Recent advances in radiofrequency ablation for the management of hepatocellular carcinoma

Radiofrequency versus microwave ablation for hepatocellular carcinoma within the Milan criteria in challenging locations: a retrospective controlled study

PURPOSE

The aim of this study was to compare the safety and efficacy of radiofrequency ablation (RFA) with microwave ablation (MWA) for hepatocellular carcinoma (HCC) within the Milan criteria in challenging locations.

METHODS

This study retrospectively investigated 201 consecutive patients with Milan criteria HCCs who underwent RFA (RFA group, n = 150) or MWA (MWA group, n = 51) between January 2012 and December 2016. Overall survival (OS), recurrence-free survival (RFS), local tumor control, and treatment-related complications were compared between the two groups. Prognostic factors were analyzed using the Cox proportional hazard regression model.

RESULTS

Median follow-up duration was 36.7 months (range: 6.2-64.0 months). Cumulative 1-, 3-, and 5-year OS rates were 97.9%, 92.3%, and 80.6% in the MWA group and 96.4%, 87.4%, and 78.2% in the RFA group, respectively, (P = 0.450). Cumulative RFS rates at 1, 3, and 5 years were 93.2%, 74.4%, and 63.7% in the MWA group and 80.3%, 57.3%, and 49.6% in the RFA group, respectively, (P = 0.097). Multivariate analyses showed that variable categories "patient age above 65 years" (P = 0.004) and "more than one tumor" (P = 0.004) were associated with overall mortality, and "patient age above 65 years" (P = 0.048) and "tumor size greater than 3 cm" (P = 0.009) were associated with inferior RFS. The incidences of major complications were not significantly different between the two groups (3.3% vs 3.9%, P = 0.843).

CONCLUSIONS

RFA and MWA were associated with comparable safety and efficacy for HCC within the Milan criteria in challenging locations. Further study in a large, multi-center patient cohort is necessary to validate the results.

Real-time virtual sonography-assisted radiofrequency ablation in liver tumors with conspicuous or inconspicuous images or peritumoral landmarks under ultrasonography

Objectives

The objectives of this study were to determine the primary technique effectiveness (PTE), to compare the complete response and local recurrence rates between conspicuous and inconspicuous tumors using single and switching electrodes of real-time virtual sonography (RVS)-assisted radiofrequency ablation (RFA) in conspicuous and inconspicuous hepatic tumors under conventional ultrasonography (US).

Subjects and method

We compared the complete ablation of inconspicuous tumors with and without anatomical landmark (N = 54) with conspicuous liver tumors (N = 272). Conventional US imaging was done initially, and then these images were fused with CT or MRI arterial-venous-wash-out cross-sectional studies and synchronized with real-time US images.

Results

RVS-assisted RFA was technically feasible in all patients. The PTE rate after the first ablation was 94% (245/261) for conspicuous tumors, 88% (7/8) in inconspicuous tumors with landmark, and 78% (36/46) in inconspicuous tumors without landmark. The complete response (p = 0.1912 vs. p = 0.4776) and local recurrence rate (p = 0.1557 vs. p = 0.7982) were comparable in conspicuous tumors of both HCC and liver metastasis group when single or multiple switching was used. The cumulative local recurrence in the conspicuous and inconspicuous tumors of the HCC group (p = 0.9999) was almost parallel after 12 (10% vs. 4%) and 24 (13% vs. 4%) months of follow-up. In the liver metastasis group, the cumulative local recurrence for conspicuous tumors (p = 0.9564) was nearly equal after 12 and 24 months of monitoring (24% vs. 27%) while no recurrence was incurred for the inconspicuous tumors.

Conclusion

RVS-assisted RFA is an effective tool for the treatment of conspicuous and inconspicuous HCC and hepatic metastasis.

Blocking exposed PD-L1 elicited by nanosecond pulsed electric field reverses dysfunction of CD8+ T cells in liver cancer

As a promising method for local tumor treatment, nanosecond pulsed electric field (nsPEF) ablation elicits a potent anti-tumor immune response. However, the mechanism of the nsPEF-mediated anti-tumor immune response and its effects on the tumor microenvironment remains unclear. Here, we demonstrated that nsPEF treatment increased the level of membrane PD-L1 in liver cancer cells. Furthermore, nsPEF induced the release of PD-L1-associated extra-cellular vesicles, leading to the dysfunction of CD8⁺ T cells, which could potentially be reversed by PD-L1 blockade. Biological and functional assays also demonstrated that nsPEF treatment resulted in the increased PD-L1 level and dysfunction of infiltrated CD8⁺ T cells in tumor tissues in vivo, indicating the long term antitumor efficacy of nsPEF treatment. A combination of nsPEF treatment and PD-L1 blockade effectively inhibited tumor growth and improved the survival of the tumor-bearing mouse. In conclusion, nsPEF treatment induced the translocation and release of PD-L1 and contributed to the dysfunction of infiltrated CD8⁺ T cells, resulting in tumor progression at later stages. The combination of nsPEF treatment and PD-L1 blockade is a promising therapeutic strategy for liver cancer.

Ablation for hepatocellular carcinoma: beyond the standard indications

Hepatocellular carcinoma (HCC), the most common primary liver neoplasia, represents the fifth most common malignant disease in men. Percutaneous ablation treatment is recommended among the treatments suggested for HCC patients in the very early/early stage. In the last decade, very important results in terms of survival benefits have been obtained with local ablative therapies, also outside the standard indications, thanks to many technical innovations. In particular, important results of ablation as a safe and effective technique have been obtained in the treatment of intermediate- or advanced-stage patients with HCC, and in the treatment of unfavourable tumour locations. Moreover, awareness is growing regarding the necessity of overcoming the rigidity of traditional guidelines in the treatment of HCC due to the complexity of patients with HCC, focusing on Precision Medicine. In this context, it is important to know the standard and non-standard indications of ablation in the treatment of HCC in order to offer the best therapeutic option tailored for each patient. The aim of this study was to analyse the possible clinical applications of ablative therapies for HCC patients, beyond the traditional indications recommended in the most widespread clinical practice guidelines for the management of HCC.

Dual-function of Baicalin in nsPEFs-treated Hepatocytes and Hepatocellular Carcinoma cells for Different Death Pathway and Mitochondrial Response

Nanosecond pulsed electric fields (nsPEFs) is emerged as a potential curative modality to ablate hepatocellular carcinoma (HCC). The application of local ablation is usually limited by insufficiency of liver function. While baicalin, a flavonoid isolated from Scutellaria baicalensis Georgi, has been proven to possess both anti-tumor and protective effects. Our study aimed to estimate different responses of hepatic cancer cells and hepatocytes to the combination of nsPEFs and baicalin. Cell viability, apoptosis and necrosis, mitochondrial transmembrane potential (MTP) and reactive oxygen species (ROS) were examined by CCK-8, FCM, JC-1 and fluorescent probe, respectively. After treatment by nsPEFs, most hepatocytes died by apoptosis, nevertheless, nearly all cancer cells were killed through necrosis. Low concentration of baicalin synergically enhanced nsPEFs-induced suppression and necrosis of HCC cells, nevertheless, the application of baicalin protected normal hepatocytes from the injury caused by nsPEFs, owing to elevating mitochondrial transmembrane potential and reducing ROS generation. Our work provided an advantageous therapy for HCC through the enhanced combination treatment of nsPEFs and baicalin, with which could improve the tumor-ablation effect and alleviate the injury of hepatic tissues simultaneously.

Synthesis and characterization of image-able polyvinyl alcohol microspheres for image-guided chemoembolization

Therapeutic embolization of blood vessels is a minimally invasive, catheter-based procedure performed with solid or liquid emboli to treat bleeding, vascular malformations, and vascular tumors. Hepatocellular carcinoma (HCC) affects about half a million people per year. When unresectable, HCC is treated with embolization and local drug therapy by transarterial chemoembolization (TACE). For TACE, drug eluting beads (DC Bead(®)) may be used to occlude or reduce arterial blood supply and deliver chemotherapeutics locally to the tumor. Although this treatment has been shown to be safe and to improve patient survival, the procedure lacks imaging feedback regarding the location of embolic agent and drug coverage. To address this shortcoming, herein we report the synthesis and characterization of image-able drug eluting beads (iBeads) from the commercial DC Bead(®) product. Two different radiopaque beads were synthesized. In one approach, embolic beads were conjugated with 2,3,5-triiodobenzyl alcohol in the presence of 1,1'-carbonyldiimidazol to give iBead I. iBead II was synthesized with a similar approach but instead using a trimethylenediamine spacer and 2,3,5-triiodobenzoic acid. Doxorubicin was loaded into the iBeads II using a previously reported method. Size and shape of iBeads were evaluated using an upright microscope and their conspicuity assessed using a clinical CT and micro-CT. Bland and Dox-loaded iBeads II visualized with both clinical CT and microCT. Under microCT, individual bland and Dox loaded beads had a mean attenuation of 7904 ± 804 and 11,873.96 ± 706.12 HU, respectively. These iBeads have the potential to enhance image-guided TACE procedures by providing localization of embolic-particle and drug.

Percutaneous microwave ablation vs radiofrequency ablation in the treatment of hepatocellular carcinoma

Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse, steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative potential, but fewer than 20% of patients are suitable candidates. Interventional treatments are offered to the vast majority of patients. Radiofrequency (RFA) and microwave ablation (MWA) are among the therapeutic modalities, with similar indications which include the presence of up to three lesions, smaller than 3 cm in size, and the absence of extrahepatic disease. The therapeutic effect of both methods relies on thermal injury, but MWA uses an electromagnetic field as opposed to electrical current used in RFA. Unlike MWA, the effect of RFA is partially limited by the heat-sink effect and increased impedance of the ablated tissue. Compared with RFA, MWA attains a more predictable ablation zone, permits simultaneous treatment of multiple lesions, and achieves larger coagulation volumes in a shorter procedural time. Major complications of both methods are comparable and infrequent (approximately 2%-3%), and they include haemorrhage, infection/abscess, visceral organ injury, liver failure, and pneumothorax. RFA may incur the additional complication of skin burns. Nevertheless, there is no compelling evidence for differences in clinical outcomes, including local recurrence rates and survival.

An overview of loco-regional treatments in patients and mouse models for hepatocellular carcinoma

Hepatocellular carcinoma is a highly aggressive malignancy and is the third leading cause of cancer-related deaths worldwide. Although surgery is currently considered the most effective curative treatment for this type of cancer, it is note that most of patients have a poor prognosis due to chemioresistence and tumor recurrence. Loco-regional therapies, including radiofrequency ablation, surgical resection and transcatheter arterial chemoembolization play a major role in the clinical management of hepatocellular carcinoma. In order to improve the treatment outcome of patients diagnosed with this disease, several in vivo studies by using different techniques on cancer mouse models have been performed. This review will focus on the latest papers on the efficacy of loco-regional therapy and combined treatments in patients and mouse models of hepatocellular carcinoma.

Nanosecond pulsed electric field (nsPEF) treatment for hepatocellular carcinoma: a novel locoregional ablation decreasing lung metastasis

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy. Nanosecond pulsed electric field (nsPEF) is a new technology destroying tumor cells with a non-thermal high voltage electric field using ultra-short pulses. The study's aim was to evaluate the ablation efficacy of nsPEFs with human HCC cell lines and a highly metastatic potential HCC xenograft model on BALB/c nude mice. The in vivo study showed nsPEFs induced HCC cell death in a dose dependent manner. On the high metastatic hepatocellular carcinoma cell line (HCCLM3) xenograft mice model, tumor growth was inhibited significantly in nsPEF-treated- groups (single dose and multi-fractionated dose). Besides a local effect, the nsPEF treatment reduced pulmonary metastases. The nsPEFs also enhanced HCC cell phagocytosis by human macrophage cell (THP1) in vitro. The nsPEF is efficient in controlling HCC progression and reducing its metastasis. NsPEF treatment may elicit a host immune response against tumor cells. This study suggests nsPEF therapy could be used as a potential locoregional therapy for hepatocellular carcinoma.

Percutaneous ablation therapy versus surgical resection in the treatment for early-stage hepatocellular carcinoma: a meta-analysis of 21,494 patients

PURPOSE

To compare comprehensively the benefits of radiofrequency ablation (RFA) and percutaneous ethanol injection (PEI) with those of surgical resection (SR) in early-stage hepatocellular carcinoma (HCC).

METHODS

The potentially relevant studies comparing the efficacy and safety of RFA and/or PEI with those of SR were searched using the databases such as PubMed, MEDLINE, Embase and Chinese databases (CNKI and Wanfang data). Overall survival rate, recurrence-free survival rate and complications were compared and analyzed. Pooled odds ratios with 95 % confidence intervals (95 % CIs) were calculated using either the fixed-effects model or random-effects model. All statistic analyses were conducted using the Review Manager (version 5.1.) from the Cochrane Collaboration.

RESULTS

Our analysis showed that the overall survival rate in patients treated with SR was significantly higher than that of percutaneous ablation therapy (PAT) [SR vs. PAT: 95 % confidence interval (95 % CI)2-year 0.46-0.89, P = 0.009; 95 % CI3-year 0.57-0.83, P < 0.0001; 95 % CI5-year 0.45-0.46, P < 0.0001]. SR was associated with significantly higher recurrence-free survival rate compared with PAT (SR vs. PAT: 95 % CI1-year 0.51-0.90, P = 0.008; 95 % CI2-year 0.41-0.78, P = 0.0004; 95 % CI3-year 0.38-0.77, P = 0.0006; 95 % CI5-year 0.33-0.61, P < 0.0001). SR resulted in longer survival than PAT in HCCs no larger than 3 cm. PAT was associated with less complications compared with SR (PAT vs. SR: 95 % CI 0.14-0.76, P = 0.01).

CONCLUSIONS

Although SR was associated with more complications, SR was superior to RFA and PEI for treatment of patients with early-stage HCC.

Radiofrequency ablation during continuous saline infusion can extend ablation margins

AIM: To determine whether fluid injection during radiofrequency ablation (RFA) can increase the coagulation area.

METHODS: Bovine liver (1-2 kg) was placed on an aluminum tray with a return electrode affixed to the base, and the liver was punctured by an expandable electrode. During RFA, 5% glucose; 50% glucose; or saline fluid was infused continuously at a rate of 1.0 mL/min through the infusion line connected to the infusion port. The area and volume of the thermocoagulated region of bovine liver were determined after RFA. The Joule heat generated was determined from the temporal change in output during the RFA experiment.

RESULTS: No liquid infusion was 17.3 ± 1.6 mL, similar to the volume of a 3-cm diameter sphere (14.1 mL). Mean thermocoagulated volume was significantly larger with continuous infusion of saline (29.3 ± 3.3 mL) than with 5% glucose (21.4 ± 2.2 mL), 50% glucose (16.5 ± 0.9 mL) or no liquid infusion (17.3 ± 1.6 mL). The ablated volume for RFA with saline was approximately 1.7-times greater than for RFA with no liquid infusion, representing a significant difference between these two conditions. Total Joule heat generated during RFA was highest with saline, and lowest with 50% glucose.

CONCLUSION: RFA with continuous saline infusion achieves a large ablation zone, and may help inhibit local recurrence by obtaining sufficient ablation margins. RFA during continuous saline infusion can extend ablation margins, and may be prevent local recurrence.