PURPOSE: Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin tumor.  This tumor has a propensity to metastasize early and recur both locally and regionally. A better understanding of the prognostic indicators for recurrence may improve outcomes. 
METHOD: A retrospective review of 37 charts was performed of patients with Merkel Cell Carcinoma of the skin treated with surgery at the Cleveland Clinic between May 1980 and August 2007.  By using univariate analysis, we aim to delineate prognostic factors for recurrence both locally and regionally. 17/33 recurrent cases and 16/33 disease-free cases at one-year post-surgery were included in a univariate analysis. 
RESULTS: The mean age at diagnosis was 73.6 years (±9.0).  59% were male (22/37) and 41% (15/37) were female.  56% of the tumors were located in the head and neck region. Comorbidities among the patients included a history of diabetes (31%), connective tissue disease (11%), immunosuppressive therapy (14%), and cancer (25%).  The median follow-up was 23.3 months (IQR: 13.1 mo, 53.3 mo).  81% (30/37) were treated with adjuvant therapies including radiation, chemotherapy or both.  64% of patients underwent lymph node sampling. 14% (5/13) of sentinel node and 40% (6/15) of regional node resections were positive.  The median time to recurrence was 10.0 months (6.0 mo, 15.0 mo) and the median margin was 2.0 cm (IQR: 1.0 cm, 3.0 cm).  Patients who recurred had smaller margins resected, 1.6 cm (±1.2 cm) vs. 2.9 cm (±1.6 cm) for disease-free patients (P=0.03).
CONCLUSION: These data suggest that patients with smaller margins may be at increased risk for recurrence. Neither stage at diagnosis nor location of the tumor appears to significantly affect recurrence.  Despite adjuvant radiation therapy, patients with smaller margin sizes recurred more frequently.