Single-Institution Experience with Irreversible Electroporation for T4 Pancreatic Cancer: First 50 Patients

Irreversible electroporation for metastatic pancreatic carcinoma with liver metastasis: What does the evidence say

Irreversible electroporation is a promising non-thermal ablation method that has been shown to increase overall survival in locally advanced pancreatic cancer in some studies. However, higher quality studies with proper controls and randomization are required to establish its superiority when added with neoadjuvant chemotherapy over the current management of choice, which is chemotherapy alone. Further studies are required before establishment of any survival benefit in metastatic pancreatic carcinoma, and such evidence is lacking at present.

Irreversible Electroporation Margin Accentuation in Pancreaticoduodenectomy: A Propensity Score Matching Analysis

BACKGROUND

Margin accentuation using irreversible electroporation (MA-IRE) improves recurrence and overall survival (OS) in pancreatic cancer patients; however, there have been limited outcome comparisons to similarly risked patients who did not receive MA-IRE.

METHODS

Patients with borderline resectable or locally advanced pancreatic adenocarcinoma who underwent a pancreaticoduodenectomy (PD) between 2017 and 2022 were included. Those who did not receive neoadjuvant chemotherapy for major vessel involvement were excluded. One-to-one propensity score matching (PSM) was used to match the MA-IRE group with the corresponding non-MA-IRE control group with similar risk factors.

RESULTS

A total of 36 patients were included in this study. Seventeen (47.2%) patients who underwent MA-IRE matched with 19 control patients (52.8%) with similar risk factors who did not have MA-IRE. Before matching, OS and disease-free survival (DFS) were comparable between the MA-IRE and non-MA-IRE groups. After matching, the MA-IRE group showed improved OS (746 vs. 509 days, hazard ratio 0.313; p = 0.034) compared with the non-MA-IRE group. DFS (p = 0.768), negative margin status (p = 0.317), and 30-day complication rates (p = 1.000) remained statistically different between the groups.

CONCLUSIONS

MA-IRE in PD results in longer OS but does not impact margin status, DFS, or postoperative complication rates in our cohort. These findings suggest that MA-IRE is safe and potentially promotes immune cell activation rather than upfront margin mitigation.

Trends in the Care of Locally Advanced Pancreatic Cancer in the Modern Era of Chemotherapy

INTRODUCTION

Current guidelines for treatment for locally advanced pancreatic cancer recommend chemotherapy ± radiation, or radiation alone when multimodal therapy is contraindicated. In a subset of patients, guideline-recommended treatment (GRT) achieves sufficient response to qualify for potentially curative resection. This study evaluated trends in treatment utilization and aimed to identify barriers to GRT.

METHODS

Patients with clinical T4M0 disease in the National Cancer Database from 2010 to 2017 were included. Potential predictors were assessed by relative risk regression with Poisson distribution and compared by log-link function.

RESULTS

In total, 28 056 patients met the criteria. Among 17 059 (67.67%) patients treated primarily with chemotherapy, 41.19% also had radiation and 8.89% went onto resection. Many received no cancer-directed treatment or failed to receive GRT. Another 710 patients had radiation (±surgery) without chemotherapy despite few contraindications to chemotherapy. Over time, patients were more likely to undergo resection after chemotherapy (aRR = 1.58; p < 0.0001) and less likely to have chemoradiation (aRR = 0.78; p < 0.0001) or go untreated (aRR = 0.90; p < 0.0001). Socioeconomic factors (race, education, income, and insurance status) affected the likelihood of receiving chemotherapy and surgery. Median overall survival (OS) was significantly improved for patients treated with chemotherapy and particularly in those patients who went on to receive RT or undergo surgical resection. OS was also longer for patients treated at high-volume academic centers. Patients insured by Medicaid, Medicare, or those without insurance had worse OS.

CONCLUSIONS

Despite improvement over time, many patients go untreated. Clinical factors were influential, but the impact of vulnerable social standing suggests persistent inequity in access to care.

Image-guided percutaneous microwave ablation for unresectable pancreatic cancers: A multicenter retrospective study

OBJECTIVE

This study aims to assess the feasibility, effectiveness, and safety of image-guided percutaneous microwave ablation (PMWA) for unresectable pancreatic cancer.

METHODS

In this retrospective study, 72 patients from four hospitals were enrolled between November 2009 and October 2022. Descriptive statistics were employed to describe the patients' characteristics and prognostic factors. The primary endpoint compassed the complete ablation rate (CAR), incidence of complications and the pain relief rate (PRR).

RESULTS

The median age of the 72 patients was 61 (interquartile range (IQR) 52.5-67.0) years, with 62.5 % (45/72) being male. 26 cases received computed tomography (CT) guidance; 46 cases received ultrasound guidance. A total of 74 tumors were identified (2 in 2 patients), with 56.8 % (42/74) at the body and tail, and the rest at the head and neck. Overall, 73 ablation sessions were carried out, achieving a technical success rate (TSR) of 100 %. The CAR was 40.5 % (30/74). The median follow-up time was 4.6 (1-43.4) months. 50 % (36/72) of patients had died with a median overall survival (OS) of 5.6 (1-27) months. Regarding complications, 18.1 % (13/72) of cases were classified as grade I and II, and 9.8 % (7/72) as grade IIIa. Before surgery, 33 patients experienced pain symptoms, and the postoperative PRR was 96.7 % (32/33). The average pain score decreased from 6.3 (4-10) before surgery to 2.0 (0-8) after ablation (P<0.001).

CONCLUSIONS

Image-guided PMWA for unresectable pancreatic cancer is safe and feasible, effectively relieving cancer pain and improving patients' the quality of life.

Advances in Image-Guided Ablation Therapies for Solid Tumors

Image-guided solid tumor ablation methods have significantly advanced in their capability to target primary and metastatic tumors. These techniques involve noninvasive or percutaneous insertion of applicators to induce thermal, electrochemical, or mechanical stress on malignant tissue to cause tissue destruction and apoptosis of the tumor margins. Ablation offers substantially lower risks compared to traditional methods. Benefits include shorter recovery periods, reduced bleeding, and greater preservation of organ parenchyma compared to surgical intervention. Due to the reduced morbidity and mortality, image-guided tumor ablation offers new opportunities for treatment in cancer patients who are not candidates for resection. Currently, image-guided ablation techniques are utilized for treating primary and metastatic tumors in various organs with both curative and palliative intent, including the liver, pancreas, kidneys, thyroid, parathyroid, prostate, lung, breast, bone, and soft tissue. The invention of new equipment and techniques is expanding the criteria of eligible patients for therapy, as now larger and more high-risk tumors near critical structures can be ablated. This article provides an overview of the different imaging modalities, noninvasive, and percutaneous ablation techniques available and discusses their applications and associated complications across various organs.

Mechanisms of action behind the protective effects of proactive esophageal cooling during radiofrequency catheter ablation in the left atrium

Proactive esophageal cooling for the purpose of reducing the likelihood of ablation-related esophageal injury resulting from radiofrequency (RF) cardiac ablation procedures is increasingly being used and has been Food and Drug Administration cleared as a protective strategy during left atrial RF ablation for the treatment of atrial fibrillation. In this review, we examine the evidence supporting the use of proactive esophageal cooling and the potential mechanisms of action that reduce the likelihood of atrioesophageal fistula (AEF) formation. Although the pathophysiology behind AEF formation after thermal injury from RF ablation is not well studied, a robust literature on fistula formation in other conditions (eg, Crohn disease, cancer, and trauma) exists and the relationship to AEF formation is investigated in this review. Likewise, we examine the abundant data in the surgical literature on burn and thermal injury progression as well as the acute and chronic mitigating effects of cooling. We discuss the relationship of these data and maladaptive healing mechanisms to the well-recognized postablation pathophysiological effects after RF ablation. Finally, we review additional important considerations such as patient selection, clinical workflow, and implementation strategies for proactive esophageal cooling.

Consensus Guidelines of Irreversible Electroporation for Pancreatic Tumors: Protocol Standardization Using the Modified Delphi Technique

Since no uniform treatment protocol for pancreatic irreversible electroporation (IRE) exists, the heterogeneity throughout literature complicates the comparison of results. To reach agreement among experts, a consensus study was performed. Eleven experts, recruited according to predefined criteria regarding previous IRE publications, participated anonymously in three rounds of questionnaires according to a modified Delphi technique. Consensus was defined as having reached ≥80% agreement. Response rates were 100, 64, and 64% in rounds 1 to 3, respectively; consensus was reached in 93%. Pancreatic IRE should be considered for stage III pancreatic cancer and inoperable recurrent disease after previous local treatment. Absolute contraindications are ventricular arrhythmias, implantable stimulation devices, congestive heart failure NYHA class 4, and severe ascites. The inter-electrode distance should be 10 to 20 mm and the exposure length should be 15 mm. After 10 test pulses, 90 treatment pulses of 1,500 V/cm should be delivered continuously, with a 90-µs pulse length. The first postprocedural contrast-enhanced computed tomography should take place 1 month post-IRE, and then every 3 months. This article provides expert recommendations regarding patient selection, procedure, and follow-up for IRE treatment in pancreatic malignancies through a modified Delphi consensus study. Future studies should define the maximum tumor diameter, response evaluation criteria, and the optimal number of preoperative FOLFIRINOX cycles.

Atrioesophageal Fistula Rates Before and After Adoption of Active Esophageal Cooling During Atrial Fibrillation Ablation

BACKGROUND

Active esophageal cooling reduces the incidence of endoscopically identified severe esophageal lesions during radiofrequency (RF) catheter ablation of the left atrium for the treatment of atrial fibrillation. A formal analysis of the atrioesophageal fistula (AEF) rate with active esophageal cooling has not previously been performed.

OBJECTIVES

The authors aimed to compare AEF rates before and after the adoption of active esophageal cooling.

METHODS

This institutional review board (IRB)-approved study was a prospective analysis of retrospective data, designed before collecting and analyzing the real-world data. The number of AEFs occurring in equivalent time frames before and after adoption of cooling using a dedicated esophageal cooling device (ensoETM, Attune Medical) were quantified across 25 prespecified hospital systems. AEF rates were then compared using generalized estimating equations robust to cluster correlation.

RESULTS

A total of 14,224 patients received active esophageal cooling during RF ablation across the 25 hospital systems, which included a total of 30 separate hospitals. In the time frames before adoption of active cooling, a total of 10,962 patients received primarily luminal esophageal temperature (LET) monitoring during their RF ablations. In the preadoption cohort, a total of 16 AEFs occurred, for an AEF rate of 0.146%, in line with other published estimates for procedures using LET monitoring. In the postadoption cohort, no AEFs were found in the prespecified sites, yielding an AEF rate of 0% (P < 0.0001).

CONCLUSIONS

Adoption of active esophageal cooling during RF ablation of the left atrium for the treatment of atrial fibrillation was associated with a significant reduction in AEF rate.

Present and future of metal nanoparticles in tumor ablation therapy

Cancer is an important factor affecting the quality of human life as well as causing death. Tumor ablation therapy is a minimally invasive local treatment modality with unique advantages in treating tumors that are difficult to remove surgically. However, due to its physical and chemical characteristics and the limitation of equipment technology, ablation therapy cannot completely kill all tumor tissues and cells at one time; moreover, it inevitably damages some normal tissues in the surrounding area during the ablation process. Therefore, this technology cannot be the first-line treatment for tumors at present. Metal nanoparticles themselves have good thermal and electrical conductivity and unique optical and magnetic properties. The combination of metal nanoparticles with tumor ablation technology, on the one hand, can enhance the killing and inhibiting effect of ablation technology on tumors by expanding the ablation range; on the other hand, the ablation technology changes the physicochemical microenvironment such as temperature, electric field, optics, oxygen content and pH in tumor tissues. It helps to stimulate the degree of local drug release of nanoparticles and increase the local content of anti-tumor drugs, thus forming a synergistic therapeutic effect with tumor ablation. Recent studies have found that some specific ablation methods will stimulate the body's immune response while physically killing tumor tissues, generating a large number of immune cells to cause secondary killing of tumor tissues and cells, and with the assistance of metal nanoparticles loaded with immune drugs, the effect of this anti-tumor immunotherapy can be further enhanced. Therefore, the combination of metal nanoparticles and ablative therapy has broad research potential. This review covers common metallic nanoparticles used for ablative therapy and discusses in detail their characteristics, mechanisms of action, potential challenges, and prospects in the field of ablation.

Portal Vein or Superior Mesenteric Vein Thrombosis with Dose-Escalated Radiation for Borderline or Locally Advanced Pancreatic Cancer

PURPOSE

Portal vein and superior mesenteric vein thrombosis (PVT/SMVT) are potentially morbid complications of radiation dose-escalated local therapy for pancreatic cancer. We retrospectively reviewed records for patients treated with and without intraoperative radiation (IORT) to identify risk factors for PVT/SMVT.

METHODS

Ninety-six patients with locally advanced or borderline resectable pancreatic adenocarcinoma received neoadjuvant therapy followed by surgical exploration from 2009 to 2014. Patients at risk for close or positive surgical margins received IORT boost to a biologically effective dose (BED10) > 100. Prognostic factors for PVT/SMVT were evaluated using competing risks regression.

RESULTS

Median follow-up was 79 months for surviving patients. Fifty-six patients (58%) received IORT. Twenty-nine patients (30%) developed PVT/SMVT at a median time of 18 months. On univariate competing risks regression, operative blood loss and venous repair with a vascular interposition graft, but not IORT dose escalation or diabetes history, were significantly associated with PVT/SMVT. The development of thrombosis in the absence of recurrence was significantly associated with a longstanding diabetes history, post-neoadjuvant treatment CA19-9, and operative blood loss. All 4 patients who underwent both IORT and vascular repair with a graft developed PVT/SMVT. PVT/SMVT in the absence of recurrence is not associated with significantly worsened overall survival but led to frequent medical interventions.

CONCLUSIONS

Approximately 30% of patients who underwent neoadjuvant chemoradiation for PDAC developed PVT/SMVT a median of 18 months following surgery. This was significantly associated with venous reconstruction with vascular grafts, but not with escalating radiation dose. PVT/SMVT in the absence of recurrence was associated with significant morbidity.

Irreversible Electroporation in Pancreatic Cancer-An Evolving Experimental and Clinical Method

Pancreatic cancer has no symptoms until the disease has advanced and is aggressive cancer with early metastasis. Up to now, the only curative treatment is surgical resection, which is possible in the early stages of the disease. Irreversible electroporation treatment offers new hope for patients with unresectable tumors. Irreversible electroporation (IRE) is a type of ablation therapy that has been explored as a potential treatment for pancreatic cancer. Ablation therapies involve the use of energy to destroy or damage cancer cells. IRE involves using high-voltage, low-energy electrical pulses to create resealing in the cell membrane, causing the cell to die. This review summarizes experiential and clinical findings in terms of the IRE applications. As was described, IRE can be a non-pharmacological approach (electroporation) or combined with anticancer drugs or standard treatment methods. The efficacy of irreversible electroporation (IRE) in eliminating pancreatic cancer cells has been demonstrated through both in vitro and in vivo studies, and it has been shown to induce an immune response. Nevertheless, further investigation is required to assess its effectiveness in human subjects and to comprehensively understand IRE's potential as a treatment option for pancreatic cancer.

Early Single-Center Experience With Irreversible Electroporation for Stage 2, 3, and 4 Pancreatic Adenocarcinomas

OBJECTIVES

Irreversible electroporation (IRE) is an ablation technology that uses electrical energy delivered between electrodes. If the electrodes are placed atraumatically, there is little to no risk of collateral injury, making IRE appealing for the treatment of pancreatic tumors.

METHODS

We report on 20 patients with pancreatic adenocarcinoma (PAC) who underwent 21 IRE in our center. There were 6 IRE for stage 2 PAC, 11 for stage 3 PAC, 1 for stage 4 PAC, and 2 patients treated with IRE for recurrence after pancreaticoduodenectomy. One patient had local progression 18 months after IRE and received a second IRE treatment. Using propensity score matching (age, sex, stage, tumor size, and chemotherapy), cases were matched 2 to 1 with patients from the Surveillance, Epidemiology, and End Results database.

RESULTS

A total of 7 cases experienced 8 complications; 4 complications were mild, and 4 were severe. Significant survival benefit was seen for patients with stage 3 PAC (27.5 vs 14.6 months for the matched group, P = 0.003); for stage 2, median survival was 15 months, and the single stage 4 patient survived 9 months after IRE treatment.

CONCLUSIONS

Pancreatic cancers were safely and effectively treated with image-guided IRE in our medium-sized center.

Long-term follow-up experience with adjuvant therapy after irreversible electroporation of locally advanced pancreatic cancer

BACKGROUND

Irreversible electroporation (IRE) expands the surgical options for patients with unresectable pancreatic cancer. This study evaluated for differences in survival stratified by type of IRE and receipt of adjuvant chemotherapy.

METHODS

Patients with locally advanced pancreatic cancer treated by IRE (2012-2020) were retrospectively included. Overall survival (OS) and recurrence-free survival (RFS) were compared by type of IRE (in situ for local tumor control or IRE of potentially positive margins with resection) and by receipt of adjuvant chemotherapy.

RESULTS

Thirty-nine patients had IRE in situ, 61 had IRE for margin extension, and 19 received adjuvant chemotherapy. Most (97.00%) underwent induction chemotherapy. OS was 28.71 months (interquartile range [IQR] 19.17, 51.19) from diagnosis, with no difference by IRE type (hazard ratio [HR] 1.05 for margin extension [p = 0.85]) or adjuvant chemotherapy (HR 1.14 [p = 0.639]). RFS was 8.51 months (IQR 4.95, 20.17) with no difference by IRE type (HR 0.90 for margin extension [p = 0.694]) or adjuvant chemotherapy (HR 0.90 [p = 0.711]).

CONCLUSION

These findings suggest that adjuvant therapy may have limited benefit for patients treated with induction chemotherapy followed by local control with IRE for unresectable pancreatic cancer. Further study of the duration and timing of systemic therapy is warranted to maximize benefit and limit toxicity.

The Synergistic Role of Irreversible Electroporation and Chemotherapy for Locally Advanced Pancreatic Cancer

Irreversible electroporation (IRE) is a local ablative technique used in conjunction with chemotherapy to treat locally advanced pancreatic cancer (LAPC). The combination of IRE and chemotherapy has showed increased overall survival when compared to chemotherapy alone, pointing towards a possible facilitating effect of IRE on chemotherapeutic drug action and delivery. This review aims to present current chemotherapeutic regimens for LAPC and their co-implementation with IRE, with an emphasis on possible molecular augmentative mechanisms of drug delivery and action. Moreover, the potentiating mechanism of IRE on immunotherapy, M1 oncolytic virus and dendritic cell (DC)-based treatments is briefly explored. Investigating the synergistic effect of IRE on currently established treatment regimens as well as newer ones, may present exciting new possibilities for future studies seeking to improve current LAPC treatment algorithms.

Treatment of unresectable locally advanced pancreatic cancer with percutaneous irreversible electroporation (IRE) following initial systemic chemotherapy (LAP-PIE) trial: study protocol for a feasibility randomised controlled trial

BACKGROUND

Approximately 30% of patients with pancreas cancer have unresectable locally advanced disease, which is currently treated with systemic chemotherapy. A new treatment option of irreversible electroporation (IRE) has been investigated for these patients since 2005. Cohort studies suggest that IRE confers a survival advantage, but with associated, procedure-related complications. Selection bias may account for improved survival and there have been no prospective randomised trials evaluating the harms and benefits of therapy. The aim of this trial is to evaluate the feasibility of a randomised comparison of IRE therapy with chemotherapy versus chemotherapy alone in patients with locally advanced pancreatic cancer (LAPC).

METHODS AND ANALYSIS

Eligible patients with LAPC who have undergone first-line 5-FluoroUracil, Leucovorin, Irinotecan and Oxaliplatin chemotherapy will be randomised to receive either a single session of IRE followed by (if indicated) further chemotherapy or to chemotherapy alone (standard of care). Fifty patients from up to seven specialist pancreas centres in the UK will be recruited over a period of 15 months. Trial follow-up will be 12 months. The primary outcome measure is ability to recruit. Secondary objectives include practicality and technical success of treatment, acceptability of treatment to patients and clinicians and safety of treatment. A qualitative study has been incorporated to evaluate the patient and clinician perspective of the locally advanced pancreatic cancer with percutaneous irreversible electroporation trial. It is likely that the data obtained will guide the structure, the primary outcome measure, the power and the duration of a subsequent multicentre randomised controlled trial aimed at establishing the clinical efficiency of pancreas IRE therapy. Indicative procedure-related costings will be collected in this feasibility trial, which will inform the cost evaluation in the subsequent study on efficiency.

ETHICS AND DISSEMINATION

The protocol has received approval by London-Brent Research Ethics Committee reference number 21/LO/0077.Results will be analysed following completion of trial recruitment and follow-up. Results will be presented to international conferences with an interest in oncology, hepatopancreaticobiliary surgery and interventional radiology and be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ISRCTN14986389.

Optimizing Patient Selection for Irreversible Electroporation of Locally Advanced Pancreatic Cancer: Analyses of Survival

Background

Irreversible electroporation (IRE) has emerged as a viable consolidative therapy after induction chemotherapy, in which this combination has improved overall survival of locally advanced pancreatic cancer (LAPC). Optimal timing and patient selection for irreversible electroporation remains a clinically unmet need. The aim of this study was to investigate preoperative factors that may assist in predicting progression-free and overall survival following IRE.

Methods

A multi-institutional, prospectively maintained database was reviewed for patients with LAPC treated with induction chemotherapy followed by open-technique irreversible electroporation from 7/2015-5/2019. RECIST 1.1 criteria were used to assess tumor response and radiological progression. Overall survival (OS) and progression-free survival (PFS) were recorded. Survival analyses were performed using Kaplan Meier and Cox multivariable regression analyses.

Results

187 LAPC patients (median age 62 years range, 21 – 91, 65% men, 35% women) were treated with IRE. Median PFS was 21.7 months and median OS from diagnosis was 25.5 months. On multivariable analysis, age ≤ 61 (HR 0.41, 95%CI 0.21-0.78, p<0.008) and no prior radiation (HR 0.49, 95%CI 0.26-0.94, p=0.03) were positive predictors of OS after IRE. Age ≤ 61(HR 0.53, 95%CI, 0.28-.99, p=0.046) and FOLFIRINOX followed by gemcitabine/abraxane induction chemotherapy (HR 0.37,95%CI 0.15-0.89, p=0.027) predicted prolonged PFS after IRE. Abnormal CA19-9 values at the time of surgery negatively impacted both OS (HR 2.46, 95%CI 1.28-4.72, p<0.007) and PFS (HR 2.192, 95%CI 1.143-4.201, p=0.018) following IRE.

Conclusions

Age, CA 19-9 response, avoidance of pre-IRE radiation, and FOLFIRINOX plus gemcitabine/abraxane induction chemotherapy are prominent factors to consider when referring or selecting LAPC patients to undergo IRE.

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.

Open radiofrequency ablation as upfront treatment for locally advanced pancreatic cancer: Requiem from a randomized controlled trial

BACKGROUND

Local ablation of pancreatic cancer has been suggested as an option to manage locally advanced pancreatic cancer (LAPC) although no robust evidence has been published to date to support its application. The aim of this study is to compare overall survival (OS) and progression-free survival (PFS) in patients receiving both radiofrequency ablation (RFA) and conventional chemoradiotherapy (CHRT) with patients receiving CHRT only.

METHODS

This is a multicentre prospective randomized controlled trial (RCT). Patients with LAPC diagnosed by the Pancreas-Ablation-Team-Verona were randomly assigned to open RFA (Group A) or CHRT (Group B). Survival analyses were performed using the Kaplan-Meier method and compared using the log-rank test. Statistical significance was set at p < 0.05.

RESULTS

One hundred LAPC patients were enrolled from January 2014 to August 2016. 33% of patients in Group A did not receive the designated procedure because of intraoperative findings of liver (18.7%) or peritoneal metastases (43.8%), or technical contraindications (37.5%). We did not observe any statistically significant survival benefit from RFA compared to CHRT, neither in terms of OS (medians of 14.2 months and 18.1 months, respectively, p = 0.639) nor PFS (medians of 8 months and 6 months respectively, p = 0.570). Mortality was nil and RFA-related morbidity was 15.6%. In 13% of subjects, conversion to surgery occurred (2 after RFA and 11 after CHRT).

CONCLUSIONS

This is the first RCT evaluating the impact of upfront RFA in the multimodal treatment of LAPC. Compared to CHRT, RFA alone did not provide any advantage in terms of OS or PFS. It could be considered as a therapeutic option for LAPC within a multimodal context and after neoadjuvant therapies.

Immunomodulatory Effect of Irreversible Electroporation Alone and Its Cooperating With Immunotherapy in Pancreatic Cancer

Emerging studies have showed irreversible electroporation (IRE) focused on pancreatic cancer (PC). However, the effects of IRE treatment on the immune response of PC remain unknown. Moreover, there are few studies on the therapeutic effect of IRE combining with immunotherapy on PC. Thus, we review recent advances in our understanding of IRE alone and its working with immunotherapy towards the immune response of PC, discussing potential opportunities for exploring future treatment strategies.

Irreversible Electroporation and Nivolumab Combined with Intratumoral Administration of a Toll-Like Receptor Ligand, as a Means of In Vivo Vaccination for Metastatic Pancreatic Ductal Adenocarcinoma (PANFIRE-III). A Phase-I Study Protocol

Simple Summary

Metastatic pancreatic ductal adenocarcinoma has a dismal prognosis, and to date no curative treatment options exist. The image guided tumor ablation technique irreversible electroporation (IRE) employs high-voltage electrical pulses through the application of several needle electrodes in and around the tumor in order to induce cell death. IRE ablation of the primary tumor has the ability to reduce pancreatic tumor induced immune suppression while allowing the expansion of tumor specific effector T cells, hereby possibly shifting the pancreatic tumor microenvironment into a more immune permissive state. The addition of immune enhancing therapies to IRE might work synergistically and could potentially induce a clinically significant treatment effect. This study protocol describes the rationale and design of the PANFIRE-III trial that aims to assess the safety of the combination of IRE with IMO-2125 (toll-like receptor 9 ligand) and/or nivolumab in patients with metastatic pancreatic ductal adenocarcinoma.

Abstract

Irreversible electroporation (IRE) is a novel image-guided tumor ablation technique with the ability to generate a window for the establishment of systemic antitumor immunity. IRE transiently alters the tumor’s immunosuppressive microenvironment while simultaneously generating antigen release, thereby instigating an adaptive immune response. Combining IRE with immunotherapeutic drugs, i.e., electroimmunotherapy, has synergistic potential and might induce a durable antitumor response. The primary objective of this study is to assess the safety of the combination of IRE with IMO-2125 (a toll-like receptor 9 ligand) and/or nivolumab in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). In this randomized controlled phase I clinical trial, 18 patients with mPDAC pretreated with chemotherapy will be enrolled in one of three study arms: A (control): nivolumab monotherapy; B: percutaneous IRE of the primary tumor followed by nivolumab; or C: intratumoral injection of IMO-2125 followed by percutaneous IRE of the primary tumor and nivolumab. Assessments include contrast enhanced computed tomography (ceCT), ¹⁸F-FDG and ¹⁸F-BMS-986192 (PD-L1) positron emission tomography (PET)-CT, biopsies of the primary tumor and metastases, peripheral blood samples, and quality of life and pain questionnaires. There is no curative treatment option for patients with mPDAC, and palliative chemotherapy regimens only moderately improve survival. Consequently, there is an urgent need for innovative and radically different treatment approaches. Should electroimmunotherapy establish an effective and durable anti-tumor response, it may ultimately improve PDAC’s dismal prognosis.

Minimally invasive image-guided therapy of primary and metastatic pancreatic cancer

Pancreatic cancer is a challenging malignancy with limited treatment options and poor life expectancy. The only curative option is surgical resection, but only 15%-20% of patients are resectable at presentation because more than 50% of patients has distant metastasis at diagnosis and the rest of them has locally advanced pancreatic cancer (LAPC). The standard of care first line treatment for LAPC patients is chemotherapy with or without radiation therapy. Recent developments in minimally invasive ablative techniques may add to the treatment armamentarium of LAPC. There are increasing number of studies evaluating these novel ablative techniques, including radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation. Most studies which included pancreatic tumor ablation, demonstrated improved overall survival in LAPC patients. However, the exact protocols are yet to set up to which stage of the treatment algorithm ablative techniques can be added and in what kind of treatment combinations. Patients with metastatic pancreatic cancer has dismal prognosis with 5-year survival is only 3%. The most common metastatic site is the liver as 90% of pancreatic cancer patients develop liver metastasis. Chemotherapy is the primary treatment option for patients with metastatic pancreatic cancer. However, when the tumor is not responding to chemotherapy or severe drug toxicity develops, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease progression and improve survival in selected patients. During the last decade new therapeutic options arose with the advancement of minimally invasive technologies to treat pancreatic cancer patients. These new therapies have been a topic of increasing interest due to the severe prognostic implications of locally advanced and metastatic pancreatic cancer and the low comorbid risk of these procedures. This review summarizes new ablative options for patients with LAPC and percutaneous liver-directed therapies for patients with liver-dominant metastatic disease.

Multicenter randomized controlled trial and registry study to assess the safety and efficacy of the NanoKnife® system for the ablation of stage 3 pancreatic adenocarcinoma: overview of study protocols

BACKGROUND

Irreversible electroporation (IRE) is a local ablation technique utilizing high voltage, low energy direct current to create nanopores in cell membrane which disrupt homeostasis and leads to cell death. Previous reports have suggested IRE may have a role in treating borderline resectable and unresectable Stage 3 pancreatic tumors.

METHODS

Patients with Stage 3 pancreatic ductal adenocarcinoma (PDAC) will be enrolled in either a randomized, controlled, multicenter trial (RCT) or a multicenter registry study. Subjects enrolled in the RCT must have no evidence of disease progression after 3 months of modified FOLFIRINOX (mFOLFIRINOX) treatment prior to being randomization to either a control or IRE arm. Post-induction and post-IRE treatment for the control and IRE arms, respectively, will be left to the discretion of the treating physician. The RCT will enroll 528 subjects with 264 per arm and include up to 15 sites. All subjects will be followed for at least 24 months or until death. The registry study will include two cohorts of patients with Stage 3 PDAC, patients who received institutional standard of care (SOC) alone and those treated with IRE in addition to SOC. Both cohorts will be required to have undergone at least 3 months of SOC without progression prior to enrollment. The registry study will enroll 532 patients with 266 patients in each arm. All patients will be followed for at least 24 months or until death. The primary efficacy endpoint for both studies will be overall survival (OS). Co-primary safety endpoints will be 1) time from randomization or enrollment in the registry to death or new onset of Grade 4 adverse event (AE), and (2 high-grade complications defined as any AE or serious AE (SAE) with a CTCAE v5.0 grade of 3 or higher. Secondary endpoints will include progression-free survival, cancer-related pain, quality of life, and procedure-related pain for the IRE arm only.

DISCUSSION

These studies are intended to provide Level 1 clinical evidence and real-world data demonstrating the clinical utility and safety of the use of IRE in combination with chemotherapy in patients with Stage 3 PDAC.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03899636 and NCT03899649. Registered April 2, 2019. Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trial G180278 approved on May 3, 2019.

Irreversible Electroporation (IRE) Combined With Chemotherapy Increases Survival in Locally Advanced Pancreatic Cancer (LAPC)

OBJECTIVES

Locally advanced pancreatic cancer (LAPC) is found in about 40% of patients with pancreatic cancer. Irreversible electroporation (IRE) is a nonthermal ablative technique that provides an alternative in patients with LAPC and can be safely combined with chemotherapy.

MATERIALS AND METHODS

From 2015 until October of 2019, we performed laparotomic IRE in a total of 40 patients with stage III LAPC. The median age of these patients was 65.2 years (range: 46 to 81 y), and the median tumor size was 3.8 cm (range: 2 to 5.2 cm). 33 of 40 patients were treated preoperatively with FOLFIRINOX or nab-paclitaxel plus gemcitabine and in case of disease control, IRE was performed, whereas in 7 patients, IRE was performed without previous chemotherapy.

RESULTS

All patients were treated successfully with IRE as the tumor evaluation showed no disease progression after the completion of induction chemotherapy. No IRE-related deaths occurred. Two major grade III complications were reported: pancreatic fistula grade A in 8 patients and 3 patients diagnosed with delayed gastric emptying. Up to October 31, 2019, the median overall survival (OS) of all patients was 24.2 months (range: 6 to 36 mo), and the median progression-free survival was 10.3 months (range: 3 to 24 mo). After the completion of IRE, 30 patients (75%) continued with adjuvant chemotherapy. Fifteen patients (37%) have >24 months OS and 3 patients (8%) have reached 36 months OS and are still alive.

CONCLUSION

The combination of chemotherapy with IRE, which is a safe and effective procedure, may result in a survival benefit for patients with LAPC.

Margin Accentuation Irreversible Electroporation in Stage III Pancreatic Cancer: A Systematic Review

Simple Summary

This literature review shows preliminary evidence to suggest that electroporation, the use of electricity to cause the death of cells around the tumour, may be associated with an improved survival and complete resection rates following pancreatic surgery for higher stage pancreatic cancer. However, one in five patients have a complication from the procedure that alters their normal course in hospital. Moreover, the number of patients who underwent this technique is small and further data is needed to support the preliminary evidence. The results therefore should be interpreted with caution.

Abstract

The present systematic review aimed to summarise the available evidence on indications and oncological outcomes after MA IRE for stage III pancreatic cancer (PC). A literature search was performed in the Pubmed, MEDLINE, EMBASE, SCOPUS databases using the PRISMA framework to identify all MA IRE studies. Nine studies with 235 locally advanced (LA) (82%, 192/235) or Borderline resectable (BR) PC (18%, 43/235) patients undergoing MA IRE pancreatic resection were included. Patients were mostly male (56%) with a weighted-mean age of 61 years (95% CI: 58–64). Pancreatoduodenectomy was performed in 51% (120/235) and distal pancreatectomy in 49% (115/235). R0 resection rate was 73% (77/105). Clavien Dindo grade 3–5 postoperative complications occurred in 19% (36/187). Follow-up intervals ranged from 3 to 29 months. Local and systematic recurrences were noted in 8 and 43 patients, respectively. The weighted-mean progression free survival was 11 months (95% CI: 7–15). The weighted-mean overall survival was 22 months (95% CI 20–23 months) and 8 months (95% CI 1–32 months) for MA IRE and IRE alone, respectively. Early non-randomised data suggest MA IRE during pancreatic surgery for stage III pancreatic cancer may result in increased R0 resection rates and improved OS with acceptable postoperative morbidity. Further, larger studies are warranted to corroborate this evidence.

Usefulness of Imaging Response Assessment after Irreversible Electroporation of Localized Pancreatic Cancer-Results from a Prospective Cohort

Simple Summary

Irreversible electroporation (IRE) is a novel therapy that is being studied for the treatment of nonmetastatic pancreatic cancer. The current methods for evaluating the treatment response after IRE have been adapted from the Response Evaluation Criteria in Solid Tumors (RECIST). However, it is uncertain whether these methods are appropriate, because the methods have not been validated. The aim of the current study was to evaluate the correlation between survival time and the most commonly used imaging assessment methods on FDG-PET/CT scans. We confirmed that the Response Evaluation Criteria in Solid Tumors (RECIST) are correlated with survival, when applied as intended. However, no correlation was found when the often-used lesion-level method was used. FDG-PET-derived data did not provide any benefit over conventional CT data. Several novel methods for lesion-level analysis were explored.

Abstract

(1) Background: Irreversible electroporation (IRE) is a nonthermal ablation technique that is being studied in nonmetastatic pancreatic cancer (PC). Most published studies use imaging outcomes as an efficacy endpoint, but imaging interpretation can be difficult and has yet to be correlated with survival. The aim of this study was to examine the correlation of imaging endpoints with survival in a cohort of IRE-treated PC patients. (2) Methods: Several imaging endpoints were examined before and after IRE on ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) with computed tomography. Separate analyses were performed at the patient and lesion levels. Mortality rate (MR) ratios for imaging endpoints after IRE were estimated. (3) Results: Forty-one patients were included. Patient-level analysis revealed that progressive disease (PD), as defined by RECIST 1.1, is correlated with a higher MR at all time intervals, but PD, as defined by EORTC PET response criteria, is only correlated with the MR in the longest interval. No correlation was found between PD, as defined by RECIST, and the MR in the lesion-level analysis. (4) Conclusions: Patient-level PD, as defined by RECIST, was correlated with poorer survival after IRE ablation, whereas no correlations were observed in the lesion-level analyses. Several promising lesion-level outcomes were identified.

Margin ACcentuation for resectable Pancreatic cancer using Irreversible Electroporation - Results from the MACPIE-I study

INTRODUCTION

Margin accentuation (MA) using Irreversible electroporation (IRE) offers an unique opportunity to reduce the R1 resections in resectable pancreatic cancer (RPC). This study aims to assess the rate of margin positivity using IRE for MA during pancreaticoduodenectomy (PD) for resectable pancreatic head tumours.

MATERIALS AND METHODS

Following ethical approval, MA using IRE was carried out in 20 consecutive patients to posterior and superior mesenteric vein (SMV) margin, and the pancreatic neck, prior to the PD resection. The control group (non-IRE; n = 91) underwent PD without MA over the study period, March 2018 to March 2020.

RESULTS

There was no difference between the two groups in terms of patients' age, gender, pre-op biliary drainage, site of malignancy or pre-operative TNM stage. The overall margin positive rate for IRE group was lesser (35.0%) when compared to non-IRE group (51.6%; p = 0.177), with significantly less posterior pancreatic margin positivity (5.0% vs. 25.3%; p = 0.046). When only treated margins (SMA margin excluded) were compared, the IRE group had significantly lower margin positive rates (20.0% vs. 51.6%; p = 0.013). There was no difference between the two groups in terms of intra- or post-operative complications. With a median follow-up of 15.6 months, the median DFS and OS for IRE and non-IRE groups were 17 and 18 months (p = 0.306) and 19 and 22 months (p = 0.227) respectively.

CONCLUSION

Our pilot study confirms the safety of MA using IRE for RPC, with reduction in margin positivity. These results as a proof of concept are promising and need further validation with a randomised controlled trial.

Irreversible electroporation of pancreatic cancer - Effect on quality of life and pain perception

BACKGROUND

Most pancreatic cancer (PC) patients are incurable and may need palliative treatment at some point in time. Irreversible electroporation (IRE) is a novel ablative treatment, which aims to provide local tumor control. The aim of this study was to examine how consolidative treatment with IRE affects quality of life (QOL) and pain perception (PP) in patients with non-metastatic pancreatic cancer.

METHODS

Secondary outcomes were extracted from a prospective cohort of non-metastatic PC patients treated with IRE from 2013 to 2019. Patients filled in two questionnaires examining QOL and PP at different timepoints during treatment and follow-up. Data from a selected panel of subscales were extracted and analyzed using a mixed random intercept regression model.

RESULTS

Subscales from 41 patients at four different timepoints were included in the model. Global health status, physical functioning, fatigue, nausea and vomiting, appetite loss and mean pain interference were negatively impacted (p < 0.05) in the short- and mid-term, corresponding to a low or moderate clinical effect size. However, all negative effects showed a tendency to dissipate over time.

CONCLUSIONS

IRE treatment negatively impacted QOL and PP in the short- and mid-term. No positive long-term effects of IRE were found.

Locally Advanced Pancreatic Cancer: Percutaneous Management Using Ablation, Brachytherapy, Intra-arterial Chemotherapy, and Intra-tumoral Immunotherapy

PURPOSE OF REVIEW

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive neoplasms, bearing a terrible prognosis. Stage III tumors, also known as locally advanced pancreatic cancer (LAPC), are unresectable, and current palliative chemotherapy regimens have only modestly improved survival in these patients. At this stage of disease, interventional techniques may be of value and further prolong life. The aim of this review was to explore current literature on locoregional percutaneous management for LAPC.

RECENT FINDINGS

Locoregional percutaneous interventional techniques such as ablation, brachytherapy, and intra-arterial chemotherapy possess cytoreductive abilities and have the potential to increase survival. In addition, recent research demonstrates the immunomodulatory capacities of these treatments. This immune response may be leveraged by combining the interventional techniques with intra-tumoral immunotherapy, possibly creating a durable anti-tumor effect. This multimodality treatment approach is currently being examined in several ongoing clinical trials. The use of certain interventional techniques appears to improve survival in LAPC patients and may work synergistically when combined with immunotherapy. However, definitive conclusions can only be made when large prospective (randomized controlled) trials confirm these results.

Irreversible Electroporation (IRE) in Locally Advanced Pancreatic Cancer: A Review of Current Clinical Outcomes, Mechanism of Action and Opportunities for Synergistic Therapy

Locally advanced pancreatic cancer (LAPC) accounts for 30% of patients with pancreatic cancer. Irreversible electroporation (IRE) is a novel cancer treatment that may improve survival and quality of life in LAPC. This narrative review will provide a perspective on the clinical experience of pancreas IRE therapy, explore the evidence for the mode of action, assess treatment complications, and propose strategies for augmenting IRE response. A systematic search was performed using PubMed regarding the clinical use and safety profile of IRE on pancreatic cancer, post-IRE sequential histological changes, associated immune response, and synergistic therapies. Animal data demonstrate that IRE induces both apoptosis and necrosis followed by fibrosis. Major complications may result from IRE; procedure related mortality is up to 2%, with an average morbidity as high as 36%. Nevertheless, prospective and retrospective studies suggest that IRE treatment may increase median overall survival of LAPC to as much as 30 months and provide preliminary data justifying the well-designed trials currently underway, comparing IRE to the standard of care treatment. The mechanism of action of IRE remains unknown, and there is a lack of data on treatment variables and efficiency in humans. There is emerging data suggesting that IRE can be augmented with synergistic therapies such as immunotherapy.

Irreversible Electroporation in Locally Advanced Pancreatic Adenocarcinoma: Aiming to Improve Overall Survival

Irreversible electroporation (IRE) is a non-thermic ablation therapy which has been proposed for locally advanced pancreatic adenocarcinoma (LAPC) as well as for the local control of other types of tumors (kidney or liver). Its use has been extended in the last few years worldwide. Its advantage over other ablation techniques is that it only affects the lipids bilayer of the cell membrane avoiding vascular damage. Safety and viability have been demonstrated in recent studies. Overall survival seems (OS) to improve when it is combined with chemotherapy compared to chemotherapy with or without radiotherapy. Clinical trials should confirm these encouraging data.

Irreversible electroporation of locally advanced pancreatic cancer

Locally advanced pancreatic cancer (LAPC) constitutes approximately one-third of all pancreatic cancer, with standard of care inconsistently defined and achieving modest outcomes at best. While resection after downstaging offers the chance for cure, only a fraction of patients with LAPC become candidates for resection. Chemotherapy remains the mainstay of treatment for the remainder. In these patients, ablative therapy may be given for local control of the tumor. Irreversible electroporation (IRE) is an attractive ablative technique. IRE changes the permeability of tumor cell membranes to induce apoptosis. Unlike other ablative therapies, IRE causes little thermal injury to the target area, making it ideal for LAPC involving major vessels. Compared to systemic chemotherapy alone, IRE seems to offer some survival benefit. Although early studies reported notable morbidity and mortality rates, IRE presents opportunities for those who cannot undergo resection and who otherwise have limited options. Another role of IRE is to extend the margins of resected tumors when there is a concern for R1 resection. Perhaps most exciting, IRE is thought to have effects beyond local ablation. IRE has immunomodulatory effects, which may induce in vivo vaccination and may potentially synergize with immunotherapy. Through electrochemotherapy, IRE may enhance drug delivery to residual tumor cells. Ultimately the role of IRE in the treatment of LAPC still needs to be validated through well designed randomized trials. Investigations of its future possibilities are in the early stages. IRE offers the potential to provide more options to LAPC patients.

Initial experience of irreversible electroporation for locally advanced pancreatic cancer in a Korean population

BACKGROUND

Locally advanced pancreatic cancer (LAPC) is one of the most aggressive malignancies. Irreversible electroporation (IRE) is a novel technique that uses a non-thermal ablation to avoid vessel or duct injury.

PURPOSE

To investigate the safety and efficacy of IRE for the management of LAPC in a Korean population.

MATERIAL AND METHODS

Twelve patients (median age 64 years; age range 46-73 years) treated between December 2015 and March 2017 underwent intraoperative IRE for LAPC. Technical success and clinical outcomes, including complications, serum pancreatic enzyme levels, overall survival (OS), and progression-free survival (PFS), were evaluated.

RESULTS

Tumors were located in the pancreas head in 7 (58.3%) patients and in the body/tail in 5 (41.7%) patients. The median tumor diameter in the longest axis was 3.1 cm. Vascular invasion was observed in all patients and bowel abutment in 3 (25%) patients. Technical success was achieved in all patients. The median serum levels of amylase and lipase were 55 U/L and 31 U/L, respectively, at baseline, increased to 141.5 U/L (P = 0.008) and 53 U/L (P = 0.505), respectively, one day after IRE, and normalized after one week. The rate of 30-day mortality of unknown relation was 8.3% (one individual experienced massive hematemesis 12 days after IRE). The median OS from diagnosis and IRE was 24.5 months and 13.5 months, respectively. The median PFS from diagnosis and IRE was 19.2 months and 8.6 months, respectively.

CONCLUSION

For patients with LAPC, IRE appears to be a promising treatment modality with an acceptable safety profile.

Imaging response evaluation after local ablative treatments in locally advanced pancreatic cancer: an expedited systematic review

BACKGROUND

Several local ablative modalities have been introduced for the treatment of locally advanced pancreatic cancer (LAPC). However, there is no consensus on how to evaluate the imaging response after treatment. A systematic review was performed regarding the use of imaging for response assessment in LAPC.

METHODS

A systematic literature search was conducted in PubMed. Studies reporting imaging outcomes were included in the review. Studies were excluded if the imaging outcomes could not be differentiated between different disease stages, tumor histology or surgical approaches.

RESULTS

Thirty-four studies were included in the analysis. Fourteen studies used standardized response criteria, while six studies did not report the response evaluation method. The rest used self-determined criteria, absolute size comparisons or similar methods. One study found a correlation between early systemic progression (<6 months) and overall survival.

CONCLUSION

There was notable variation in the use of imaging for response assessment in LAPC. This significantly hinders cross-comparison of results among studies. There is currently only sparse evidence of an association between imaging responses and overall survival. The field calls for standardized recommendations regarding the choice of response assessment method, timing of scans, target definition and reporting of outcomes.

Effects of high-intensity focused ultrasound treatment on peripancreatic arterial and venous blood vessels in pancreatic cancer

The present study aimed to evaluate the safety of high-intensity focused ultrasound (HIFU) treatment on peripancreatic arterial and venous blood vessels in patients with pancreatic cancer. This trial included 15 patients with pancreatic cancer (9 females and 6 males; age, 39-81 years; median age, 62 years). All patients underwent preoperative computed tomography (CT) or magnetic resonance imaging (MRI) and color Doppler flow imaging (CDFI) to assess the vascular hemodynamics of peripancreatic arterial and venous blood vessels pre-treatment. These patients were re-examined within 1 week post-HIFU treatment. Then, vascular adverse events were observed and followed up clinically. Prior to HIFU treatment, vessel involvement was recorded in 13 patients, including tumor lesions invading 19 veins and 14 arteries, which refers to the growth of pancreatic tumor lesions surrounding blood vessels, or tumor growth into blood vessels. In addition, 9 veins and 13 arteries were <1 cm from the lesions. The hemodynamic parameters of peripancreatic vessels were measured using CDFI, including mean blood flow velocity, peak systolic blood flow velocity, vascular resistance index, vascular pulsatility index, vascular diameter, vascular blood flow and other indicators, to assess vascular perfusion in CT/MRI. There were no significant differences in preoperative and postoperative hemodynamic data (P>0.05). Overall, HIFU demonstrated no negative effects on peripancreatic arterial and venous blood vessels in patients with pancreatic cancer, even with tumor lesions wrapped in blood vessels. In addition, no complications of vascular stenosis and vascular adverse events were observed in the present study.

The efficacy and safety of the open approach irreversible electroporation in the treatment of pancreatic cancer: A systematic review

BACKGROUND

Irreversible Electroporation (IRE) is a novel non-thermal ablation technique used in patients with locally advanced pancreatic cancer (LAPC), in the proximity of sensitive structures such as vessels, intestinal wall and the bile duct. Currently, it is only used in the setting of clinical trials. This systematic review aimed to tackle the knowledge gap in the literature, in relation to the safety and efficacy of the open approach IRE.

METHODS

MEDLINE, EMBASE and Cochrane libraries were searched for English language articles published from January 2000 to December 2019. Data related to safety and efficacy were extracted.

RESULTS

Nine studies involving 460 patients with LAPC were included. Open approach IRE was associated with high morbidity (29.4%) but with a survival benefit compared to traditional treatment. Median overall survival (OS) was at 17.15 months. Major morbidity was at 10.2% and mortality at 3.4%.

CONCLUSIONS

Despite the paucity of literature and the low quality of evidence, the results regarding safety and efficacy appear to be encouraging. The high morbidity seems to be mitigated by a demonstrated improvement in OS. The potential of this technique is more evident when mortality and major morbidity are considered, since they are at acceptable levels. The limitations of this review have made it difficult to extract definitive conclusions. Higher quality evidence is needed in the form of large-scale multicentre randomized controlled trials. It remains to be elucidated whether the rate of adverse events decreases as our experience with this technique increases.

Irreversible Electroporation for Locally Advanced Pancreatic Cancer

Several minimally invasive image guided tumor ablation techniques have been added to the treatment spectrum for locally advanced pancreatic cancer (LAPC). Irreversible electroporation (IRE) might have a significant additive value in the management of this difficult-to-treat disease. As opposed to thermal ablative techniques, IRE induces cell death by the delivery of high-voltage electrical pulses. The electrical energy disrupts the cellular membrane integrity, causes loss of cellular homeostasis and ultimately results in cell death. The extracellular matrix of connective tissue in surrounding delicate structures such as bile ducts, bowel wall, and larger blood vessels is spared. The preservation of these structures makes IRE attractive for the treatment of pancreatic cancers that are unresectable due to their anatomical location (ie, LAPC and local recurrence after surgical resection). In addition to its cytoreductive abilities, evidence is emerging on IRE's capability to induce systemic immunomodulation through active in vivo vaccination against pancreatic cancer cells. These effects in combination with immunotherapy may offer a new treatment paradigm for tumors with low immunogenic potential like pancreatic ductal adenocarcinoma (PDAC). This review discusses several practical and technical issues of IRE for LAPC: clinical evaluation, indications, patient preparations, procedural steps, imaging characteristics, clinical results, and "tricks of the trade" used to improve the safety and efficacy of the treatment. Future directions such as the combination of IRE with immunotherapy will be shortly addressed.

[Ablative treatment options for locally advanced unresectable and borderline resectable pancreatic carcinoma]

BACKGROUND

Locally advanced unresectable (nonmetastatic) and borderline resectable pancreatic carcinomas represent a therapeutic challenge. Several minimally invasive local ablative techniques are available for local treatment in these situations.

OBJECTIVE

Which interventional techniques and application options are currently available for pancreatic carcinoma and which oncological results could be achieved so far?

MATERIAL AND METHODS

An analysis of reviews and studies was carried out. The selection of literature was based on searches in PubMed and the Cochrane library. The studies analyzed were reviews, meta-analyses and original articles mainly from the period between 2013 and 2018. Single case reports were not included in this review.

RESULTS

Local ablative techniques are performed with various forms of energy and are associated with specific advantages and disadvantages. They have to be individually tailored to the specific patient and situation. Noninvasive thermal ablation with high-intensity focused ultrasound (HIFU) is primarily used for palliative pain relief. Solid tumors are the main indication for thermal necrosis with microwave ablation (MWA) and radiofrequency ablation (RFA). The use of irreversible electroporation (IRE) enables a selective destruction of tumor cells and can be performed in the vicinity of sensitive structures. This technique is applied for primary tumor control and also for accentuation of tumor margins during resection.

CONCLUSION

With local ablative techniques an improvement in the quality of life and possibly the prognosis can be achieved in patients with unresectable pancreatic cancer; however, the latter aspect has to be viewed with caution due to a current lack of well-founded data.

High-Voltage Electrical Pulses in Oncology: Irreversible Electroporation, Electrochemotherapy, Gene Electrotransfer, Electrofusion, and Electroimmunotherapy

This review summarizes the use of high-voltage electrical pulses (HVEPs) in clinical oncology to treat solid tumors with irreversible electroporation (IRE) and electrochemotherapy (ECT). HVEPs increase the membrane permeability of cells, a phenomenon known as electroporation. Unlike alternative ablative therapies, electroporation does not affect the structural integrity of surrounding tissue, thereby enabling tumors in the vicinity of vital structures to be treated. IRE uses HVEPs to cause cell death by inducing membrane disruption, and it is primarily used as a radical ablative therapy in the treatment of soft-tissue tumors in the liver, kidney, prostate, and pancreas. ECT uses HVEPs to transiently increase membrane permeability, enhancing cellular cytotoxic drug uptake in tumors. IRE and ECT show immunogenic effects that could be augmented when combined with immunomodulatory drugs, a combination therapy the authors term electroimmunotherapy. Additional electroporation-based technologies that may reach clinical importance, such as gene electrotransfer, electrofusion, and electroimmunotherapy, are concisely reviewed. HVEPs represent a substantial advancement in cancer research, and continued improvement and implementation of these presented technologies will require close collaboration between engineers, interventional radiologists, medical oncologists, and immuno-oncologists.

Irreversible Electroporation: Background, Theory, and Review of Recent Developments in Clinical Oncology

Irreversible electroporation (IRE) has established a clinical niche as an alternative to thermal ablation for the eradication of unresectable tumors, particularly those near critical vascular structures. IRE has been used in over 50 independent clinical trials and has shown clinical success when used as a standalone treatment and as a single component within combinatorial treatment paradigms. Recently, many studies evaluating IRE in larger patient cohorts and alongside other novel therapies have been reported. Here, we present the basic principles of reversible electroporation and IRE followed by a review of preclinical and clinical data with a focus on tumors in three organ systems in which IRE has shown great promise: the prostate, pancreas, and liver. Finally, we discuss alternative and future developments, which will likely further advance the use of IRE in the clinic.

Prognostic factor analysis of irreversible electroporation for locally advanced pancreatic cancer - A multi-institutional clinical study in Asia

INTRODUCTION

Irreversible electroporation (IRE) is a modality that utilizes high electric voltage to cause cell apoptosis. IRE has been used to treat locally advanced pancreatic cancer (LAPC). However, studies of IRE via surgical approaches for LAPC are limited. This study aims to analyse the outcomes and related prognostic factors of IRE for Asian patients with LAPC.

MATERIALS AND METHODS

From 2012 to 2017, this prospective trial for using IRE through surgical approaches for LAPC was conducted in 11 medical centres in Asia. All related and treatment outcomes were analysed from a prospective database.

RESULTS

Seventy-four patients were enrolled. Thirty complications occurred in thirteen (17.6%) patients without mortality. The electrode placement direction (anteroposterior vs. craniocaudal, HR = 14.2, p < 0.01) and gastrointestinal invasion (HR = 15.7, p < 0.01) were significant factors for complications. The progression-free survival (PFS) rate in one year, three years, and five years were 69.1%, 48.7%, and 28.8%, and the overall survival (OS) rate in one year, three years, and five years were 97.2%, 53%, and 31.2%. In univariate analysis, the chemotherapy regimen, local tumour recurrence, axial tumour length, tumour volume, and serum carbohydrate antigen 19-9 levels were all significantly associated with PFS and OS. In multivariate analysis, the chemotherapy regimen was the only significant factor associated with PFS and OS. TS-1 (Tegafur, gimeracil, and oteracil) group has superior survival outcome than gemcitabine group.

CONCLUSION

This study showed that combined induction chemotherapy and surgical IRE for LAPC is safe. For well-selected patients, IRE can achieve encouraging survival outcomes.

Intraoperative Irreversible Electroporation in Locally Advanced Pancreatic Cancer: A Guide for the Interventional Radiologist

Efforts to improve mortality associated with locally advanced pancreatic cancer (LAPC) have shown minimal gains despite advances in surgical technique, systemic treatments, and radiation therapy. Locoregional therapy with ablation has not been routinely adopted due to the high risk of complications associated with thermal destruction of the pancreas. Irreversible electroporation (IRE) is an emerging, nonthermal, ablative technology that has demonstrated the ability to generate controlled ablation of LAPC while preserving pancreatic parenchymal integrity. IRE may be performed percutaneously or via laparotomy and will commonly involve multidisciplinary treatment teams. This article will describe the technical aspects of how multidisciplinary IRE is performed during laparotomy at a single tertiary care institution.

Systematic Review of Irreversible Electroporation Role in Management of Locally Advanced Pancreatic Cancer

BACKGROUND

Ablative techniques provide in patients with locally advanced pancreatic cancer (LAPC) symptomatic relief, survival benefit and potential downsizing. Irreversible Electroporation (IRE) represents potentially an ideal solution as no thermal tissue damage occurs. The purpose of this review is to present an overview on safety, feasibility, oncological results, survival and quality of life improvement obtained by IRE.

METHODS

A systematic search was performed in PubMed, regarding the use of IRE on PC in humans for studies published in English up to March 2019.

RESULTS

15 original studies embodying 691 patients with unresectable LAPC who underwent IRE were included. As emerged, IRE works better on tumour sizes between 3-4 cm. Oncological results are promising: median OS from diagnosis or treatment up to 27 months. Two groups investigated borderline resectable tumours treated with IRE before resection with margin attenuation, whereas IRE has proved to be effective in pain control.

CONCLUSIONS

Electroporation is bringing new hopes in LAPC management. The first aim of IRE is to offer a palliative treatment. Further efforts are needed for patient selection, as well as the use of IRE for 'margin accentuation' during surgical resection. Even if promising, IRE needs to be validated in large, randomized, prospective series.

Normal and fibrotic liver parenchyma respond differently to irreversible electroporation

BACKGROUND

The safety and efficacy of irreversible electroporation (IRE) in treating hepatic, biliary, and pancreatic malignancies are active areas of clinical investigation. In addition, recent studies have shown that IRE may enable regenerative surgery and in vivo tissue engineering. To use IRE effectively in these clinical applications, it is important to understand how different tissue microenvironments impact the response to IRE. In this study, we characterize the electrical and histological properties of non-fibrotic and fibrotic liver parenchyma before and after IRE treatment.

METHODS

Electrical resistivity and histology of fibrotic liver from C57BL/6 mice fed a 0.1% 3,5-diethylcarbonyl-1,4-dihydrocollidine (DDC) diet were compared to those of non-fibrotic liver from matched control mice before and after IRE treatment.

RESULTS

At baseline, the electrical resistivity of fibrotic liver was lower than that of non-fibrotic liver. Post-IRE, resistivity of non-fibrotic liver declined and then recovered back to baseline with time, correlating with hepatocyte repopulation of the ablated parenchyma without deposition of fibrotic scar. In contrast, resistivity of fibrotic liver remained depressed after IRE treatment, correlating with persistent inflammation.

CONCLUSION

Non-fibrotic and fibrotic liver respond to IRE differently. The underlying tissue microenvironment is an important modifying factor to consider when designing IRE protocols for tissue ablation.

Irreversible Electroporation of the Pancreas

Irreversible electroporation (IRE) is a relatively recent method of ablation. In contrast to many ablation devices that use thermal methods to induce cell death, IRE employs the use of an electric field to cause irreversible permeability of the cell membrane, thus inducing apoptosis. Since its use in the pancreas was first described in 2012, IRE has become established as part of the armamentarium of ablation devices currently available. The crucial advantage of IRE compared with other devices employing thermal ablation is the safety around vital structures such as vessels and ducts. This is especially important in the pancreas due to the close proximity of multiple major vascular structures, biliary ducts, and adjacent gastrointestinal organs. This article will explore the current evidence regarding the use of IRE in the pancreas.

Surgery or Locoregional Approaches for Hepatic Oligometastatic Pancreatic Cancer: Myth, Hope, or Reality?

Despite extensive research, pancreatic ductal adenocarcinoma (PDAC) remains a difficult-to-treat cancer associated with poor survival. Due to the known aggressive disease biology, palliative chemotherapy is the only routinely recommended treatment in the metastatic setting in patients with adequate performance status. However, in a subset of patients with oligometastatic disease, multimodality treatment with surgery and/or locoregional approaches may provide long-term disease control and prolong survival. In fact, in highly selected cases, median overall survival has been reported to extend to 56 months in patients treated with surgery. In particular, liver and extraregional nodal resections may provide long-term tumor control with acceptable morbidity. Current guidelines do not recommend surgery for patients with metastatic PDAC and, in the case of PDAC with oligometastases, there are no published randomized controlled trials regarding locoregional or surgical approaches. Here we review the literature on surgical and locoregional approaches including radiofrequency ablation, irreversible electroporation, and stereotactic body radiation, and focus on patients with hepatic oligometastatic pancreatic cancer. We provide a summary regarding survival outcomes, morbidity and mortality and discuss selection criteria that may be useful to predict the best outcomes for such strategies.

A prospective, multi-institution assessment of irreversible electroporation for treatment of locally advanced pancreatic adenocarcinoma: initial outcomes from the AHPBA pancreatic registry

BACKGROUND

The optimal treatment and management of locally advanced pancreatic cancer (LAPC) remains unclear and controversial. This study aimed to report the initial outcomes of the AHPBA Registry and evaluate the reproducibility of existing evidence that the addition of Irreversible Electroporation (IRE), a nonthermal ablative treatment, confers survival benefits beyond standard therapeutic options for patients with LAPC.

METHODS

From December 2015 to October 2017, patients with LAPC were treated with open-technique IRE following the AHPBA Registry Protocols. Patient demographics, long-term outcomes, and adverse events were recorded. Survival analyses were performed using Kaplan-Meier (KM) curves for overall survival (OS), progression free survival (PFS) and time to progression (TTP).

RESULTS

A total of 152 patients underwent successful IRE. Morbidity and mortality were 18% and 2% respectively, with 19 (13%) patients experiencing severe adverse events. Nine (6%) patients presented with local recurrence. Median TTP, PFS, and OS from diagnosis were 27.3 months, 22.8 months, and 30.7 months respectively.

CONCLUSION

The combination of IRE with established multiagent therapy is safe and demonstrates encouraging survival among patients with LAPC. IRE is associated with a low rate of serious adverse events and has been optimized for more widespread adoption through the standardized protocols available through the AHPBA registry.

Locally Advanced Pancreatic Cancer: Work-Up, Staging, and Local Intervention Strategies

Locally advanced pancreatic cancer (LAPC) has several definitions but essentially is a nonmetastasized pancreatic cancer, in which upfront resection is considered not beneficial due to extensive vascular involvement and consequent high chance of a nonradical resection. The introduction of FOLFIRINOX chemotherapy and gemcitabine-nab-paclitaxel (gem-nab) has had major implications for the management and outcome of patients with LAPC. After 4-6 months induction chemotherapy, the majority of patients have stable disease or even tumor-regression. Of these, 12 to 35% are successfully downstaged to resectable disease. Several studies have reported a 30-35 months overall survival after resection; although it currently remains unclear if this is a result of the resection or the good response to chemotherapy. Following chemotherapy, selection of patients for resection is difficult, as contrast-enhanced computed-tomography (CT) scan is unreliable in differentiating between viable tumor and fibrosis. In case a resection is not considered possible but stable disease is observed, local ablative techniques are being studied, such as irreversible electroporation, radiofrequency ablation, and stereotactic body radiation therapy. Pragmatic, multicenter, randomized studies will ultimately have to confirm the exact role of both surgical exploration and ablation in these patients. Since evidence-based guidelines for the management of LAPC are lacking, this review proposes a standardized approach for the treatment of LAPC based on the best available evidence.

Is irreversible electroporation safe and effective in the treatment of hepatobiliary and pancreatic cancers?

BACKGROUND

Irreversible electroporation (IRE) is a novel ablative technique for hepatobiliary and pancreatic cancers. This review summarizes the data regarding the safety and efficacy of IRE in the treatment of hepatobiliary and pancreatic cancers.

DATA SOURCES

Studies were identified by searching PubMed and Embase for articles published in English from database inception through July 31, 2017. For inclusion, each clinical study had to report morbidity and survival data on hepatobiliary and pancreatic cancers treated with IRE and contain at least 10 patients. Studies that met these criteria were included for analysis. Two authors assessed each clinical study for data extraction. The controversial parts were resolved through discussion with seniors.

RESULTS

A total of 24 clinical studies were included. Fourteen focused on hepatic ablation with IRE comprising 437 patients with 666 lesions of different tumor types. Two patients (0.5%) died after the IRE procedure. Morbidity of hepatic ablation with IRE ranged from 7% to 35%. Most complications were mild. Complete response for hepatic tumors was reported as 57%-97%. Ten studies with 455 patients focused on pancreatic IRE. The overall mortality of IRE in pancreatic cancer was 2%. Overall severe morbidity of IRE in pancreatic cancer ranged from 0 to 20%. The median overall survival after IRE ranged from 7 to 23 months. Patients treated with IRE combined with surgical resection showed a longer overall survival.

CONCLUSIONS

IRE significantly improves the prognosis of advanced hepatobiliary and pancreatic malignances, and companied with less complications. Hence, IRE is a relatively safe and effective non-thermal ablation strategy and potentially recommended as an option for therapy of patients with hepatobiliary and pancreatic malignances.