Association between excision margins and local recurrence in 1407 patients with primary in situ melanomas

Abstract

BackgroundReliable evidence to guide the management of melanoma in situ (MIS) and minimize the risk of recurrence is lacking.ObjectiveTo identify clinicopathological predictors of local recurrence (LR) in patients with MIS and evaluate long-term outcomes according to pathological excision margins.MethodsA case-control study of patients with MIS treated at a large Australian melanoma treatment center from January 2008 to December 2012 was undertaken. Clinicopathological characteristics of patients who developed LR and those who did not were compared.ResultsLR developed in 34 of 1407 patients with MIS (2.5%). Median time to LR was 20 months. The primary lesion was removed with pathological margins <4 mm (P < .001) in 67.6 % of patients with LR. Four patients died of metastatic melanoma following LR. Comparing patients with pathological margins <4 mm and ≥4 mm, the former were older (>60y, P < .001), more frequently had MIS on the head or neck (P < .001), had a greater LR rate (P < .001), and had a higher mortality from all causes (P < .001).LimitationsRetrospective, single-institution study.ConclusionsPathological margins of ≥4 mm should be considered for patients with MIS who are treated with standard surgical excision and assessed by examining serial slices taken from the formalin-fixed, paraffin-embedded specimen.