional RFA for small HCC.

Direct-acting antivirals improve survival and recurrence rates after treatment of hepatocellular carcinoma within the Milan criteria

BACKGROUND

The effects of direct-acting antivirals (DAAs) on survival and recurrence rates after curative hepatocellular carcinoma (HCC) treatment in patients with hepatitis C virus (HCV) infection remain controversial.

METHODS

This retrospective, multicenter study involved Child-Pugh class A patients within the Milan criteria who had a first diagnosis of HCC and survived 6 months or longer after undergoing hepatectomy or radiofrequency ablation (RFA). The DAA-treated group (DAA group) included 56 patients, and the DAA-untreated group (untreated group) included 261 patients. The study was conducted using the propensity score-matched (1:2) DAA group and untreated group, 56 and 112 patients, respectively.

RESULTS

The survival rate at 48 months in the DAA group and the untreated group was 91.0% and 68.7%, respectively, showing significantly better survival in the DAA group (HR: 0.33; 95% CI 0.13-0.84; p = 0.021). The recurrence rate at 48 months was 36.7% and 66.7%, respectively, showing a significantly lower recurrence rate in the DAA group (HR, 0.46; 95% CI 0.27-0.77; p = 0.003). The median albumin-bilirubin (ALBI) score at 3 years post-HCC treatment was - 2.84 in the DAA group and - 2.34 in the untreated group. The ALBI score showed a significant improvement from baseline to 3 years post-HCC treatment (p = 0.001), whereas that in the untreated group showed a significant decline (p = 0.040).

CONCLUSIONS

DAAs after HCC treatment prevents deterioration of hepatic functional reserve and significantly improves both recurrence and survival rates.

Radiofrequency ablation with four electrodes as a building block for matrix radiofrequency ablation: Ex vivo liver experiments and finite element method modelling. Influence of electric and activation mode on coagulation size and geometry

PURPOSE

Radiofrequency ablation (RFA) is increasingly being used to treat unresectable liver tumors. Complete ablation of the tumor and a safety margin is necessary to prevent local recurrence. With current electrodes, size and shape of the ablation zone are highly variable leading to unsatisfactory local recurrence rates, especially for tumors >3 cm. In order to improve predictability, we recently developed a system with four simple electrodes with complete ablation in between the electrodes. This rather small but reliable ablation zone is considered as a building block for matrix radiofrequency ablation (MRFA). In the current study we explored the influence of the electric mode (monopolar or bipolar) and the activation mode (consecutive, simultaneous or switching) on the size and geometry of the ablation zone.

MATERIALS AND METHODS

The four electrode system was applied in ex vivo bovine liver. The electric and the activation mode were changed one by one, using constant power of 50 W in all experiments. Size and geometry of the ablation zone were measured. Finite element method (FEM) modelling of the experiment was performed.

RESULTS

In ex vivo liver, a complete and predictable coagulation zone of a 3 × 2 × 2 cm block was obtained most efficiently in the bipolar simultaneous mode due to the combination of the higher heating efficacy of the bipolar mode and the lower impedance by the simultaneous activation of four electrodes, as supported by the FEM simulation.

CONCLUSIONS

In ex vivo liver, the four electrode system used in a bipolar simultaneous mode offers the best perspectives as building block for MRFA. These results should be confirmed by in vivo experiments.

Intraprocedural computed tomography/magnetic resonance-contrast-enhanced ultrasound fusion imaging improved thermal ablation effect of hepatocellular carcinoma: Comparison with conventional ultrasound

AIM

To retrospectively compare the treatment effect of intraprocedural computed tomography/magnetic resonance-contrast-enhanced ultrasound (CT/MR-CEUS) fusion imaging (FI) with that of conventional ultrasound (US) in the guidance and assessment of thermal ablation of hepatocellular carcinoma (HCC).

METHODS

The FI group (112 patients with 129 HCC) was treated between April 2010 and December 2012, whereas the US group (83 patients with 90 HCC) was treated between January 2008 and March 2010. Either CT/MR-CEUS FI or US was used to guide puncture, provide immediate assessment, and guide supplementary ablation. Technical efficacy, cumulative local tumor progression rate (LTP), recurrence-free survival (RFS), and overall survival (OS) were evaluated and compared during follow-up. Technical success rate of CT/MR-CEUS FI was also recorded.

RESULTS

Technical efficacy was significantly higher in the FI group than in the US group (100% vs. 86.7%, P < 0.001). The 1-, 2-, 3-, 4-, 5-, and 6-year cumulative LTP rates in the FI group were significantly lower than in the US group (3.8%, 4.9%, 6.0%, 6.0%, 7.2%, and 7.2% vs. 16.9%, 20.1%, 25%, 25%, 25%, and 25%, respectively; P < 0.001); RFS and OS were significantly higher in the FI group than in the US group (P = 0.027 and P = 0.049, respectively). The technical success rate of FI was 85.3%.

CONCLUSIONS

Intraprocedural CT/MR-CEUS FI improved the treatment effect of thermal ablation of HCC by immediately assessing treatment response and guiding supplementary ablation relative to those resulting from the use of conventional US.

Effect of Sodium Glucose Co-Transporter 2 Inhibitors on Liver Fat Mass and Body Composition in Patients with Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus

BACKGROUND AND OBJECTIVE

Sodium glucose co-transporter 2 inhibitors increase urinary glucose excretion and reduce visceral adiposity and body weight, but their efficacy on patients with nonalcoholic fatty liver disease has not been sufficiently investigated. The aim of this study was to assess the effect of sodium glucose co-transporter 2 inhibitors on liver fat mass and body composition in patients with nonalcoholic fatty liver disease and type 2 diabetes mellitus.

METHODS

We retrospectively analyzed 17 patients with nonalcoholic fatty liver disease and type 2 diabetes who received sodium glucose co-transporter 2 inhibitors between November 2016 and July 2017. Changes in liver fat, subcutaneous and visceral fat, body composition, and liver function-related parameters were assessed after 24 weeks of sodium glucose co-transporter 2 inhibitor treatment and compared to baseline values.

RESULTS

Ten patients received dapagliflozin at 5 mg/day and seven patients received canagliflozin at 100 mg/day for 24 weeks. All patients completed the study without any serious adverse effects and achieved body weight loss and improved glycated hemoglobin levels. Liver fat mass evaluated by proton magnetic resonance spectroscopy was significantly reduced (19.1% vs. 9.2%, p < 0.01), and so were both subcutaneous and visceral fat mass. The body fat/body weight ratio decreased, whereas the skeletal muscle mass/body weight ratio increased. Liver function (aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transpeptidase) improved significantly.

CONCLUSIONS

Sodium glucose co-transporter 2 inhibitor treatment not only improved glycemic control but also reduced liver fat mass in patients with nonalcoholic fatty liver disease and type 2 diabetes. Body weight loss was primarily attributable to a reduction in fat mass, especially visceral fat. Thus, sodium glucose co-transporter 2 inhibitors could potentially serve as a therapeutic agent for patients with nonalcoholic fatty liver disease and type 2 diabetes.