Outcomes of Mohs micrographic surgery versus wide local excision in sebaceous carcinoma: A comparative analysis

Summary: Abstract Body: Sebaceous carcinoma (SC) is a rare skin cancer that is treated with both wide local excision (WLE) and Mohs micrographic surgery (MMS). Given its high recurrence rate and metastatic potential, we sought to compare outcomes of both treatment modalities. Using the National Cancer Database, we identified SC cases diagnosed from 2004-2017. Multivariate logistic regression and Cox proportional hazard models were used to identify factors associated with MMS utilization and 5-year mortality, respectively. Our cohort consisted of 3638 patients (MMS [n=697], WLE [n=2657]). Multivariate analysis revealed tumor location on the head/neck was associated with increased MMS use compared to WLE (OR [95% CI] = 2.94 [2.20-4.11]). Treatment at a non-academic facility (0.28 [0.22-0.35]), tumor size over 1cm (0.53 [0.36-0.80]), and TNM stage 4 (0.05 [0.01-0.18]) were associated with decreased MMS use. Independent risk factors for 5-year mortality included age over 65 years (HR [95% CI] = 2.05 [1.63-2.58]), public insurance (1.71 [1.37-2.15]), TNM stage 4 (8.22 [3.94-17.15]), treatment at a non-academic facility (1.23 [1.06-1.44]), and chemotherapy receipt (2.26 [1.23-3.99]). Female patients (0.74 [0.64-0.87]) and radiation therapy (RT) (0.68 [0.52-0.90]) had significantly decreased 5-year mortality risk. We appreciated an insignificant trend towards decreased 5-year mortality with MMS versus WLE (0.85 [0.69-1.04]). To our knowledge, this is the largest comparative analysis of SC treated with MMS or WLE in a racially diverse population. Our analysis highlights use of MMS among small, low stage tumors which likely reflects the lower recurrence rates associated with MMS over WLE. Consistent with prior literature, however, we did not find improved survival among patients treated with MMS over WLE. Finally, the association between RT and decreased mortality is novel and requires further exploration to better define the role of RT in management of SC. Maggie Zhou¹, Vijay Kodumudi², Amanda Rosenthal³, Nima Gharavi³ 1. Columbia University Vagelos College of Physicians and Surgeons, New York, NY, United States. 2. Dermatology, Tufts University, Boston, MA, United States. 3. Dermatology, Cedars-Sinai Medical Center, Los Angeles, CA, United States. Clinical Research: Interventional Research