LAUSR

Merkel cell carcinoma (MCC) is a neuroendocrine carcinoma of the skin with potentially aggressive clinical behaviour. Surgically treated patients with MCC frequently experience recurrence (30–60%) and often within 2 years. Until recently, in case of distant metastases or irresectable disease, chemotherapy was the only systemic treatment option, with response rates of 50–60%. Yet, these responses were seldom durable with median progression-free survival (PFS) of only 3 months. The recent introduction of immunotherapy (IT) has changed the outlook for patients with metastatic MCC, with comparable response rates but with an observed median PFS of 17 months. Serum biomarkers are frequently used to estimate prognosis or guide treatment decisions. To date, no serum biomarker for patients with MCC is established for clinical practice. The high recurrence rate and the recent introduction of a promising systemic treatment emphasize the need for a serum biomarker. Neuron-specific enolase (NSE) was already accepted as a prognosticator and to evaluate response in other malignancies. In MCC, only one previously performed study and case reports are known evaluating NSE in MCC patients, with variable results. PRESENT