Investigation of the diagnostic precision and utility of sentinel lymph node biopsy in the treatment of patients with Merkel cell carcinoma (MCC).

Abstract

9042 Background: Merkel cell carcinoma (MCC) is a relatively uncommon and aggressive cutaneous neuroendocrine neoplasm with a high incidence of local recurrence and regional and distant metastasis. The management and identification of prognostic factors remains of value in the treatment of these patients. Although the optimal multidisciplinary treatment of MCC has yet to be determined, the purpose of this study was to investigate whether sentinel lymph node biopsy confers a lower risk of recurrent disease in patients with Merkel cell carcinoma at our institution. Methods: After obtaining institutional review board approvals, all patients with a diagnosis of MCC from 2002-2012 were obtained from our tumor registries. Clinical features, pathologic characteristics, management modalities, and patient outcomes were retrospectively reviewed. Results: Of 20 patients with MCC, nine patients underwent sentinel lymph node biopsy, another four received therapeutic lymph node dissections, and seven patients did not have lymph node evaluation at the initial operation. The most common nodal basins involved were cervical and axillary. Recurrent disease was observed in seven patients (35%). Three patients underwent complete regional lymph node dissection after developing clinically positive nodal disease subsequent to only wide local excision at the index operation (15%). Three patients developed locoregional recurrence and the seventh patient developed metastatic disease to the liver. Of these seven patients with recurrent disease, only two (28.57%) had initial lymph node evaluation. Twelve patients (60%) received adjuvant therapy with chemotherapy (carboplatin/etoposide) and/ or radiation therapy. Conclusions: Merkel cell carcinoma continues to demonstrate its propensity for high rates of recurrence and metastatic disease. Of the seven patients with recurrent locoregional and/or nodal disease in our study, only two patients had initial lymph node evaluation, which was statistically significant with a p value of 0.01175. Further analysis focusing on additional prognostic factors is necessary to optimize our management algorithms and patient outcomes.