Demer, Addison M.

BACKGROUND Current consensus guidelines have discouraged the use of sub-0.5-cm (in situ) and sub-1-cm (invasive) margins when performing Mohs micrographic surgery (Mohs) for melanoma, with minimal evidence to guide this recommendation. OBJECTIVE To compare melanoma local recurrence rates after Mohs based on initial margin size. MATERIALS AND METHODS A systematic review and meta-analysis was conducted with search terms including Mohs micrographic surgery, surgical margin, recurrent disease, and melanoma. RESULTS Forty-three studies were included. The 5- to 10-mm margin category had a statistically significant lower local recurrence compared with 1- to 5-mm and 5-mm categories. Recurrence for 1- to 5-mm, 5-mm, 5- to 10-mm, and 10-mm categories were 2.3% (CI 0.8–3.5, p < .001), 1.4% (CI 0.6–2.2, p < .001), 0.3% (CI 0.2–0.5, p < .001), and 6.1% (CI -6.7 - 18.8, p = .349), respectively. Number of stages for 1 to 5, 5, 5 to 10, and 10-mm categories were 1.8, 1.8, 1.6, and 1.6, respectively. There was no statistically significant difference between the groups (p = .694). CONCLUSION Five- to 10-mm margins were associated with the lowest local recurrence rates. A 5- to 10-mm initial margin should be considered where other factors (tumor characteristics, anatomical or functional considerations) allow.