Outcome of patients with microscopic and macroscopic metastatic nodal Merkel cell carcinoma: an Australian experience.

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy with a high rate of nodal metastasis. The American Joint Committee on Cancer staging system subclassifies nodal disease into microscopic and macroscopic groups based on prognosis. OBJECTIVE: To compare the outcome of patients with microscopic and macroscopic nodal metastases. MATERIALS AND METHODS: Patients were identified from a database of 180 patients with MCC who presented to Westmead Hospital, Sydney, Australia, from 1980 to 2013. Disease-free survival (DFS), overall survival (OS), and follow-up were calculated using Kaplan-Meier curves and compared using the log-rank (Mantel-Cox) test. RESULTS: Forty-one patients were diagnosed with node-positive MCC; 11 patients had microscopic nodal metastases, with five (45%) relapsing, and 30 had macroscopic disease, with 17 (57%) relapsing. There was no significant difference in DFS (p = .93) or OS (p = .63) between the two groups. CONCLUSION: The nonsignificant difference in DFS and OS suggest that even microscopic nodal metastases can predict a poor outcome. Because more than half of patients subsequently relapse, often at a distant site, there is a need to develop an effective systemic treatment.