Clinical outcomes in high-risk squamous cell carcinoma patients treated with Mohs micrographic surgery alone

Background: There is little evidence to predict patient outcomes after the treatment of high-risk cutaneous SCC (hrSCC) using Mohs micrographic surgery (MMS). Objective: We sought to report the rates of poor outcomes in patients with hrSCC treated by MMS alone and to determine if any specific clinical factors may be more predictive of these outcomes. Methods: We conducted a retrospective chart review of all patients with hrSCC who were treated in our clinic between October 2011 and December 2015. Results: We identified 647 hrSCC tumors that met the inclusion criteria. During the follow-up period, there were 19 local recurrences (2.9%), 31 nodal metastases (4.8%), 7 distant metastases (1.1%), and 7 disease-specific deaths (1.1%). Two factors, poor differentiation and invasion beyond the subcutaneous fat, were positively associated with local recurrence, nodal metastasis, and disease-specific death through multivariate analysis. Conclusions: Invasion beyond the subcutaneous fat and poor histologic differentiation may carry a greater risk of poor outcomes than other factors in hrSCC. MMS alone provides excellent marginal control with low rates of local recurrence, nodal metastasis, and disease-specific death.