Electrochemotherapy is now in routine clinical use to treat cutaneous metastases of any histology, and is listed in national and international guidelines for cutaneous metastases and primary skin cancer. Electrochemotherapy is used by dermatologists, surgeons, and oncologists, and for different degrees and manifestations of metastases to skin and primary skin tumours not amenable to surgery. This treatment utilises electric pulses to permeabilize cell membranes in tumours, thus allowing a dramatic increase of the cytotoxicity of anti-cancer agents. Response rates, often after only one treatment, are very high across all tumour types. The most frequent indications are cutaneous metastases from malignant melanoma and breast cancer. In 2006, standard operating procedures (SOPs) were written for this novel technology, greatly facilitating introduction and dissemination of the therapy. Since then considerable experience has been obtained treating a wider range of tumour histologies and increasing size of tumours which was not originally thought possible. A pan-European expert panel drawn from a range of disciplines from dermatology, general surgery, head and neck surgery, plastic surgery, and oncology met to form a consensus opinion to update the SOPs based on the experience obtained. This paper contains these updated recommendations for indications for electrochemotherapy, pre-treatment information and evaluation, treatment choices, as well as follow-up.

Summary Background (ECT) is an effective local treatment for cutaneous metastasis. Treatment involves the administration of chemotherapeutic drugs followed by delivery of electrical pulses to the tumour. Objectives To investigate the effectiveness of ECT in cutaneous metastases of melanoma and to identify factors that affect (beneficially or adversely) the outcome. Methods Thirteen cancer centres in the International Network for Sharing Practices on Electrochemotherapy consecutively and prospectively uploaded data to a common database. ECT consisted of intratumoral or intravenous injection of bleomycin, followed by application of electric pulses under local or general anaesthesia. Results In total, 151 patients with metastatic melanoma were identified from the database, 114 of whom had follow‐up data of 60 days or more. Eighty‐four of these patients (74%) experienced an overall response (OR = complete response + partial response). Overall, 394 lesions were treated, of which 306 (78%) showed OR, with 229 showing complete response (58%). In multivariate analysis, factors positively associated with overall response were coverage of deep margins, absence of visceral metastases, presence of lymphoedema and treatment of nonirradiated areas. Factors significantly associated with complete response to ECT treatment were coverage of deep margins, previous irradiation of the treated area and tumour size (< 3 cm). One‐year overall survival in this cohort of patients was 67% (95% confidence interval 57–77%), while melanoma‐specific survival was 74% (95% confidence interval 64–84%). No serious adverse events were reported, and the treatment was in general very well tolerated. Conclusions ECT is a highly effective local treatment for melanoma metastases in the skin, with no severe adverse effects noted in this study. In the presence of certain clinical factors, ECT may be considered for local tumour control as an alternative to established local treatments, or as an adjunct to systemic treatments.

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The majority of patients had no or mild pain after electrochemotherapy. Patients at risk for post-procedure pain could be identified at the pre-treatment visit, and/or at the time of treatment, enabling a pain management strategy for this group.

Electrochemotherapy performed with reduced bleomycin dosages could be as effective as with currently recommended dose. Patients with impaired renal function or candidate to multiple ECT cycles could benefit from a reduced dose protocol. Our findings need prospective confirmation before being adopted in clinical practice.