Merkel Cell Carcinoma: Characteristics, Management, and What's on the Horizon

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous malignancy with a steadily increasing incidence. Advancing age, fair skin, ultraviolet light exposure, and immunocompromise are risk factors. Sixty to eighty percent are associated with the Merkel cell polyomavirus, and the remainder carry a high mutational burden. Recently immunotherapy has been shown to be a highly effective and well tolerated treatment. The disease is also very chemosensitive similar to small-cell lung cancer. Ongoing trials are evaluating the role of adjuvant immunotherapy and novel immunotherapy agents as well as targeted therapy and endocrine therapy with somatostatin analogues. Also included in this review is our institution's experience with MCC in 6 patients treated with pembrolizumab, 5 of whom experienced an excellent response.