Margin of resection in the management of primary melanoma.

In the last 20 years, it has become evident that the continued use of 4 to 5 cm margins of resection around a primary melanoma is not justified. A prospective randomized trial by the World Health Organization (WHO) Melanoma Group showed that for melanomas up to 2 mm thick, a 1 cm margin provides local control similar to that observed after a 3 cm margin. Another prospective randomized trial by the Melanoma Intergroup Committee in the United States concluded that for melanomas 1 to 4 mm in thickness, a 2 cm margin of resection provides local control that is as good as a 4 cm margin. For melanomas thicker than 4 mm, the current evidence suggests that a 2 cm margin is adequate, the chief manifestation of recurrence for these thick lesions being hematogenous and lymphogenous spread. The adoption of the narrower surgical margins suggested above should reduce the morbidity caused by the radical margins of the past without compromising local control of the disease.