Selective lymphadenectomy in patients with Merkel cell (cutaneous neuroendocrine) carcinoma

Background: Merkel cell carcinoma (MCC) is an aggressive cutaneous tumor with a propensity for local recurrence, regional and distant metastases. There are no well-defined prognostic factors that predict behavior of this tumor, nor are treatment guidelines well established. Methods: Staging of patients with a new diagnosis of MCC was attempted using selective lymphadenectomy concurrent with primary excision. Preoperative and intraoperative mapping, excision, and thorough histologic evaluation of the first lymph node draining the tumor primary site [sentinel node] was performed. Patients with tumor metastasis in the sentinel node underwent complete resection of the remainder of the lymph node basin. Results: Twelve patients underwent removal of 22 sentinel nodes. Two patients demonstrated metastatic disease in their sentinel lymph nodes, and complete dissection of the involved nodal basin revealed additional positive nodes. The node-negative patients received no further surgical therapy, with no evidence of recurrent local or regional disease at a maximum of 26 months follow-up (median 10.5 months). Conclusions: While the data are preliminary and initial follow-up is limited, early results suggest that sentinel lymph node mapping and excision may be a useful adjunct in the treatment of MCC. This technique may identify a population of patients who would benefit from further surgical lymph node excision.