Histopathologic comparison of monopolar versus no-touch multipolar radiofrequency ablation to treat hepatocellular carcinoma within Milan criteria

Incidence and clinical impact of bile ducts changes after multibipolar radiofrequency ablation for hepatocellular carcinoma

OBJECTIVES

This study aimed to evaluate the incidence and clinical implications of bile duct changes following multibipolar radiofrequency ablation (mbpRFA) for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Radiological, clinical, and biological data from consecutive cirrhotic patients who underwent first-line mbpRFA between 2007 and 2014 for uninodular HCC ≤ 5 cm were retrospectively collected. Follow-up imaging was reviewed to identify bile duct changes and factors associated with biliary changes were assessed using multivariable analysis. Baseline and 6-month liver function tests were compared in patients with and without bile duct changes. Complications, cirrhosis decompensation, and survival rates were compared in both groups.

RESULTS

A total of 231 patients (mean age 68 years [39-85], 187 men) underwent 266 mbpRFA sessions for uninodular HCC (mean size 26 mm). Of these, 76 (33%) developed bile duct changes (upstream bile duct dilatations and/or bilomas) with a mean onset time of 3 months. Identified risk factors for these changes were the infiltrative aspect of the tumor (p = 0.035) and its location in segment VIII (p < 0.01). The average increase in bilirubin at 6 months was higher in the group with biliary changes (+2.9 vs. +0.4 µg/mL; p = 0.03). There were no significant differences in terms of complications, cirrhosis decompensation at 1 year (p = 0.95), local and distant tumor progression (p = 0.91 and 0.14 respectively), and overall survival (p = 0.4) between the two groups.

CONCLUSION

Bile duct changes are common after mbpRFA for HCC, especially in tumors with an infiltrative aspect or those located in segment VIII. These changes do not appear to negatively impact the course of cirrhosis at 1 year or overall survival.

CLINICAL RELEVANCE STATEMENT

Bile duct changes following mbpRFA for HCC are relatively common. Nevertheless, they do not raise clinical concerns in terms of complications, deterioration in liver function, or survival rates. Consequently, specific monitoring or interventions for these bile duct changes are not warranted.

KEY POINTS

• Bile duct changes are frequently observed after multibipolar radiofrequency ablation for hepatocellular carcinoma, occurring in 33% of cases in our study. • Patients with bile duct changes exhibited a higher increase in bilirubin levels at 6 months but no more cirrhosis decompensation or liver abscesses. • Biliary changes following multibipolar radiofrequency ablation for hepatocellular carcinoma are not alarming and do not necessitate any specific monitoring or intervention.

Quantitative dual-energy computed tomography with cesium as a novel contrast agent for localization of thermochemical ablation in phantoms and ex vivo models

BACKGROUND

Thermochemical ablation (TCA) is a minimally invasive therapy under development for hepatocellular carcinoma. TCA simultaneously delivers an acid (acetic acid, AcOH) and base (sodium hydroxide, NaOH) directly into the tumor, where the acid/base chemical reaction produces an exotherm that induces local ablation. However, AcOH and NaOH are not radiopaque, making monitoring TCA delivery difficult.

PURPOSE

We address the issue of image guidance for TCA by utilizing cesium hydroxide (CsOH) as a novel theranostic component of TCA that is detectable and quantifiable with dual-energy CT (DECT).

MATERIALS AND METHODS

To quantify the minimum concentration of CsOH that can be positively identified by DECT, the limit of detection (LOD) was established in an elliptical phantom (Multi-Energy CT Quality Assurance Phantom, Kyoto Kagaku, Kyoto, Japan) with two DECT technologies: a dual-source system (SOMATOM Force, Siemens Healthineers, Forchheim, Germany) and a split-filter, single-source system (SOMATOM Edge, Siemens Healthineers). The dual-energy ratio (DER) and LOD of CsOH were determined for each system. Cesium concentration quantification accuracy was evaluated in a gelatin phantom before quantitative mapping was performed in ex vivo models.

RESULTS

On the dual-source system, the DER and LOD were 2.94 and 1.36-mM CsOH, respectively. For the split-filter system, the DER and LOD were 1.41- and 6.11-mM CsOH, respectively. The signal on cesium maps in phantoms tracked linearly with concentration (R2  = 0.99) on both systems with an RMSE of 2.56 and 6.72 on the dual-source and split-filter system, respectively. In ex vivo models, CsOH was detected following delivery of TCA at all concentrations.

CONCLUSIONS

DECT can be used to detect and quantify the concentration of cesium in phantom and ex vivo tissue models. When incorporated in TCA, CsOH performs as a theranostic agent for quantitative DECT image-guidance.

Conversion of the bronchial tree into a conforming electrode to ablate the lung nodule in a porcine model

BACKGROUND

Radiofrequency ablation (RFA) is one of the treatment options for lung nodules. However, the need for exact delivery of the rigid metal electrode into the center of the target mass often leads to complications or suboptimal results. To overcome these limitations, a concept of conforming electrodes using a flexible material has been tested in this study.

METHODS

A bronchoscopy-guided RFA (CAROL) under a temperature-controlled mode was tested in in-vivo and ex-vivo porcine lungs. Gallium-based liquid metal was used for turning the bronchial tree into temporary RF electrodes. A customized bronchoscopy-guided balloon-tipped guiding catheter (CAROL catheter) was used to make the procedure feasible under fluoroscopy imaging guidance. The computer simulation was also performed to gain further insight into the ablation results. Safety was also assessed including the liquid metal remaining in the body.

RESULTS

The bronchial electrode injected from the CAROL catheter was able to turn the target site bronchial air pipe into a temporally multi-tined RF electrode. The mean volume of Gallium for each effective CAROL was 0.46 ± 0.47 ml. The ablation results showed highly efficacious and consistent results, especially in the peripheral lung. Most bronchial electrodes were also retrieved by either bronchoscopic suction immediately after the procedure or by natural expectoration thereafter. The liquid metal used in these experiments did not have any significant safety issues. Computer simulation also supports these results.

CONCLUSION

The CAROL ablation was very effective and safe in porcine lungs showing encouraging potential to overcome the conventional approaches.

No-Touch Radiofrequency Ablation for Early Hepatocellular Carcinoma: 2023 Korean Society of Image-Guided Tumor Ablation Guidelines

Radiofrequency ablation (RFA) has been widely used to manage hepatocellular carcinomas (HCCs) equal to or smaller than 3 cm. No-touch RFA has gained attention and has recently been implemented in local ablation therapy for HCCs, despite its technical complexity, as it provides improved local tumor control compared to conventional tumor-puncturing RFA. This article presents the practice guidelines for performing no-touch RFA for HCCs, which have been endorsed by the Korean Society of Image-Guided Tumor Ablation (KSITA). The guidelines are primarily designed to assist interventional oncologists and address the limitations of conventional tumor-puncturing RFA with describing the fundamental principles, various energy delivery methods, and clinical outcomes of no-touch RFA. The clinical outcomes include technical feasibility, local tumor progression rates, survival outcomes, and potential complications.

Radiofrequency ablation of hepatocellular carcinoma: Current status, challenges, and prospects

Local ablation technologies, such as radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation, have become a standard treatment option for hepatocellular carcinoma (HCC) less than 5 cm in size, particularly in individuals who are not candidates for hepatectomy. Except for equivalent prognosis and efficiency, RFA has various advantages over surgical excision, including a lower rate of complications, a cheaper cost, more normal tissue preservation, and a shorter hospital stay. However, the rate of tumor recurrence and/or distant metastasis after RFA therapy is still high. RFA has been widely employed in multiple cancers, large cancer, and lesion identified at "high-risk" sites in recent years, with the advancement of ablation types and operating techniques, particularly the combined use of many technologies. The real value of RFA technology has been more fully reflected. We will examine the status, progress, and problems of RFA in the treatment of HCC in this review.

Outcomes of laparoscopic radiofrequency ablation versus percutaneous radiofrequency ablation for hepatocellular carcinoma

BACKGROUND

Few studies have compared the therapeutic outcomes in patients with HCC who underwent laparoscopic radiofrequency ablation (LRFA) versus percutaneous radiofrequency ablation (PRFA) for hepatocellular carcinoma (HCC). Therefore, this study compared the recurrence and survival outcomes of the two RFA methods in patients with HCC.

METHODS

Recurrence and overall survival outcomes were evaluated in 307 patients who underwent LRFA (n = 151) or PRFA (n = 156) as a treatment method for de novo HCC. Inverse probability of treatment weighting (IPTW) analysis was performed to reduce the impact of treatment selection bias.

RESULTS

There were no significant differences in major baseline characteristics between the LRFA and PRFA groups. However, the proportion of cirrhotic patients was higher in the LRFA group, whereas the LRFA group had more tumors and a more advanced tumor-node-metastasis stage. Moreover, the mean tumor size was significantly larger in the LRFA group than in the PRFA group. In a multivariate analysis, serum albumin level, more than three tumors, and the RFA method were identified as significant predictors of recurrence-free survival. Moreover, for the overall survival of HCC patients, serum albumin levels, days of hospital stay during RFA, and the RFA method were independent predictors. In the IPTW-adjusted analysis, the LRFA group showed significantly higher recurrence-free survival and overall survival.

CONCLUSIONS

Our study revealed that compared with PRFA, LRFA was associated with longer recurrence-free survival and favorable overall survival in patients with HCC. Therefore, LRFA should be considered the primary therapy in patients with HCC eligible for RFA.

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.

Long‐term efficacy of no‐touch radiofrequency ablation in the treatment of single small hepatocellular carcinoma: A single center long‐term follow‐up study

OBJECTIVE

To evaluate the long-term efficacy of no-touch radiofrequency ablation (NT-RFA) for treating single hepatocellular carcinoma (HCC) less than 3 cm.

METHODS

A total of 331 patients with HCC less than 3 cm undergoing RFA in Southwest Hospital from 2015 to 2020 were analyzed retrospectively. All patients were divided into NT-RFA group (n = 113) and conventional RFA (C-RFA) group (n = 218). The survival rate, local tumor progression (LTP) and intrahepatic distant recurrence (IDR) of the two groups were calculated and compared.

RESULTS

A significant difference was observed in ablation range (p = 0.000) and safety margin (p = 0.000) between the two groups. The 1-, 2-, 3-, 4-and 5-year overall survival (OS) rates in NT-RFA and C-RFA group were 99.12%, 93.73%, 76.18%, 57.00%, 45.17% and 99.08%, 89.91%, 71.26%, 54.28%, 41.77%, respectively. There was no significant difference between the two groups (p = 0.281). The 1-, 2-, 3-, 4-and 5-year recurrence-free survival (RFS) rates in NT-RFA and C-RFA group were 78.51%, 52.59%, 41.02%, 34.36%, 30.92% and 68.81%, 44.95%, 30.88%, 23.73%, 22.88%, respectively. The two groups differed significantly (p = 0.044). The 1-, 3-and 5-year LTP-free survival rates in NT-RFA and C-RFA group were 87.12%, 74.99%, 72.32% and 75.75%, 65.52%, 65.52%, respectively. The two groups also differed significantly (p = 0.024). Furthermore, the RFS rates of D ≤ 2 cm subgroups in NT-RFA and C-RFA groups differed significantly (p = 0.037), while the RFS rates of 2 cm < D ≤ 3 cm subgroups in two groups showed no significant difference (p = 0.578).

CONCLUSIONS

The RFS rates of single HCC less than 3 cm treated by NT-RFA was significantly higher than that of C-RFA. Due to a larger ablation range and safety margin, NT-RFA could significantly reduce LTP and improve RFS. Dual-electrode NT-RFA can significantly improve the RFS rate of patients with HCC less than 2 cm, but there is no obvious advantage compared with C-RFA in the treatment of HCC over 2 cm.

Can "no-touch" radiofrequency ablation for hepatocellular carcinoma improve local tumor control? Systematic review and meta-analysis

OBJECTIVES

Percutaneous radiofrequency ablation (RFA) is one of the curative treatments for hepatocellular carcinoma (HCC), but local tumor progression (LTP) has been a main limitation of RFA. This study aims to evaluate the LTP of percutaneous no-touch RFA (NtRFA) for HCC ≤ 5 cm and compare with conventional RFA (intratumoral puncture) through a systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE, and Cochrane Library were searched for studies on percutaneous NtRFA for HCC ≤ 5 cm. The pooled proportions of the overall and cumulative incidence rates at 1, 2, and 3 years for LTP after NtRFA were assessed using a random-effects model. For studies comparing NtRFA with conventional RFA, relative risks (RR) and hazard ratios (HR) were meta-analytically pooled with LTP as the outcome.

RESULTS

Twelve studies with 900 patients were included. The pooled overall rate of LTP after NtRFA was 6% (95% CI, 4-8%). The pooled 1-, 2-, and 3-year cumulative incidence rates of LTP were 3% (95% CI, 2-5%), 5% (95% CI, 3- 9%), and 8% (95% CI, 6-11%), respectively. Compared to conventional RFA, the pooled RR and HR of LTP were 0.26 (95% CI, 0.16-0.41) and 0.28 (95% CI, 0.11-0.70), respectively (both p < 0.01). Subgroup analysis including only randomized controlled studies also showed better local tumor control of NtRFA with HR of 0.13 (95% CI, 0.14-0.42).

CONCLUSIONS

Percutaneous NtRFA is an effective treatment for HCC ≤ 5 cm with an overall LTP rate of 6% and provides lower LTP compared with conventional RFA.

KEY POINTS

• The pooled 1-, 2-, and 3-year cumulative incidence rates of local tumor progression after no-touch radiofrequency ablation for HCC ≤ 5 cm were 3% (95% CI, 2-5%), 5% (95% CI, 3-9%), and 8% (95% CI, 6-11%). • No-touch radiofrequency ablation had significantly lower rates of local tumor progression compared to conventional radiofrequency ablation (hazard ratio, 0.28; 95% CI, 0.11-0.70; relative risk, 0.26; 95% CI, 0.16-0.41; p < 0.01, respectively).

Advances in the interventional therapy of hepatocellular carcinoma originating from the caudate lobe

Hepatocellular carcinoma originating from the caudate lobe, also known as segment I hepatocellular carcinoma, is difficult to treat because of its special location, complex vascular supply, and the proximity of important vessels, bile ducts, and organs. This research is conducted to examine the efficacy and safety of interventional therapy for hepatocellular carcinoma in the caudate lobe.

Conclusion

Superselective chemoembolization and ablation techniques for the treatment of caudate lobe hepatocellular carcinoma still need to be improved. The combination of multiple interventional methods and the application of multiple imaging techniques can improve the effectiveness and safety of interventional therapy for hepatocellular carcinoma in the caudate lobe. Multidisciplinary treatment is also essential to improve the prognosis of patients with caudate lobe hepatocellular carcinoma.

•

The anatomical characteristics of the arteries in the caudate lobe hepatocellular carcinoma remains an important factor restricting the success rate of superselective transcatheter arterial chemoembolization.

•

The application of multiple imaging techniques may improve the effectiveness and safety of interventional therapy.

•

The combination of multiple interventional methods has more advantages than disadvantages.

•

Multidisciplinary treatment is increasingly becoming a trend in the treatment of caudate lobe hepatocellular carcinoma.

Ablative Outcomes of Various Energy Modes for No-Touch and Peripheral Tumor-Puncturing Radiofrequency Ablation: An Ex Vivo Simulation Study

OBJECTIVE

To compare the outcomes of radiofrequency ablation (RFA) using dual switching monopolar (DSM), switching bipolar (SB), and combined DSM + SB modes at two different interelectrode distances (25 and 20 mm) in an ex vivo study, which simulated ablation of a 2.5-cm virtual hepatic tumor.

MATERIALS AND METHODS

A total of 132 ablation zones were created (22 ablation zones for each protocol) using three separable clustered electrodes. The performances of the DSM, SB, and combined DSM + SB ablation modes were compared by evaluating the following parameters of the RFA zones at two interelectrode distances: shape (circularity), size (diameter and volume), peritumoral ablative margins, and percentages of the white zone at the midpoint of the two electrodes (ablative margin at midpoint, AMm) and in the electrode path (ablative margin at electrode path, AMe).

RESULTS

At both distances, circularity was the highest in the SB mode, followed by the DSM + SB mode, and was the lowest in the DSM mode. The circularity of the ablation zone showed a significant difference among the three energy groups (p < 0.001 and p = 0.002 for 25-mm and 20-mm, respectively). All size measurements, AMm, and AMe were the greatest in the DSM mode, followed by the DSM + SB mode, and the lowest were with the SB mode (all statistically significant). The white zone proportion in AMm and AMe were the greatest in the SB mode, followed by the DSM + SB mode and DSM in general.

CONCLUSION

DSM and SB appear to be complementary in creating an ideal ablation zone. RFA with the SB mode can efficiently eradicate tumors and create a circular ablation zone, while DSM is required to create a sufficient ablative margin and a large ablation zone.

Intra-articular hip joint osteoid osteoma: Challenging diagnosis and percutaneous radiofrequency ablation treatment

Atypical intra-articular osteoid osteoma can be difficult to diagnose and challenging to treat. We report a case of a right acetabular subchondral intra-articular osteoid osteoma in a young male patient which was initially diagnosed as femoroacetabular impingement due to its atypical clinical and radiological presentations. After fully working up the patient the lesion was successfully treated with percutaneous CT-guided low-power bipolar radiofrequency ablation using several per procedural articular cartilage thermal protective measures including intra-articular thermocouple, and continuous per procedural joint space cooling with Dextrose 5% solution. A precise RFA electrode placement, using the No-touch technique, and applying different passive and active thermal protective measures were helpful in avoiding collateral damage of the hip joint articular cartilages. atypical intra-articular osteoid osteomas necessitate pertinent correlation between the clinical and radiological presentations. As far as intra-articular or subchondral nidus ablation is concerned, thermal protective measures should be considered.

No-Touch vs. Conventional Radiofrequency Ablation Using Twin Internally Cooled Wet Electrodes for Small Hepatocellular Carcinomas: A Randomized Prospective Comparative Study

Objective

This study aimed to compare the efficacy between no-touch (NT) radiofrequency ablation (RFA) and conventional RFA using twin internally cooled wet (TICW) electrodes in the bipolar mode for the treatment of small hepatocellular carcinomas (HCC).

Materials and Methods

In this single-center, two-arm, parallel-group, prospective randomized controlled study, we performed a 1:1 random allocation of eligible patients with HCCs to receive NT-RFA or conventional RFA between October 2016 and September 2018. The primary endpoint was the cumulative local tumor progression (LTP) rate after RFA. Secondary endpoints included technical conversion rates of NT-RFA, intrahepatic distance recurrence, extrahepatic metastasis, technical parameters, technical efficacy, and rates of complications. Cumulative LTP rates were analyzed using Kaplan-Meier analysis and the Cox proportional hazard regression model. Considering conversion cases from NT-RFA to conventional RFA, intention-to-treat and as-treated analyses were performed.

Results

Enrolled patients were randomly assigned to the NT-RFA group (37 patients with 38 HCCs) or the conventional RFA group (36 patients with 38 HCCs). Among the NT-RFA group patients, conversion to conventional RFA occurred in four patients (10.8%, 4/37). According to intention-to-treat analysis, both 1- and 3-year cumulative LTP rates were 5.6%, in the NT-RFA group, and they were 11.8% and 21.3%, respectively, in the conventional RFA group (p = 0.073, log-rank). In the as-treated analysis, LTP rates at 1 year and 3 years were 0% and 0%, respectively, in the NT-RFA group sand 15.6% and 24.5%, respectively, in the conventional RFA group (p = 0.004, log-rank). In as-treated analysis using multivariable Cox regression analysis, RFA type was the only significant predictive factor for LTP (hazard ratio = 0.061 with conventional RFA as the reference, 95% confidence interval = 0.000–0.497; p = 0.004). There were no significant differences in the procedure characteristics between the two groups. No procedure-related deaths or major complications were observed.

Conclusion

NT-RFA using TICW electrodes in bipolar mode demonstrated significantly lower cumulative LTP rates than conventional RFA for small HCCs, which warrants a larger study for further confirmation.

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.

Comparison of ablation performance between dual internally cooled wet tip and conventional dual internally cooled tip radiofrequency electrodes: an experimental study in ex vivo bovine liver

OBJECTIVE

To evaluate the performance of dual internally cooled wet tip (ICWT) radiofrequency electrodes in comparison to dual internally cooled tip (ICT) electrodes.

METHODS

Twenty ablation zones were created for each type of electrodes. Planned procedure time was 6 min. Diameters of the ablation zone along the x-, y-, and z-axes (Dx, Dy, and Dz), ablation zone sphericity, quantitative sphericity measurement, and ablation volume were measured and compared between the two electrode types. Circularity of the ablation zone on the surface with x- and z- axes (zx plane) and amount of energy applied were also compared.

RESULTS

Dx and Dz were significantly longer with ICWT than those with ICT (Dx: 3.0 vs. 2.8 cm, p = .018; and Dz: 2.7 vs. 2.3 cm, p < .001, respectively). Dy was not significantly different (3.0 vs. 2.9 cm, p = .220). Moreover, 85% (17/20) and 30% (6/20) of ablation zones from ICWT and ICT were spherical (p = .001), respectively. Quantitative measurement showed that ICWT was more spherical compared to ICT (0.962 vs. 0.881, p = .001). The ablation volume was also significantly higher with ICWT (11.55 vs. 9.45 cm3, p = .003). The ablation zone on the zx plane was more circular with ICWT (0.907 vs. 0.883, p = .028). The amount of energy applied was significantly bigger with ICWT (18508 vs. 16998 WS, p = .003).

CONCLUSION

Dual ICWT electrodes were better able to create more spherical and larger ablation zones than dual ICT electrodes.

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.

Histological Correlation for Radiofrequency and Microwave Ablation in the Local Control of Hepatocellular Carcinoma (HCC) before Liver Transplantation: A Comprehensive Review

Simple Summary

Liver cancer is a growing problem around the world. Drugs for liver cancer have limited effect, there are not enough donors for liver transplants and many patients are not candidates for surgery to remove the tumor. In many of these cases, hyperthermia can destroy the tumor in situ with minimally invasive methods such as radiofrequency or microwave ablation. In this paper we review the literature evaluating success rates for complete ablation as judged by actual examination of treated tumors that were removed when patients received a liver transplant. While notable successes can be achieved with ablation, the published studies indicate both that complete treatment is not as common as thought and that imaging methods such as computed tomography and magnetic resonance scans do not completely identify residual cancer. There is therefore an important opportunity for improvement in the treatment of this disease.

Abstract

Radiofrequency ablation (RFA) and microwave ablation (MWA) are the most widely studied and applied ablation techniques for treating primary and secondary liver tumors. These techniques are considered curative for small hepatic tumors, with post-ablation outcomes most commonly assessed by an imaging follow up. However, there is increasing evidence of a discrepancy between radiological and pathological findings when ablated lesions are evaluated following liver resection or liver transplantation. A comprehensive review of the available literature reporting the complete pathological response (cPR) following RFA and MWA was performed to estimate the success rate and identify the factors associated with treatment failure. Following RFA, cPR is reported in 26–96% of tumors compared to 57–95% with MWA. Larger tumor size and vessels larger than 3 mm adjacent to the treated tumor are the most important factors identified by previous studies associated with viable residual tumors after RFA. Correlating post-ablation radiological studies with pathological findings shows that computed tomography (CT) and magnetic resonance imaging (MRI) have low sensitivity but high specificity for detecting residual viable or recurrent hepatocellular carcinoma (HCC) tumors. There are promising recent reports combining multiprobe ablation techniques with three-dimensional treatment planning software and stereotactic-aiming instrumentation to achieve more than 90% cPR in both small and large HCC tumors. In conclusion, the reported success for achieving cPR in HCC following RFA and MWA is highly variable in different studies and decreases with increasing lesion size and unfavorable tumor characteristics. Very few studies have reported a high rate of cPR. As these studies are single-center and retrospective, they need to be further validated and reproduced in other clinical settings.

Influence of interapplicator distance on multibipolar radiofrequency ablation during physiological and interrupted liver perfusion in an in vivo porcine model

Radiofrequency ablation (RFA) is a curative treatment option for early stage hepatocellular carcinoma (HCC). Vascular inflow occlusion to the liver (Pringle manoeuvre) and multibipolar RFA (mbRFA) represent possibilities to generate large ablations. This study evaluated the impact of different interapplicator distances and a Pringle manoeuvre on ablation area and geometry of mbRFA. 24 mbRFA were planned in porcine livers in vivo. Test series with continuous blood flow had an interapplicator distance of 20 mm and 15 mm, respectively. For a Pringle manoeuvre, interapplicator distance was predefined at 20 mm. After liver dissection, ablation area and geometry were analysed macroscopically and histologically. Confluent and homogenous ablations could be achieved with a Pringle manoeuvre and an interapplicator distance of 15 mm with sustained hepatic blood flow. Ablation geometry was inhomogeneous with an applicator distance of 20 mm with physiological liver perfusion. A Pringle manoeuvre led to a fourfold increase in ablation area in comparison to sustained hepatic blood flow (p < 0.001). Interapplicator distance affects ablation geometry of mbRFA. Strict adherence to the planned applicator distance is advisable under continuous blood flow. The application of a Pringle manoeuvre should be considered when compliance with the interapplicator distance cannot be guaranteed.

Radiofrequency ablation using internally cooled wet electrodes in bipolar mode for the treatment of recurrent hepatocellular carcinoma after locoregional treatment: A randomized prospective comparative study

Objective

This study aimed to compare the efficacy between bipolar radiofrequency ablation (RFA), using twin internally cooled wet (TICW) electrodes, and switching monopolar RFA, using separable clustered (SC) electrodes, in the treatment of recurrent hepatocellular carcinoma (HCC) after locoregional treatment.

Materials and methods

In this single-center, two-arm, parallel-group, randomized controlled study, we performed a 1:1 random allocation on eligible patients with recurrent HCC after locoregional treatment, to receive TICW-RFA or SC-RFA. The primary endpoint was the minimum diameter of the ablation zone per unit ablation time. Secondary endpoints included other technical parameters, complication rate, technical success and technique efficacy, and clinical outcomes.

Results

Enrolled patients were randomly assigned to the TICW-RFA group (n = 40) or SC-RFA group (n = 37). The two groups did not show significant differences in the primary endpoint, the minimum diameter of the ablation zone per unit ablation time was 2.71 ± 0.98 mm/min and 2.61 ± 0.96 mm/min in the TICW-RFA and SC-RFA groups, respectively (p = 0.577). Total RF energy delivery (11.75 ± 9.04 kcal vs. 22.61 ± 12.98 kcal, p < 0.001) and energy delivery per unit time (0.81 ± 0.49 kcal/min vs. 1.45 ± 0.42 kcal/min, p < 0.001) of the TICW-RFA group were less than those of the SC-RFA group. No procedure-related death or major complications occurred. Technical success was achieved in all patients in both groups, and technique efficacy rates were 100% (46/46) in the TICW-RFA group and 95.0% (38/40) in the SC-RFA group (p = 0.213). The 1-year and 2-year cumulative LTP rates were 11.8% and 24.2%, respectively, in the TICW-RFA group, and 8.6% and 18.1%, respectively, in the SC-RFA group (p = 0.661).

Conclusion

In this single-center randomized controlled study from a Korean tertiary referral hospital, TICW-RFA demonstrated similar therapeutic efficacy and safety profile for recurrent HCC after locoregional treatment compared with SC-RFA.

Trial registration

ClinicalTrials.gov (NCT03806218)

Efficacy of combining electric-field and coronal-plane imaging to obtain ultrasound-ultrasound fusion images in monopolar radiofrequency ablation for patients with liver cancer

AIM

For radiofrequency ablation to treat patients diagnosed with liver cancer, the ablation area cannot be envisaged beforehand, even by experts. This study aimed to assess the clinical feasibility of applying a combination of electric (E)-field and coronal (C)-plane simulations to ultrasound-ultrasound (US-US) fusion images.

METHODS

The study protocols were approved by the institutional ethics committee. Between October 2017 and July 2019, 151 patients with 151 hepatocellular carcinoma nodules (80 treated with navigation images and 71 without navigation images) were retrospectively compared in this cross-sectional study. The E-field, which is a simulated image that predicts the ablation area, was applied to the US-US fusion images. The C-plane is defined as a sagittal plane in relation to the original 2-D US images. The positions of each E-field area in the maximum cross-sectional area of the tumor were easily identified from C-plane results. The primary end-point of this study was achievement of an adequate safety margin (greater than 5 mm). The sphericity of the ablation volume was used as a secondary end-point.

RESULTS

The rate of achieving a sufficient safety margin was significantly higher in the group treated with navigation images (71/80) than in the group treated without navigation images (31/71, P < 0.001). The median sphericity was 0.55 with navigation images and 0.42 without navigation images (P < 0.001).

CONCLUSION

Using the combination of an E-field and a C-plane on US-US fusion images can be a feasible method for acquiring a sufficient safety margin.

No-Touch Multi-bipolar Radiofrequency Ablation for the Treatment of Subcapsular Hepatocellular Carcinoma ≤ 5 cm Not Puncturable via the Non-tumorous Liver Parenchyma

PURPOSE

The percutaneous ablation of subcapsular hepatocellular carcinoma (S-HCC) may involve a risk of complications such as hemorrhage and tumor seeding, mainly linked to the direct tumor puncture often inevitable with mono-applicator ablation devices. The purpose of this study was to assess the efficacy and safety of no-touch multi-bipolar radiofrequency ablation (NTMBP-RFA) for the treatment of S-HCC ≤ 5 cm not puncturable via the non-tumorous liver parenchyma.

MATERIALS AND METHODS

Between September 2007 and December 2014, 58 consecutive patients (median age: 63 years [46-86], nine females) with 59 S-HCC ≤ 5 cm (median diameter: 25 mm [10-50 mm]), not puncturable via the non-tumorous liver parenchyma, were treated with NTMBP-RFA. Response and follow-up were assessed by CT or MRI. Complications were graded using the Cardiovascular and Interventional Radiological Society of Europe classification. Overall local tumor progression (OLTP)-free survival was assessed using the Kaplan-Meier method. A Cox proportional model evaluated the factors associated with OLTP. Signs of peritoneal or parietal tumor seeding were noted during follow-up imaging studies.

RESULTS

A complete ablation was achieved in 57/58 patients (98.3%) after one (n = 51) or two (n = 6) procedures. Three patients (5.2%) experienced complications (sepsis, cirrhosis decompensation; CIRSE grade 2 or 3). After a median follow-up period of 30.5 months [1-97], no patients had tumor seeding. The 1, 2 and 3-year OLTP-free survival rates were 98%, 94% and 91%, respectively. No factors were associated with OLTP.

CONCLUSION

NTMBP-RFA is a safe and effective treatment for S-HCC not puncturable via the non-tumorous liver parenchyma.

The short-term efficacy of no-touch radiofrequency ablation in treating cirrhosis-based small hepatocellular carcinoma

Background

Radiofrequency ablation (RFA) for the treatment of small hepatocellular carcinoma (HCC) has a drawback of high recurrence rate. No-touch technique was developed to overcome it. However, it has barely been studied in Chinese populations. The aim of this study is to determine the safety and efficacy of no-touch RFA in the treatment of cirrhosis-based small HCC patients.

Methods

A total of 130 patients of small HCC in Southwest Hospital were enrolled in this study, 46 cases treated by no-touch RFA and 84 cases by conventional RFA. Treatment complications and tumor-free survival rate and overall survival rate were compared and analyzed.

Results

There were no significant differences in baseline confounding factors between the two groups. The ablation volume of no-touch RFA technique was significantly higher than conventional RFA (P = 0.002) but the remaining liver volume and treatment complications of the two techniques were the same (P = 0.702 and P = 0.269, respectively). Cox regression model revealed that conventional RFA was a predictive factor for short-term HCC recurrence (P = 0.041 for 2-year recurrence rate). Kaplan-Meier survival showed that tumor-free survival in no-touch group was significantly higher than conventional group (P = 0.047).

Conclusions

Our data showed that no-touch RFA provided a higher short-term tumor-free survival rate than conventional RFA but was as safe as conventional RFA.

Multibipolar Radiofrequency Ablation for the Treatment of Mass-Forming and Infiltrative Hepatocellular Carcinomas > 5 cm: Long-Term Results

AIMS AND BACKGROUND

Only few patients with cirrhosis and hepatocellular carcinoma (HCC) larger than 5 cm are amenable to resection or straight liver transplantation, and in such circumstances, multibipolar radiofrequency ablation (mbp-RFA) could be a reliable alternative. This study was aimed to assess the long-term outcome in patients treated with mbp-RFA for unresectable HCC > 5 cm.

METHODS

Eighty-three consecutive patients with cirrhosis (median age 70 years [37-93 years], 67 males, BCLC A/B/C: 54/21/8, 74 naive) with up to three HCCs, the largest > 5 cm in diameter (median: 6.2 cm, 5.1-9 cm, 22 infiltrative forms, 12 with segmental portal invasion of which 10 were infiltrative forms) were treated with mbp-RFA. Overall (OS) and recurrence-free (RFS) survival and their associated predictive factors were assessed.

RESULTS

Complete ablation was observed in 78/83 (94%) patients. Thirty-one side effects occurred, including 6 (7%) severe complications. After a median follow-up of 26.1 months (1-112 months), in naive patients the 3- and 5-year OS was 51% (38-62) and 24% (13-36), 63 and 30% for mass-forming and 25 and 6% for infiltrative form, respectively. Infiltrative form (HR: 2.5 [1.33-4.69], p = 0.004) was the only independent OS predictor. In naive patients with mass-forming and infiltrative form, the 3- and 5-year RFS were 47 and 17 and 18 and 18%, respectively. Alpha-fetoprotein (HR: 2.86 [1.32-6.21], p = 0.008), multinodular form (HR: 2.74 [1.4-5.38], p = 0.003) and infiltrative form (HR: 3.43 [1.67-7.01], p = 0.0007) were independent RFS predictors.

CONCLUSIONS

mbp-RFA offers good OS in inoperable patients with cirrhosis and large HCC, with acceptable safety profile. For infiltrative forms, although mbp-RFA leads to complete responses in more than 80% cases, few only remain tumor progression-free in long-term.

No-Touch Radiofrequency Ablation of VX2 Hepatic Tumors In Vivo in Rabbits: A Proof of Concept Study

Objective

In a proof of concept study, we compared no-touch radiofrequency ablation (NtRFA) in bipolar mode with conventional direct tumor puncture (DTP) in terms of local tumor control (LTC), peritoneal seeding, and tumorigenic factors, in the rabbit VX2 subcapsular hepatic tumor model.

Materials and Methods

Sixty-two rabbits with VX2 subcapsular hepatic tumors were divided into three groups according to the procedure: DTP-RFA (n = 25); NtRFA (n = 25); and control (n = 12). Each of the three groups was subdivided into two sets for pathologic analysis (n = 24) or computed tomography (CT) follow-up for 6 weeks after RFA (n = 38). Ultrasonography-guided DTP-RFA and NtRFA were performed nine days after tumor implantation. LTC was defined by either achievement of complete tumor necrosis on histopathology or absence of local tumor progression on follow-up CT and autopsy. Development of peritoneal seeding was also compared among the groups. Serum hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) were measured via ELISA (Elabscience Biotechnology Co.) after RFA for tumorigenic factor evaluation.

Results

Regarding LTC, there was a trend in NtRFA (80%, 20/25) toward better ablation than in DTP-RFA (56%, 14/25) (p = 0.069). Complete tumor necrosis was achieved in 54.5% of DTP-RFA (6/11) and 90.9% of NtRFA (10/11). Peritoneal seeding was significantly more common in DTP-RFA (71.4%, 10/14) than in NtRFA (21.4%, 3/14) (p = 0.021) or control (0%). Elevations of HGF, VEGF or IL-6 were not detected in any group.

Conclusion

No-touch radiofrequency ablation led to lower rates of peritoneal seeding and showed a tendency toward better LTC than DTP-RFA.

Long-term follow-up of unresectable medium-large hepatocellular carcinoma nodules treated with radiofrequency ablation using a multiple-electrode switching system

OBJECTIVE

The purpose of this study was to prospectively evaluate the safety and effectiveness of radiofrequency ablation (RFA) by using a multiple-electrode switching system to treat unresectable medium-large (3.1-6.0 cm) HCC nodules.

METHODS

RFA using a multiple-electrode switching system was performed for HCC nodules with size > 3.0 < 6.0 cm in nonsurgical candidates. Two electrodes were consecutively placed for 3.1-4.0 cm tumours, and three electrodes for 4.1-5.9 cm tumours, with a 2.0-2.5 cm spacing. The power was switched from one electrode to the next automatically when the impedance reached 30 Ω above the baseline level. 25 patients (M/F = 9/16; median age 76 years, range 61-84) with liver cirrhosis (20 HCV-positive) in Child's Class A (22 cases) and B (3 cases) and 26 HCC nodules (median diameter 4.0 cm; range 3.2-5.5 cm) underwent treatment in 25 sessions from 2013 and 2018. Therapeutic effectiveness was assessed through CT or MRI exam at 30-40 days post-ablation.

RESULTS

No procedure-related death or major complications occurred. Complete ablation was obtained in all nodules (100%). At a median follow up of 30 months, local tumor progression occurred in five out of 26 nodules (19.2%). Overall survival at 4 years was 49%.

CONCLUSION

RFA with a multiple-electrode switching system may be a safe, quick and effective therapeutic option for treatment of 3.1-6.0 cm unresectable HCC tumours.

ADVANCES IN KNOWLEDGE

RFA with multiple electrodes provides favourable clinical results in patients with medium-large HCC nodules who are not suitable for surgery.

No-touch multibipolar radiofrequency ablation vs. surgical resection for solitary hepatocellular carcinoma ranging from 2 to 5 cm

BACKGROUND & AIMS

No-touch multibipolar radiofrequency ablation (NTM-RFA) represents a novel therapy that surpasses standard RFA for hepatocellular carcinoma (HCC), but it has not been compared to surgical resection (SR). We aimed to compare the outcomes of NTM-RFA and SR for intermediate-sized HCC.

METHODS

Between 2012 and 2016, 141 patients with solitary HCC ranging from 2 to 5 cm were treated by NTM-RFA or SR at a single-center. The outcomes of 128 patients were compared after using inverse probability of treatment weighting (IPTW).

RESULTS

Seventy-nine patients had NTM-RFA and 62 had SR. After IPTW, the two groups were well-balanced for most baseline characteristics including tumor size, location, etiology, severity of underlying liver disease and alpha-fetoprotein level. Morbidity was higher (67.9% vs. 50.0%, p = 0.042) and hospital stay was longer (12 [IQR 8-13] vs. 7 [IQR 5-9] days, p <0.001) after SR. Local recurrence rates at one and three years were 5.5% and 10.0% after NTM-RFA and 1.9% and 1.9% after SR, respectively (p = 0.065). The rates of systematized recurrence (within the treated segment or in an adjacent segment within a 2 cm distance from treatment site) were higher after NTM-RFA (7.4% vs. 1.9% at one year, 27.8% vs. 3.3% at three years, p = 0.008). Most patients with recurrence were eligible for rescue treatment, resulting in similar overall survival (86.7% after NTM-RFA, 91.4% after SR at three years, p = 0.954) and disease-free survival (40.8% after NTM-RFA, 56.4% after SR at three years, p = 0.119).

CONCLUSION

Compared to SR, NTM-RFA for solitary intermediate-sized HCC was associated with less morbidity and more systematized recurrence, while the rate of local recurrence was not significantly different. Most patients with intrahepatic recurrence remained eligible for rescue therapies, resulting in equivalent long-term oncological results after both treatments.

LAY SUMMARY

Outcomes of patients treated for intermediate-sized hepatocellular carcinoma by surgical resection or no-touch multibipolar radiofrequency ablation were compared. No-touch multibipolar radiofrequency ablation was associated with a lower overall morbidity and a higher rate of systematized recurrence within the treated segment or in an adjacent segment within a 2 cm distance from the initial tumor site. Most patients with intrahepatic recurrence remained eligible for rescue curative therapy, enabling them to achieve similar long-term oncological results after both treatments.

Hepatocellular carcinoma abutting large vessels: comparison of four percutaneous ablation systems

PURPOSE

To compare overall local tumour progression (OLTP), defined as the failure of primary ablation or local tumour progression, with single applicator monopolar radiofrequency ablation (RFA), microwave ablation (MWA), cluster-RFA and multi-bipolar radiofrequency (mbpRFA) in the treatment of hepatocellular carcinoma (HCC) ≤ 5 cm abutting large vessels (≥3 mm).

MATERIALS AND METHODS

This multicenter, retrospective, per-nodule study was performed from 2007 to 2015. The study was approved by the ethics review board, and informed consent was waived. A total of 160/914 HCC nodules treated by thermal ablation and abutting large vessels (40 per treatment group) treated by monopolar RFA, MWA, cluster-RFA or mbpRFA were matched for tumour size, alpha-feto-protein level and vessel size. OLTP rates were compared by the log-rank test and the multivariate Cox model after matching.

RESULTS

No differences were observed in tumour size, vessel size or alpha-feto-protein levels among the three groups (p = 1). The cumulative 4-year OLTP rates following monopolar RFA, cluster-RFA, multi-bipolar RFA and MWA were 50.5%, 16.3%, 16.3% and 44.2%, respectively (p = 0.036). On multivariate Cox regression, vessel size ≥10 mm, monopolar RFA and MWA were independent risk factors of OLTP compared to cluster-RFA or mbpRFA.

CONCLUSION

Multi-applicator RFA provides better local tumour control in HCC abutting large vessels than single-applicator techniques (monopolar RFA or MWA).

Percutaneous treatment of hepatocellular carcinoma: State of the art and innovations

Percutaneous treatment of hepatocellular carcinoma (HCC) encompasses a vast range of techniques, including monopolar radiofrequency ablation (RFA), multibipolar RFA, microwave ablation, cryoablation and irreversible electroporation. RFA is considered one of the main curative treatments for HCC of less than 5 cm developing on cirrhotic liver, together with surgical resection and liver transplantation. However, controversies exist concerning the respective roles of ablation and liver resection for HCC of less than 3 to 5 cm on cirrhotic liver. In line with the therapeutic algorithm of early HCC, percutaneous ablation could also be used as a bridge to liver transplantation or in a sequence of upfront percutaneous treatment, followed by transplantation if the patient relapses. Moreover, several innovations in ablation methods may help to efficiently treat early HCC, initially considered as "non-ablatable", and might, in some cases, extend ablation criteria beyond early HCC, enabling treatment of more patients with a curative approach.

Clinical utility of multipolar ablation with a 3-D simulator system for patients with liver cancer

BACKGROUND AND AIM

The aim of this study is to confirm the efficacy of multipolar ablation with a new simulator system, three-dimensional (3-D) sim-Navigator, for patients with hepatocellular carcinoma by assessing relapse-free survival and shape of the ablation volume under clinical conditions.

METHODS

All participants provided written, informed consent, and study protocols were approved by the institutional ethics committee. Twenty-seven patients with 27 nodules were treated by no-touch ablation using the new simulator system. Another 21 patients with 21 nodules treated without the simulator system were enrolled as controls. Tumor progression and shape of ablation volume were assessed. Predictors of tumor progression were assessed by Cox proportional hazard model.

RESULTS

No significant differences in clinical characteristics were seen between groups. Mean sphericity was 0.48 ± 0.07 with 3-D sim-Navigator and 0.37 ± 0.07 without 3-D sim-Navigator (P < 0.001). Median surface-to-volume ratio and compactness were also significantly closer to those of a sphere with 3-D sim-Navigator (P = 0.017, P < 0.001). Relapse-free survival rates at 1 and 1.5 years were 94.1% and 82.4%, respectively, with 3-D sim-Navigator, compared with 83.2% and 55.5% without (P = 0.056). The only independent factor predicting relapse-free survival was use of 3-D sim-Navigator (hazard ratio, 0.12; 95%CI, 0.01-0.87; P = 0.035).

CONCLUSIONS

Ideal ablation area was acquired by this simulation and navigation system in clinics. This system improved local tumor progression by facilitating appropriate insertion of multiple electrodes.

Percutaneous Dual-Switching Monopolar Radiofrequency Ablation Using a Separable Clustered Electrode: A Preliminary Study

Objective

To prospectively evaluate the safety and therapeutic effectiveness of dual-switching monopolar (DSM) radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC), and to retrospectively compare the results with those of single-switching monopolar (SSM) RFA in a historical control group.

Materials and Methods

This study was approved by the Institutional Review Board, with informed consent obtained from all patients. Fifty-two HCC patients who underwent DSM-RFA using a separable clustered electrode and dual-generators were prospectively enrolled. Technical parameters, complications, technical success, technical effectiveness, and local tumor progression (LTP) rates were evaluated by means of post-procedural and follow-up imaging. Thereafter, the outcome of DSM-RFA was compared with those of 249 retrospectively included HCC patients treated with SSM-RFA.

Results

There were two major complications (3.8%, 2/52) including pleural and pericardial effusion in the DSM-RFA group. The DSM-RFA yielded a 100% technical success rate, a 98.1% technical effectiveness rate, and a 4.3% 2-year LTP rate. In a retrospective comparison between the two groups, DSM-RFA created significantly larger ablation volume (4.20 ± 2.07 cm³/min vs. 3.03 ± 1.99 cm³/min, p < 0.01), and delivered higher energy (1.43 ± 0.37 kcal/min vs. 1.25 ± 0.50 kcal/min, p < 0.01) per given time, than SSM-RFA. There was no significant difference in major procedure-related complications (3.8% vs. 4.4%) and technical effectiveness rate (98.1% vs. 96.4%) between the two groups (p = 1.00). In addition, the 2-year LTP rate of DSM-RFA and SSM-RFA were 4.3% and 10.1%, respectively (p = 0.15).

Conclusion

DSM-RFA using a separable clustered electrode is safe and provides high local tumor control and good preliminary clinical outcome for small HCCs, which are at least comparable to those of SSM-RFA.

Multipolar versus monopolar radiofrequency ablation for hepatocellular carcinoma in the caudate lobe: Results of a propensity score analysis

AIM

This study aimed to compare multipolar radiofrequency ablation (RFA) with monopolar RFA as the major treatment for nodules of hepatocellular carcinoma in the caudate lobe.

METHODS

This retrospective study was approved by the institutional review board. Data were reviewed from 101 patients who met the Milan criteria and were treated by multipolar RFA (n = 22) or monopolar RFA (n = 79). After propensity score matching, complications and local tumor progression were compared between the two groups.

RESULTS

Before propensity score matching (n = 101), the 2-year relapse-free survival rates for multipolar and monopolar RFA (65.1% vs. 38.8%, respectively; P = 0.064) and the local tumor progression rate (12.5% vs. 14.9%, respectively; P = 0.313) were not significantly different. There were no significant differences between the two RFA techniques by treatment efficacy of transcatheter hepatic arterial embolization, location of tumor, and puncture route. After matching (n = 44), the 2-year relapse-free survival rate for the multipolar and monopolar groups (65.1% vs. 22.7%, respectively; P = 0.004) was significantly different, and the local tumor progression rate (12.5% vs. 22.9%, respectively; P = 0.004) was significantly different. No severe complications occurred in the patients treated by multipolar RFA.

CONCLUSION

Multipolar RFA appears to be a safe and effective method for hepatocellular carcinoma nodules in the caudate lobe.

Transarterial chemoembolization for early stage hepatocellular carcinoma decrease local tumor control and overall survival compared to radiofrequency ablation

BACKGROUND & AIMS

To compare treatment failure and survival associated with ultrasound-guided radiofrequency ablation (RFA) and trans-arterial chemoembolization (TACE) for early-stage HCC in Child-Pugh A cirrhosis patients.

METHODS

122 cirrhotic patients (RFA: 61; TACE: 61) were well matched according to cirrhosis severity; tumor size and serum alpha-fetoprotein. TACE was performed in case of inconspicuous nodule on US or nodule with "at risk location". Treatment failure was defined as local tumor progression (LTP) and primary treatment failure (failing to obtain complete response after two treatment session). Treatment failure and overall survival (OS) were compared after coarsened exact matching. Cox proportional model to assess independent predictive factors was performed.

RESULTS

No significant difference was seen for baseline characteristics between the two groups. Mean tumor size was 3cm in both group with 41% HCC>3cm. Treatment failure rates after TACE was 42.6% (14 primary treatment failures and 12 LTP) and 9.8% after RFA (no primary treatment failure and 6 LTP) P < 0.001. TACE was the only predictive factor of treatment failure (Hazard ratio: 5.573). The 4-years OS after RFA and TACE were 54.1% and 31.5% (P = 0.042), respectively.

CONCLUSION

For Child-Pugh A patients with early-stage HCC, alternative treatment as supra-selective TACE to RFA regarded as too challenging using common US guidance decrease significantly the local tumor control and overall survival. Efforts to improve feasibility of RFA especially for inconspicuous target have to be made.

No-touch radiofrequency ablation using multiple electrodes: An in vivo comparison study of switching monopolar versus switching bipolar modes in porcine livers

Objective

To evaluate the in vivo technical feasibility, efficiency, and safety of switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) as a no-touch ablation technique in the porcine liver.

Materials and methods

The animal care and use committee approved this animal study and 16 pigs were used in two independent experiments. In the first experiment, RFA was performed on 2-cm tumor mimickers in the liver using a no-touch technique in the SM mode (2 groups, SM1: 10 minutes, n = 10; SM2: 15 minutes, n = 10) and SB-mode (1 group, SB: 10 minutes, n = 10). The technical success with sufficient safety margins, creation of confluent necrosis, ablation size, and distance between the electrode and ablation zone margin (DEM), were compared between groups. In the second experiment, thermal injury to the adjacent anatomic organs was compared between SM-RFA (15 minutes, n = 13) and SB-RFA modes (10 minutes, n = 13).

Results

The rates of the technical success and the creation of confluent necrosis were higher in the SB group than in the SM1 groups (100% vs. 60% and 90% vs. 40%, both p < 0.05). The ablation volume in the SM2 group was significantly larger than that in the SB group (59.2±18.7 cm³ vs. 39.8±9.7 cm^3,p < 0.05), and the DEM in the SM2 group was also larger than that in the SB group (1.39±0.21 cm vs. 1.07±0.10 cm, p < 0.05). In the second experiment, the incidence of thermal injury to the adjacent organs and tissues in the SB group (23.1%, 3/13) was significantly lower than that in the SM group (69.2%, 8/13) (p = 0.021).

Conclusion

SB-RFA was more advantageous for a no-touch technique for liver tumors, showing the potential of a better safety profile than SM-RFA.

No-Touch Radiofrequency Ablation: A Comparison of Switching Bipolar and Switching Monopolar Ablation in Ex Vivo Bovine Liver

OBJECTIVE

To evaluate the feasibility, efficiency, and safety of no-touch switching bipolar (SB) and switching monopolar (SM) radiofrequency ablation (RFA) using ex vivo bovine livers.

MATERIALS AND METHODS

A pork loin cube was inserted as a tumor mimicker in the bovine liver block; RFA was performed using the no-touch technique in the SM (group A1; 10 minutes, n = 10, group A2; 15 minutes, n = 10) and SB (group B; 10 minutes, n = 10) modes. The groups were compared based on the creation of confluent necrosis with sufficient safety margins, the dimensions, and distance between the electrode and ablation zone margin (DEM). To evaluate safety, small bowel loops were placed above the liver surface and 30 additional ablations were performed in the same groups.

RESULTS

Confluent necroses with sufficient safety margins were created in all specimens. SM RFA created significantly larger volumes of ablation compared to SB RFA (all p < 0.001). The DEM of group B was significantly lower than those of groups A1 and A2 (all p < 0.001). Although thermal injury to the small bowel was noted in 90%, 100%, and 30% of the cases in groups A1, A2, and B, respectively, full depth injury was noted only in 60% of group A2 cases.

CONCLUSION

The no-touch RFA technique is feasible in both the SB and SM modes; however, SB RFA appears to be more advantageous compared to SM RFA in the creation of an ablation zone while avoiding the unnecessary creation of an adjacent parenchymal ablation zone or adjacent small bowel injuries.

Short-Term Results of Laparoscopic Radiofrequency Ablation Using a Multipolar System for Localized Hepatocellular Carcinoma

BACKGROUND AND AIM

Multipolar radiofrequency ablation (RFA) is feasible for the treatment of hepatocellular carcinoma (HCC) for which a large ablative area is planned, and it imposes a light physical burden on patients. Multipolar RFA via the percutaneous approach is performed in the majority of cases, but the efficacy of multipolar RFA with a laparoscopic approach has rarely been studied. This study aimed to evaluate the efficacy and safety of multipolar laparoscopic RFA (LRA) for localized HCC over the short term.

METHODS

From January 2014 to January 2016, 77 consecutive patients with 130 HCCs treated by multipolar LRA were assessed. One to three bipolar needle applicators were inserted under laparoscopic ultrasonography guidance, regardless of tumor location. We intended to achieve parallel insertions and no-touch ablation as much as possible.

RESULTS

The median size of the main tumor was 22 mm (range, 10-42 mm). The median follow-up time was 13.6 months (range, 3.1-24.8 months). In all cases, a sufficient ablative area was obtained as planned, without thermal injury of adjacent organs. During the follow-up period, all patients were alive with no local tumor progression, while intrahepatic recurrence distant from the primary site occurred in 7 patients. The 2-year local tumor progression-free survival rate and overall cancer-free survival rate were 100 and 81.6%, respectively. There were no procedural major complications caused prolonging the hospitalization, and all patients were discharged without subjective symptoms 4-7 days after LRA.

CONCLUSIONS

Multipolar LRA was efficacious in the treatment of localized HCCs by safely achieving a good ablative area.

Comparison of no-touch multi-bipolar vs. monopolar radiofrequency ablation for small HCC

BACKGROUND & AIMS

The primary aim of this study was to compare the rate of global radiofrequency ablation (RFA) failure between monopolar RFA (MonoRFA) vs. no-touch multi-bipolar RFA (NTmbpRFA) for small hepatocellular carcinoma (HCC) ⩽5cm in cirrhotic patients.

METHODS

A total of 362 cirrhotic patients were included retrospectively across four French centres (181 per treatment group). Global RFA failure (primary RFA failure or local tumour progression) was analysed using the Kaplan-Meier method after coarsened exact matching. Cox regression models were used to identify factors associated with global RFA failure and overall survival (OS).

RESULTS

Patients were well matched according to tumour size (⩽30/>30mm); tumour number (one/several); tumour location (subcapsular and near large vessel); serum AFP (<10; 10-100; >100ng/ml); Child-Pugh score (A/B) and platelet count (</⩾100G/L), p=1 for all. One case of perioperative mortality was observed in the NTmbpRFA group and the rate of major complications was 7.2% in both groups (p=1). The cumulative rates of global RFA failure at 1, 3 and 5years were respectively 13.3%, 31% and 36.7% for MonoRFA vs. 0.02%, 7.9% and 9.2% for NTmbpRFA, p<0.001. Monopolar RFA, tumour size >30mm and HCC near large vessel were independent factors associated with global RFA failure. Five-year OS was 37.2% following MonoRFA vs. 46.4% following NTmbpRFA p=0.378.

CONCLUSIONS

This large multicentre case-matched study showed that NTmbpRFA provided better primary RFA success and sustained local tumour response without increasing severe complications rates, for HCC ⩽5cm.

LAY SUMMARY

Using no-touch multi-bipolar radiofrequency ablation for hepatocellular carcinoma ⩽5cm provide a better sustained local tumour control compared to monopolar radiofrequency ablation.

Quick and stable parallel puncture of hepatic tumors using a double-barreled needle direction system for ultrasound-guided bipolar radiofrequency ablation

AIM

In bipolar radiofrequency ablation (RFA) therapy, insertion of multiple needles at appropriate points on a target is difficult. The aim of our study was to evaluate a simplified method for multi-electrode insertion using a newly developed double-barreled needle guidance system for percutaneous RFA of hepatic tumors.

METHODS

RFA using two bipolar electrodes was performed in 15 consecutive patients (nine men, six women; mean age, 72.0 ± 8.2 years) with a solitary small (≤3 cm) hepatic tumor. The first five nodules were treated using the conventional puncture method with the standard attachment, then 10 nodules were ablated using the parallel puncture method with the double-barreled attachment. The times required for double-needle placement and the shapes of the ablated areas were compared between the two puncture methods.

RESULTS

The parallel puncture method required a shorter time for double-needle placement than the conventional method (12 s [range, 8-24] vs 96 s [range, 50-240]; P = 0.0003), and allowed continuous observation of the tip of all needles and the size of the ablated area as it increased until completion of the ablation. The method also provided a stable ellipsoidal ablated area. The median height, width and thickness were 30 mm (range, 22-34), 30 mm (range, 21-33) and 20 mm (range, 7-25), respectively, using 20-mm electrodes, and 34 mm (range, 32-41), 36 mm (range, 35-38) and 24 mm (range, 23-24), respectively, using 30-mm electrodes.

CONCLUSION

The parallel puncture method may be a feasible procedure for multi-needle RFA therapy.

Switching Monopolar Radiofrequency Ablation Using a Separable Cluster Electrode in Patients with Hepatocellular Carcinoma: A Prospective Study

OBJECTIVE

This study was conducted to evaluate the outcomes of multi-channel switching RFA using a separable cluster electrode in patients with HCC.

METHODS

From November 2011 to July 2013, 79 patients with 98 HCCs < 5 cm were enrolled and treated with RFA using a multi-channel switching radiofrequency system and a separable cluster electrode under the guidance of a real-time fusion imaging system. The primary and secondary endpoints were the 3-year local tumor progression (LTP) rate and recurrence-free survival (RFS) rate, respectively. For post hoc analyses, LTP, RFS, and major complication rates were retrospectively compared with a historical control group treated with RFA using the same radiofrequency system but with multiple internally-cooled electrodes.

RESULTS

The technique success rate of the 98 tumors was 100%. Cumulative 1-year, 2-year, and 3-year LTP rates were 3.4%, 6.9%, and 12.4%, respectively. For patient-level data, cumulative 1-year, 2-year, and 3-year RFS rates were 83.9%, 68.6%, and 45.4%, respectively. On post hoc analyses, none of the baseline characteristics showed a significant difference between the separable cluster electrode and multiple internally-cooled electrodes group. Cumulative LTP and RFS rates of the two groups also showed no significant difference (p = 0.401 and p = 0.881, respectively). Finally, major complication rates of the separable cluster electrode group (5.0%, 4/79) and multiple internally-cooled electrodes group (5.9%, 4/74) were also comparable (p = 1.000).

CONCLUSION

Switching monopolar RFA using a separable cluster electrode is a feasible and efficient technique for the treatment of HCCs smaller than 5 cm, providing comparable local tumor control to multiple internally-cooled electrodes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02745483.

Percutaneous treatment of extrahepatic recurrence of hepatocellular carcinoma

PURPOSE

The goal of this study was to retrospectively evaluate the results of imaging-guided percutaneous ablation in patients with controlled intrahepatic hepatocellular carcinoma (HCC) with limited extrahepatic disease.

MATERIALS AND METHODS

Eleven patients with limited extrahepatic disease and/or potential short-term clinical manifestations with controlled primary intrahepatic HCC were included into the study. There were nine men and two women, with a mean age of 67.4 years±10.2 (SD) (range: 54-85 years). All patients had extrahepatic disease treated by either radiofrequency ablation or electroporation. Extrahepatic disease consisted of lymph node metastases (5 patients), tumor seeding along a needle tract (3 patients), adrenal gland metastasis, bone metastasis and pulmonary metastasis (one patient each).

RESULTS

Response to treatment was complete in 7/11 patients (64%). The mean survival time after treatment was 18.8±12.7 (SD) months (median, 16 months; range: 4-42 months). No severe complications associated with percutaneous treatment were observed.

CONCLUSION

Our results suggest that imaging-guided percutaneous ablation techniques should be considered as a useful option for the treatment of extrahepatic disease in patients with HCC. Further studies are needed, however to fully determine the potential role of these techniques in this elective application.

Hepatocellular Carcinoma within Milan Criteria: No-Touch Multibipolar Radiofrequency Ablation for Treatment-Long-term Results

Purpose To assess the long-term outcome in 108 consecutive patients treated with no-touch multibipolar radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) that met the Milan criteria. Materials and Methods This retrospective study was approved by the ethical review board, and the need to obtain informed consent was waived. Between November 1, 2006, and December 31, 2011, 132 HCC tumors (diameter, 10-45 mm; 39 tumors ≥ 30 mm) in 108 consecutive patients (106 with cirrhosis) that met Milan criteria were treated with no-touch multibipolar RFA, which consisted of activating, in bipolar mode, three or four electrodes inserted just beyond the tumor margins. Follow-up was performed every 3 months for 2 years and every 6 months thereafter with computed tomographic or magnetic resonance imaging. Survival probabilities were computed by using the Kaplan-Meier method. Predictive factors of tumor progression and overall survival were assessed by using the Cox proportional hazard model. Results No technical failure occurred, and complete ablation was achieved for all the nodules. After a median of 40.5 months (range, 2-84 months) of follow-up, 3- and 5-year local and overall tumor progression-free survival were 96%, 94%, 52%, and 32%, respectively. Neither tumor diameter greater than 30 mm nor location abutting a large vessel were associated with local tumor progression. Tumor diameter greater than 30 mm was the only parameter predictive of overall tumor progression (P = .0036). Independent factors associated with shorter overall survival were Child-Pugh class B disease, age greater than 65 years, and platelet count of less than 150 g/L (P < .003). Three major complications occurred (2.7%): hemothorax in one patient and liver failure in two, with major portal-systemic shunts. One patient (0.9%) died, and one underwent transplantation. Conclusion No-touch multibipolar RFA for HCC tumors that meet Milan criteria provides a high local tumor progression-free survival rate. An ongoing randomized trial might help to clarify the role of this new approach for the treatment of early HCC. (©) RSNA, 2016 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on March 30, 2016.

Radiofrequency ablation of hepatocellular carcinoma: Mono or multipolar?

BACKGROUND AND AIMS

Thermo-ablation by radiofrequency is recognized as a curative treatment for early-stage hepatocellular carcinoma. However, local recurrence may occur because of incomplete peripheral tumor destruction. Multipolar radiofrequency has been developed to increase the size of the maximal ablation zone. We aimed to compare the efficacy of monopolar and multipolar radiofrequency for the treatment of hepatocellular carcinoma and determine factors predicting failure.

METHODS

A total of 171 consecutive patients with 214 hepatocellular carcinomas were retrospectively included. One hundred fifty-eight tumors were treated with an expandable monopolar electrode and 56 with a multipolar technique using several linear bipolar electrodes. Imaging studies at 6 weeks after treatment, then every 3 months, assessed local effectiveness. Radiofrequency failure was defined as persistent residual tumor after two sessions (primary radiofrequency failure) or local tumor recurrence during follow-up. This study received institutional review board approval (number 2014/77).

RESULTS

Imaging showed complete tumor ablation in 207 of 214 lesions after the first session of radiofrequency. After a second session, only two cases of residual viable tumor were observed. During follow-up, there were 46 local tumor recurrences. Thus, radiofrequency failure occurred in 48/214 (22.4%) cases. By multivariate analysis, technique (P < 0.001) and tumor size (P = 0.023) were independent predictors of radiofrequency failure. Failure rate was lower with the multipolar technique for tumors < 25 mm (P = 0.023) and for tumors between 25 and 45 mm (P = 0.082). There was no difference for tumors ≥ 45 mm (P = 0.552).

CONCLUSIONS

Compared to monopolar radiofrequency, multipolar radiofrequency improves tumor ablation with a subsequent lower rate of local tumor recurrence.

Usefulness of a New Three-Dimensional Simulator System for Radiofrequency Ablation

Multipuncture radiofrequency ablation is expected to produce a large ablated area and reduce intrahepatic recurrence of hepatocellular carcinoma; however, it requires considerable skill. This study evaluated the utility of a new simulator system for multipuncture radiofrequency ablation. To understand positioning of multipuncture electrodes on three-dimensional images, we developed a new technology by expanding real-time virtual ultrasonography. We performed 21 experimental punctures in phantoms. Electrode insertion directions and positions were confirmed on computed tomography, and accuracy and utility of the simulator system were evaluated by measuring angles and intersections for each electrode. Moreover, to appropriately assess placement of the three electrodes, puncture procedures with or without the simulator were performed by experts and non-experts. Technical success was defined as maximum angle and distance ratio, as calculated by maximum and minimum distances between electrodes. In punctures using 2 electrodes, correlations between angles on each imaging modality were strong (ultrasound vs. simulator: r = 0.991, p<0.001, simulator vs. computed tomography: r = 0.991, p<0.001, ultrasound vs. computed tomography: r = 0.999, p<0.001). Correlations between distances in each imaging modality were also strong (ultrasound vs. simulator: r = 0.993, p<0.001; simulator vs. computed tomography: r = 0.994, p<0.001; ultrasound vs. computed tomography: r = 0.994, p<0.001). In cases with 3 electrodes, distances between each electrode correlated strongly (yellow-labeled vs. red-labeled: r = 0.980, p<0.001; red-labeled vs. blue-labeled: r = 0.953, p<0.001; yellow-labeled vs. blue-labeled: r = 0.953, p<0.001). Both angle and distance ratio (expert with simulator vs. without simulator; p = 0.03, p = 0.02) were significantly smaller in procedures performed by experts using the simulator system. The new simulator system appears to accurately guide electrode positioning. This simulator system could allow multipuncture radiofrequency ablation to be performed more effectively and comfortably.