Irreversible electroporation versus radiotherapy after induction chemotherapy on survival in patients with locally advanced pancreatic cancer: a propensity score analysis

Pulsed Electric Fields in Oncology: A Snapshot of Current Clinical Practices and Research Directions from the 4th World Congress of Electroporation

The 4th World Congress of Electroporation (Copenhagen, 9-13 October 2022) provided a unique opportunity to convene leading experts in pulsed electric fields (PEF). PEF-based therapies harness electric fields to produce therapeutically useful effects on cancers and represent a valuable option for a variety of patients. As such, irreversible electroporation (IRE), gene electrotransfer (GET), electrochemotherapy (ECT), calcium electroporation (Ca-EP), and tumour-treating fields (TTF) are on the rise. Still, their full therapeutic potential remains underappreciated, and the field faces fragmentation, as shown by parallel maturation and differences in the stages of development and regulatory approval worldwide. This narrative review provides a glimpse of PEF-based techniques, including key mechanisms, clinical indications, and advances in therapy; finally, it offers insights into current research directions. By highlighting a common ground, the authors aim to break silos, strengthen cross-functional collaboration, and pave the way to novel possibilities for intervention. Intriguingly, beyond their peculiar mechanism of action, PEF-based therapies share technical interconnections and multifaceted biological effects (e.g., vascular, immunological) worth exploiting in combinatorial strategies.

COL12A1 Acts as a Novel Prognosis Biomarker and Activates Cancer-Associated Fibroblasts in Pancreatic Cancer through Bioinformatics and Experimental Validation

Pancreatic cancer remains one of the most challenging malignancies to date and is associated with poor survival. Cancer-associated fibroblasts (CAFs) are key stromal cells in the tumor microenvironment (TME) that play a crucial role in tumor progression in pancreatic cancer. Thus, uncovering the key genes involved in CAF progression and determining their prognostic value is critically important. Herein, we report our discoveries in this research area. Analysis of The Cancer Genome Atlas (TCGA) dataset and investigation of our clinical tissue samples indicated that COL12A1 expression was aberrantly highly expressed in pancreatic cancer. Survival and COX regression analyses revealed the significant clinical prognostic value of COL12A1 expression in pancreatic cancer. COL12A1 was mainly expressed in CAFs but not in tumor cells. This was verified with our PCR analysis in cancer cells and CAFs. The knocking down of COL12A1 decreased the proliferation and migration of CAFs and down-regulated the expression of CAF activation markers actin alpha 2 (ACTA2), fibroblast activation protein (FAP), and fibroblast-specific protein 1 (FSP1). Meanwhile, the interleukin 6 (IL6), CXC chemokine Ligand-5 (CXCL5), and CXC chemokine Ligand-10 (CXCL10) expressions were inhibited, and the cancer-promoting effect was reversed by COL12A1 knockdown. Therefore, we demonstrated the potential prognostic and target therapy value of COL12A1 expression in pancreatic cancer and elucidated the molecular mechanism underlying its role in CAFs. The findings of this study might provide new opportunities for TME-targeted therapies in pancreatic cancer.

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.

Electroporation and Immunotherapy-Unleashing the Abscopal Effect

Simple Summary

Electrochemotherapy and irreversible electroporation are primarily used for treating patients with cutaneous and subcutaneous tumors and pancreatic cancer, respectively. Increasing numbers of studies have shown that the treatments may elicit an immune response in addition to eliminating the tumor cells. The purpose of this review is to give an in-depth introduction to the electroporation-induced immune response and the local and peripheral immune systems, and to describe the various studies investigating the combination of electroporation and immunotherapy. The review may help guide and inspire the design of future clinical trials investigating the potential synergy of electroporation and immunotherapy in cancer treatment.

Abstract

The discovery of electroporation in 1968 has led to the development of electrochemotherapy (ECT) and irreversible electroporation (IRE). ECT and IRE have been established as treatments of cutaneous and subcutaneous tumors and locally advanced pancreatic cancer, respectively. Interestingly, the treatment modalities have been shown to elicit immunogenic cell death, which in turn can induce an immune response towards the tumor cells. With the dawn of the immunotherapy era, the potential of combining ECT and IRE with immunotherapy has led to the launch of numerous studies. Data from the first clinical trials are promising, and new combination regimes might change the way we treat tumors characterized by low immunogenicity and high levels of immunosuppression, such as melanoma and pancreatic cancer. In this review we will give an introduction to ECT and IRE and discuss the impact on the immune system. Additionally, we will present the results of clinical and preclinical trials, investigating the combination of electroporation modalities and immunotherapy.

Intraoperative HIFU Ablation of the Pancreas Using a Toroidal Transducer in a Porcine Model. The First Step towards a Clinical Treatment of Locally Advanced Pancreatic Cancer

Apart from palliative chemotherapy, no other therapy has been proven effective for the treatment of locally advanced pancreatic tumors. In this study, an intraoperative high-intensity focused ultrasound (HIFU) device was tested in vivo to demonstrate the feasibility of treating the pancreatic parenchyma and tissues surrounding the superior mesenteric vessels prior to clinical translation of this technique. Twenty pigs were included and treated using a HIFU device equipped with a toroidal transducer and an integrated ultrasound imaging probe. Treatments were performed with energy escalation (from 30 kJ to 52 kJ). All treatments resulted in visible (macroscopically and in ultrasound images) homogeneous thermal damage, which was confirmed by histology. The dimensions of thermal lesions measured in ultrasound images and those measured macroscopically were correlated (r = 0.82, p < 0.05). No arterial spasms or occlusion were observed at the lowest energy setting. Temporary spasm of the peripancreatic artery was observed when using an energy setting greater than 30 kJ. The possibility of treating the pancreas and tissues around mesenteric vessels without vascular thrombosis holds great promise for the treatment of locally advanced pancreatic cancers. If clinically successful, chemotherapy followed by HIFU treatment could rapidly become a novel treatment option for locally advanced pancreatic cancer.

Can local ablative techniques replace surgery for locally advanced pancreatic cancer?

In the treatment of pancreatic ductal adenocarcinoma (PDAC) the best chance at long term survival or cure has to date always included the complete surgical removal of the tumor. However, locally advanced pancreatic cancer (LAPC), about 25% of all newly diagnosed PDAC, is defined by its primary technical unresectability due to infiltration of visceral arteries and absence of metastasis. Induction therapies, especially FOLFIRINOX treatment, together with technical surgical advancement have increased the numbers for conversion to secondary resectability. Recent data on resections after induction therapy show promising, almost doubled survival compared to palliative treatment. Yet, around 70% of LAPC remain unresectable after induction therapy, often due to persistent local invasion. As locally ablative techniques are becoming more widely available this review examines their possible applicability to substitute for surgery in these cases which we propose to group under the new term "Inconvertible LAPC". The need for defining this novel subgroup who might benefit from ablative treatment is based on the findings in our review that high-level evidence on ablative techniques for PDAC is largely lacking and the latest effective, harmonized treatment guidelines for LAPC are not often incorporated in these studies. The "inconvertible LAPC" label requires persistent unresectability after staging and induction therapy of LAPC according to current guidelines followed by liberal indication for aggressive surgical exploration at a center equipped for extended pancreatic resections. Ideally, this specification of a new, distinct patient group will also put it in the spotlight more, hopefully prompt more trials designed to generate robust evidence and optimize transferability of study results.

Aortoesophageal fistula involving the central aortic arch salvaged with emergent percutaneous TEVAR, great vessel coverage and in vivo graft fenestration

Immediate intervention is needed for aortoesophageal fistulas (AEF), a rare but highly lethal cause of massive gastrointestinal hemorrhage. Emergent thoracic endovascular aortic repair (TEVAR) is considered first-line treatment for massive bleeding from AEFs. We describe an unusual and challenging case of TEVAR coverage of an AEF involving the central aortic arch immediately followed by in vivo endograft fenestration to regain arch vessel perfusion. In vivo fenestration, currently a procedure for emergency or investigational purposes only, was shown to be life saving in our case. The main complications associated with the procedure included stroke and infection, requiring esophagectomy and cervical diversion as well as ongoing antibiotic treatment.

Electrochemotherapy with Mitomycin C Potentiates Apoptosis Death by Inhibiting Autophagy in Squamous Carcinoma Cells

We investigated the chemosensitizing effect of electroporation (EP), which, using electrical pulses, permeabilizes cancer cells to drugs. The study involved two human hypopharyngeal and tongue carcinoma cell lines. The surface and intracytoplasmic expression of P-gp were evaluated by flow cytometry, demonstrating that both lines were intrinsically resistant. After establishing the optimal dose of mitomycin C (MMC) to be used, in combination with EP, we showed, by both MTT assay and optical and electron scanning microscopy, the potentiating cytotoxic effect of EP with MMC compared to single treatments. Flow cytometry showed that the cytotoxicity of EP + MMC was due to the induction of apoptosis. In addition to verifying the release of cytochrome C in EP + MMC samples, we performed an expression analysis of caspase-3, caspase-9, Akt, pAkt, HMGB1, LC3I, LC3II, p62, Beclin1, and associated proteins with both apoptotic and autophagic phenomena. Our results were confirmed by two veterinary patients in whom the EP + MMC combination was used to control margins after the resection of corneal squamous carcinoma. In conclusion, we affirmed that the effect for which EP enhances MMC treatment is due to the inhibition of the autophagic process induced by the drug in favor of apoptosis.

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.

Ablation in Pancreatic Cancer: Past, Present and Future

The insidious onset and aggressive nature of pancreatic cancer contributes to the poor treatment response and high mortality of this devastating disease. While surgery, chemotherapy and radiation have contributed to improvements in overall survival, roughly 90% of those afflicted by this disease will die within 5 years of diagnosis. The developed ablative locoregional treatment modalities have demonstrated promise in terms of overall survival and quality of life. In this review, we discuss some of the recent studies demonstrating the safety and efficacy of ablative treatments in patients with locally advanced pancreatic cancer.

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.

Identification of Circulating Biomarkers and Construction of a Prognostic Signature for Survival Prediction in Locally Advanced Pancreatic Cancer After Irreversible Electroporation

Background

Irreversible electroporation (IRE) is a novel treatment for locally advanced pancreatic cancer (LAPC), but the predictive factors, based on cytokines and immunocytes of survival, are still lacking. This study aimed to establish a risk model based on cytokines and immunocytes for LAPC patients undergoing IRE treatment.

Patients and Methods

Peripheral blood samples were obtained from 31 LAPC patients and 8 healthy control subjects before IRE. The phenotypes of lymphocytes were analyzed by flow cytometry, and the cytokines were evaluated with Luminex microarray assay. Least absolute shrinkage and selection operator (LASSO) and Cox regression were applied to assess the prognostic factors for overall survival (OS) and progression-free survival (PFS). A receiver operating characteristic (ROC) curve and a concordance index (C-index) were used to compare the abilities to predict survival rates.

Results

The relationship between multiple cytokines and clinical factors was evaluated and their prognostic value was compared. The five best predictors for OS and PFS, including CA19-9, CD3⁺CD4⁺ T cells, CD3⁺CD8⁺ T cells, IL-17A, and TNF-α were selected and incorporated into a new immune panel. A risk model based on this immune panel was established and exhibited significantly higher values of C-indexes and AUC for OS and PFS prediction as compared with tumor marker score and TNM stage system.

Conclusion

We presented a risk model based on a microarray assay of cytokines and lymphocytes for LAPC patients after receiving IRE treatment for the first time. The established risk model showed relatively good performance in survival prediction and was able to facilitate tailed patient management in clinical practice.

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.

Combining NanoKnife with M1 oncolytic virus enhances anticancer activity in pancreatic cancer

NanoKnife, a nonthermal ablation technique also termed irreversible electroporation (IRE), has been adopted in locally advanced pancreatic cancer (LAPC) treatment. However, reversible electroporation (RE) caused by heterogeneous electric field magnitude leads to inadequate ablation and tumor recurrence. Alphavirus M1 has been identified as a novel natural oncolytic virus which is nonpathogenic and with high tumor selectivity. This study evaluated improvements to therapeutic efficacy through combination therapy incorporating NanoKnife and M1 virus. We showed that IRE triggered reactive oxygen species (ROS)-dependent apoptosis in pancreatic cancer cells (PCCs) mediated by phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway suppression. When NanoKnife was combined with M1 virus, the therapeutic efficacy was synergistically enhanced. The combinatorial treatment further inhibited tumor proliferation and prolonged the survival of orthotopic pancreatic cancer (PC)-bearing immunocompetent mice. In depth, NanoKnife enhanced the oncolytic effect of M1 by promoting its infection. The combination turned immune-silent tumors into immune-inflamed tumors characterized by T cell activation. Clinicopathologic analysis of specific M1 oncolytic biomarkers indicated the potential of the combination regimen. The combinatorial therapy represents a promising therapeutic efficacy and may ultimately improve the prognosis of patients with LAPC.

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.

The Landmark Series: Locally Advanced Pancreatic Cancer and Ablative Therapy Options

Locally advanced pancreatic cancer (LAPC) is a challenging disease to treat. There is consensus that systemic chemotherapy should be the first line of therapy for most patients. However, there is no consensus on how to manage those patients who do not have sufficient response to become candidates for resection but also do not have distant progression after weeks or months of systemic therapy. Radiation therapy is the most commonly used and best-studied local ablative therapy. One recent randomized controlled trial (LAP-07) failed to demonstrate an overall survival benefit for conventional chemoradiation therapy after induction chemotherapy versus chemotherapy alone. This study had several limitations, and ongoing studies are re-evaluating the role of chemoradiation after more effective chemotherapy regimens as well as more advanced radiation techniques. In parallel, there has been increasing interest in other thermal and non-thermal methods of ablation. In particular, irreversible electroporation has gained traction for treatment of LAPC, with at least one ongoing randomized controlled trial designed to address its role compared with systemic chemotherapy alone. Multiple preclinical and clinical studies are investigating combinations of local ablation and immunotherapy with the goal of generating immune responses that will meaningfully improve outcomes.

Survival Comparison of Neoadjuvant Chemotherapy Followed by Irreversible Electroporation Versus Conversional Resection for Locally Advanced Pancreatic Cancer

Locally advanced pancreatic cancer (LAPC) is a lethal disease and neoadjuvant chemotherapy and conversional resection is shown to provide the best survival for LAPC patients. Irreversible electroporation (IRE) is a new and effective method for the treatment of LAPC. This study aimed to compare the long-term survival of LAPC patients after neoadjuvant chemotherapy followed by conversional resection and IRE. A total of 140 LAPC patients were included from August 2015 to March 2020. The survival outcomes of patients after treatment with chemotherapy, chemotherapy combined with conversional resection or IRE were analyzed and compared. Patients in these three groups had similar clinical and pathological characteristics. Patients in the resection and IRE groups had similar median OS time (resection group vs. IRE group: 25.3 months vs. 26.0 months, P>0.050), which was significantly longer than that of the chemotherapy group (8.7 months, P<0.001). Additionally, patients in the resection and IRE groups had a median PFS of 10.6 and 12.0 months, respectively. Also, they were significantly higher than that of patients in the chemotherapy group. Chemotherapy combined with conversional resection and IRE was identified as significant prognostic factors for OS and PFS in LAPC patients. It was shown that compared with neoadjuvant chemotherapy followed by surgical resection, chemotherapy and IRE provided similar OS and PFS for LAPC patients with minimal invasion. This combination therapy may be a suitable treatment for LAPC patients.

CT-guided 125I brachytherapy combined with chemotherapy for the treatment of unresectable or locally advanced pancreatic carcinoma

PURPOSE

We aimed to explore the feasibility and clinical effectiveness of percutaneous CT-guided iodine-125 (¹²⁵I) brachytherapy combined with chemotherapy for the treatment of patients with unresectable or locally advanced pancreatic carcinoma (PC).

METHODS

We retrospectively reviewed 66 patients with Stage III and IV PC who had received chemotherapy. A total of 35 (53%) patients receiving 125I brachytherapy and chemotherapy (gemcitabine + cisplatin, GP) were classified as Group A, and 31 (47%) patients who received GP chemotherapy alone were categorized as Group B. The evaluated indications were local control rate (LCR), local progression-free survival (LPFS), overall survival (OS), treatment-related complications, and the degree of symptom relief. Kaplan-Meier curves, log-rank test and Cox regression models were generated and used for further analysis to identify predictors of outcomes.

RESULTS

The median follow-up time was 6.00±0.84 months. The 1-, 3-, 6-, 12- and 18-month LCRs for Group A were 100% (35/35), 89.3% (25/28), 71.4% (15/21), 37.5% (3/8) and 33.3% (1/3), respectively; and those for Group B were 87.1% (27/31), 69.6% (16/23), 41.2% (7/17), 14.3% (1/7) and 0% (0/3), respectively. The LCR differed at 1-, 3- and 6-months (P = 0.032; P = 0.009; P = 0.030; respectively). The median LPFS was 7.00±0.30 months and 5.00±0.75 months for Groups A and B (P = 0.023), respectively; however, the median OS of the groups were not significantly different (8.00±0.77 months vs. 6.00±1.04 months. P = 0.917). No life-threatening complications occurred during or after the procedures. Patients in Group A experienced better pain control and relief of abdominal distension than those in Group B.

CONCLUSION

CT-guided 125I brachytherapy is a feasible, safe, and valuable treatment for patients with unresectable PC.

Gemcitabine plus concurrent irreversible electroporation vs gemcitabine alone for locally advanced pancreatic cancer

BACKGROUND

Locally advanced pancreatic cancer (LAPC) is a common malignant digestive system tumor that ranks as the fourth leading cause of cancer-related death in the world. The prognosis of LAPC is poor even after standard treatment. Irreversible electroporation (IRE) is a novel ablative strategy for LAPC. Several studies have confirmed the safety of IRE. To date, no prospective studies have been performed to investigate the therapeutic efficacy of conventional gemcitabine (GEM) plus concurrent IRE.

AIM

To compare the therapeutic efficacy between conventional GEM plus concurrent IRE and GEM alone for LAPC.

METHODS

From February 2016 to September 2017, a total of 68 LAPC patients were treated with GEM plus concurrent IRE n = 33) or GEM alone n = 35). Overall survival (OS), progression free survival (PFS), and procedure-related complications were compared between the two groups. Multivariate analyses were performed to identify any prognostic factors.

RESULTS

There were no treatment-related deaths. The technical success rate of IRE ablation was 100%. The GEM + IRE group had a significantly longer OS from the time of diagnosis of LAPC (19.8 mo vs 9.3 mo, P < 0.0001) than the GEM alone group. The GEM + IRE group had a significantly longer PFS (8.3 mo vs 4.7 mo, P < 0.0001) than the GEM alone group. Tumor volume less than 37 cm3 and GEM plus concurrent IRE were identified as significant favorable factors for both the OS and PFS.

CONCLUSION

Gemcitabine plus concurrent IRE is an effective treatment for patients with LAPC.

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.

T-cell activation and immune memory enhancement induced by irreversible electroporation in pancreatic cancer

Background

Irreversible electroporation is shown to induce immune changes in pancreatic cancer while the histology evidences are still lacking. The aim of this study is to show the immune changes in histology and explore whether irreversible electroporation (IRE) can induce immunogenic cell death (ICD) of tumor cells and activate specific immune responses.

Methods

Subcutaneous and orthotopic pancreatic cancer models were established and used to evaluate the effect of immune modulation of IRE. The infiltration of T cells was assessed in several tissue samples before and after IRE. Abscopal effect was then assessed by comparing the tumor growth of subcutaneous tumors after in situ ablation with IRE or exposure to tumor culture supernatant (TSN) of IRE‐treated Pan02. The expression of damage‐associated molecular patterns (DAMPs) of tumor cells after IRE was detected in vitro.

Results

IRE could significantly suppress the tumor growth and increase the infiltration of CD8⁺ T cells. After ablation with IRE or stimulation with TSN of Pan02 treated by IRE, the growth of untreated tumor was suppressed and the effector CD8⁺ T cells and memory T cells increased significantly in mice. Additionally, the inhibition effect of tumor growth increased along with the increasing strength levels of electroporation. IRE induced ICD of tumor cells by increasing the synthesis and secretion of DAMPs.

Conclusions

IRE induced local immunomodulation by increasing specific T cells infiltration. Through enhancing specific immune memory, IRE not only led a complete tumor regression in suit, but also induced abscopal effect, suppressing the growth of the latent lesions.

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.

Comparison of combination therapies in the management of locally advanced pancreatic cancer: Induction chemotherapy followed by irreversible electroporation vs radiofrequency ablation

Background

Locally advanced pancreatic cancer (LAPC) remains a challenge for current treatments. Local destructive therapies, such as irreversible electroporation (IRE) and radiofrequency ablation (RFA), were used more and more frequently in the treatment of LAPC.

Objective

This study aimed to compare the efficacy of IRE with RFA in patients with LAPC.

Methods

From August 2015 to August 2017, 58 LAPC patients after IRE or RFA therapy, which was performed through open approach, were retrospectively reviewed. The survival outcomes after IRE (36 patients) and RFA (18 patients) were compared after propensity score matching (PSM) analysis.

Results

Before PSM analysis, IRE after the induction chemotherapy resulted in significant higher overall survival (OS) rates and progression‐free survival (PFS) rates to RFA (2‐year OS, 53.5% vs 30.8%, P = .013; 2‐year PFS, 28.4% vs 12.1%, P = .043). After PSM analysis, compared with RFA, the survival benefit of IRE was even more obvious, (2‐year OS, 53.5% vs 27.0%, P = .010; 2‐year PFS, 28.4% vs 6.4%, P = .018). For patients with tumor larger than 4 cm, IRE resulted in comparable OS and PFS between RFA and IRE while IRE also achieved better long‐term OS to RFA for those with tumor smaller than 4 cm. Multivariate analysis illustrated that IRE was a favorable prognostic factor in terms of OS and PFS in patients with LAPC.

Conclusions

IRE after induction chemotherapy is superior to RFA after induction chemotherapy for treating LAPC patients while these two therapies have comparable efficacy for tumors which were larger than 4 cm.

Comparison of Survival Between Irreversible Electroporation Followed by Chemotherapy and Chemotherapy Alone for Locally Advanced Pancreatic Cancer

Locally advanced pancreatic cancer (LAPC) has a dismal prognosis even after standard chemotherapy, and local progression contributes to nearly one-third of the deaths of these patients. As a local destructive method, irreversible electroporation (IRE) can feasibly treat LAPC. The aim of this study was to evaluate IRE combined with chemotherapy as a new treatment and compare its efficacy with that of chemotherapy alone in patients with LAPC. The data of LAPC patients who received chemotherapy with or without IRE were extracted from Surveillance, Epidemiology, and End Results (SEER) database and medical records of Sun Yat-sen University Cancer Center (SYSUCC). The efficacy of these two treatments was compared using propensity score matching (PSM) analysis. LAPC patients treated with the combination therapy had better overall survival (OS). Significantly higher cancer-specific survival (CSS) and progression-free survival (PFS) rates were also observed in patients after IRE combined with chemotherapy, compared with chemotherapy alone. IRE combined with chemotherapy was established as a favorable factor for OS, CSS, and PFS in LAPC patients. This combination method may be a more suitable treatment for patients with LAPC.

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.