Electrochemotherapy for the management of melanoma skin metastasis: a review of the literature and possible combinations with immunotherapy

Despite surgical treatment of primary tumor, about 5-10 % of melanoma patients will eventually suffer from cutaneous or subcutaneous metastasis. The presence of skin metastases decreases patients' quality of life. Their management is a challenge and depends on several variables such as size and number of the lesions, their location, the presence or absence of visceral metastasis. When possible, radical surgical resection is the best approach; if surgery is not expected to provide a reasonable functional outcome, alternative treatments must be considered. Several local and loco-regional treatments, such as electrochemotherapy and regional chemotherapy, are available for the management of melanoma skin metastasis. Even if high response rates have been observed in several clinical trials, their impact on survival is not clear. Efforts are being made to improve their efficacy and minimize toxicity. The combination of such treatments with immunotherapy could be a strategy to induce durable responses and improve survival. In fact, regionally treated patients do not have the immune suppression associated with most systemic treatments, which could compromise the efficacy of immunotherapy, and recent findings suggest that the inflammatory reactions following loco-regional cytotoxic treatments, such as electrochemotherapy, may enhance the activity of immunotherapeutic agents. In this manuscript, we review recent studies on electrochemotherapy and melanoma skin metastasis, and we comment about the role that combinations with immunotherapy may have based on the data provided by clinical trials and translational research.