RESUMEN
BACKGROUND: Merkel cell carcinoma (MCC) is a rare neuroendocrine malignancy of the skin first described by Toker as 'trabecular carcinoma of the skin' in 1972. To date, the origin of the tumour cells still remains unclear. OBJECTIVES: The present study analyses prognostic factors of MCC. PATIENTS AND METHODS: The medical records of 57 patients with MCC treated between 1988 and 2006 at the Department of Dermatology in Tübingen were reviewed. RESULTS: We identified 26 (45.6%) male and 31 (54.4%) female patients with MCC; the age at diagnosis ranged from 26 to 97 years (median 71 years). Primary tumours were located mainly on the head and neck areas (27 cases, 47.4%) and upper extremities (14 cases, 24.6%); 11 tumours were found on the lower extremities (19.3%) and four lesions on the chest (7%); one patient had an unknown primary location. Forty-five (78.9%) patients were diagnosed at stage I of the disease, 11 (19.3%) at stage II, and one patient (1.8%) at stage III at initial presentation. Stage of the disease and age at initial presentation were statistically significant with regard to overall (P < 0.0001; P = 0.0327) and tumour-specific survival (P < 0.0001; P = 0.0156). Use of the Cox regression model revealed initial stage of the disease as the only significant factor in the multivariate analysis. Radiotherapy applied promptly after excision of the primary tumour extended the time to progression significantly (P = 0.0376) but did not prolong overall or tumour-specific survival. Other parameters such as sex, site of tumour, sentinel node biopsy, excision margins, skin and noncutaneous malignancies were found to be not significant. CONCLUSIONS: Currently, early recognition of the disease seems to be the only method of ensuring overall survival. However, evidence-based treatment modalities are still urgently needed.