Update in treatment for Merkel Cell Carcinoma and clinical practice guide

Merkel Cell Carcinoma (MCC) is a rare neuroendocrine skin cancer that is associated with frequent recurrences and a high mortality rate. In the recent past years, incidence rates of MCC have increased in the USA, Australia and Europe. About one third of patients present metastatic disease at the time of diagnosis or will develop metastases in the course of their disease. Although advanced MCC is chemosensitive, responses to cytotoxic chemotherapy are mostly of short duration and toxicity is potentially high. Recently, considerable progress has been made in the MCC field with the arrival of immunotherapy, particularly anti-PD-1 and anti-PD-L1 antibodies which have demonstrated impressive frequency and durability of response and were well-tolerated. However, about 50 % of advanced patients do not respond to immunotherapy and urgent need exists to identify biomarkers and predictive factors. Moreover, many randomized prospective studies are evaluating the efficacy and safety of novel therapeutics and patients with advanced stages are encouraged to participate in clinical trials. This article synthetizes the actual clinical practice guidelines, the safety and efficacy data from the recent clinical trials and the ongoing clinical trials to help clinicians in the treatment of MCC patients.