Demographics and outcomes of stage I and II Merkel cell carcinoma treated with Mohs micrographic surgery compared with wide local excision in the National Cancer Database

Background: The optimal surgical approach (wide local excision [WLE] vs Mohs micrographic surgery [MMS]) for treating Merkel cell carcinoma (MCC) is yet to be determined. Objective: To compare survival outcomes in patients with early-stage MCC treated with MMS versus with WLE. Methods: A retrospective review of all cases in the National Cancer Database (NCDB) of MCC of clinical stage I or II MCC treated with WLE or MMS was performed. Results: A total of 1795 cases of stage I or II MCC who underwent WLE (n = 1685) or MMS (n = 110) were identified. There was no difference in residual tumor on surgical margins between the 2 treatment groups (P = .588). On multivariate analysis, there was no difference in overall survival between the treatment modalities (adjusted hazard ratio, 1.02; 95% confidence interval, 0.72-1.45; P = .897). There was no difference in overall survival between the 2 groups on propensity score-matched analysis. Limitations: Disease-specific survival was not reported, as these data are not available in the National Cancer Database. Conclusions: MMS appears to be as effective as WLE in treating early-stage MCC.