Outcome of Patients with Microscopic and Macroscopic Metastatic Nodal Merkel Cell Carcinoma: An Australian Experience

Abstract

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. To compare the outcome of patients with microscopic and macroscopic nodal metastases. 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. 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. 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.