Abstract Number: 219

Excisional margin for melanoma-in-situ: Is 5 mm not enough?

Cong Sun, Jim Muir, Lim Alvin

Meeting: 2023 Dermcoll

Session Information

Date: -

Session Title: Surgery for the general dermatologist

Session Time: -

Background: The incidence of melanoma has increased over the past 3 decades much of this due to 9.5% annual increase in the diagnosis of melanoma-in-situ (MIS). Previous Australian guidelines endorsed a 5 mm excisional margin in 2008. In 2014, based on data derived from studies using Mohs surgery the recommended margin was increased to 5–10 mm. More recently, again based on results from MMS even wider margins have been advocated. Has the increased morbidity and financial burden of more aggressive surgery improved patient outcomes? To date increased margins have shown no survival benefit and equivocal results in terms of reduced recurrence._x000D_
Objectives: This study aims to investigate the recurrence rate of MIS excised with 5 mm margin._x000D_
Method: A retrospective cohort study involving all MIS excised with 5 mm margin between January 1 2011 and December 31 2012 in a single dermatology practice was conducted. Histopathology reports for identified lesions were retrieved through the Sullivan Nicolaides database. Patient records were used to identify recurrence._x000D_
Results: A total of 326 melanoma-in-situ were identified and 16 were excluded due to missing data. 27% (n = 87) of the lesion were of lentigo maligna subtype with the recurrence rate of 1.1% (n = 1). 0.9% (n = 3) of all lesions recurred within 5 years of the initial wide-local excision; the reported rate of recurrence for MIS in the MMS studies with 6–12 mm margins has been between 0.26% and 1.1%. Gender, lesion location, diameter and the subtype of MIS did not have a significant affect on recurrence rate. There was no patient mortality for the duration of this study._x000D_
Conclusions: Excision of MIS with 5 mm margins is a highly effective treatment strategy. Given the increased morbidity and financial burden of increased surgical margins our figures do not support going beyond 5 mm margins for MIS._x000D_