Electrochemotherapy in the treatment of melanoma

Role of Isolated Limb Perfusion in the Era of Targeted Therapies and Immunotherapy in Melanoma. A Systematic Review of The Literature

BACKGROUND

Isolated limb perfusion (ILP) is a locoregional procedure indicated by the unresectable melanoma of the limbs. Its complexity and highly demanding multidisciplinary approach means that it is a technique only implemented in a few referral centers around the globe. This report aims to examine its potential role in the era of targeted therapies and immunotherapy by conducting a systematic review of the literature on ILP.

METHODS

PubMed, Embase and Cochrane Library were searched. The eligibility criteria included publications from 2000-2020 providing valid data o effectiveness, survival or toxicity. Studies in which the perfusion methodology was not clearly described, letters to the editor, non-systematic reviews and studies that applied outdated clinical guidelines were excluded. To rule out studies of a low methodological quality and assess the risk of bias, the following aspects were also required: a detailed description of the applied ILP regimen, the clinical context, follow-up periods, analyzed clinical endpoints, and the number of analyzed ILPs. The disagreements were resolved by consensus. The results are presented in tables and figures.

RESULTS

Twenty-seven studies including 2637 ILPs were selected. The median overall response rate was 85%, with a median complete response rate of 58.5%. The median overall survival was 38 months, with a 5-year overall survival of 35%. The toxicity was generally mild according to Wieberdink toxicity criteria.

DISCUSSION

ILP still offer a high efficacy in selected patients. The main limitation of our review is the heterogeneity and age of most of the articles, as well as the absence of clinical trials comparing ILP with other procedures, making it difficult to transfer its results to the current era.

CONCLUSIONS

ILP is still an effective and safe procedure for selected patients with unresectable melanoma of the limbs. In the era of targeted therapies and immunotherapy, ILP remains an acceptable and reasonable palliative treatment alternative, especially to avoid limb amputations. The ongoing clinical trials combining systemic therapies and ILP will provide more valuable information in the future to clarify the potential synergism of both strategies.

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.

The effect of calcium electroporation on viability, phenotype and function of melanoma conditioned macrophages

Electroporation in combination with chemotherapy is an established treatment used on solid malignancies that results in enhanced chemotherapeutic uptake. Recent advances have begun to transition to the use of non-toxic compounds, such as calcium, in lieu of chemotherapy, which can also induce tumour cell death. While the effect of treatment on tumour cell death has been well characterized and has been shown to induce an immunogenic form of cell death, the effect of treatment on intratumoural immune cells has not been investigated. Here we present data showing the effect of calcium electroporation on immune cells, using melanoma-conditioned bone marrow-derived macrophages. Similar to tumour cells, macrophage cell membranes are susceptible to poration following treatment and subsequently reseal. Macrophages are less susceptible to calcium electroporation induced cell death in comparison to B16F10 melanoma cells. However treatment with electroporation with or without bleomycin or calcium was shown to affect macrophage phenotype and function. Coculture of calcium electroporated macrophages revealed that both the capacity of macrophages to stimulate and direct T cell responses are affected following exposure to treatment. We conclude that calcium electroporation has the potential to boost the immunogenic capacity of exposed tumour associated macrophages, and further research is warranted to determine if calcium electroporation can be optimised to generate systemic anti-cancer immune responses.

Palliative electrochemotherapy in primary or recurrent vulvar cancer

OBJECTIVE

Since vulvar cancer is such a rare disease, the international experience with electrochemotherapy has been derived from only a few centers. The aim of this study was to evaluate clinical outcome and side effects profile with the use of electrochemotherapy in patients with primary or recurrent vulvar cancer.

METHODS

Data were retrospectively collected from November 2017 to November 2019 in two major Italian oncologic institutes: Regina Elena Institute and Fondazione Policlinico Universitario Agostino Gemelli IRCCS. Electrochemotherapy was offered in a palliative setting to patients with a primary or recurrent vulvar cancer who were not candidates for surgery or any other treatment, because of poor performance status or previous delivered treatments. All patients underwent general anesthesia. Electrical pulses were delivered using a pulse generator. Intravenous bleomycin was administered in conjunction with electrochemotherapy. Follow-up examinations were performed at 1, 3, and 6 months. Primary endpoint was to assess the response rate of electrochemotherapy as palliative treatment in patients with vulvar cancer.

RESULTS

A total of 15 patients were included in the study. Fourteen patients (93.3%) had a squamous cell carcinoma and one patient had vulvar carcinosarcoma. Ten patients (66.7 %) had a single lesion and 5 patients (33.3%) had multiple lesions. Median number of electrical pulses was 22 (range 3-42) and median operative time was 13 (range 7-20) min. No intra-procedure complications occurred. One patient had pneumonia during their post-operative stay. Overall response rate after 1 month was 80%. At the 3-month follow-up, 3 patients (20%) had disease progression, 3 patients (20%) had died from ongoing disease, 1 patient (6.7%) died for other reasons, whereas the other patients maintained their 1-month clinical response. A total of 8/13 patients (61.5%) were alive at 6-month follow-up, whereas 6/12 patients (50%) were alive at 1-year follow-up.

CONCLUSIONS

Electrochemotherapy is a feasible, easy to perform, and reproducible procedure in patients with primary or recurrent vulvar cancer who are unable to undergo surgery. Survival after 1 year in this population was 50%. Electrochemotherapy may have a role in the management of vulvar cancer, especially as palliative treatment when other therapies are no longer applicable.

Feasibility of Electroacoustic Tomography: A Simulation Study

The feasibility of electroacoustic tomography (EAT) was investigated for in situ monitoring the electric field distribution in soft tissue. EAT exploits the phenomenon that the amplitude of acoustic emission generated by an electric field is proportional to the electrical energy deposition in tissue. After detecting these acoustic waves with ultrasound transducers, an image of the electric field distribution can be reconstructed in real-time. In our computer simulations, the electric field distribution in soft tissue was generated by solving general partial differential equations (PDEs) using finite element analysis (FEA). The electric field distributions were converted into initial pressure distributions, and the propagation of the induced acoustic waves was simulated using K-Wave simulation. A circular array of 128 ultrasound transducers was placed around the target to detect the acoustic waves, and a time reversal reconstruction algorithm was used to reconstruct the EAT image. A different number of electrodes set at different distances with different voltage inputs on the electrodes were performed to simulate different electric field distributions during electroporation. It was found that the electrical energy deposition in reconstructed EAT imaging is decreased as the distance of the electrodes increases. We also have investigated the sensitivity of the EAT imaging with different voltage inputs. The minimal voltage we can detect with EAT is 970 V at the pulsewidth of 180 ns. The results of this study demonstrated that EAT is a feasible technique for monitoring the electric field distribution and guiding the electrotherapy in future clinical practice.

Intratumoral and Combination Therapy in Melanoma and Other Skin Cancers

Skin cancer, as the most physically accessible malignancy, allows for the greatest variety in treatment innovation. The last 2 decades have seen striking increases in the life expectancies of those diagnosed with malignant melanoma. However, many cases remain in which disease prevails against standard treatment, and those patients rely on continuing ingenuity. Drugs that can be injected directly into patients' tumors have become increasingly promising, not least for the reduction in side effects observed. Intratumoral therapy encompasses a wide array of agents, from chemotherapeutic drugs to cancer vaccines. While each show some efficacy, those agents which regulate the immune system likely have the greatest potential for preventing disease progression or recurrence. Recent research has highlighted the importance of the presence of cytotoxic T cells and of keeping regulatory T cells in check. Thus, manipulating the tumor microenvironment is a need in skin cancer therapy, which intratumoral delivery can potentially address. In order to find the best approach to each person's disease, more studies are needed to test intralesional agents in combination with currently approved therapies and with each other.

Electrochemotherapy Causes Caspase-Independent Necrotic-Like Death in Pancreatic Cancer Cells

Pancreatic cancer represents a major challenge in oncology. Poor permeability of the pancreas and resistance to currently available therapies are impediments to improved patient survival. By transiently increasing cell membrane porosity and increasing drug uptake, Electrochemotherapy (ECT) has the potential to overcome these issues. In this study, we have evaluated the response of human and murine pancreatic cancer cells, in vitro, to electroporation in combination with Bleomycin, Cisplatin, or Oxaliplatin (ECT). The cytotoxic actions of all three drugs are potentiated when combined with electroporation in these cells. The biochemical and morphological changes post ECT are associated with immunogenic cell death that occurs with necroptosis rather than apoptosis. Moreover, ECT-induced cell death is rescued by Nec-1 suggesting that necroptosis may play a role in cell death mediated by cancer therapies.

Application of CO2 laser evaporation in locally advanced melanoma

Aim

This study aims to investigate the role of CO₂ laser evaporation in the treatment of melanoma patients with satellite or in-transit metastases.

Materials & methods

Patients who underwent CO₂ laser evaporation were retrospectively included between November 2002 and August 2018. The Sharplan 40C CO₂ laser was used with a high pulse wave mode. Data concerning patient and tumor characteristics, CO₂ laser evaporation and subsequent therapies were collected.

Results

A total of 26 patients were included. Median duration of local control was 5.5 months. The median number of lesions evaporated per treatment was three (1-16); patients received a median of three (1-19) treatments.

Conclusion

In a selected group of melanoma patients with satellite or in-transit metastases, CO₂ laser evaporation should be considered as treatment for local control.