Guidelines for the diagnosis and treatment of Merkel cell carcinoma - Cutaneous Oncology Group of the French Society of Dermatology.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin. The epidemiological factors strongly associated with this tumor are: age over 65 years, fair skin, chronic sun exposure and immune suppression. Data are sparse in the literature and many questions remain unanswered regarding the diagnosis and treatment of this tumor. OBJECTIVE: To provide clinical practice guidelines for the diagnosis and treatment of MCC. METHOD: The literature data were analyzed and the current American and German practice guidelines were compared. Consensus items between these two guidelines were adopted as recommendations. Regarding discordant points, a formalized expert consensus process was devised. The guidelines were then written up by an editorial panel and validated by the Cutaneous Oncology Group of the French Society of Dermatology. RESULTS: The guidelines were drawn up according to three levels of scientific evidence: (a) complete agreement between the American and German guidelines; (b) the results of the formalized expert consensus process; and (c) the expert opinion of the steering group, based on analysis of the available evidence. The guidelines presented here are up-to-date recommendations on the clinical and pathological procedures for MCC diagnosis, staging, surgical treatment, sentinel node biopsy, radiotherapy and follow-up. CONCLUSION: These guidelines for diagnosis and treatment of MCC should standardize MCC management, which may not be optimal in France today.