Canine squamous cell carcinoma: Electrochemotherapy association with surgery and correlation with overall survival

Squamous cell carcinoma (SCC) is an important malignancy in dogs, due to its incidence and clinical presentation, which can be of locally aggressive single or multiple lesions with a metastatic potential. The objective of this investigation was to evaluate SCC response to treatment, anatomopathological and immunohistochemical characteristics, disease-free interval and overall survival time. 54 dogs with histopathologically diagnosed SCC were included in this study. Their mean age was 9.16 years with a range of 1-14 years. Of the 54 animals in the study, 34 (65.4%) had white skin and white fur coats. There was a significant correlation between fur coat colour and the development of tumours in areas of sun exposure (p = .001). Animals with tumours in areas of the body exposed to the sun had longer overall survival time than animals with tumours in areas not associated with sun exposure (p = .001). Surgery combined with electrochemotherapy (ECT) yielded a survival rate 32% higher than using a surgical approach alone (HR = 0.32, p = .038, IC = 0.11-0.94). ECT, with or without surgery, had an objective response rate of 90.9%. Local lymph node and/or distant site metastasis at diagnosis, or at some point during follow-up, occurred in 34.6% (18/52) of animals. Animals with tumours in sun exposed locations had more aggressive histopathological characteristics but had longer overall survival time. This is probably due to individualised therapeutic treatment with both surgery and ECT.

Electroporation in Head-and-Neck Cancer: An Innovative Approach with Immunotherapy and Nanotechnology Combination

Squamous cell carcinoma is the most common malignancy that arises in the head-and-neck district. Traditional treatment could be insufficient in case of recurrent and/or metastatic cancers; for this reason, more selective and enhanced treatments are in evaluation in preclinical and clinical trials to increase in situ concentration of chemotherapy drugs promoting a selectively antineoplastic activity. Among all cancer treatment types (i.e., surgery, chemotherapy, radiotherapy), electroporation (EP) has emerged as a safe, less invasive, and effective approach for cancer treatment. Reversible EP, using an intensive electric stimulus (i.e., 1000 V/cm) applied for a short time (i.e., 100 μs), determines a localized electric field that temporarily permealizes the tumor cell membranes while maintaining high cell viability, promoting cytoplasm cell uptake of antineoplastic agents such as bleomycin and cisplatin (electrochemotherapy), calcium (Ca²⁺ electroporation), siRNA and plasmid DNA (gene electroporation). The higher intracellular concentration of antineoplastic agents enhances the antineoplastic activity and promotes controlled tumor cell death (apoptosis). As secondary effects, localized EP (i) reduces the capillary blood flow in tumor tissue ("vascular lock"), lowering drug washout, and (ii) stimulates the immune system acting against cancer cells. After years of preclinical development, electrochemotherapy (ECT), in combination with bleomycin or cisplatin, is currently one of the most effective treatments used for cutaneous metastases and primary skin and mucosal cancers that are not amenable to surgery. To reach this clinical evidence, in vitro and in vivo models were preclinically developed for evaluating the efficacy and safety of ECT on different tumor cell lines and animal models to optimize dose and administration routes of drugs, duration, and intensity of the electric field. Improvements in reversible EP efficacy are under evaluation for HNSCC treatment, where the focus is on the development of a combination treatment between EP-enhanced nanotechnology and immunotherapy strategies.

Phosphatidylserine: The Unique Dual-Role Biomarker for Cancer Imaging and Therapy

Cancer is among the leading causes of death worldwide. In recent years, many cancer-associated biomarkers have been identified that are used for cancer diagnosis, prognosis, screening, and early detection, as well as for predicting and monitoring carcinogenesis and therapeutic effectiveness. Phosphatidylserine (PS) is a negatively charged phospholipid which is predominantly located in the inner leaflet of the cell membrane. In many cancer cells, PS externalizes to the outer cell membrane, a process regulated by calcium-dependent flippases and scramblases. Saposin C coupled with dioleoylphosphatidylserine (SapC-DOPS) nanovesicle (BXQ-350) and bavituximab, (Tarvacin, human-mouse chimeric monoclonal antibodies) are cell surface PS-targeting drugs being tested in clinical trial for treating a variety of cancers. Additionally, a number of other PS-selective agents have been used to trigger cytotoxicity in tumor-associated endothelial cells or cancer cells in pre-clinical studies. Recent studies have demonstrated that upregulation of surface PS exposure by chemodrugs, radiation, and external electric fields can be used as a novel approach to sensitize cancer cells to PS-targeting anticancer drugs. The objectives of this review are to provide an overview of a unique dual-role of PS as a biomarker/target for cancer imaging and therapy, and to discuss PS-based anticancer strategies that are currently under active development.

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.

Large Liver Blood Vessels and Bile Ducts Are Not Damaged by Electrochemotherapy with Bleomycin in Pigs

The first clinical studies on the use of electrochemotherapy to treat liver tumours that were not amenable to surgery or thermal ablation techniques have recently been published. However, there is still a lack of data on the effects of electrochemotherapy on normal liver tissue. Therefore, we designed a translational animal model study to test whether electrochemotherapy with bleomycin causes clinically significant damage to normal liver tissue, with emphasis on large blood vessels and bile ducts. We performed electrochemotherapy with bleomycin or delivered electric pulses alone using a potentially risky treatment strategy in eight pigs. Two and seven days after treatment, livers were explanted, and histological analysis was performed. Blood samples were collected before treatment and again before euthanasia to evaluate blood biomarkers of liver function and systemic inflammatory response. We found no thrombosis or other clinically significant damage to large blood vessels and bile ducts in the liver. No clinical or laboratory findings suggested impaired liver function or systemic inflammatory response. Electrochemotherapy with bleomycin does not cause clinically significant damage to normal liver tissue. Our study provides further evidence that electrochemotherapy with bleomycin is safe for treatment of patients with tumours near large blood vessels in the liver.

Electrochemotherapy - Emerging applications technical advances, new indications, combined approaches, and multi-institutional collaboration

The treatment of tumors with electrochemotherapy (ECT) has surged over the past decade. Thanks to the transient cell membrane permeabilization induced by the short electric pulses used by ECT, cancer cells are exposed to otherwise poorly permeant chemotherapy agents, with consequent increased cytotoxicity. The codification of the procedure in 2006 led to a broad diffusion of the procedure, mainly in Europe, and since then, the progressive clinical experience, together with the emerging technologies, have extended the range of its application. Herein, we review the key advances in the ECT field since the European Standard Operating Procedures on ECT (ESOPE) 2006 guidelines and discuss the emerging clinical data on the new ECT indications. First, technical developments have improved ECT equipment, with custom electrode probes and dedicated tools supporting individual treatment planning in anatomically challenging tumors. Second, the feasibility and short-term efficacy of ECT has been established in deep-seated tumors, including bone metastases, liver malignancies, and pancreatic and prostate cancers (long-needle variable electrode geometry ECT), and gastrointestinal tumors (endoscopic ECT). Moreover, pioneering studies indicate lung and brain tumors as suitable future targets. A further advance relates to new combination strategies with immunotherapy, gene electro transfer (GET), calcium EP, and radiotherapy. Finally and fourth, cross-institutional collaborative groups have been established to refine procedural guidelines, promote clinical research, and explore new indications.

Electrochemotherapy in the treatment of melanoma

Electrochemotherapy is a new therapeutic option for patients with locally spread melanoma. It is based on the phenomenon of reversible electroporation, i.e. a transient increase in permeability of cell membranes under the influence of an appropriately modulated electric field. This allows multiplication of toxicity of a cytostatic agent entering the tumour cell. It is highly effective, especially in the palliative treatment of cancers located in the integument of the human body (skin and subcutaneous tissue). Available literature provides a mandate both for the application of this method in the aforementioned cases as well as for further work on its development.

This paper focuses on reviewing the literature concerning the use of electrochemotherapy in the treatment of melanoma.

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.

CD4+FOXP3+ T regulatory cells decrease and CD3+CD8+ T cells recruitment in TILs from melanoma metastases after electrochemotherapy

Electrochemotherapy (ECT) represents an effective local treatment for skin unresectable melanoma metastases with high overall objective response rate. ECT is based on the combination of anti-neoplastic drugs administration and cancer cells electroporation. Whether ECT can also activate the immune system is a matter of debate, however a significant recruitment of dendritic cells in melanoma treated metastases has been described. Herein we investigated immediate and late effects of ECT treatment on T cell subsets in ECT-treated lesions by fluorescent immunohistochemistry. Biopsies from melanoma patients (n = 10) were taken before ECT (t0), at d1 and d14 from treatment. At t0, CD3⁺CD4⁺ T cells were the most represented T cells, well detected in the perilesional dermis, particularly at tumour margin, while CD3⁺CD8⁺ T cells were less represented. CD4⁺FOXP3⁺ T regulatory (Treg) cells were present in the perilesional dermis and within the lesion. ECT induced a significant decrease of CD4⁺FOXP3⁺ Treg cells percentage in the perilesional dermis, observed at d1 and at d14 (p < 0.001). CD3⁺CD8⁺ T cells frequency significantly increased at d14 from treatment in the perilesional dermis (p < 0.001). Furthermore calreticulin translocation to the plasma membrane, a hallmark of immunogenic cell death, was observed in metastatic cells after ECT. The data reported here confirm that ECT induces a local response, with a lymphoid infiltrate characterized by CD4⁺FOXP3⁺ Treg cells decrease and CD3⁺CD8⁺ T cells recruitment in the treated lesions. These results might contribute to design novel combinational therapeutic approaches with ECT and immunotherapy in order to generate a systemic long-lasting anti-melanoma immunity.

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.

Electrochemotherapy in melanoma patients: a single institution experience

AIM

This study was undertaken to update the outcome of the treated lesions with electrochemotherapy (ECT) plus intravenous injection of bleomycin in patients with in-transit disease or distant cutaneous metastases in melanoma patients.

PATIENTS & METHODS

89 patients with relapsed and refractory cutaneous melanoma metastases or in-transit disease were submitted to 126 treatments of ECT.

RESULTS

34 patients (38.2%) had a partial response and 43 had a complete response (48.3%). 12 patients (13.5%) had no change or progressive disease. The objective response rate was 67.5%.

CONCLUSION

The favorable outcome obtained in the present study demonstrates that ECT is a reliable, easy, fast and effective procedure showing benefits in terms of curative and palliative treatment for unresectable cutaneous lesions respecting the quality of life.

Melanoma: diagnosis, staging, and treatment. Consensus group recommendations

The incidence of malignant melanoma is increasing worldwide. In Spain, its incidence is increasing faster than any other cancer type, with a 5-year survival rate of about 85%. The impact and characteristics of malignant melanoma in the Spanish population can be ascertained from the national melanoma registry of the Academia Española de Dermatología y Venereología. This review presents consensus group recommendations for the diagnosis, staging and treatment of malignant melanoma in Spain. Incidence and mortality are discussed, as well as evaluation of various prevention and treatment strategies. Prognostic factors, such as BRAF and C-KIT mutations, which are expected to become routine staging procedures over the next few years, are outlined, especially in relation to treatment options. The use of recently approved targeted agents such as ipilimumab, a cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) inhibitor, and vemurafenib, a BRAF inhibitor, in metastatic disease are also discussed.

Electrochemotherapy in Breast Cancer: A Review of References

Electrochemotherapy is a new method for the local treatment of cutaneous and subcutaneous metastases. If surgery and/or radiotherapy are no longer possible, this innovative technology can be used effectively for local tumour control. The minor side effects of the therapy and the low intraoperative duration of treatment make it possible to admit patients to hospital for just a short time. Thus, the repeated use of electrochemotherapy has allowed for an increase in the rate of complete remissions. In fact, in 2013, this form of treatment, which consists of a low-dose cytostatic and electroporation, was also included in the mammary guidelines of the Working Group for Gynaecological Oncology (AGO) and the German Cancer Society (DKG). The favourable cost-benefit ratio makes this method of treatment very interesting in clinical practice and, as a result, it is already being used successfully in many German hospitals.

Long-lasting response to electrochemotherapy in melanoma patients with cutaneous metastasis

BACKGROUND

Treatment of early and multiple cutaneous unresectable recurrences is a major therapeutic problem with around 80% of patients relapsing within 5 years. For lesions refractory to elective treatments, electrochemotherapy (ECT) involving electroporation combined with antineoplastic drug treatment appears to be a new potential option. This study was undertaken to analyze the short- and long-term responses of lesions treated with ECT with intravenous injection of bleomycin in melanoma patients with in-transit disease or distant cutaneous metastases.

METHODS

Between June 2007 and September 2012, 60 patients with relapsed and refractory cutaneous melanoma metastases or in-transit disease underwent 100 courses of ECT with intravenous injection of bleomycin. Response to treatment was evaluated three months after ECT. A long-lasting response was defined as no cutaneous or in-transit relapse after a minimum of six months.

RESULTS

Three months after ECT, a complete response was observed in 29 patients (48.4%), a partial response in 23 patients (38.3%) and no change or progressive disease in 8 patients (13.3%). The objective response rate of all treated lesions was 86.6%. Thirteen patients (44.8% of complete responders) experienced a long-lasting response after one ECT session and were disease-free after a mean duration of follow-up of 27.5 months.

CONCLUSIONS

The favorable outcome obtained in the present study demonstrates that ECT is a reliable, and effective procedure that provides long-term benefit in terms of curative and palliative treatment for unresectable cutaneous lesions without adversely impacting the quality of life of patients.

Desmoplastic melanoma on the nose: electrochemotherapy as an alternative treatment to local advanced disease

BACKGROUND

Desmoplastic malignant melanoma (DMM) is a rare and usually misdiagnosed type of melanoma. Delayed detection at complicated anatomical locations can lead to the necessity of alternative therapies.

OBJECTIVE

Characterization of DMM on the nose, which is the second more frequent type of MM.

METHODS

Review of case series of eight pathologically proven DMM on the nose from two referral centres with a mean follow-up of 69 ± 40.5 months.

RESULTS

According to a single centre experience, there is a more than 70-fold increased risk of having a DMM on the nose compared with a non-DMM (P < 0.0005, CI99% 16.3-317.3). Clinical and pathological misdiagnoses were frequent, only three of the eight cases were properly diagnosed and treated and indeed they did not experience relapses. Due to non-clinical suspicion and superficial biopsies, three cases were initially pathologically misdiagnosed as basal cell carcinomas and a nevus respectively. Atypical vessels and remnants of pigment on dermoscopy are indicative findings even in non-pigmented cases. Although not significant, the mean disease-free survival differed between cases with a correct initial management (four cases, 66.7 ± 57.3 months) in contrast to improper (four cases, 16.25 ± 18.9 months). Electrochemotherapy achieved a complete local control of disease in two cases unsuitable for surgery.

CONCLUSIONS

Use of dermoscopy and correctly selected biopsy of lesions on the face is mandatory to improve early diagnosis of DMM. Improper management of challenging cases implies a more complicated therapy and loco-regional invasion risk. Electrochemotherapy could be a promising therapy in local advanced tumours.

Tumor size and effectiveness of electrochemotherapy

BACKGROUND

Electrochemotherapy (ECT) is an effective and safe method for local treatment of tumors. However, relatively large variability in effectiveness of ECT has been observed, which likely results from different treatment conditions and tumor characteristics. The aim of this study was to investigate the relationship between tumor size and effectiveness of a single-session ECT.

MATERIALS AND METHODS

A systematic search of various bibliographic databases was performed and nine studies eligible for this study were extracted. Different statistical methods including meta-analysis were applied to analyze the data.

RESULTS

The results of analysis based on data from 1466 tumors of any histotype show significantly lower effectiveness of ECT on tumors with maximal diameter equal to or larger than 3 cm (complete response (CR) of 33.3%, objective response (OR) of 68.2%) in comparison to smaller tumors (CR% of 59.5%, OR% of 85.7%). The results of meta-analysis indicated that ECT performed on tumors smaller than 3 cm statistically significantly increases the probability of CR by 31.0% and OR by 24.9% on average in comparison to larger tumors. The analysis of raw data about the size and response of tumors showed statistically significant decrease in effectiveness of ECT progressively with increasing tumor diameter. The biggest drop in CR% was detected at tumor diameters as small as 2 cm.

CONCLUSIONS

The standard operating procedures for ECT should be reexamined and refined for the treatment of large tumors. We propose that future clinical trials should include accurate ECT treatment planning and/or multiple ECT cycles, besides a prolonged observation for tumor response evaluation.

Antitumor effectiveness of electrochemotherapy: a systematic review and meta-analysis

BACKGROUND

This systematic review has two purposes: to consolidate the current knowledge about clinical effectiveness of electrochemotherapy, a highly effective local therapy for cutaneous and subcutaneous tumors; and to investigate the differences in effectiveness of electrochemotherapy with respect to tumor type, chemotherapeutic drug, and route of drug administration.

METHODS

All necessary steps for a systematic review were applied: formulation of research question, systematic search of literature, study selection and data extraction using independent screening process, assessment of risk of bias, and statistical data analysis using two-sided common statistical methods and meta-analysis. Studies were eligible for the review if they provided data about effectiveness of single-session electrochemotherapy of cutaneous or subcutaneous tumors in various treatment conditions.

RESULTS

In total, 44 studies involving 1894 tumors were included in the review. Data analysis confirmed that electrochemotherapy had significantly (p < .001) higher effectiveness (by more than 50%) than bleomycin or cisplatin alone. The effectiveness was significantly higher for intratumoral than for intravenous administration of bleomycin (p < .001 for CR%, p = .028 for OR%). Bleomycin and cisplatin administered intratumorally resulted in equal effectiveness of electrochemotherapy. Electrochemotherapy was more effective in sarcoma than in melanoma or carcinoma tumors.

CONCLUSIONS

The results of this review shed new light on effectiveness of electrochemotherapy and can be used for prediction of tumor response to electrochemotherapy with respect to various treatment conditions and should be taken into account for further refinement of electrochemotherapy protocols.

Identification of In Vitro Electropermeabilization Equivalent Pulse Protocols

Exposure of cells to an external sufficiently strong electric field results in the formation of pores across the membrane. This phenomenon, termed electropermeabilization, permits the transport of poorly permeant molecules into cytosol. In clinical practice, cell membrane permeabilization for drug electrotransfer is achieved using the ESOPE pulse protocol (1000 V/cm, 8 pulses, 100 μs, 5 kHz). The aim of this study was to investigate several combinations of electric field amplitude and pulse number able to induce electropermeabilization as the one observed when the ESOPE protocol was applied. Decreasing electric field amplitudes (1000 to 300 V/cm) in combination with increasing number of pulses (8 to 320) were applied to in vitro MG63 cells. Propidium iodide and Calcein blue AM uptake were used to evaluate cell electropermeabilization and viability. Results showed that the threshold of local electric field needed to obtain electropermeabilization decreased exponentially with increasing the number of pulses delivered (r2 50.92, p < 0.0001). The absorbed dose threshold was dependent on the number of pulses for each voltage applied (r2 50.96, p < 0.0001). In conclusion, the possibility of applying an increased number of pulses rather than increasing the electric field amplitude to perform electropermeabilization, may become an important tool for electropermeabilization - related clinical applications.

Drug delivery by electropulsation: Recent developments in oncology

Electro-permeabilisation allows the free access of polar compounds to the cytoplasm by a reversible alteration of the cell membrane. It is now used in clinics for the eradication of cutaneous solid tumors. New developments predict its future applications for other anti-cancer treatments.

Microsecond and nanosecond electric pulses in cancer treatments

New local treatments based on electromagnetic fields have been developed as non-surgical and minimally invasive treatments of tumors. In particular, short electric pulses can induce important non-thermal changes in cell physiology, especially the permeabilization of the cell membrane. The aim of this review is to summarize the present data on the electroporation-based techniques: electrochemotherapy (ECT), nanosecond pulsed electric fields (nsPEFs), and irreversible electroporation (IRE). ECT is a safe, easy, and efficient technique for the treatment of solid tumors that uses cell-permeabilizing electrical pulses to enhance the activity of a non-permeant (bleomycin) or low permeant (cisplatin) anticancer drug with a very high intrinsic cytotoxicity. The most interesting feature of ECT is its unique ability to selectively kill tumor cells without harming normal surrounding tissue. ECT is already used widely in the clinics in Europe. nsPEFs could represent a drug free, purely electrical cancer therapy. They allow the inhibition of tumor growth, and interestingly, nsPEF can target intracellular organelles. However, many questions remain on the mechanism of action of these pulses. Finally, IRE is a new ablation procedure using pulses that provoke the permanent permeabilization of the cells resulting in their death. This technique does not result in any thermal effect, which is its main advantage in current physical ablation technologies. For both the nsPEF and the IRE, the preservation of the normal tissue, which is characteristic of ECT, has not yet been shown and their safety and efficacy still have to be investigated thoroughly in vivo and in the clinics.

Muscle gene electrotransfer is increased by the antioxidant tempol in mice

Electropermeabilization (EP) is an effective method of gene transfer into different tissues. During EP, reactive oxygen species (ROS) are formed, which could affect transfection efficiency. The role of generated ROS and the role of antioxidants in electrotransfer in myoblasts in vitro and in Musculus tibialis cranialis in mice were, therefore, investigated. We demonstrate in the study that during EP of C2C12 myoblasts, ROS are generated on the surface of the cells, which do not induce long-term genomic DNA damage. Plasmid DNA for transfection (pEGFP-N1), which is present outside the cells during EP, neutralizes the generated ROS. The ROS generation is proportional to the amplitude of the electric pulses and can be scavenged by antioxidants, such as vitamin C or tempol. When antioxidants were used during gene electrotransfer, the transfection efficiency of C2C12 myoblasts was statistically significantly increased 1.6-fold with tempol. Also in vivo, the transfection efficiency of M. tibialis cranialis in mice was statistically significantly increased 1.4-fold by tempol. The study indicates that ROS are generated on cells during EP and can be scavenged by antioxidants. Specifically, tempol can be used to improve gene electrotransfer into the muscle and possibly also to other tissues.

Electrochemotherapy for cutaneous and subcutaneous tumor lesions: a novel therapeutic approach

Electroporation uses pulsed, high-intensity electric fields to temporarily increase cell membrane permeability by creation of pores, through which small molecules, such as chemotherapeutic agents, can diffuse inside cells before they reseal. The combination of electroporation with the administration of otherwise low-permeant cytotoxic drugs is known as electrochemotherapy (ECT). The two most commonly used drugs are bleomycin and cisplatin. ECT has already been proven to be effective in diverse tumor histotypes, including melanoma and basal and squamous cell carcinoma, Kaposi sarcoma, and breast cancer, also in those cases nonresponding to classical chemotherapies or other loco-regional treatment modalities, with a good safety profile. ECT can be proposed as loco-regional therapy for disseminated cutaneous and subcutaneous tumor lesions as alternative treatment modality to conventional therapies or as palliative care, in order to improve patients' quality of life.

Antivascular effects of electrochemotherapy: implications in treatment of bleeding metastases

Solid tumors of various etiologies can be treated efficiently by electrochemotherapy (ECT), a combined use of electroporation (EP) and chemotherapeutic drugs, such as bleomycin and cisplatin. EP alone and ECT in particular, induce a profound reduction in tumor blood flow, which contributes to the antitumor effect. After EP and ECT, the time course of blood flow changes and follows the same two-phase pattern. The first rapid and short-lived vasoconstriction phase is followed by the second much longer-lived phase resulting from disrupted cytoskeletal structures and a compromised barrier function of the microvascular endothelium. In the case of ECT, however, tumor vascular endothelial cells are also affected by the chemotherapeutic drug, which leads to irrecoverable damage to tumor vessels and to a further decrease in tumor blood flow within hours after application of ECT. Tumor cells surviving the direct effects of ECT are consequently exposed to lack of oxygen and nutrients and are pushed into the secondary cascade of induced cell death. Clinically, the antitumor effectiveness of ECT has been proven extensively in the treatment of melanoma metastases, with 70-80% complete responses. The antivascular effects of ECT were also exploited for palliative treatment of bleeding melanoma metastases, with immediate cessation of bleeding and very good antitumor effectiveness. The antivascular effect of ECT is of utmost importance for translation of ECT into the treatment of deep-seated tumors, especially in well vascularized organs, such as the liver, where it prevents bleeding of the treated area.