Merkel cell carcinoma: high recurrence rate despite aggressive treatment

Merkel cell carcinoma (MCC) is a rare aggressive neuroendocrine cancer of the skin whose incidence has been increasing. The objective of the study was to evaluate current treatment modalities, including sentinel lymph node (SLN) biopsy and outcomes and identify prognostic factors in patients with MCC.

A retrospective chart review of patients with MCC. Clinical, pathologic, treatment characteristics, disease status, and survival were collected. All slides were reviewed by a single pathologist, and additional pathologic elements were evaluated for prognosis.

Twenty-six patients were identified in the study period. All patients were Caucasian with an average age of 71.3 y. Twenty-one patients had tumors in sun-exposed locations, and 13 had a prior history of skin cancer. All nonmetastatic patients underwent wide excision. SLN biopsy was successful in 19 patients. The SLN was positive in 21% of patients. Radiation therapy was used in 13 patients. Average follow-up was 26 mo, and median survival was 29 mo. Recurrence occurred in eight patients: four locoregional, two distant, one combined, and one unknown. Recurrence occurred in five patients with stage I disease. Five patients with negative SLN later developed recurrence. The presence of metastasis to the nodes was significant for recurrence. No other pathologic factor was found to have prognostic significance.

Despite aggressive surgical and radiation treatment, MCC has a high rate of locoregional recurrence, even in early stage disease. SNLB is useful for the staging and management of patients. Further research is needed to identify better prognostic markers.