Electrochemotherapy: aspects of preclinical development and early clinical experience

Evolution of Bioelectric Membrane Potentials: Implications in Cancer Pathogenesis and Therapeutic Strategies

Electrophysiology typically deals with the electrical properties of excitable cells like neurons and muscles. However, all other cells (non-excitable) also possess bioelectric membrane potentials for intracellular and extracellular communications. These membrane potentials are generated by different ions present in fluids available in and outside the cell, playing a vital role in communication and coordination between the cell and its organelles. Bioelectric membrane potential variations disturb cellular ionic homeostasis and are characteristic of many diseases, including cancers. A rapidly increasing interest has emerged in sorting out the electrophysiology of cancer cells. Compared to healthy cells, the distinct electrical properties exhibited by cancer cells offer a unique way of understanding cancer development, migration, and progression. Decoding the altered bioelectric signals influenced by fluctuating electric fields benefits understanding cancer more closely. While cancer research has predominantly focussed on genetic and molecular traits, the delicate area of electrophysiological characteristics has increasingly gained prominence. This review explores the historical exploration of electrophysiology in the context of cancer cells, shedding light on how alterations in bioelectric membrane potentials, mediated by ion channels and gap junctions, contribute to the pathophysiology of cancer.

Electrochemotherapy in the Locoregional Treatment of Metastatic Colorectal Liver Metastases: A Systematic Review

BACKGROUND

The global incidence of secondary liver cancer is rising due to multiple risk factors, presenting significant challenges in public health. Similarly, colorectal cancer (CRC) remains a leading cause of cancer-related mortality with the development of frequent liver metastases. Surgical resection of CRC liver metastases is only suitable for a limited subset of patients, necessitating alternative nonsurgical treatments such as electrochemotherapy (ECT); Methods: This review adhered to the S.P.I.D.E.R.

FRAMEWORK

Systematic searches of PubMed, Cochrane, and Scopus databases were conducted for studies published between 2003 and 2023, following PRISMA guidelines. Inclusion criteria were full-text clinical studies in English focusing on ECT-treated CRC liver metastases, excluding reviews, editorials, and non-clinical papers. The GRADE approach was utilized to assess evidence quality, considering study limitations, consistency, and other factors; Results: From 38 identified articles, 4 met the inclusion criteria, encompassing 78 patients and 128 treated lesions. The studies demonstrated variability in design and follow-up duration (3-11 months). Complete response (CR) rates ranged from 33.3% to 63.0%, while progression disease (PD) rates were high, ranging from 23.0% to 55.6%. Median overall survival (OS) spanned 11.3 to 29.0 months. No severe ECT-related complications were reported.

CONCLUSIONS

ECT appears to be a safe and effective modality for the treatment of CRC liver metastases, especially for lesions unsuitable for other ablative techniques. Further prospective and randomized studies are essential to better define the role of ECT in managing CRC liver metastases and to compare its efficacy with other ablative methods.

The comparison of the dynamics of Ca2+ and bleomycin intracellular delivery after cell sonoporation and electroporation in vitro

Ca2+, in combination with SP or EP, induces cell cytotoxicity much faster compared to BLM. The application of BLM in combination with, SP or EP, reaches the level of cell death, induced by similar combination with Ca2+, only after 72 h. The methods of SP and EP were calibrated according to the level of differential cytotoxicity, determined after 6 days (using cell clonogenic assay). The combination of Ca2+ SP induces cell death faster than Ca2+ EP - after Ca2+ SP it increases to a maximum level after 15 min and remains constant for up to 6 days, while the cytotoxic efficiency after Ca2+ EP increases to the level of Ca2+ SP only after 72 h. The combination of BLM SP shows a very similar dynamics to BLM EP - both reach maximal level of cytotoxicity after 48-72 h. Ca2+ and BLM in combination with SP have shown similar levels of cytotoxicity at higher acoustic pressures (≥250 kPa); therefore, Ca2+ SP can be used to induce immediate and maximal level of cytotoxic effect. The faster cytotoxic efficiency of Ca2+ in combination with SP than EP was determined to be due to the involvement of microbubble inertial cavitation.

EW-7197, transforming growth factor β inhibitor, combined with irreversible electroporation for improving skin wound in a rat excisional model

To evaluate the safety and efficacy of combining EW-7197 with irreversible electroporation (IRE) for improving wound healing, 16 male Sprague-Dawley rats were randomly divided into four groups of four rats each after dorsal excisional wound induction: sham control group; oral administration of EW-7197 for 7 days group; one-time application of IRE group; and one-time application of IRE followed by oral administration of EW-7197 for 7 days group. Measurement of wound closure rate, laser Doppler scanning, histological staining (hematoxylin and eosin and Masson's trichrome), and immunohistochemical analyses (Ki-67 and α-SMA) were performed to evaluate the efficacy. Fifteen of 16 rats survived throughout the study. Statistically significant differences in wound closure rates were observed between the combination therapy group and the other three groups (all P < 0.05). The degrees of inflammation, α-SMA, and Ki-67 were reduced in the EW-7197 and IRE monotherapy groups; however, not statistically significant. The fibrosis score exhibited significant reduction in all three treatment groups, with the most prominent being in the combination therapy group. This study concludes that oral administration of EW-7197 combined with IRE demonstrated effectiveness in improving skin wound in a rat excisional model and may serve as a potential alternative for promoting healing outcomes.

Optimal Dosing and Patient Selection for Electrochemotherapy in Solid Abdominal Organ and Bone Tumors

The primary aim of this study was to analyze studies that use electrochemotherapy (ECT) in "deep-seated" tumors in solid organs (liver, kidney, bone metastasis, pancreas, and abdomen) and understand the similarities between patient selection, oncologic selection, and use of new procedures and technology across the organ systems to assess response rates. A literature search was conducted using the term "Electrochemotherapy" in the title field using publications from 2017 to 2023. After factoring in inclusion and exclusion criteria, 29 studies were analyzed and graded based on quality in full. The authors determined key patient and oncologic selection characteristics and ECT technology employed across organ systems that yielded overall responses, complete responses, and partial responses of the treated tumor. It was determined that key selection factors included: the ability to be administered bleomycin, life expectancy greater than three months, unrespectability of the lesion being treated, and a later stage, more advanced cancer. Regarding oncologic selection, all patient cohorts had received chemotherapy or surgery previously but had disease recurrence, making ECT the only option for further treatment. Lastly, in terms of the use of technology, the authors found that studies with better response rates used the ClinporatorTM and updated procedural guidelines by SOP. Thus, by considering patient, oncologic, and technology selection, ECT can be further improved in treating lesions in solid organs.

Electrochemotherapy as an Effective Alternative in the Treatment of Local Advanced Oral Squamous Cell Carcinoma: A Retrospective Analysis of Treated Cases

Advanced oral squamous cell carcinomas represent a major challenge for maxillofacial surgeons, oncologists and radiation therapists. They also account for a large share of healthcare costs. They respond little and/or poorly to conventional therapies (surgery, radiotherapy and chemotherapy). Electrochemotherapy is a new method used as a palliative treatment in patients with advanced cancer of the neck/head region who are not eligible for standard therapies. It combines the use of cytotoxic drugs with the physical principle of electroporation; it effectively controls the tumour locally and preserves organ function. To date, ECT has been little used for oral mucosal tumours, as this is difficult to access for electrodes. We report six cases of advanced oral squamous cell carcinoma treated with electrochemotherapy. This study aims to assess the debulking effect of cancer via ECT in patients with advanced oral squamous cell carcinoma. It also aims to assess the safety and tolerability of this treatment.

Calcium Electroporation Reduces Viability and Proliferation Capacity of Four Uveal Melanoma Cell Lines in 2D and 3D Cultures

Simple Summary

Calcium electroporation (CaEP) is an innovative anti-tumor treatment modality that induces cell death by introducing supraphysiological concentrations of calcium into cells with a limited effect on normal cells. The objective of the present study is to assess the effect of CaEP in uveal melanoma (UM) cell lines in comparison to electrochemotherapy (ECT) with bleomycin using 2D monolayer cell cultures as well as 3D tumor spheroid models in four different UM cell lines. The morphological changes of the spheroids, the cell viability, growth rate as well as the cytotoxic effect of electroporation (EP) with calcium chloride and bleomycin were evaluated with various drug concentrations. The results of CaEP and ECT both suggest a comparable dose-dependent reduction in cell viability and proliferation rate in all tested 2D cell lines and 3D tumor spheroids. These data point out that CaEP is an established anticancer treatment causing cell death by ATP depletion in in vitro and in vivo, representing an efficient alternative therapy with a lower cytotoxic potency for the local UM tumor control.

Abstract

Electrochemotherapy (ECT) is the combination of transient pore formation following electric pulse application with the administration of cytotoxic drugs, which enhances the cytotoxic effect of the applied agent due to membrane changes and permeabilization. Although EP represents an established therapeutic option for solid malignancies, recent advances shift to the investigation of non-cytotoxic agents, such as calcium, which can also induce cell death. The present study aims to evaluate the cytotoxic effect, the morphological changes in tumor spheroids, the effect on the cell viability, and the cell-specific growth rate following calcium electroporation (CaEP) in uveal melanoma (UM) 2D monolayer cell cultures as well as in 3D tumor spheroid models. The experiments were conducted in four cell lines, UM92.1, Mel270, and two primary UM cell lines, UPMD2 and UPMM3 (UPM). The 2D and 3D UM cell cultures were electroporated with eight rectangular pulses (100 µs pulse duration, 5 Hz repetition frequency) of a 1000 V/cm pulse strength alone or in combination with 0.11 mg/mL, 0.28 mg/mL, 0.55 mg/mL or 1.11 mg/mL calcium chloride or 1.0 µg/mL or 2.5 µg/mL bleomycin. The application of calcium chloride alone induced an ATP reduction only in the UM92.1 2D cell cultures. Calcium alone had no significant effect on ATP levels in all four UM spheroids. A significant decrease in the intracellular adenosine triphosphate (ATP) level was documented in all four 2D and 3D cell cultures for both CaEP as well as ECT with bleomycin. The results suggest a dose-dependent ATP depletion with a wide range of sensitivity among the tested UM cell lines, control groups, and the applied settings in both 2D monolayer cell cultures and 3D tumor spheroid models. The colony formation capacity of the cell lines after two weeks reduced significantly after CaEP only with 0.5 mg/mL and 1.1 mg/mL, whereas the same effect could be achieved with both applied bleomycin concentrations, 1.0 µg/mL and 2.5 µg/mL, for the ECT group. The specific growth rate on day 7 following CaEP was significantly reduced in UM92.1 cell lines with 0.5 and 1.1 mg/mL calcium chloride, while Mel270 showed a similar effect only after administration of 1.1 mg/mL. UM92.1 and Mel270 spheroids exhibited lower adhesion and density after CaEP on day three in comparison to UPM spheroids showing detachment after day 7 following treatment. CaEP and bleomycin electroporation significantly reduce cell viability at similar applied voltage settings. CaEP may be a feasible and inexpensive therapeutic option for the local tumor control with fewer side effects, in comparison to other chemotherapeutic agents, for the treatment of uveal melanoma. The limited effect on normal cells and the surrounding tissue has already been investigated, but further research is necessary to clarify the effect on the surrounding tissue and to facilitate its application in a clinical setting for the eye.

Prospektive Kohortenstudie von InspECT zur Sicherheit und Wirksamkeit der Elektrochemotherapie bei Hauttumoren und Metastasen in Abhängigkeit von Ulzeration

HINTERGRUND

Elektrochemotherapie (ECT) ist eine wirksame lokale Behandlung von Hauttumoren. Ziel dieser Studie war es, die Wirksamkeit der ECT bei ulzerierten gegenüber nichtulzerierten Tumoren zu vergleichen und den Effekt auf tumorassoziierte Symptome zu untersuchen.

METHODIK

20 Krebszentren des International Network for Sharing Practices on Electrochemotherapy (InspECT) sammelten prospektiv Daten. Die ECT wurde nach dem ESOPE-Protokoll durchgeführt. Das Therapieansprechen wurde anhand der Entwicklung der Läsionsgröße bewertet. Zusätzlich wurden Schmerzen, Symptome, Leistungsstatus (ECOG-Index) und Gesundheitszustand (EQ-5D-Fragebogen) untersucht.

ERGEBNISSE

716 Patienten mit ulzerierten (n = 302) und nichtulzerierten (n = 414) Hauttumoren und Metastasen wurden eingeschlossen (Mindest-Nachsorge 45 Tage). Nicht-ulzerierte Läsionen sprachen besser auf die ECT an als ulzerierte Läsionen (vollständiges Ansprechen: 65 % gegenüber 51 %, p = 0,0061). Nur 38 % (115/302) der Patienten mit ulzerierten Läsionen vor der ECT wiesen bei der letzten Nachuntersuchung ulzerierte Läsionen auf. Patienten mit ulzerierten Läsionen berichteten über stärkere Schmerzen und schwerere Symptome im Vergleich zu Patienten mit nichtulzerierten Läsionen, die sich nach der ECT signifikant und kontinuierlich besserten. Bei Patienten mit nichtulzerierten Läsionen hingegen nahmen die Schmerzen während der Behandlung vorübergehend zu. Es wurden keine schwerwiegenden Nebenwirkungen beobachtet.

SCHLUSSFOLGERUNGEN

Die ECT ist eine sichere und wirksame lokale Behandlung von Hauttumoren. Während die ECT die Symptome insbesondere bei Patienten mit ulzerierten Läsionen verbessert, sollte auf Basis der Daten die Implementation eines perioperativen Schmerzmanagements besonders bei nichtulzerierten Läsionen während der ECT erwogen werden.

Electroporation and Electrochemotherapy in Gynecological and Breast Cancer Treatment

Gynecological carcinomas affect an increasing number of women and are associated with poor prognosis. The gold standard treatment plan is mainly based on surgical resection and subsequent chemotherapy with cisplatin, 5-fluorouracil, anthracyclines, or taxanes. Unfortunately, this treatment is becoming less effective and is associated with many side effects that negatively affect patients’ physical and mental well-being. Electroporation based on tumor exposure to electric pulses enables reduction in cytotoxic drugs dose while increasing their effectiveness. EP-based treatment methods have received more and more interest in recent years and are the subject of a large number of scientific studies. Some of them show promising therapeutic potential without using any cytotoxic drugs or molecules already present in the human body (e.g., calcium electroporation). This literature review aims to present the fundamental mechanisms responsible for the course of EP-based therapies and the current state of knowledge in the field of their application in the treatment of gynecological neoplasms.

Prospective cohort study by InspECT on safety and efficacy of electrochemotherapy for cutaneous tumors and metastases depending on ulceration

BACKGROUND

Electrochemotherapy (ECT) is an effective local treatment for cutaneous tumors. The aim of this study was to compare the effectiveness of ECT in ulcerated vs. non-ulcerated tumors and investigate the effect on tumor-associated symptoms.

METHODS

Twenty cancer centers in the International Network for Sharing Practices on Electrochemotherapy (InspECT) prospectively collected data. ECT was performed following ESOPE protocol. Response was evaluated by lesion size development. Pain, symptoms, performance status (ECOG-Index) and health status (EQ-5D questionnaire) were evaluated.

RESULTS

716 patients with ulcerated (n = 302) and non-ulcerated (n = 414) cutaneous tumors and metastases were included (minimum follow-up of 45 days). Non-ulcerated lesions responded to ECT better than ulcerated lesions (complete response 65 % vs. 51 %, p = 0.0061). Only 38 % (115/302) with ulcerated lesions before ECT presented with ulcerated lesions at final follow-up. Patients with ulcerated lesions reported higher pain and more severe symptoms compared to non-ulcerated lesions, which significantly and continuously improved following ECT. In non-ulcerated lesions however, pain spiked during the treatment. No serious adverse events were reported.

CONCLUSIONS

ECT is a safe and effective local treatment for cutaneous tumors. While ECT improves symptoms especially in patients with ulcerated lesions, data suggest the implementation of a perioperative pain management in non-ulcerated lesions during ECT.

Advances in heterocycles as DNA intercalating cancer drugs

The insertion of a molecule between the bases of DNA is known as intercalation. A molecule is able to interact with DNA in different ways. DNA intercalators are generally aromatic, planar, and polycyclic. In chemotherapeutic treatment, to suppress DNA replication in cancer cells, intercalators are used. In this article, we discuss the anticancer activity of 10 intensively studied DNA intercalators as drugs. The list includes proflavine, ethidium bromide, doxorubicin, dactinomycin, bleomycin, epirubicin, mitoxantrone, ellipticine, elinafide, and echinomycin. Considerable structural diversities are seen in these molecules. Besides, some examples of the metallo-intercalators are presented at the end of the chapter. These molecules have other crucial properties that are also useful in the treatment of cancers. The successes and limitations of these molecules are also presented.

Ca2+ roles in electroporation-induced changes of cancer cell physiology: From membrane repair to cell death

The combination of Ca²⁺ ions and electroporation has gained attention as potential alternative to electrochemotherapy. Ca²⁺ is an important component of the cell membrane repair system and its presence directly influences the dynamics of the pore cycle after electroporation which can be exploited for cancer therapies. Here, the influence of Ca²⁺ concentration is investigated on small molecule electrotransfer and release of Calcein from 4T1, MX-1, B16F10, U87 cancer cells after cell exposure to microsecond electric pulses. Moreover, we investigated simultaneous molecule electrotransfer and intracellular calcium ion influx when media was supplemented with different Ca²⁺ concentrations. Results show that increased concentrations of calcium ions reduce the electrotransfer of small molecules to different lines of cancer cells as well as the release of Calcein. These effects are related with an enhanced membrane repair mechanism. Overall, we show that the efficiency of molecular electrotransfer can be controlled by regulating Ca²⁺ concentration in the electroporation medium. For the first time, the cause of cancer cell death in vitro from 1 mM CaCl₂ concentrations is related to the irreversible loss of Ca²⁺ homeostasis after cell electroporation. Our findings provide fundamental insight on the mechanisms of Ca²⁺ electroporation that might lead to improved therapeutic outcomes.

Electrochemotherapy and Other Clinical Applications of Electroporation for the Targeted Therapy of Metastatic Melanoma

Electrochemotherapy (ECT) is an effective bioelectrochemical procedure that uses controlled electrical pulses to facilitate the increase of intracellular concentration of certain substances (electropermeabilization/ reversible electroporation). ECT using antitumor drugs such as bleomycin and cisplatin is a minimally invasive targeted therapy that can be used as an alternative for oncologic patients not eligible for surgery or other standard therapies. Even though ECT is mainly applied as palliative care for metastases, it may also be used for primary tumors that are unresectable due to size and location. Skin neoplasms are the main clinical indication of ECT, the procedure reporting good curative results and high efficiency across all tumor types, including melanoma. In daily practice, there are many cases in which the patient’s quality of life can be significantly improved by a safe procedure such as ECT. Its popularity must be increased because it has a safe profile and minor local adverse reactions. The method can be used by dermatologists, oncologists, and surgeons. The aim of this paper is to review recent literature concerning electrochemotherapy and other clinical applications of electroporation for the targeted therapy of metastatic melanoma.

Electrochemotherapy with Bleomycin Enhances Radiosensitivity of Uveal Melanomas: First In Vitro Results in 3D Cultures of Primary Uveal Melanoma Cell Lines

Simple Summary

Uveal melanoma (UM) is the most common primary intraocular tumor in adults. Treatment options for UM include radiotherapy, thermotherapy and tumor resection. Electrochemotherapy (ECT) is a new therapeutic modality for local tumor control in various cancer entities. The current study assesses the radiosensitizing effect of concomitant ECT with bleomycin and irradiation on 3D tumor spheroids with primary and radioresistant uveal melanoma cell lines. The evaluation of the radiosensitizing effect of ECT as a drug delivery system was based on the changes in the spheroid growth, the cell viability as well as the cytotoxic long-term effect of the combined treatment. The primary cell lines showed a higher radiosensitivity and required lower irradiation and bleomycin doses in comparison to cell lines originating from previously irratiated tumors. ECT should be further assessed for its applicability in clinical settings as a therapeutic radiosensitizing option for radioresistant tumors.

Abstract

Electrochemotherapy (ECT) is emerging as a complementary treatment modality for local tumor control in various cancer entities. Irradiation is an established therapeutic option for oncologic patients, which is commonly combined with chemotherapy due to its insufficient targeting ability. The efficiency of radiotherapy for tumors can be enhanced with different radiosensitizers. ECT can potentiate the radiosensitizing effect of chemotherapeutic agents such as bleomycin. The present study aims to evaluate the radiosensitizing effect of concomitant ECT with bleomycin on 3D tumor spheroids with primary and radioresistant uveal melanoma cell lines (UPMD2, UPMM3, UM92.1, Mel270) and irradiation. The changes in the spheroid growth and the cell viability as well the cytotoxic long-term effect of the combination treatment were evaluated with various combinations of electroporation settings and bleomycin concentrations as well as radiotherapy doses. A broad range of radiosensitivity was documented among the spheroids from different uveal melanoma cell lines. The primary cell lines showed a higher radiosensitivity and required lower irradiation and bleomycin doses. The maximal tumor control with a reduction of cell survival <10% was achieved with a 5 Gy irradiation only in the primary uveal melanoma cell lines and in combination with all tested ECT settings, whereas the same result could be obtained in UM92.1 spheroids only after ECT with 20 Gy irradiation. Based on the spheroid growth and the measurement of the cross-sectional area, the Mel270 spheroids, originating from a previously irradiated recurrent uveal melanoma, required higher doses of bleomycin and ECT settings after irradiation with 5 Gy in order to achieve a significant growth reduction. No significant difference could be demonstrated for the reduction of cell viability in the combination therapy with 20 Gy and 1000 V/cm between 1 and 2.5 µg/mL bleomycin even in Mel270 spheroids, underlying the importance of a drug delivery system to potentiate the radiosensitizing effect of agents in lower doses. ECT should be further assessed for its applicability in clinical settings as a therapeutic radiosensitizing option for radioresistant tumors and a sufficient local tumor control with lower chemotherapy and irradiation doses.

Reduction of muscle contraction and pain in electroporation-based treatments: An overview

BACKGROUND

In the first studies of electrochemotherapy (ECT), small cutaneous metastases were treated and only mild or moderate pain was observed; therefore, pain was not considered a significant issue. As the procedure began to be applied to larger cutaneous metastases, pain was reported more frequently. For that reason, reduction of both muscle contractions and pain have been investigated over the years.

AIM

To present an overview of different protocols described in literature that aim to reduce muscle contractions and pain caused by the electroporation (EP) effect in both ECT and irreversible EP treatments.

METHODS

Thirty-three studies published between January 1999 and November 2020 were included. Different protocol designs and electrode geometries that reduce patient pain and the number of muscle contractions and their intensity were analysed.

RESULTS

The analysis showed that both high frequency and bipolar/biphasic pulses can be used to reduce pain and muscle contractions in patients who undergo EP treatments. Moreover, adequate electrode design can decrease EP-related morbidity. Particularly, needle length, diameter and configuration of the distance between the needles can be optimised so that the muscle volume crossed by the current is reduced as much as possible. Bipolar/biphasic pulses with an inadequate pulse length seem to have a less evident effect on the membrane permeability compared with the standard pulse protocol. For that reason, the number of pulses and the voltage amplitude, as well as the pulse duration and frequency, must be chosen so that the dose of delivered energy guarantees EP efficacy.

CONCLUSION

Pain reduction in EP-based treatments can be achieved by appropriately defining the protocol parameters and electrode design. Most results can be achieved with high frequency and/or bipolar/biphasic pulses. However, the efficacy of these alternative protocols remains a crucial point to be assessed further.

The electrical pulse application enhances intra-cellular localization and potentiates cytotoxicity of curcumin in breast cancer cells

Breast cancer is the most common cancer of women, and fifth leading cause of mortality worldwide. Existing breast cancer regimens are costly and produce severe side effects. This highlights a need for the development of efficient novel therapies, which are cost effective and limit side effects. An electrical pulse (EP)-based chemo therapy, known as electrochemotherapy (ECT) using the natural compound curcumin could be an effective alternative. ECT is a non-surgical modality, which produces excellent anti-tumor efficacy at small drug concentrations due to increased uptake of drugs. In clinics, ECT is shown to be effective in treating advanced, recurrent, and metastatic breast cancers, which are refractory to multiple modalities. ECT with curcumin triggers apoptotic cell death in breast cancer cells and could be an effective alternative, due to curcumin's low cost and reduced side-effects. However, there is a lack of studies quantifying the uptake of curcumin in response to EP application. Towards this, we determined the uptake of different curcuminoids (curcumin, desmethoxycurcumin, and bisdemethoxycurcumin) upon EP application and their impact on cell cytotoxicity. Additionally, we studied the combined effect of calcium chloride (CaCl₂) and a curcuminoids (Cur) mixture, based on initial studies suggesting calcium electroporation as a potential inexpensive anti-cancer treatment. Our results indicate EP with Cur increases cellular uptake, cell shrinkage, and cytotoxicity. The EP + Cur resulted in the highest uptake of the bisdemethoxycurcumin. Further, EP also potentiated the cytotoxicity of CaCl₂ and of the Cur and CaCl₂ combination against breast cancer cells and caused apoptosis. Our preliminary data pave the way to further studies on Cur and CaCl₂ combination treating breast cancer.

Case Report: Cytoreductive Surgery and HIPEC Associated With Liver Electrochemotherapy in a Cholangiocarcinoma Patient With Peritoneal Carcinomatosis and Liver Metastasis Case Report

Introduction: Cholangiocarcinoma (CCA) is the second most common primary tumor of the liver, and the recurrence after hepatic resection (HR), the only curative therapy, is linked with a worse prognosis. Systemic chemotherapy (SC) and liver loco-regional treatments, like trans-arterial chemoembolization (TACE) or radio embolization (TARE), have been employed for the treatment of unresectable intrahepatic metastasis (IM) with benefit on overall survival (OS), but SC has a limited effect on peritoneal metastasis (PM). In the last years, novel treatments like electrochemotherapy (ECT) with bleomycine (BLM) for IM and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS and HIPEC) for PM have been applied in small series but with encouraging results. We hereby describe the first synchronous application of ECT and CRS and HIPEC for the treatment of a patient with IM and PM from CCA. Case Description: A 47-year-old male patient with CCA underwent HR followed by adjuvant SC. After 14 months, for the occurrence of IM, the patient underwent a second HR and SC. Nonetheless, a new recurrence occurred and a third attempt of HR was proposed. Due to the intraoperative finding of unresectable IM with PM, no resective procedure was performed and the patient was referred to our center. CRS and HIPEC with cisplatin and mitomycin for PM and ECT with BLM on a bulky metastasis of the hepatic hilum were performed after 38 months from the first HR. The length of hospital stay was 19 days. At the computed tomography (CT) performed 11 days after treatment complete necrosis of the treated IM was detected. Results: CT scan after 3 and 6 months and magnetic resonance after 9 months were performed. Necrosis of the treated IM nor PM but progression of the residual liver lesions was observed. After 3 months, the patient received SC and underwent TACE after 8 months and TARE after 9 months for the residual liver metastases. At 14 months from CRS and HIPEC, the patient is alive, in good condition, and with stability of the disease. Conclusions: The association of ECT and CRS and HIPEC could be safe and effective for the treatment of unresectable recurrent intrahepatic CCA with PM.

Electrochemotherapy in the Treatment of Head and Neck Cancer: Current Conditions and Future Directions

Simple Summary

Electrochemotherapy (ECT) was first introduced in the late 1980s and was initially used mainly on cutaneous tumors. It has now evolved into a clinically verified treatment approach. Thanks to its high feasibility, it has been extended to treating mucosal and deep-seated tumors, including head and neck cancer (HNC) and in heavily pretreated settings. This review describes current knowledge and data on the use of ECT in various forms of HNCs across different clinical settings, with attention to future clinical and research perspectives.

Abstract

Despite recent advances in the development of chemotherapeutic drug, treatment for advanced cancer of the head and neck cancer (HNC) is still challenging. Options are limited by multiple factors, such as a prior history of irradiation to the tumor site as well as functional limitations. Against this background, electrochemotherapy (ECT) is a new modality which combines administration of an antineoplastic agent with locally applied electric pulses. These pulses allow the chemotherapeutic drug to penetrate the intracellular space of the tumor cells and thereby increase its cytotoxicity. ECT has shown encouraging efficacy and a tolerable safety profile in many clinical studies, including in heavily pre-treated HNC patients, and is considered a promising strategy. Efforts to improve its efficacy and broaden its application are now ongoing. Moreover, the combination of ECT with recently developed novel therapies, including immunotherapy, represented by immune checkpoint inhibitor (ICI)s, has attracted attention for its potent theoretical rationale. More extensive, well-organized clinical studies and timely updating of consensus guidelines will bring this hopeful treatment to HNC patients under challenging situations.

Electrochemotherapy in the head and neck area: an addition to the treatment armamentarium

PURPOSE OF REVIEW

Electrochemotherapy (ECT) is increasingly used in different settings in head and neck cancer patients when conventional treatment options are not available.

RECENT FINDINGS

Recent improvements of electroporation and ECT include new advanced electrode probes, the combination with intratumorally injected supraphysiological doses of calcium and an update of the standard operating procedures.

SUMMARY

ECT is a treatment modality that combines administration of a chemotherapeutic drug, for example, bleomycin, with electroporation therapy (EPT). EPT uses brief, high-intensity, pulsed electrical currents to enhance the uptake of cytotoxic drugs by producing a transient increase in cell wall permeability. ECT increases the effect of cytostatic drugs, is independent on histology of the lesion, enables treatment to previously treated areas, preserves healthy tissue, has no significant side effects (low-dose chemotherapy) and enables repeated treatments. ECT can be combined with other treatment modalities and is an addition to the current treatment options of head and neck cancer. ECT is not only able to palliate symptoms but can also provide complete responses and curation.

Electrochemotherapy Modulates Mammary Tumor Growth in Rats on a Western Diet Supplemented with Curcumin

In the US, every 12 min, six women are diagnosed with breast cancer and one dies. This highlights a critical need for developing alternate therapies using natural compounds, which are cost effective and with less side effects. Curcumin, the yellow pigment of turmeric has been found to suppress initiation, progression, and metastasis of a variety of tumors. Multiple clinical trials highlight the efficacy of curcumin in treating breast cancer and other diseases. Our in vitro studies have demonstrated that the electrical pulse (EP) application can further enhance the effectiveness of curcumin against breast cancer cells in a therapy called electrochemotherapy (ECT). In a direct extension of these results, we studied the effect of ECT coupled with intratumoral curcumin administration (EP+Cur) on N-methyl-N-nitrosourea (MNU) induced mammary tumors in female Sprague Dawley rats. Beginning at the weaning and throughout the study, rats were fed either western diet (West) or western diet, supplemented with 1% curcumin (W+Cur). Our results showed that EP+Cur treatment led to a reduced growth rate in rats fed with W+Cur diet compared to West diet (57.14% vs. 16.67% in West diet). These results provide a foundation for further studies towards utilizing it in clinical practice.

Cell morphology impact on the set-up of electroporation protocols for in-suspension and adhered breast cancer cells

In order to establish cancer-type-specific electroporation protocols for breast cancer, electroporation was performed in vitro in two modalities: in-suspension and adhered cells. Electroporation of cell suspensions was carried out through commercial electroporation cuvettes whereas a novel electrode for electroporation of adhered cells was designed and manufactured aimed to preserve cell structure, to provide a closer model to an in vivo scenario, and as a means to visualize the mechanical effects of electroporation on the cell membrane by using scanning electron microscopy. Electroporation protocols and electric field thresholds were predicted in silico and experimentally tuned through propidium iodide uptake and cell viability. Three breast-cancer cell lines (BT-20, MCF-7 and HCC1419) and a non-cancerous cell line (BEAS-2B) were used. Cancerous cells responded differently to electroporation depending on the electric parameters, cell histology, the cell culture modality, and the cell morphology (membrane thickness mainly), which was evaluated trough confocal and transmission electron microscopy. Particularly, it was found that electrochemotherapy may represent a promising alternative as an adjuvant treatment of metastatic breast tumours, and as a neoadjuvant therapy for Her2/neu tumours. Oppositely, triple negative breast tumours may show a high sensitivity to electroporation and therefore, they could be efficiently treated with irreversible electroporation. On the other hand, noncancerous cells demanded the highest voltage in both cell culture modalities in order to be electroporated. Hence, these cells in suspension may provide a reliable, easy-to-perform, low-cost model for the development of electroporation protocols for eradication of healthy tissue around a tumour in a safety margin.

The use of cisplatin electrochemotherapy in nonmelanoma skin cancers: A single-center study

Electrochemotherapy (ECT) is a well-known nonconventional skin cancer ablative method that was shown to be safe and effective for treating both locoregional disease spreading and disseminated cutaneous and subcutaneous lesions from different types of cancer. The most common medications used are bleomycin and cisplatin. In the last years many studies were performed on ECT, lead it to be a valid therapeutic option in many international guidelines. Nevertheless, there are still no clear indications regarding timing of its use. The main aim of this study was first to assess the safety and effectiveness of intralesional cisplatin ECT for treating different types of nonmelanoma skin cancer in a group of eligible patients. The second endpoint was to assess patients' tolerability and symptoms improvement through the treatment. A single-center prospective study was performed. Patients with squamous cell carcinoma, basal cell carcinoma, or skin metastases were selected during 1 month. The ideal setting was the presence of two or three lesions with a maximum diameter of 2 cm. Both primary, recurrent, and metastatic lesions were included. Before and 8 weeks after treatment, all patients were evaluated to assess the number, measurement, and anatomical site of skin lesions using photography and metric notation. The medical device for membrane electroporation was the CLINIPORATOR EPS02 model. The cisplatin concentration was at least 1 mg/mL. The dose for each single lesion was calculated based on its volume, as is the standard procedure for ECT. Local or systemic adverse events and changes in symptoms were evaluated with a questionnaire based on a visual analog scale that was administrated before and after ECT. Eight patients with a total of 18 lesions underwent the procedure (six men and two women). Four out of eight (50%) patients had a complete response to the treatment. However, all eight patients had an overall tumor response (100%), experiencing an improvement in symptoms including less pain and bleeding from the tumor. Our study clearly show that ECT with intralesional cisplatin is a valuable and safety procedure for nonmelanoma skin cancer and cutaneous tumor metastasis. ECT with cisplatin was able to achieve a good local disease control leading to complete response in an half of cases. The results were stable after 1 year of follow-up. The outer ear area displayed a really good response, due to both ear's anatomical configuration and intralesional cisplatin pharmacological characteristics.

Electrochemotherapy of superficial tumors - Current status:: Basic principles, operating procedures, shared indications, and emerging applications

Treatment of superficial tumors with electrochemotherapy (ECT) has shown a steep rise over the past decade and indications range from skin cancers to locally advanced or metastatic neoplasms. Based on reversible electroporation, which is a physical method to achieve transient tumor cell membrane permeabilization by means of short electric pulses, ECT increases cellular uptake of bleomycin and cisplatin and their cytotoxicity by 8,000- and 80-fold, respectively. Standard operating procedures were established in 2006 and updated in 2018. Ease of administration, patient tolerability, efficacy across histotypes, and repeatability are peculiar advantages, which make standard ECT (ie, ECT using fixed-geometry electrodes) a reliable option for controlling superficial tumor growth locally and preventing their morbidity. Consolidated indications include superficial metastatic melanoma, breast cancer, head and neck skin tumors, nonmelanoma skin cancers, and Kaposi sarcoma. In well-selected patients with oropharyngeal cancers, ECT ensures appreciable symptom control. Emerging applications include skin metastases from visceral or hematological malignancies, vulvar cancer, and some noncancerous skin lesions (keloids and capillary vascular malformations). Repeatability and integration with other oncologic therapies allow for consolidation of response and sustained tumor control. In this review, we present the basic principles of ECT, recently updated operating procedures, anesthesiological management, and provide a synthesis of the efficacy of standard ECT across histotypes.

Electroporation of the Liver: More Than 2 Concurrently Active, Curved Electrodes Allow New Concepts for Irreversible Electroporation and Electrochemotherapy

Irreversible electroporation and electrochemotherapy are 2 innovative electroporation-based minimally invasive therapies for the treatment of cancer. Combining nonthermal effects of irreversible electroporation with local application of chemotherapy, electrochemotherapy is an established treatment modality for skin malignancies. Since the application of electrochemotherapy in solid organs is a promising approach, this article describes a novel electrode configuration and field generating method. For the treatment of hepatic malignancies, the shape of the electric field should resemble a spherical 3-dimensional geometry around the target tissue inside the liver. To adapt the actual shape of the field, the probe is designed in computer-aided design with a live link to a computer simulation software: Changes in design can be revalued quickly, regarding different quality criteria for field strength inside and outside the tumor. To rate these criteria, a set of formulas with weighting coefficients has been included. As a result of this design process, a needle-shaped prototype applicator has been built, designed for an intracorporal electroporation-based treatment. It can be used as percutaneous, image-guided, minimally invasive treatment option for malignant liver tumors. The shaft of the probe is used as central electrode and fitted with additional 4 expandable electrodes. These satellite electrodes are hollow, thus serving as injectors for chemotherapeutic agents within the area of the electric field. This configuration can be used for electrochemotherapy as well as irreversible electroporation. By placing 5 electrodes with just one needle, the procedure duration as well as the radiation dose can be reduced tremendously. Additionally, the probe offers an option to adapt the field geometry to the tumor geometry by connecting the 5 electrodes to 5 individually chosen electric potentials: By fine-tuning the ablation zone via the potentials instead of adjusting the location of the electrode(s), the procedure duration as well as the radiation dose will decrease further.

Electrochemotherapy in the Treatment of Breast Cancer Metastasis to the Skin and Subcutaneous Tissue - Multicenter Experience

INTRODUCTION

Breast cancer is responsible for more than 50% of cutaneous metastases. One of the treatment options is electrochemotherapy (ECT). It is an effective method of local tumor ablation through the application of electroporation. The primary objective of the study was to demonstrate a response to the treatment in our group of patients.

METHODS

Between February 2015 and October 2016, in 3 centers in Poland, 47 ECT procedures were performed in 38 patients with metastasis of breast cancer to the skin.

RESULTS

At 12 weeks after the procedures, 71% of patients showed a positive response to the treatment (42% with complete response, and 29% with partial response). Multivariate analysis demonstrated that only the estrogen receptor status and the size of the metastatic lesion were predictive of overall response (p = 0.0243 and p = 0.03716, respectively).

CONCLUSION

The results of our study demonstrate a high effectiveness of ECT in the treatment of cutaneous metastasis from breast cancer. This method, although used for palliative treatment, brings a significant improvement in the quality of life of patients.

ESOPE-Equivalent Pulsing Protocols for Calcium Electroporation: An In Vitro Optimization Study on 2 Cancer Cell Models

Reversible electroporation is used to increase the uptake of chemotherapeutic drugs in local tumor treatment (electrochemotherapy) by applying the pulsing protocol (8 rectangular pulses, 1000 V/cm, 100 µs) standardized in the framework of the European Standard Operating Procedure on Electrochemotherapy multicenter trial. Currently, new electrochemotherapy strategies are under development to extend its applicability to tumors with different histology. Electrical parameters and drug type are critical factors. A possible approach is to test pulse parameters different from European Standard Operating Procedure on Electrochemotherapy but with comparable electroporation yield (European Standard Operating Procedure on Electrochemotherapy-equivalent protocols). Moreover, the use of non-toxic drugs combined with electroporation represents the new frontier for electrochemotherapy applications; calcium electroporation has been recently proposed as a simple tool for anticancer therapy. In vitro investigations facilitate the optimization of electrical parameters and drugs for in vivo and clinical testing. In this optimization study, new pulsing protocols have been tested by increasing the pulse number and reducing the electric field with respect to the standard. European Standard Operating Procedure on Electrochemotherapy-equivalent protocols have been identified in HL-60 and A431 cancer cell models, and a higher sensitivity in terms of electroporation yield has been recorded in HL-60 cells. Moreover, cell killing efficacy of European Standard Operating Procedure on Electrochemotherapy-equivalent protocols has been demonstrated in the presence of increasing calcium concentrations on both cell lines. Equivalent European Standard Operating Procedure on Electrochemotherapy protocols can be used to optimize the therapeutic effects in the clinic, where different regions of the same cancer tissue, with different electrical properties, might result in a differential electroporation yield of the standard protocol over the same tissue, or, eventually, in an override of the operational limits of the instrument. Moreover, using calcium can help overcome the drawbacks of standard drugs (side effects, high costs, difficult handling, preparation, and storage procedures). These results support the possibility of new treatment options in both standard electrochemotherapy and calcium electroporation, with clear advantages in the clinic.

Electrochemotherapy in head and neck cancer: A review of an emerging cancer treatment

Patients affected by aggressive neoplasms with a high propensity to metastasize to the skin, including some types of head and neck cancer, may benefit from electrochemotherapy, a modality that combines the electroporation of cell membranes and chemotherapy to facilitate the transport of non-permeant molecules into cells; the host immune response consequently participates in achieving the abolition of tumors. Electrochemotherapy can be successfully used for skin metastases of head and neck tumors and, with some limitations, for primary and relapsing neoplasms; it can also be applied on an outpatient basis with a favorable cost-benefit ratio and it is a repeatable treatment that, if necessary, can be followed by traditional antineoplastic therapies. Although still a palliative treatment, the good level of tolerability and the high success rates of electrochemotherapy make it worth consideration among treatment options in selected patients.

Calcium electroporation for treatment of cutaneous metastases; a randomized double-blinded phase II study, comparing the effect of calcium electroporation with electrochemotherapy

BACKGROUND

Calcium electroporation is a novel anticancer treatment, which utilizes high voltage pulses to permeabilize cell membranes and expose the cell to supraphysiological doses of calcium. Preclinical studies on calcium electroporation have shown strikingly high tumor response with cell necrosis. Calcium electroporation builds on the treatment electrochemotherapy, where chemotherapeutic drugs, mostly bleomycin, are internalized by electroporation. This double-blinded randomized study compared calcium electroporation to electrochemotherapy in terms of objective response measured 6 months after treatment.

METHODS

Seven patients with a total of 47 cutaneous metastases from breast cancer and malignant melanoma were included in the protocol. A total of 37 metastases were randomized and evaluated for response, another 10 metastases were used for biopsy. This was a non-inferiority trial and metastases were randomized individually in each patient to either intratumoral calcium or bleomycin followed by application of electric pulses to tumor site. All metastases were treated once, and after 6-months of follow-up, the randomization code was revealed.

RESULTS

Objective response of calcium electroporation was 72% (13/18) with complete response in 66% (12/18). For electrochemotherapy, objective response was 84% (16/19) with complete response in 68% (13/19). There was no statistically significant difference between the two treatments (p = 0.5). After 1 year, only three out of 25 metastases had relapsed. Ulceration, itching and exudation were reported slightly more frequently in metastases treated with bleomycin, and hyperpigmentation was only seen in metastases treated with bleomycin.

CONCLUSION

This study shows that calcium electroporation is feasible and effective in patients with cutaneous metastases.

Parametric optimization of electric field strength for cancer electrochemotherapy on a chip-based model

Electrochemotherapy (ECT), as one of the very few available treatments for cutaneous and subcutaneous tumors when surgery and radiotherapy are no longer available, requires applying a proper electric field to the tumor to realize electroporation-mediated cytotoxic drug delivery. It is impossible to exhaust all possible electrical parameters on patients to realize the optimal tradeoff between tumor suppression and adverse effects. To address this issue, this study provides a feasible solution by developing a four-leaf micro-electrode chip (F-MEC) in which the electric field was specially designed by linear distribution to cover all possible electric field strengths for ECT. Methods: We developed a F-MEC that provides a linearly varied electric field and a capacity for in situ observation of cell status. By culturing tumor cells on the F-MEC surface and in situ monitoring the cell responses to ECT drugs, the optimal electric field strength for any given cell type could be rapidly and accurately calculated in a few, or even only one, simple assay. Results: Using this chip, we monitored MCF-7 and A315 cell responses to ECT and determined the optimum ECT voltage. More importantly, we successfully verified that the in vitro determined voltage coincided with the optimal value for in vivo ECT in mice. Conclusion: In this proof-of-concept study, the in vivo tumor suppression assays proved that the optimal parameters acquired from in vitro F-MEC assay could be used for in vivo ECT.

Electrochemotherapy in Breast Cancer - Discussion of the Method and Literature Review

Breast cancer is the most common cause of skin metastases in women. The probability of their occurrence ranges from about 5% in the entire population to as much as 30% in the late stages of the disease. Although rarely life-threatening, they have a major impact on the quality of life of patients with this diagnosis, being the cause of pain, effusion, ulceration, infection, and psychological discomfort. Available methods of treatment, both local and systemic, often fail to provide adequate control of the disease. A particular challenge seems to be the treatment of those patients with cutaneous metastases who, due to the extent of their metastases, are not eligible for resection, in whom the possibility of radiation therapy has already been used, and in whom systemic therapy is ineffective or contraindicated. A new method providing the opportunity for effective treatment is electrochemotherapy (ECT). ECT combines electropulsation of tumor cells (by local application of electric pulses) and administration of antineoplastic drugs such as cisplatin or bleomycin (either intravenous or intratumoral). Several clinical studies have demonstrated that ECT provides safe, efficient, and non-invasive locoregional treatment for chest wall breast cancer recurrence.

Electrochemotherapy - Supplementary Treatment for Loco-regional Metastasized Breast Carcinoma Administered to Concomitant Systemic Therapy

Background

Electrochemotherapy (ECT) is an established procedure for treating breast cancer loco-regional recurrences following surgical intervention and/or radiotherapy. Limited information is available on ECT application as a concomitant procedure to systemic therapy in recurrent breast cancer. The primary objective of this study was to determine if the application of ECT in close temporal relation to systemic chemotherapy could lead to increased local and/or systemic side effects. For this purpose we evaluated the safety of ECT as a supplemental local therapy to systemic therapy. ECT local and systemic toxicity and side effects were recorded and whether the anticipated local therapeutic effect of ECT would be influenced by the concomitant use of systemic therapies was investigated.

Patients and methods

This is an observational study. Thirty three patients with loco-regional metastasized breast carcinoma were treated and observed over a period of three years with 46 ECT applications for local tumour control in addition to established systemic therapy. A specific timeline for ECT administration was not fixed up, but was generally performed one week before the following chemotherapy administration with the aim to avoid the so called nadir, this means the peak period with risk of neutropenia.

Results

Data was collected over a period of three years on a population of 33 metastatic patients. Fifteen patients, received neo-adjuvant therapy as part of their primary treatment, but still had an advanced stage tumour. Some patients received repeated ECT applications. Objective tumour response was observed in 90% of the treated patients. Patients showed no increased local toxicity, especially no higher dermal toxicity, e.g. formation of local necrosis.

Conclusions

ECT proved to be an effective supplement to a cytotoxic systemic therapy, especially for high-risk patients who did not respond well to systemic therapy of loco-regional metastases, without creating any greater systemic or loco-regional toxicities.

Calcium electroporation induces tumor eradication, long-lasting immunity and cytokine responses in the CT26 colon cancer mouse model

Electroporation is used in cancer treatment because of its ability to increase local cytotoxicity of e.g. bleomycin (electrochemotherapy) and calcium (calcium electroporation). Calcium electroporation is a novel anticancer treatment that selectively kills cancer cells by necrosis, a cell death pathway that stimulates the immune system due to high release of antigens and "danger signals." In this exploratory study, we aimed to investigate whether calcium electroporation could initiate an anticancer immune response similar to electrochemotherapy. To this end, we treated immunocompetent balb/c mice with CT26 colon tumors with calcium electroporation, electrochemotherapy, or ultrasound-based delivery of calcium or bleomycin. High treatment efficiency was observed with 100% complete remission in all four groups (12/12 with complete remission in each treatment group). In addition, none of the surviving mice from these groups formed new tumors when re-challenged with CT26 cancer cells 100-d post treatment, whereas mice challenged with different cancer cells (4T1 breast cancer) all developed tumors. Treatment of immunodeficient mice with calcium electroporation and electrochemotherapy showed no long-lasting tumor response. Calcium electroporation and electrochemotherapy was associated with a release of High Mobility Group Box 1 protein (HMGB1) in vitro (p = 0.029) and a significant increase of the overall systemic level of pro-inflammatory cytokines in serum from the treated mice (p < 0.003). These findings indicate that calcium electroporation as well as electrochemotherapy could have a role as immune stimulators in future treatments.

The controversial role of electrochemotherapy in head and neck cancer: a systematic review of the literature

Electroporation, also known as electrochemotherapy, combines an antineoplastic agent with electroporation, causing localized progressive necrosis in the treated area. Today it is primarily used in the palliative treatment of cutaneous and subcutaneous metastases and has been found to be safe and efficacious in head and neck cancer recurrences. Despite the steady increase in the number of published studies this treatment is not universally available and used systematically in head and neck carcinomas. To shed light on its limitations and analyze treatment outcome we have, therefore, reviewed all available literature regarding this topic. This systematic review includes 16 studies on head and neck squamous cell carcinoma and reports the data of 200 treated patients. The combined results show a very heterogeneous overall response rate, ranging from 0 to 100%, while the complete response rate ranges between 0 and 83.3%. No major side effects have been described in those who used electrochemotherapy as a mono modality palliative treatment. This systematic review shows how standardization of treatment is still pivotal to achieve a more homogeneous response rate in the approach to head and neck tumors. In conclusion, due to the scarcity of alternatives of treatment in advanced stage cancer in this anatomical region and the good tolerability and mostly high success rates of electrochemotherapy, this palliative approach should be taken into consideration in these patients.

Diagnosis and treatment of in-transit melanoma metastases

In transit metastases (ITM) from extremity or trunk melanomas are subcutaneous or cutaneous lymphatic deposits of melanoma cells, distant from the primary site but not reaching the draining nodal basin. Superficial ITM metastases develop in 5-10% of melanoma patients and are thought to be caused by cells spreading along lymphatics; ITM appear biologically different from distant cutaneous metastases, these probably due to a haematogenous dissemination. The diagnosis is usually clinical and by patients, but patients need to be adequately educated in the recognition of this clinical situation. Ultrasound or more sophisticated instrumental devices may be required if the disease develops more deeply in the soft tissues. According to AJCC 2009 staging classification, ITM are included in stages IIIb and IIIc, which are considered local advanced disease with quite poor 5-year survival rates and outcomes of 24-54% at 5 years.² Loco-regional recurrence is in fact an important risk factor for distant metastatic disease, either synchronous or metachronous. Therapy for this pattern of recurrence is less standardised then in most other clinical situations and options vary based on the volume and site of the disease. Definitive surgical resection remains the preferred therapeutic approach. However, when surgery cannot be performed with a reasonable cosmetic and functional outcome, other options must be utilized.^3-6 Treatment options are classified as local, regional or systemic. The choice of therapy depends on the number of lesions, their anatomic location, whether or not these are dermal or subcutaneous, the size and the presence or absence of extra-regional disease.

Electroporation in veterinary oncology

Cancer treatments in veterinary medicine continue to evolve beyond the established standard therapies of surgery, chemotherapy and radiation therapy. New technologies in cancer therapy include a targeted mechanism to open the cell membrane based on electroporation, driving therapeutic agents, such as chemotherapy (electro-chemotherapy), for local control of cancer, or delivery of gene-based products (electro-gene therapy), directly into the cancer cell to achieve systemic control. This review examines electrochemotherapy and electro-gene therapy in veterinary medicine and considers future directions and applications.

Preclinical evaluation of an endoscopic electroporation system

BACKGROUND AND STUDY AIMS

Targeted delivery of specific chemotherapeutic drugs into tumors can be achieved by delivering electrical pulses directly to the tumor tissue. This causes a transient formation of pores in the cell membrane that enables passive diffusion of normally impermeant drugs. A novel device has been developed to enable the endoscopic delivery of this tumor permeabilizing treatment. The aim of the preclinical studies described here was to investigate the efficacy and safety of this nonthermal ablation system in the treatment of gastrointestinal cancer models.

METHODS

Murine, porcine, and canine gastrointestinal tumors and tissues were used to assess the efficacy and safety of electroporation delivered through the special device in combination with bleomycin. Tumor cell death, volume, and overall survival were recorded.

RESULTS

Murine tumors treated with electrochemotherapy showed excellent responses, with cell death being induced rapidly, mainly via an apoptotic-type mechanism. Use of the system in canine gastrointestinal cancers demonstrated successful local endoluminal tumor resolution, with no safety or adverse effects noted.

CONCLUSIONS

Electroporation via the new device in combination with bleomycin offers a nonthermal tumor ablative approach, and presents clinicians with a new option for the management of gastrointestinal cancers.

Electrochemotherapy as palliative treatment in patients with thyroid papillary carcinoma

Introduction

Local progression of papillary thyroid carcinoma (PTC) after failure of standard therapies may cause pain, ulceration, and bleeding. As patients are fully aware of the tumor growth, they might suffer high grade anxiety. Electrochemotherapy (ECT) is a new local palliative treatment for skin metastases of malignant melanoma or other tumors, including squamous head e neck cancer patients.

Objective

To evaluate the impact of ECT in patients with local progression of PTC.

Methods

Four patients with local progression of PTC were treated with ECT based on Bleomycin, and evaluated according to tumor response, local pain and side effects.

Results

In all cases, some grade of tumor response was observed, lasting 6, 7, 12 and 8 months, respectively. Also, reduction of local pain and anxiety was registered in all patients. Tumor infiltrated skin necrosis was the only collateral effect of the treatment. ECT induced a tumor response in all PTC patients with improvement of symptoms.

Conclusions

ECT may be an option for local palliative treatment in PTC patients with local tumor progression.

Recommendations for improving the quality of reporting clinical electrochemotherapy studies based on qualitative systematic review

BACKGROUND

Electrochemotherapy is becoming a well-established treatment for malignancies of skin and non-skin origin and its use is widening across Europe. The technique was developed and optimized from solid experimental and clinical evidence. A consensus document is now warranted to formalize reporting results, which should strengthen evidence-based practice recommendations. This consensus should be derived from high quality clinical data collection, clinical expertise and summarizing patient feedback. The first step, which is addressed in this paper, aims to critically analyze the quality of published studies and to provide the recommendations for reporting clinical trials on electrochemotherapy.

METHODS

The quality of reporting in published studies on electrochemotherapy was analyzed in order to produce procedure specific reporting recommendations. A comprehensive literature search of studies published from 2006 to 2015 was performed followed by qualitative analysis of manuscripts assessing for 47 quality criteria grouped into four major clusters: (1) trial design, (2) description of patient population, (3) description of treatment delivery and patient outcome, (4) analysis of results and their interpretation. The summary measure during literature assessment was the proportion of studies fulfilling each manuscript quality criteria.

RESULTS

A total of 56 studies were screened, from the period 2006 to 2015, of which 33 were included in the qualitative analysis, with a total of 1215 patients. Overall, the quality of reporting was highly variable. Twenty-four reports (73%) were single-center, non-comparative studies, and only 15 (45%) were prospective in nature (only 2 of them were entered into a clinical trials registry). Electrochemotherapy technique was consistently reported, with most studies (31/33) adhering closely to published standard operating procedures. The quality of reporting the patient population was variable among the analyzed studies, with only between 45% and 100% achieving dedicated quality criteria. Reporting of treatment delivery and patient outcome was also highly variable with studies only fulfilling between 3% and 100%. Finally, reporting study results critically varied, fulfilling from 27% to 100% of the quality criteria. Based on the critical issues emerging from this analysis, recommendations and minimal requirements for reporting clinical data on electrochemotherapy were prepared and summarized into a checklist.

CONCLUSIONS

There is an increasing body of published clinical data on electrochemotherapy, but more high quality clinical data are needed. Published papers often lack accurate description of study population, treatment delivery as well as patient outcome. Our recommendations, provided in the form of a summary checklist, are intended to ameliorate data reporting in future studies on electrochemotherapy and help researchers to provide a solid evidence basis for clinical practice.