Electrochemotherapy for the treatment of ocular basal cell carcinoma; a novel adjunct in the disease management

Calcium Electroporation versus Electrochemotherapy with Bleomycin in an In Vivo CAM-Based Uveal Melanoma Xenograft Model

Despite recent advancements in the diagnosis and treatment of uveal melanoma (UM), its metastatic rate remains high and is accompanied by a highly dismal prognosis, constituting an unmet need for the development of novel adjuvant therapeutic strategies. We established an in vivo chick chorioallantoic membrane (CAM)-based UM xenograft model from UPMD2 and UPMM3 cell lines to examine its feasibility for the improvement of selection of drug candidates. The efficacy of calcium electroporation (CaEP) with 5 or 10 mM calcium chloride (Ca) and electrochemotherapy (ECT) with 1 or 2.5 µg/mL bleomycin in comparison to monotherapy with the tested drug or electroporation (EP) alone was investigated on the generated UM tumors. CaEP and ECT showed a similar reduction of proliferation and melanocytic expansion with a dose-dependent effect for bleomycin, whereas CaEP induced a significant increase of the apoptosis and a reduction of vascularization with varying sensitivity for the two xenograft types. Our in vivo results suggest that CaEP and ECT may facilitate the adequate local tumor control and contribute to the preservation of the bulbus, potentially opening new horizons in the adjuvant treatment of advanced UM.

Treatment of Basal Cell Carcinoma with Electrochemotherapy: Insights from the InspECT Registry (2008–2019)

This prospective registry-based study aims to describe electrochemotherapy (ECT) modalities in basal cell carcinoma (BCC) patients and evaluate its efficacy, safety, and predictive factors. The International Network for Sharing Practices of Electrochemotherapy (InspECT) multicentre database was queried for BCC cases treated with bleomycin-ECT between 2008 and 2019 (n = 330 patients from seven countries, with 623 BCCs [median number: 1/patient; range: 1–7; size: 13 mm, range: 5–350; 85% were primary, and 80% located in the head and neck]). The procedure was carried out under local anaesthesia in 68% of cases, with the adjunct of mild sedation in the remaining 32%. Of 300 evaluable patients, 242 (81%) achieved a complete response (CR) after a single ECT course. Treatment naïvety (odds ratio [OR] 0.35, 95% confidence interval [C.I.] 0.19–0.67, p = 0.001) and coverage of deep tumour margin with electric pulses (O.R. 5.55, 95% C.I. 1.37–21.69, p = 0.016) predicted CR, whereas previous radiation was inversely correlated (O.R. 0.25, p = 0.0051). Toxicity included skin ulceration (overall, 16%; G3, 1%) and hyperpigmentation (overall, 8.1%; G3, 2.5%). At a 17-month follow-up, 28 (9.3%) patients experienced local recurrence/progression. Despite no convincing evidence that ECT confers improved outcomes compared with standard surgical excision, it can still be considered an opportunity to avoid major resection in patients unsuitable for more demanding treatment. Treatment naïvety and coverage of the deep margin predict tumour clearance and may inform current patient selection and management.

Electrochemotherapy with bleomycin for basal cell carcinomas: a systematic review

Basal cell carcinoma (BCC) is the most common type of cancer and an increasing incidence stimulates the interest in new treatments such as electrochemotherapy (ECT) with bleomycin. This systematic review focuses on literature from the MEDLINE, Embase, Web of Science, and Cochrane databases. Bleomycin-ECT studies (n = 32) were sorted by the level of evidence adjusted for their BCC data only. The studies included a single randomised controlled trial (RCT), 15 uncontrolled clinical trials, three registry studies, six prospective case series and seven retrospective case series. A Cochrane risk-of-bias assessment of the RCT identified some minor concerns but no predicted risk of bias. The studies were also grouped by bleomycin administration routes: intravenous (n = 14), intralesional (n = 9) and mixed reporting/usage (n = 9). A meta-analysis was not conducted due to the lack of RCTs and the heterogeneity of the included studies. The results of the RCT generally reflected the findings of the other included studies and showed a 92% complete response in 65 bleomycin-ECT-treated BCCs after 2 months, improving to 100% after re-treatment, with a low risk of recurrence. Based on the RCT results and overall data, future studies on BCC treatment with bleomycin-ECT should include large RCTs that compare bleomycin-ECT with standard of care, cost analyses, and clinical feasibility.

Electrochemotherapy and basal cell carcinomas: First-time appraisal of the efficacy of electrochemotherapy on survivorship using FACE-Q

Introduction

The establishment and success of new treatments are significantly influenced by patient satisfaction. Post-operative scarring is an important outcome for patients, and subsequently influences overall satisfaction with treatment. The objective was to measure post-treatment scarring satisfaction using a novel scale, the FACE-Q Skin Cancer Module, to compare electrochemotherapy (ECT) to traditional surgical excision (SE) to demonstrate equivalence of ECT and SE regarding outcome and survivorship.

Methods and materials

This was a multicentre first-time appraisal study of the efficacy of ECT. All patients with facial BCCs treated with either ECT or SE were deemed eligible and subsequently recruited from either a previous clinical trial or outpatient clinics, respectively. Of the 40 participants invited, 25 responses were received. Patient information recorded included age, gender, location and size of BCCs, and time since treatment. Patient outcomes were measured using the FACE-Q Skin Cancer Module.

Results

The ECT and SE groups consisted of 14 and 11 patients, respectively. Mean age was 68 years (M:F = 16:9), while mean time since treatment was 4.98 years (range 0.3–9.58 years). Appraisal of scars was significantly higher in the ECT cohort versus SE (p = 0.034). Cancer worry was equivalent across both cohorts (p = 0.804). According to treatment type, no correlation was detected between time since treatment and both appraisal of scars (ECT p = 0.466 and SE p = 0.214) and adverse effects (ECT p = 0.924 and SE p = 0.139).

Conclusion

Based on this study, ECT has superior scar outcomes and overall equivalence to SE. This demonstrates high patient satisfaction for those treated with ECT without any additional cancer worry.

Electrochemotherapy for the treatment of primary basal cell carcinoma; A randomised control trial comparing electrochemotherapy and surgery with five year follow up

Basal cell carcinoma (BCC) are the commonest cutaneous malignancy and incidence continues to increase. There is a need to expand the therapeutic toolbox to increase options for patients that are unsuitable for or unwilling to undergo the current therapies. Electrochemotherapy (ECT) is a technique where cells are temporarily permeabilized after exposure to a brief pulsed electrical field and combined with low dose chemotherapeutics to ablate malignancies. It is a simple technique causing minimal damage to the surrounding healthy tissue and has the potential to avoid the need for complex reconstruction. ECT is an established treatment for skin metastases but its role as a primary treatment modality is not demonstrated. A prospective randomised control trial evaluating ECT against the gold standard of treatment, Surgery, was performed for patients with primary BCC and patients followed for 5 years. All lesions treated with ECT (n = 69) responded although 8/69 (12%) needed a second treatment to ensure a complete response. All surgical lesions (n = 48) showed histological evidence of complete excision with 2/48 (4%) undergoing a second excision. At 5 years, in the surgical arm there was no evidence of recurrence in 39/40 (97.5%) lesions with 1/40 (2.5%) confirmed recurrence. In the ECT arm there was no evidence of recurrence in 42/48 lesions (87.5%). There was 5 confirmed recurrences. These groups show statistical equivalence in this non inferiority study design (p = 0.33). ECT is an effective and durable treatment option for primary BCC and should be considered as part of the armamentarium of options available.

Electrochemotherapy for advanced cutaneous angiosarcoma: A European register-based cohort study from the International Network for Sharing Practices of electrochemotherapy (InspECT)

BACKGROUND

Cutaneous angiosarcoma (cAS) is a highly aggressive malignancy that challenges the radicality of surgical treatment. Electrochemotherapy (ECT), a skin-directed treatment based on cytotoxic chemotherapy combined with local electric pulses, may be an intraoperative adjunct and a new opportunity in the therapeutic strategy. This cohort study reports the experience with ECT as an option.

METHODS

Data on patients with locally-advanced/metastatic cAS who underwent ECT between October 2013 and October 2018 at eight European centres were prospectively submitted to the InspECT (International network for sharing practices of ECT) register. Patients received therapy according to the European Standard Operating Procedures of ECT (ESOPE). Treatment feasibility was assessed based on tumour coverage with electrodes and recorded tissue current; treatment toxicity and tumour response were graded according to CTCAE v5.0 and RECIST v1.1 criteria, respectively; patient-reported outcomes (PRO) were evaluated using a visual analogue score (VAS) for pain, acceptance of retreatment and the EQ-5D questionnaire.

RESULTS

We enrolled 20 patients with advanced cAS in the scalp/face (n = 7), breast/trunk (n = 10) or limbs (n = 3). Target tumours (n = 51) had a median size of 2.3 cm (range, 1-20). We administered 24 ECT courses using 1-4 cm treatment safety margin around tumours. In five patients, ECT was combined/sequenced with surgery. Median tissue current was 3 A (range, 1.5-10), tumour margins coverage rate was 75% (15/20 patients). The objective response rate (ORR) was 80% (complete, 40%). Grade-3 toxicity included skin ulceration (15%) and pain (10%), with no significant change of PRO scores. Bleeding control was achieved in 13/14 patients with ulcerated tumours. With a median overall survival of 12.5 months, the local progression-free survival (LPFS) was 10.9 months.

CONCLUSION

ECT produces sustained response rate with minimal side effects and should be considered an option for advanced cAS. Palliative benefits include patient tolerability, local haemostasis and durable local control. Definition of optimal timing, treatment safety margins and combination with surgery need further investigation.

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.

Electrochemotherapy in the treatment of locally advanced or recurrent eyelid-periocular basal cell carcinomas

There is increasing evidence about the effectiveness of electrochemotherapy (ECT) in the treatment of basal cell carcinomas in the head and neck region, although its role in the management of eyelid-periocular skin tumors has to be clarified. The aim of the present study is to evaluate the results of ECT in the treatment of locally advanced primary and recurrent eyelid-periocular skin basal cell carcinomas. Twelve patients with basal cell carcinoma involving the eyelid-periocular skin region were treated with ECT. Three patients had locally advanced primary tumors, while 9 patients had recurrent tumors. All treatments were performed according to the ESOPE guidelines, using Cliniporator TM device. All patients received bleomycin based ECT. The route of administration was intratumoral in 3 patients and intravenous in 9 patients. Tumor response was evaluated using the RECIST 1.1. criteria. ECT resulted in complete response of the periocular skin tumors in all patients. Lower eyelid ectropion was developed in 3 patients which had to be corrected surgically. ECT can be used effectively in the treatment of locally advanced or recurrent basal cell carcinomas in the eyelid-periocular skin region. Excellent tumor control can be achieved with good functional and cosmetic results without systemic adverse events with short interval follow-up.

Long-term follow-up in patients treated with electrochemotherapy for non-melanoma skin cancer in the head and neck area

BACKGROUND

Electrochemotherapy (ECT) is a cancer treatment modality where the intracellular accumulation of chemotherapeutic agents is enhanced by an applied electrical field.

AIMS/OBJECTIVES

To evaluate the long-term efficacy, safety and functional outcome after ECT treatment in high-risk non-melanoma skin cancer (NMSC) with curative intent.

MATERIALS AND METHODS

Seven patients with SCC or BCC in the head and neck area were treated with ECT with intratumoral bleomycin administration.

RESULTS

Five patients were cured by ECT as a mono-modality treatment after a median 10-year follow-up period. Two patients had recurrences and/or persisting tumors after treatment that required salvage surgery and radiotherapy. In two patients, the eye was spared with no visual impairment. In another patient, full facial nerve function was spared.

CONCLUSIONS

ECT can be a curative as well as an organ and function-sparing mono modality treatment in high-risk NMSC.

SIGNIFICANCE

Today ECT is mostly used as a palliative treatment. Its curative potential should be further investigated. Randomized studies comparing ECT with standard treatment is needed. Hopefully, this small study can encourage such studies.

Basal cell carcinoma: 10-year experience with electrochemotherapy

BACKGROUND

Electrochemotherapy (ECT), by combining manageable cytotoxic agents with short electric pulses, represents an effective palliative skin-directed therapy. The accumulated evidence indicates that ECT stands out as a safe and well-tolerated alternative treatment for patients with multiple or large basal cell carcinoma (BCC), who are not suitable for conventional treatments. However, long-term data and shared indications are lacking.

METHODS

In this observational study, we retrospectively analyzed 84 prospectively collected patients with multiple, recurrent or locally advanced BCC who were not candidate for standard therapies and received bleomycin-based ECT according to the European Standard Operative Procedures of ECT, from 2006 to 2016.

RESULTS

Disease extent was local, locally advanced and metastatic in 40 (48%), 41 (49%) and 3 (3%), respectively. Forty-four (52%) individuals had multiple BCCs. Grade 3 skin toxicity after ECT was observed in 6% of cases. Clearance rate was 50% (95% CI 39-61%). Primary presentation (p = 0.004), tumor size <3 cm (p < 0.001), well-defined borders (p = 0.021), absence of tumor ulceration (p = 0.001), non-aggressive BCC histology (p = 0.046) and age ≤69 years were associated with higher complete response rate. In patients with local BCC, the clearance rate was 72.5 and 85% after one or two ECT cycles, respectively. In the laBCC group, 32 patients (78%) achieved an objective response. Five-year recurrence rate for local and laBCC was 20 and 38%, respectively (p ≤ 0.001).

CONCLUSIONS

One or two ECT cycles with bleomycin may be a valuable palliative treatment in well-selected patients with multiple BCCs and favorable tumor features. Validation of predictive factors will be imperative to match patients with optimal ECT treatment modalities. Management of laBCC with ECT warrants further investigation. Trial registration ISRCTN14633165 Registered 24 March 2017 (retrospectively registered).

Intralesional Bleomycin as an Adjunct Therapeutic Modality in Eyelid and Extraocular Malignancies and Tumors

To present our recent experience with intralesional bleomycin (IBI) in nonmelanoma extraocular tumors, and present previous experience on periocular capillary hemangiomas and orbital lymphangiomas in a tertiary referral hospital. This was a retrospective descriptive study of patients with eyelid and extraocular malignancies where conventional therapies failed, or surgery was contraindicated or refused and were offered IBI as an alternate therapy. All patients were recruited from the Oculoplastics Clinic at Tygerberg Academic Hospital, Cape Town, South Africa. A solution containing 1 international unit of bleomycin per milliliter saline was injected intralesionally together with 2% lignocaine in a ratio of 4:1. The injected volume was calculated to be equivalent to the estimated volume of the lesion. A multipuncture technique with a 29-gauge needle was used. Patients requiring retreatment were injected every 4–8 weeks until satisfactory clinical endpoints were achieved. Our previous experience with IBI in extensive capillary hemangiomas and orbital lymphangiomas is reviewed. Cases are presented to illustrate that IBI induced significant regression and reduction in tumor size and marked clinical improvement of the eyelid and orbital basal cell carcinomas, Kaposi sarcoma, and mycosis fungoides. The improvements obviated the need for further surgical intervention in most cases. Based on clinical experience we propose that IBI should be considered a treatment modality in select cases of the malignant eyelid and ophthalmic vascular tumors where the conventional standard of care is not possible. IBI is a reasonable alternative or adjunct to consider in such cases.

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.

Electroporation Enhances Bleomycin Efficacy in Cats with Periocular Carcinoma and Advanced Squamous Cell Carcinoma of the Head

Background

Advanced carcinoma of the head represents a substantial health problem in cats for local control and overall survival.

Objectives

Evaluate the capability of electrochemotherapy (ECT) to improve bleomycin efficacy in cats with periocular carcinoma and advanced carcinoma of the head.

Animals

Twenty‐one cats with periocular carcinoma (17 squamous cell carcinoma [SCC] and 4 anaplastic carcinoma) and 26 cats with advanced SCC of the head.

Methods

Nonrandomized prospective controlled study. Periocular carcinoma cohorts: 12 cats were treated with bleomycin (15 mg/m²IV) coupled with ECT under anesthesia; 9 cats were treated with bleomycin alone. Advanced head SCC cohorts: 14 cats were treated with bleomycin (15 mg/m²IV) coupled with ECT administered under sedation; 12 control cats were treated with bleomycin alone. ECT treatments (2–8) were performed every other week until complete remission (CR) or tumor progression occurred.

Results

Toxicities were minimal and mostly treated symptomatically. Overall response rate in the ECT treated animals was 89% (21 Complete Response [CR] and 2 Partial Response [PR]) whereas controls had response rate of 33% (4 CR and 3 PR). Median time to progression in ECT group was 30.5 months, whereas in controls it was 3.9 months (P < .0001). Median time to progression for ECT cohorts was 24.2 months for periocular cohort and 20.6 in advanced head SCC cohort, respectively.

Conclusions

Electrochemotherapy is well tolerated for advanced SCC of the head in cats; its use may be considered among loco‐regional strategies for cancer therapy in sensitive body regions such as periocular region.

Electrochemotherapy: a good idea in recurrent basal cell carcinoma treatment

Basal cell carcinoma (BCC) is the most common skin cancer in Caucasian population. Surgical excision is the gold standard treatment for BCC. Secondary surgical approach in patients presenting surgical scars after multiple surgical excisions or submitted to radiotherapy without obtaining a safe clearance margin, should be avoided. In recent years the use of electrochemotherapy (ECT) in head and neck cancers using intravenous bleomycin was specifically addressed and BCC resulted to be among tumors with the best response to ECT. We report a case of a recurrent nasal BCC treated with ECT with a complete regression of lesions after 8 weeks and a disease free period of 7 months. ECT is a good palliative treatment not affecting survival rate but improving quality of life in patients.

Non-viral immune electrogene therapy induces potent antitumour responses and has a curative effect in murine colon adenocarcinoma and melanoma cancer models

Antitumour efficacy of electroporated pEEV, coding for granulocyte–macrophage colony-stimulating factor and the B7-1 costimulatory immune molecule (pEEVGmCSF-b7.1) in growing solid tumours, was investigated and compared with a standard plasmid. Application of pEEVGmCSF-b7.1 led to complete tumour regression in 66% of CT26-treated tumours and 100% in the B16F10-treated tumours at day 150 post-treatment. pEEVGmCSF-b7.1 treatment was found to significantly enhance levels of both innate and adaptive immune populations in tumour and systemic sites, which corresponded to significantly increased tissue levels of proinflammatory cytokines including interferon-γ (IFN-γ) and interleukin-12 (IL-12). In contrast, pEEVGmCSF-b7.1 treatment significantly reduced the T-regulatory populations and also the anti-inflammatory cytokine IL-10. Upon further characterisation of functional immune responses, we observed a significant increase in cytotoxic (CD107a+) and IFN-γ-producing natural killer cells and also significantly more in IL-12-producing B cells. Importantly, splenocytes isolated from pEEVGmCSF-b7.1-treated ‘cured' mice were tumour-specific and afforded significant protection in a tumour rechallenge model (Winn assay). Our data indicate that electroimmunogene therapy with the non-viral pEEVGmCSF-b7.1 is able to induce potent and durable antitumour immune responses that significantly reduce primary and also secondary tumour growth, and thus represents a solid therapeutic platform for pursuing future clinical trials.

Development and characterization of an enhanced nonviral expression vector for electroporation cancer treatment

Nonviral plasmid DNA gene therapy represents a promising approach for the treatment of many diseases including cancer. Intracellular delivery of DNA can be achieved with the application of electroporation, which facilitates the initial transport of exogenous DNA across the cell membrane into the cytoplasm. However, it does not guarantee further transport of the DNA from the cytoplasm to the nucleus for subsequent mRNA expression, resulting in varying degrees of exogenous gene translation and a major limitation in comparison to viral approaches. To overcome these expression difficulties, we developed a proof-of-concept vector enhanced expression vector (EEV), which incorporates elements from viral systems including nuclear localization sequences and a viral replicase from the Semliki Forest virus. The replicase allows for cytoplasmic mRNA expression and bypasses the need for nuclear localization to generate high levels of gene expression. We have demonstrated that our EEV is capable of achieving high levels of expression in a variety of tissue types. Antitumor effects of pEEV were demonstrated by the delayed growth and increased survival of the nontherapeutic pEEV-treated CT26 tumor model. Using a novel endoscopic electroporation system, EndoVe, we demonstrate and compare, for the first time, both standard cytomegalovirus (CMV) promoter-driven plasmid and EEV gene expression in intraluminal porcine tissues. Our EEV plasmid displays reliable and superior expression capability, and due to its inherent induced oncolytic activity in transfected cells, it may enhance the efficacy and safety of several cancer immunogene therapy approaches.

Electrochemotherapy: from the drawing board into medical practice

Electrochemotherapy is a local treatment of cancer employing electric pulses to improve transmembrane transfer of cytotoxic drugs. In this paper we discuss electrochemotherapy from the perspective of biomedical engineering and review the steps needed to move such a treatment from initial prototypes into clinical practice. In the paper also basic theory of electrochemotherapy and preclinical studies in vitro and in vivo are briefly reviewed. Following this we present a short review of recent clinical publications and discuss implementation of electrochemotherapy into standard of care for treatment of skin tumors, and use of electrochemotherapy for other targets such as head and neck cancer, deep-seated tumors in the liver and intestinal tract, and brain metastases. Electrodes used in these specific cases are presented with their typical voltage amplitudes used in electrochemotherapy. Finally, key points on what should be investigated in the future are presented and discussed.