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

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.

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.

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.

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).

Comparison of anatomical thermal ablation and routine thermal ablation for hepatocellular carcinoma≤50 mm: A propensity score matching

AIM

The present study was to evaluated the clinical value of anatomical thermal ablation to treat hepatocellular carcinoma compared with routine thermal ablation.

METHODS

Hepatocellular carcinoma patients with tumor diameter ≤50 mm treated by thermal ablation at our center were retrospectively enrolled from October 2015 to December 2018. Enrolled patients were grouped into the anatomical ablation group and routine ablation group, respectively. To minimize the effects of potential confounders from selection bias, a propensity score matching was carried out. Technical efficacy, recurrence and survivals rates were compared.

RESULTS

Altogether 101 patients (119 lesions) were grouped into the anatomical ablation group and 101 patients (131 lesions) into the routine ablation group. The ablation zone volume of the anatomical ablation group was 36.8 (2.5-176.9) ml, significantly larger than that of the routine ablation group (28.5 [28.5 (2.8-184.3) ml] (p = 0.005)). Adjusted with propensity score matching, The 1-, 2-, and 3-year local recurrence rates were 0.0%, 0.0%, and 0.0% for the anatomical ablation group and 6.9%, 10.1%, and 10.1% for the routine ablation group, respectively (p = 0.013). The cumulative 1-, 2-, and 3-year progression-free survival rates were 93.4%, 82.7%, and 79.0% for the anatomical ablation group, 74.2%, 56.9%, and 51.6% for the routine ablation group (p = 0.001).

CONCLUSIONS

Anatomical ablation could be a favorable ablation strategy to improve therapeutic effect of thermal ablation for HCC with visible feeding vessels and reserved liver function.

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.

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.