Irreversible Electroporation versus Radiofrequency Ablation: Comparison of Systemic Immune Responses in Patients with Hepatocellular Carcinoma

Irreversible Electroporation as a Valid Treatment Option for Hepatic Epithelioid Hemangioendothelioma: An International Multicenter Experience

PURPOSE

Hepatic epithelioid hemangioendothelioma (HEHE) is a rare tumor with currently no established standard of care. This international multicenter retrospective study assesses the use of percutaneous irreversible electroporation (IRE) as an ablative tool to treat HEHE and provides a clinical overview of the current management and role of IRE in HEHE treatment.

MATERIAL AND METHODS

Between 2017 and 2023, 14 patients with 47 HEHE tumors were treated with percutaneous IRE using CT-scan guidance in 23 procedures. Baseline patient and tumor characteristics were evaluated. Primary outcome measures included safety and effectiveness, analyzed using Common Terminology Criteria for Adverse Events (CTCAE) and treatment response by mRECIST criteria. Secondary outcome measures included technical success, post-treatment tumor sizes and length of hospital stay. Technical success was defined as complete ablation with an adequate ablative margin (intentional tumor free ablation margin > 5 mm).

RESULTS

IRE treatment resulted in technical success in all tumors. Following a median follow-up of 15 months, 30 tumors demonstrated a complete response according to mRECIST criteria. The average tumor size pre-treatment was 25.8 mm, accompanied by an average reduction in tumor size by 7.5 mm. In 38 out of 47 tumors, there was no evidence of local recurrence. In nine tumors, residual tumor was present. There were no cases of progressive disease. Median length of hospital stay was one day. Only one grade 3 CTCAE event occurred, a pneumothorax requiring chest tube placement.

CONCLUSION

The current study provides evidence that IRE is a safe and efficacious minimally invasive treatment option for HEHE.

Peripheral T-cell subsets in radiofrequency ablation for tumors from different origins

BACKGROUNDS

Radiofrequency ablation (RFA) is known to destroy tumoral tissue and activate immune cells. This study aimed to investigate the impact of RFA on peripheral T-cell responses and its relationship with tumor origin and hepatitis status.

METHODS

A retrospective analysis was conducted on 62 patients with various types of tumors, including hepatocellular carcinoma, colorectal cancer, lung cancer, breast cancer, and others, who underwent RFA treatment between June 2017 and December 2018. Blood samples were collected before and one day after RFA treatment. The peripheral T-cell subsets were measured by flow cytometry, and their changes were analyzed.

RESULTS

The study found a decrease in the CD4+CD8-and CD4-CD8+ T-cell subsets after RFA, but no significant changes were observed in the populations of CD4+CD8+ and the CD4+CD8-/CD4-CD8+ ratio. Furthermore, no significant differences were observed in peripheral T-cell subsets concerning tumor type or hepatitis status.

CONCLUSIONS

The study suggests that RFA treatment may have a short-term impact on peripheral T-cell responses, characterized by a decrease in certain T-cell subsets. However, these changes do not seem to be related to the tumor type or hepatitis status of the patients.

Act Local, Think Global: IR and Its Role in Immuno-Oncology in Hepatocellular Carcinoma

Interventional oncology (IO) is evolving rapidly. The treatment landscape of liver cancer is changing rapidly, and immunotherapy combinations have become the standard of care for most patients with advanced hepatocellular carcinoma (HCC). The higher response rates and improved outcomes observed with these agents are leading to initiatives for their earlier incorporation in the course of the disease, including in combination with ablative and transarterial treatment options. The intersectionality of systemic therapies and liver-directed approaches has allowed IO to be at the center stage of a rapidly evolving dynamic field across all stages of HCC. This review article will address the current state of treatment for advanced HCC and the incorporation of these options in both localized and advanced stages along with IO to further enhance the observed benefits.

Irreversible Electroporation of the Hepatobiliary System: Current Utilization and Future Avenues

Liver cancer remains a leading cause of cancer-related deaths worldwide despite numerous advances in treatment. While surgical resection remains the gold standard for curative treatment, it is only possible for a minority of patients. Thermal ablation is an effective option for the treatment of smaller tumors; however, its use is limited to tumors that are not located in proximity to sensitive structures due to the heat sink effect and the potential of thermal damage. Irreversible electroporation (IRE) is a non-thermal ablative modality that can deliver targeted treatment and the effective destruction of tumors that are in close proximity to or even surrounding vascular or biliary ducts with minimal damage to these structures. IRE produces short pulses of high-frequency energy which opens pores in the lipid bilayer of cells leading to apoptosis and cell death. IRE has been utilized clinically for over a decade in the treatment of liver cancers with multiple studies documenting an acceptable safety profile and high efficacy rates.

New Insights on Liver-Directed Therapies in Hepatocellular Carcinoma

The incidence of hepatocellular carcinoma (HCC) has been increasing over the past decades, but improvements in systemic and locoregional therapies is increasing survival. Current locoregional treatment options include ablation, transarterial chemoembolization (TACE), transarterial radioembolization (TARE), and stereotactic body radiotherapy (SBRT). There is ongoing research regarding the combination of systemic and local therapies to maximize treatment effect as well as in new non-invasive, image-guided techniques such as histotripsy. There is also active research in optimizing the delivery of therapy to tumors via nanostructures and viral-vector-mediated gene therapies. In many cases, patients require a combination of therapies to achieve tumor control and prolong survival. This article provides an overview of the most common liver-directed therapies for HCC as well as insight into more recent advances in personalized medicine and emerging techniques.

Ablative and non-surgical therapies for early and very early hepatocellular carcinoma: a systematic review and network meta-analysis

Background

A wide range of ablative and non-surgical therapies are available for treating small hepatocellular carcinoma in patients with very early or early-stage disease and preserved liver function.

Objective

To review and compare the effectiveness of all current ablative and non-surgical therapies for patients with small hepatocellular carcinoma (≤ 3 cm).

Design

Systematic review and network meta-analysis.

Data sources

Nine databases (March 2021), two trial registries (April 2021) and reference lists of relevant systematic reviews.

Review methods

Eligible studies were randomised controlled trials of ablative and non-surgical therapies, versus any comparator, for small hepatocellular carcinoma. Randomised controlled trials were quality assessed using the Cochrane Risk of Bias 2 tool and mapped. The comparative effectiveness of therapies was assessed using network meta-analysis. A threshold analysis was used to identify which comparisons were sensitive to potential changes in the evidence. Where comparisons based on randomised controlled trial evidence were not robust or no randomised controlled trials were identified, a targeted systematic review of non-randomised, prospective comparative studies provided additional data for repeat network meta-analysis and threshold analysis. The feasibility of undertaking economic modelling was explored. A workshop with patients and clinicians was held to discuss the findings and identify key priorities for future research.

Results

Thirty-seven randomised controlled trials (with over 3700 relevant patients) were included in the review. The majority were conducted in China or Japan and most had a high risk of bias or some risk of bias concerns. The results of the network meta-analysis were uncertain for most comparisons. There was evidence that percutaneous ethanol injection is inferior to radiofrequency ablation for overall survival (hazard ratio 1.45, 95% credible interval 1.16 to 1.82), progression-free survival (hazard ratio 1.36, 95% credible interval 1.11 to 1.67), overall recurrence (relative risk 1.19, 95% credible interval 1.02 to 1.39) and local recurrence (relative risk 1.80, 95% credible interval 1.19 to 2.71). Percutaneous acid injection was also inferior to radiofrequency ablation for progression-free survival (hazard ratio 1.63, 95% credible interval 1.05 to 2.51). Threshold analysis showed that further evidence could plausibly change the result for some comparisons. Fourteen eligible non-randomised studies were identified (n ≥ 2316); twelve had a high risk of bias so were not included in updated network meta-analyses. Additional non-randomised data, made available by a clinical advisor, were also included (n = 303). There remained a high level of uncertainty in treatment rankings after the network meta-analyses were updated. However, the updated analyses suggested that microwave ablation and resection are superior to percutaneous ethanol injection and percutaneous acid injection for some outcomes. Further research on stereotactic ablative radiotherapy was recommended at the workshop, although it is only appropriate for certain patient subgroups, limiting opportunities for adequately powered trials.

Limitations

Many studies were small and of poor quality. No comparative studies were found for some therapies.

Conclusions

The existing evidence base has limitations; the uptake of specific ablative therapies in the United Kingdom appears to be based more on technological advancements and ease of use than strong evidence of clinical effectiveness. However, there is evidence that percutaneous ethanol injection and percutaneous acid injection are inferior to radiofrequency ablation, microwave ablation and resection.

Study registration

PROSPERO CRD42020221357.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment (HTA) programme (NIHR award ref: NIHR131224) and is published in full in Health Technology Assessment; Vol. 27, No. 29. See the NIHR Funding and Awards website for further award information.

Effects of Inflammatory Cell Death Caused by Catheter Ablation on Atrial Fibrillation

Atrial fibrillation (AF) poses a serious healthcare burden on society due to its high morbidity and the resulting serious complications such as thrombosis and heart failure. The principle of catheter ablation is to achieve electrical isolation by linear destruction of cardiac tissue, which makes AF a curable disease. Currently, catheter ablation does not have a high long-term success rate. The current academic consensus is that inflammation and fibrosis are central mechanisms in the progression of AF. However, artificially caused inflammatory cell death by catheter ablation may have a significant impact on structural and electrical remodeling, which may affect the long-term prognosis. This review first focused on the inflammatory response induced by apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis and their interaction with arrhythmia. Then, we compared the differences in cell death induced by radiofrequency ablation, cryoballoon ablation and pulsed-field ablation. Finally, we discussed the structural and electrical remodeling caused by inflammation and the association between inflammation and the recurrence of AF after catheter ablation. Collectively, pulsed-field ablation will be a revolutionary innovation with faster, safer, better tissue selectivity and less inflammatory response induced by apoptosis-dominated cell death.

Immunomodulatory effect of locoregional therapy in the tumor microenvironment

Cancer immunotherapy appears to be a promising treatment option; however, only a subset of patients with cancer responds favorably to treatment. Locoregional therapy initiates a local antitumor immune response by disrupting immunosuppressive components, releasing immunostimulatory damage-associated molecular patterns, recruiting immune effectors, and remodeling the tumor microenvironment. Many studies have shown that locoregional therapy can produce specific antitumor immunity alone; nevertheless, the effect is relatively weak and transient. Furthermore, increasing research efforts have explored the potential synergy between locoregional therapy and immunotherapy to enhance the long-term systemic antitumor immune effect and improve survival. Therefore, further research is needed into the immunomodulatory effects of locoregional therapy and immunotherapy to augment antitumor effects. This review article summarizes the key components of the tumor microenvironment, discusses the immunomodulatory role of locoregional therapy in the tumor microenvironment, and emphasizes the therapeutic potential of locoregional therapy in combination with immune checkpoint inhibitors.

The latest research progress on minimally invasive treatments for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. Due to the high prevalence of hepatitis B virus (HBV) infection in China, the incidence of HCC in China is high, and liver cirrhosis caused by chronic hepatitis also brings great challenges to treatment. This paper reviewed the latest research progress on minimally invasive treatments for HCC, including percutaneous thermal ablation and new nonthermal ablation techniques, and introduced the principles, advantages, and clinical applications of various therapeutic methods in detail.

DATA SOURCES

The data of treatments for HCC were systematically collected from the PubMed, ScienceDirect, American Chemical Society and Web of Science databases published in English, using "minimally invasive" and "hepatocellular carcinoma" or "liver cancer" as the keywords.

RESULTS

Percutaneous thermal ablation is still a first-line strategy for the minimally invasive treatment of HCC. The effect of microwave ablation (MWA) on downgrading treatment before liver transplantation is better than that of radiofrequency ablation (RFA), while RFA is more widely used in the clinical practice. High-intensity focused ultrasound (HIFU) is mainly used for the palliative treatment of advanced liver cancer. Electrochemotherapy (ECT) delivers chemotherapeutic drugs to the target cells while reducing the blood supply around HCC. Irreversible electroporation (IRE) uses a microsecond-pulsed electric field that induces apoptosis and necrosis and triggers a systemic immune response. The nanosecond pulsed electric field (nsPEF) has achieved a good response in the ablation of mice with HCC, but it has not been reported in China for the treatment of human HCC.

CONCLUSIONS

A variety of minimally invasive treatments provide a sufficient survival advantage for HCC patients. Nonthermal ablation will lead to a new wave with its unique advantage of antitumor recurrence and metastasis.

Macrophage activity at the site of tumor ablation can promote murine urothelial cancer via transforming growth factor-β1

Cell death and injury at the site of tumor ablation attracts macrophages. We sought to understand the status and activity of these cells while focusing on transforming growth factor-β1 (TGF-β1), a potent immunosuppressive and tumorigenic cytokine. Patients with urothelial cancer who underwent ablation using electrocautery or laser demonstrated increased infiltration and numbers of CD8+ T cells, along with FoxP3+ regulatory T cells, CD68+ macrophages and elevated levels of TGF-β1 in recurrent tumors. Similar findings were reproduced in a mouse model of urothelial cancer (MB49) by partial tumor ablation with irreversible electroporation (IRE). Stimulation of bone marrow derived macrophages with MB49 cell debris produced using IRE elicited strong M2 polarization, with exuberant secretion of TGF-β1. The motility, phenotypic markers and cytokine secretion by macrophages could be muted by treatment with Pirfenidone (PFD), a clinically approved drug targeting TGF-β1 signaling. MB49 cancer cells exposed to TGF-β1 exhibited increased migration, invasiveness and upregulation of epithelial-mesenchymal transition markers α-Smooth Muscle Actin and Vimentin. Such changes in MB49 cells were reduced by treatment with PFD even during stimulation with TGF-β1. IRE alone yielded better local tumor control when compared with control or PFD alone, while also reducing the overall number of lung metastases. Adjuvant PFD treatment did not provide additional benefit under in vivo conditions.

Assessment of Hepatic Lesions After non-Thermal Tumor Ablation by Irreversible Electroporation in a Pig Model

Irreversible electroporation (IRE) is a non-thermal and minimal invasive modality to ablate pathologic lesions such as hepatic tumors. Histological analysis of the initial lesions after IRE can help predict ablation efficacy. We aimed to investigate the histological characteristics of early hepatic lesions after IRE application using animal models. IRE (1500 V/cm, a pulse length of 100 μs, 60 or 90 pulses) was applied to the liver of miniature pigs. H&E and TUNEL staining were performed and analyzed. Ablated zones of pig liver were discolored and separated from the normal zone after IRE. Histologic characteristics of ablation zones included preserved hepatic lobular architecture with a unique hexagonal-like structure. Apoptotic cells were detected, and sinusoidal dilatation and blood congestion were observed, but hepatic arteries and bile ducts were intact around the ablation zones. The early lesions obtained by delivering monophasic square wave pulses through needle electrodes reflected typical histological changes induced by IRE. Therefore, it was found that the histological assessment of the early hepatic lesion after IRE can be utilized to predict the IRE ablation effect.

First-in-man histotripsy of hepatic tumors: the THERESA trial, a feasibility study

Rationale Current hepatic locoregional therapies are limited in terms of effectiveness and toxicities. Given promising pre-clinical results, a first in-human trial was designed to assess the technical effectiveness and safety profile of histotripsy, a noninvasive, non-thermal, non-ionizing focused ultrasound therapy that creates precise, predictable tissue destruction, in patients with primary and secondary liver tumors.Methods A multicenter phase I trial (Theresa Study) was performed in a single country with 8 weeks of planned follow-up. Eight of fourteen recruited patients were deemed eligible and enrolled in the study. Hepatic histotripsy, was performed with a prototype system (HistoSonics, Inc., Ann Arbor, MI). Eleven tumors were targeted in the 8 patients who all had unresectable end-stage multifocal liver tumors: colorectal liver metastases (CRLM) in 5 patients (7 tumors), breast cancer metastases in 1 (1 tumor), cholangiocarcinoma metastases in 1 (2 tumors), and hepatocellular carcinoma (HCC) in 1 (1 tumor). The primary endpoint was acute technical success, defined as creating a zone of tissue destruction per planned volume assessed by MRI 1-day post-procedure. Safety (device-related adverse events) through 2 months was a secondary endpoint.Results The 8 patients had a median age of 60.4 years with an average targeted tumor diameter of 1.4 cm. The primary endpoint was achieved in all procedures. The secondary safety profile endpoint identified no device-related adverse events. Two patients experienced a continuous decline in tumor markers during the eight weeks following the procedure.Conclusions This first-in-human trial demonstrates that hepatic histotripsy effectively destroys liver tissue in a predictable manner, correlating very well with the planned histotripsy volume, and has a high safety profile without any device-related adverse events. Based on these results, the need for more definitive clinical trials is warranted. Trial Registration: Study to Evaluate VORTX Rx (Theresa). NCT03741088. https://clinicaltrials.gov/ct2/show/NCT03741088 KEY POINTSHistotripsy, a new noninvasive, non-thermal, non-ionizing focused ultrasound therapy, safely created a zone of tissue destruction in the liver that correlated very well with the pre-defined planned tissue destruction volume.In this first human trial histotripsy was well tolerated with no histotripsy device-related adverse events and its primary endpoint of acute technical success was achieved in all 8 enrolled patients with primary or secondary liver tumors.This new locoregional therapy for patients with liver tumors is safe and effective, warranting further trials.

High-frequency irreversible electroporation brain tumor ablation: exploring the dynamics of cell death and recovery

Improved therapeutics for malignant brain tumors are urgently needed. High-frequency irreversible electroporation (H-FIRE) is a minimally invasive, nonthermal tissue ablation technique, which utilizes high-frequency, bipolar electric pulses to precisely kill tumor cells. The mechanisms of H-FIRE-induced tumor cell death and potential for cellular recovery are incompletely characterized. We hypothesized that tumor cells treated with specific H-FIRE electric field doses can survive and retain proliferative capacity. F98 glioma and LL/2 Lewis lung carcinoma cell suspensions were treated with H-FIRE to model primary and metastatic brain cancer, respectively. Cell membrane permeability, apoptosis, metabolic viability, and proliferative capacity were temporally measured using exclusion dyes, condensed chromatin staining, WST-8 fluorescence, and clonogenic assays, respectively. Both tumor cell lines exhibited dose-dependent permeabilization, with 1,500 V/cm permitting and 3,000 V/cm inhibiting membrane recovery 24 h post-treatment. Cells treated with 1,500 V/cm demonstrated significant and progressive recovery of apoptosis and metabolic activity, in contrast to cells treated with higher H-FIRE doses. Cancer cells treated with recovery-permitting doses of H-FIRE maintained while those treated with recovery-inhibiting doses lost proliferative capacity. Taken together, our data suggest that H-FIRE induces reversible and irreversible cellular damage in a dose-dependent manner, and the presence of dose-dependent recovery mechanisms permits tumor cell proliferation.

Exploration of Novel Pathways Underlying Irreversible Electroporation Induced Anti-Tumor Immunity in Pancreatic Cancer

Advancements in medical sciences and technologies have significantly improved the survival of many cancers; however, pancreatic cancer remains a deadly diagnosis. This malignancy is often diagnosed late in the disease when metastases have already occurred. Additionally, the location of the pancreas near vital organs limits surgical candidacy, the tumor's immunosuppressive environment limits immunotherapy success, and it is highly resistant to radiation and chemotherapy. Hence, clinicians and patients alike need a treatment paradigm that reduces primary tumor burden, activates systemic anti-tumor immunity, and reverses the local immunosuppressive microenvironment to eventually clear distant metastases. Irreversible electroporation (IRE), a novel non-thermal tumor ablation technique, applies high-voltage ultra-short pulses to permeabilize targeted cell membranes and induce cell death. Progression with IRE technology and an array of research studies have shown that beyond tumor debulking, IRE can induce anti-tumor immune responses possibly through tumor neo-antigen release. However, the success of IRE treatment (i.e. full ablation and tumor recurrence) is variable. We believe that IRE treatment induces IFNγ expression, which then modulates immune checkpoint molecules and thus leads to tumor recurrence. This indicates a co-therapeutic use of IRE and immune checkpoint inhibitors as a promising treatment for pancreatic cancer patients. Here, we review the well-defined and speculated pathways involved in the immunostimulatory effects of IRE treatment for pancreatic cancer, as well as the regulatory pathways that may negate these anti-tumor responses. By defining these underlying mechanisms, future studies may identify improvements to systemic immune system engagement following local tumor ablation with IRE and beyond.

Irreversible electroporation versus radiofrequency ablation for malignant hepatic tumor: A prospective single-center double-arm trial

Objective

Irreversible electroporation (IRE) is a nonthermal ablation technique for the treatment of malignant liver tumors. IRE has demonstrated efficacy and safety in the treatment of malignant liver tumors and its unique advantages in the treatment of nearby vascular lesions. This study aimed to compare the efficacy, safety, and intermediate-term outcomes of IRE and radiofrequency (RF) therapy in malignant liver tumors.

Methods

Twenty-four patients with primary or secondary liver malignancies were included in this prospective, double-arm clinical trial. Patients were randomly divided into the IRE and RF groups. The primary outcome was the efficacy (local ablation control evaluation at 90 days). The secondary outcomes were safety (procedure-related complications at ​≤ ​90 days) and intermediate-term survival (at 24 months).

Results

The ablation assessment at 90 days after surgery with mRECIST for IRE versus RF were 70%, 20%, 0%, and 10% versus 92.9%, 7.1%, 0%, and 0% (CR, PR, SD, and PD, respectively). The complication rates of IRE versus RF with Clavien-Dindo classification were 16.7%, 25%, 0%, 8.3%, and 8.3% versus 8.3%, 50%, 0%, 0%, and 0% (Grade I, II, III, IV, and V, respectively). The average overall survival (OS) was 17.55 months in the IRE group (95% CI 15.13-22.37) and 18.75 months in the RF group (95% CI 12.48-22.61). There was no statistical difference between the IRE and RF groups in terms of efficacy (p ​= ​0.48), safety(p ​= ​0.887), or 24-month OS (p ​= ​0.959).

Conclusions

IRE ablation revealed similar efficacy and safety in a short-term follow-up, and similar OS in mid-term survival as RF ablation in treating malignant hepatic tumors.

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A prospective single-center double-arm clinical trial of IRE/RF.

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Study compared efficacy, safety in short-term and intermediate-term overall survival of IRE and RF in liver malignant tumors.

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All procedures were performed with CT-guided percutaneous ablation..

Irreversible Electroporation: An Emerging Immunomodulatory Therapy on Solid Tumors

Irreversible electroporation (IRE), a novel non-thermal ablation technique, is utilized to ablate unresectable solid tumors and demonstrates favorable safety and efficacy in the clinic. IRE applies electric pulses to alter the cell transmembrane voltage and causes nanometer-sized membrane defects or pores in the cells, which leads to loss of cell homeostasis and ultimately results in cell death. The major drawbacks of IRE are incomplete ablation and susceptibility to recurrence, which limit its clinical application. Recent studies have shown that IRE promotes the massive release of intracellular concealed tumor antigens that become an “in-situ tumor vaccine,” inducing a potential antitumor immune response to kill residual tumor cells after ablation and inhibiting local recurrence and distant metastasis. Therefore, IRE can be regarded as a potential immunomodulatory therapy, and combined with immunotherapy, it can exhibit synergistic treatment effects on malignant tumors, which provides broad application prospects for tumor treatment. This work reviewed the current status of the clinical efficacy of IRE in tumor treatment, summarized the characteristics of local and systemic immune responses induced by IRE in tumor-bearing organisms, and analyzed the specific mechanisms of the IRE-induced immune response. Moreover, we reviewed the current research progress of IRE combined with immunotherapy in the treatment of solid tumors. Based on the findings, we present deficiencies of current preclinical studies of animal models and analyze possible reasons and solutions. We also propose possible demands for clinical research. This review aimed to provide theoretical and practical guidance for the combination of IRE with immunotherapy in the treatment of malignant tumors.

Loco-Regional Treatments for Hepatocellular Carcinoma in People Living with HIV

Hepatocellular carcinoma (HCC) accounts for approximately 75–90% of primary liver cancers and is the sixth most common cancer and the third leading cause of cancer-related deaths worldwide. In the HIV-positive population, the risk of HCC is approximately four times higher than in the general population, with higher cancer-specific mortality than in HIV-negative patients. In most cases, HCC diagnosis is made in patients younger than the HIV-negative population and in the intermediate-advanced stage, thus limiting the therapeutic possibilities. Treatment choice in HIV-positive patients with HCC is subject to cancer staging, liver function and health status, as for HIV-negative and non-HIV-negative HCC patients. There are relatively few studies on the efficacy and safety in HIV-positive patients to date in loco-regional treatments for HCC. So far, literature shows that curative treatments such as radiofrequency ablation (RFA) have no significant differences in overall survival between HIV-positive and HIV-negative patients, as opposed to palliative treatments such as TACE, where there is a significant difference in overall survival. Although it can be assumed that the most recently discovered loco-regional therapies are applicable to HIV-positive patients with HCC in the same way as HIV-negative patients, further studies are needed to confirm this hypothesis. The purpose of our review is to evaluate these treatments, their efficacy, effectiveness, safety and their applicability to HIV-positive patients.

Interventional Radiology Image-Guided Locoregional Therapies (LRTs) and Immunotherapy for the Treatment of HCC

Image-guided locoregional therapies (LRTs) are a crucial asset in the treatment of hepatocellular carcinoma (HCC), which has proven to be characterized by an impaired antitumor immune status. LRTs not only directly destroy tumor cells but also have an immunomodulating role, altering the tumor microenvironment with potential systemic effects. Nevertheless, the immune activation against HCC induced by LRTs is not strong enough on its own to generate a systemic significant antitumor response, and it is incapable of preventing tumor recurrence. Currently, there is great interest in the possibility of combining LRTs with immunotherapy for HCC, as this combination may result in a mutually beneficial and synergistic relationship. On the one hand, immunotherapy could amplify and prolong the antitumoral immune response of LRTs, reducing recurrence cases and improving outcome. On the other hand, LTRs counteract the typical immunosuppressive HCC microenvironment and status and could therefore enhance the efficacy of immunotherapy. Here, after reviewing the current therapeutic options for HCC, we focus on LRTs, describing for each of them the technique and data on its effect on the immune system. Then, we describe the current status of immunotherapy and finally report the recently published and ongoing clinical studies testing this combination.

Changes of immune cells in patients with hepatocellular carcinoma treated by radiofrequency ablation and hepatectomy, a pilot study

In this pilot study, we compared the dynamic changes of circulating immune cells between patients with hepatocellular carcinoma (HCC) who underwent radiofrequency ablation (RFA) and hepatectomy. Seventy-three patients were enrolled in this study. Flow cytometry assay was performed to determine the immune cells in the peripheral blood mononuclear cells (PBMCs) before treatment and on days 7, 14, and 28 after treatment. We found that in the RFA group, the circulating cluster of differentiation (CD)4+ cells, the CD4+/CD8+ ratio, and natural killer (NK) cells continued to increase, and the circulating CD8+ cells continued to decrease after the treatment. In contrast, in the surgery group, the circulating CD4+ cells and CD4+/CD8+ ratio decreased over the first seven postoperative days and then began to increase, and CD8+ cells decreased on the first 7 postoperative days and began to increase thereafter. The changes of immune cells in tumor tissues consisted of an increase in the number of CD4+ cells, CD8+ cells, CD3+ cells, and NK cells immediately after RFA. Our results show that postoperative immune function continued to improve after RFA, but after surgery, it decreased in the first week and started to improve thereafter. These findings are important for clinicians when selecting the appropriate therapy for HCC.

Ablation Zone Involution of Liver Tumors Is Faster in Patients Treated with Irreversible Electroporation Than Microwave Ablation

Background and Objectives: To compare ablation zone involution following microwave ablation (MWA) or irreversible electroporation (IRE) of liver tumors. Materials and Methods: MWA or IRE performed for colorectal cancer liver metastasis (CRLM) or hepatocellular carcinoma (HCC) during January 2011 to December 2015 were analyzed. Patients with a tumoral response on 1-year follow-up computed tomography (CT) were included. Generalized estimating equations were used to evaluate the differences between the two modalities on ablation zone involution observed on CT at 6 (M6) and 12 months (M12), and on laboratory values (total bilirubin, alanine transaminase, aspartate transaminase, alkaline phosphatase, albumin, and platelets count). The likelihood ratio test was used to assess whether the association between ablation modalities and these outcomes differed over time. Results: Seventeen (17/44, 39%) women and 27 (27/44, 61%) men were included, with 25 HCC (25/44, 57%) and 19 CRLM (19/44, 43%) patients. IRE was used in 9 (9/19, 47%) CRLM and 5 (5/25, 20%) HCC patients, respectively. All other patients had MWA. Ablation zone size and involution between IRE and MWA differed significantly over time (interaction p < 0.01), with a mean of 241.04 vs. 771.08 mm2 (ratio 0.313; 95% CI, 0.165-0.592; p < 0.01) at M6 and 60.47 vs. 589.43 mm2 (ratio 0.103; 95% CI, 0.029-0.365; p < 0.01) at M12. Changes in liver enzymes did not differ significantly between IRE and MWA at both timepoints. Conclusions: Liver tumors treated with IRE underwent faster involution when compared to tumors treated with MWA, but liver enzymes levels were comparable.

Irreversible electroporation versus radiofrequency ablation for hepatocellular carcinoma: a single centre propensity-matched comparison

BACKGROUND AND AIMS

Irreversible electroporation (IRE) is a relatively new non-thermal ablative method for unresectable hepatocellular carcinoma (HCC). We aimed to compare the longer-term efficacy of IRE to the standard thermal technique of radiofrequency ablation (RFA) in HCC.

METHODS

All patients who underwent IRE or RFA for HCC in our centre were identified and demographic and clinical data were analysed up until 1st March, 2020. Local recurrence-free survival (LRFS) was compared between groups after propensity score matching for age, gender, Child-Pugh grade, BCLC stage, lesion size and alpha-fetoprotein (AFP) level.

RESULTS

A total of 190 HCC ablations (31 IRE and 159 RFA) were identified. After propensity score matching, we compared 25 IRE procedures (76% males, median age 62.4 years, median tumour size 20 mm) to 96 RFA procedures (84.4% males, median age 64.3 years, median tumour size 18.5 mm). LRFS did not differ between groups, with a 1-, 2- and 5-year LRFS of 80.4% (95% CI 55.8-92.2), 69.1% (95% CI 43.3-84.9) and 44.9% (95% CI 18.9-68.1%), respectively for IRE and 84.8% (95% CI 75.2-90.9), 71.3% (95% CI 58.3-81.0) and 52.1% (95% CI 35.4-66.4%), respectively for RFA (p = .63). There were no major procedure-related complications or deaths in either group.

CONCLUSIONS

Whilst IRE remains a relatively novel therapy for HCC cases where standard thermal ablation is contraindicated, the LRFS in our centre is comparable to that of RFA. IRE should therefore be considered as a treatment option in such cases when available before stage-migration to non-curative therapies such as transarterial chemoembolization (TACE).

Radiofrequency ablation of hepatocellular carcinoma: Prognostic factors and recent advances

With the improvement of technology and diagnostic level, radiofrequency ablation (RFA) has made rapid progress in the treatment of primary hepatocellular carcinoma (HCC) in the past two decades. Especially, the overall survival after the treatment of small HCCs by RFA can be comparable to that achieved by hepatic resection. The 10-year survival rates of RFA for HCC were 27.3%-46.1%, and for solitary HCC less than 3 cm, the 10-year survival rate is about 74.0%. RFA combined with other therapies can expand the indications of RFA treatment and benefit the survival of patients with HCC. The prognostic model of RFA for HCC provides a powerful tool for individualized clinical diagnosis and treatment.

Locoregional therapies in the era of molecular and immune treatments for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related mortality and has an increasing incidence worldwide. Locoregional therapies, defined as imaging-guided liver tumour-directed procedures, play a leading part in the management of 50-60% of HCCs. Radiofrequency is the mainstay for local ablation at early stages and transarterial chemoembolization (TACE) remains the standard treatment for intermediate-stage HCC. Other local ablative techniques (microwave ablation, cryoablation and irreversible electroporation) or locoregional therapies (for example, radioembolization and sterotactic body radiation therapy) have been explored, but have not yet modified the standard therapies established decades ago. This understanding is currently changing, and several drugs have been approved for the management of advanced HCC. Molecular therapies dominate the adjuvant trials after curative therapies and combination strategies with TACE for intermediate stages. The rationale for these combinations is sound. Local therapies induce antigen and proinflammatory cytokine release, whereas VEGF inhibitors and tyrosine kinase inhibitors boost immunity and prime tumours for checkpoint inhibition. In this Review, we analyse data from randomized and uncontrolled studies reported with ablative and locoregional techniques and examine the expected effects of combinations with systemic treatments. We also discuss trial design and benchmarks to be used as a reference for future investigations in the dawn of a promising new era for HCC treatment.

Immunological effect of irreversible electroporation on hepatocellular carcinoma

Background

This study intends to investigate the immunological effects of tumor ablation with irreversible electroporation (IRE).

Methods

We evaluated the systemic immune response in patients with hepatocellular carcinoma (HCC) after IRE treatment. Furthermore, we analyzed the tumor infiltrating T lymphocytes and the level of serum cytokines in IRE and control groups of tumor-bearing mice.

Results

We observed that IRE induced an increase in WBC, neutrophil and monocyte counts and a decrease in lymphocyte count 1 day post-IRE and returned to baseline values within 7 days in the patients. Meanwhile, circulating CD4⁺ T cell subsets, but not CD8⁺, decreased 1 day post-IRE. The activated T cells and natural killer (NK) cells increased, and regulatory T (Treg) cells decreased. Furthermore, a significant increase in cytotoxic CD8⁺ T cells infiltration was observed on ablative tumors in mice. The level of serum IFN-γ also significantly increased in the IRE group.

Conclusions

Our study demonstrated that IRE upregulated activated T cells and downregulated Tregs in the peripheral blood of patients. Meanwhile, the results from the animal model indicated that IRE could induce antitumor adaptive immunity dominated by the infiltration of cytotoxic CD8⁺ T cells into the tumors, accompanied by reduced Tregs.

Irreversible Electroporation of Recurrent Hepatocellular Carcinoma After Liver Transplantation: Report of Two Cases

The treatment strategies of post-transplant hepatocellular carcinoma (HCC) recurrence have not been completely clarified. Thermal ablative techniques have been increasingly performed for the treatment of post-transplant HCC recurrences. However, thermal ablation can create abnormal communication with the biliary tract and the ablation site by causing biliary injury. This abnormal communication may cause bacterial contamination and abscess formation. Irreversible electroporation (IRE) is a nonthermal ablative technique which may reduce the risk of abscess development at the ablation site due to its low risk of thermal injury to the biliary system. IRE may also preserve the perilesional blood vessels. This report describes two cases of post-transplant intrahepatic HCC recurrence which were successfully treated with IRE.

Efficacy and safety of irreversible electroporation for malignant liver tumors: a systematic review and meta-analysis

OBJECTIVE

The data regarding overall survival (OS) and progression-free survival (PFS) following irreversible electroporation (IRE) is scarce. We performed a systematic review of the safety and efficacy of IRE for liver malignancies.

METHODS

Searches of MEDLINE, EMBASE, and SCOPUS databases were performed through September 1, 2019. Studies reporting the survival data (OS and PFS) and complications (graded according to the Society of interventional Radiology classification) were included. A generalized linear mixed method with a random-effects model was used for assessing pooled incidence rates and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 25 studies (n = 776, 15 prospective, 10 retrospective) were included. Metastasis, hepatocellular carcinoma, and cholangiocarcinoma were present in 354, 285, and 100 patients, respectively. The pooled OS at 6, 12, 24, and 36 months was 93.28% (95% CI: 63.23-99.12, I²= 67%), 81.29% (95% CI: 69.80-89.22, I² = 73%), 61.47% (95% CI: 52.81-69.46, I² = 0%), and 40.88% (95% CI: 28.43-54.61, I² = 64%), respectively. The pooled PFS at 6, 12, and 24 months was 79.72% (95% CI: 67.88-87.97, I² = 70%), 64.19% (95% CI: 56.68-71.06, I² = 57%), 49.05% (95% CI: 11.47-87.73, I² = 96%), respectively. Overall complication rate was 23.7%. Major complications (grade C-F) occurred in 6.9% patients.

CONCLUSION

IRE is associated with favorable OS and PFS. Although the overall complication rate is high, most complications are graded as minor.

KEY POINTS

• The pooled OS and PFS at 6, 12, and 24 months for all the tumor types was 93.28% and 79.72%, 81.29% and 64.19%, and 61.47% and 49.05%, respectively. • HCC was associated with a better OS at 12 and 36 months. • The overall complication rate was 23.7%, with major complications (SIR grade C-F) comprising 6.9%.

Irreversible electroporation induces CD8+ T cell immune response against post-ablation hepatocellular carcinoma growth

Ablative treatment evokes antitumor immunity, but knowledge on the emerging irreversible electroporation (IRE)-induced immunity in hepatocellular carcinoma (HCC) is limited. To investigate the immune effects induced by IRE and its role in preventing post-ablation HCC progression, a C57BL/6J mouse model bearing subcutaneous H22 hepatoma was employed. IRE treatment significantly suppresses HCC growth, and treated mice are tumor-free after secondary tumor injection and show increased splenic interferon-gamma (IFN-γ)+CD8⁺ T cells. Additionally, more CD8⁺ T and dendritic cells, but not CD4⁺ T, B or NK cells, infiltrate into peri-ablation zones after IRE at day 7. Depletion of CD8⁺ T cells induces local tumor regrowth and distant metastasis after IRE. Vaccination using IRE-processed H22 lysates prevents tumorigenesis in mice, suggesting a protective immune response. IRE also alleviates immunosuppression by reducing local and splenic Treg and PD-1⁺ T cells. Regarding mechanism, IRE induces cell necrosis and significant release of danger-associated molecular patterns including ATP, high mobility group box 1 and calreticulin that are pivotal to CD8⁺ T cell immunity. Together, IRE is a promising approach to evoke CD8⁺ T cell immunity, which help prevent post-ablation HCC progression.

Intraprocedural Transcatheter Intraarterial Perfusion (TRIP)-MRI for Evaluation of Irreversible Electroporation Therapy Response in a Rabbit Liver Tumor Model

Purpose

Irreversible electroporation (IRE) is a promising new ablation method for hepatocellular carcinoma (HCC) treatment with few side-effects; however, tissue perfusion and differentiation between treatment zones have not been sufficiently studied. In this project, we analyzed HCC tumor perfusion changes immediately after IRE treatment using transcatheter intraarterial perfusion (TRIP)-MRI to monitor treatment zone margins.

Materials and Methods

All protocols were approved by the institutional animal care and use committee. A total of 34 rabbits were used for this prospective study: tumor liver group (n=17), normal liver group (n=14), and 3 for growing VX2 tumors. All procedures and imaging were performed under anesthesia. VX2 tumors were grown by injection of VX2 cells into rabbit hindlimbs. Liver tumors were induced by percutaneous US-guided injection of VX2 tumor fragments into liver. For digital subtraction angiography (DSA), a 2F catheter was advanced through left hepatic artery via femoral artery access, followed by contrast injection. All rabbits underwent baseline anatomic MRI, then IRE procedure or IRE probe placement only, and lastly post-procedure anatomic and TRIP-MRI. Liver tissues were dissected immediately after imaging for histology. All statistical analyses were performed on GraphPad Prism, with P<0.05 considered significant.

Results

IRE generated central IRE zone and peripheral reversible electroporation (RE) zone on anatomic MRI for both normal liver and liver tumor tissues. The semiquantitative analysis showed that IRE zone had the lowest AUC, PE, WIS, K^trans, v_e , and v_p as well as the highest TTP, followed by RE zone, then untreated tissues. Receiver operating characteristic analysis showed that WIS and AUC₆₀ had the highest AUC_ROC. Histologic analysis showed a positive correlation in viable area fraction between MRI and histologic measurements. IRE zone had the highest %apoptosis and lowest CD31+ staining.

Conclusion

Our results demonstrated that intraprocedural TRIP-MRI can effectively differentiate IRE and RE zones after IRE ablation in normal liver and liver tumor tissues.

Effect of microwave ablation treatment of hepatic malignancies on serum cytokine levels

Background

Microwave ablation (MWA) is widely used to treat unresectable primary and secondary malignancies of the liver, and a limited number of studies indicate that ablation can cause not only necrosis at the in situ site but also an immunoreaction of the whole body. This study aimed to investigate the effects of MWA on cytokines in patients who underwent MWA for a hepatic malignancy.

Methods

Patients admitted to the Oncology Department in the First Affiliated Hospital of Soochow University between June 2015 and February 2019 were selected. Peripheral blood was collected from patients with a hepatic malignancy treated with MWA. The levels of cytokines (IL-2, IFN-γ, TNF-α, IL-12 p40, IL-12 p70, IL-4, IL-6, IL-8, IL-10, and vascular endothelial growth factor (VEGF)) were detected with a Milliplex® MAP Kit. The comparison times were as follows: before ablation, 24 h after ablation, 15 days after ablation, and 30 days after ablation. Data were analyzed using a paired sample t-tests and Spearman’s correlation analysis.

Results

A total of 43 patients with hepatic malignancies were assessed. There were significant differences in IL-2, IL-12 p40, IL-12 p70, IL-1β, IL-8, and TNF-α at 24 h after MWA. Significant increases (> 2-fold vs. before ablation) were observed in IL-2, IL-1β, IL-6, IL-8, IL-10, and TNF-α after MWA. Elevated IL-2 and IL-6 levels after ablation were positively correlated with energy output during the MWA procedure.

Conclusions

WA treatment for hepatic malignancies can alter the serum levels of several cytokines such as IL-2 and IL-6.

Ultrasound Molecular Imaging as a Potential Non-invasive Diagnosis to Detect the Margin of Hepatocarcinoma via CSF-1R Targeting

Though radiofrequency ablation (RFA) is considered to be an effective treatment for hepatocellular carcinoma (HCC), but more than 30% of patients may suffer insufficient RFA (IRFA), which can promote more aggressive of the residual tumor. One possible method to counter this is to accurately identify the margin of the HCC. Colony-stimulating factor 1 receptor (CSF-1R) has been found to be restrictively expressed by tumor associated macrophages (TAMs) and monocytes which more prefer to locate at the boundary of HCC. Using biotinylation method, we developed a CSF-1R-conjugated nanobubble CSF-1R (NB_CSF–1R) using a thin-film hydration method for margin detection of HCC. CSF-1R expression was higher in macrophages than in HCC cell lines. Furthermore, immunofluorescence showed that CSF-1R were largely located in the margin of xenograft tumor and IFRA models. In vitro, NB_CSF–1R was stable and provided a clear ultrasound image even after being stored for 6 months. In co-culture, NB_CSF–1R adhered to macrophages significantly better than HCC cells (p = 0.05). In in vivo contrast-enhanced ultrasound imaging, the washout half-time of the NB_CSF–1R was significantly greater than that of NB_CTRL and Sonovue^® (p = 0.05). The signal intensity of the tumor periphery was higher than the tumor center or non-tumor region after NB_CSF–1R injection. Taken together, NB_CSF–1R may potentially be used as a non-invasive diagnostic modality in the margin detection of HCC, thereby improving the efficiency of RFA. This platform may also serve as a complement method to detect residual HCC after RFA; and may also be used for targeted delivery of therapeutic drugs or genes.

Spontaneous regression of ALK fusion protein-positive non-small cell lung carcinoma: a case report and review of the literature

BACKGROUND

ALK-rearrangement is observed in < 5% non-small cell lung cancer (NSCLC) cases and prior to the advent of oral tyrosine kinase inhibitors, the natural history of oncogenic NSCLC was typically poor. Literature relating to regression of treatment-naïve NSCLC is limited, and regression without treatment has not been noted in the ALK-rearranged sub-population.

CASE PRESENTATION

A 76 year old 'never smoker' female with an ALK-rearranged left upper lobe T2 N0 NSCLC experienced a stroke following elective DC cardioversion for new atrial fibrillation. Following a good recovery, updated imaging demonstrated complete regression of the left upper lobe lesion and a reduction of the previously documented mediastinal lymph node. Remaining atelectasis was non-avid on repeat PET-CT imaging, 8 months from the baseline PET-CT. When the patient developed new symptoms 6 months later a further PET-CT demonstrated FDG-avid local recurrence. She completed 55 Gy in 20 fractions but at 18 months post-radiotherapy there was radiological progression in the lungs with new pulmonary metastases and effusion and new bone metastases. Owing to poor performance status, she was not considered fit for targeted therapy and died 5 months later.

CONCLUSION

All reported cases of spontaneous regression in lung cancer have been collated within. Documented precipitants of spontaneous regression across tumour types include biopsy and immune reconstitution; stroke has not been reported previously. The favourable response achieved with radical radiotherapy alone in this unusual case of indolent oncogenic NSCLC reinforces the applicability of radiotherapy in locally advanced ALK-rearranged tumours, in cases not behaving aggressively. As a common embolic event affecting the neurological and pulmonary vasculature is less likely, an immune-mediated mechanism may underpin the phenomenon described in this patient, implying that hitherto unharnessed principles of immuno-oncology may have relevance in oncogenic NSCLC. Alternatively, high electrical voltage applied percutaneously adjacent to the tumour during cardioversion in this patient may have induced local tumour cell lethality.

Emerging Opportunities for Combining Locoregional Therapy with Immune Checkpoint Inhibitors in Hepatocellular Carcinoma

PURPOSE OF REVIEW

Immunotherapy shows great promises in solid tumors. Locoregional therapy can promote systemic immune response in hepatocellular carcinoma (HCC). The combination of locoregional therapy and immune checkpoint inhibitors (ICIs) activates a synergistic effect that can enhance the potency of anti-tumor immunity. This review aims to summarize the underlying mechanisms of locoregional therapy combined with ICIs and their applications in clinical settings.

RECENT FINDINGS

The characteristics of high invasiveness and refractoriness of HCC are what limit the outcomes of treatments. Sorafenib provides an additional treatment option for extrahepatic spread and vascular invasion, making long-term survival possible for patients with advanced HCC to some degree. However, its shortcomings of low response rate and high toxicity result in limited applications in clinical practice. Immunotherapy is a promising emerging therapy with great prospect in HCC, but the self-tolerance of HCC constrains the effectiveness of ICIs. Consequently, the efficacy of single immunotherapy is unsatisfactory. Locoregional therapy can not only destroy primary tumors but also stimulate the release of neoplasm antigens to increase the efficiency of immune response in HCC. Locoregional therapy combined with ICIs may have an amplification effect on immune response. Locoregional therapy plays a vital role in stimulating anti-tumor immune response. The combination of locoregional therapy and ICIs has a synergistic effect on anti-tumor immunity.

Recent progress in pulsed electric field ablation for liver cancer

The number of liver cancer patients is likely to continue to increase in the coming decades due to the aging of the population and changing risk factors. Traditional treatments cannot meet the needs of all patients. New treatment methods evolved from pulsed electric field ablation are expected to lead to breakthroughs in the treatment of liver cancer. This paper reviews the safety and efficacy of irreversible electroporation in clinical studies, the methods to detect and evaluate its ablation effect, the improvements in equipment and its antitumor effect, and animal and clinical trials on electrochemotherapy. We also summarize studies on the most novel nanosecond pulsed electric field ablation techniques in vitro and in vivo. These research results are certain to promote the progress of pulsed electric field in the treatment of liver cancer.