Excision margins in high-risk malignant melanoma.
BACKGROUND: Controversy exists concerning the necessary margin of excision for cutaneous melanoma 2 mm or greater in thickness. METHODS: We conducted a randomized clinical trial comparing 1-cm and 3-cm margins. RESULTS: Of the 900 patients who were enrolled, 453 were randomly assigned to undergo surgery with a 1-cm margin of excision and 447 with a 3-cm margin of excision; the median follow-up was 60 months. A 1-cm margin of excision was associated with a significantly increased risk of locoregional recurrence. There were 168 locoregional recurrences (as first events) in the group with 1-cm margins of excision, as compared with 142 in the group with 3-cm margins (hazard ratio, 1.26; 95 percent confidence interval, 1.00 to 1.59; P=0.05). There were 128 deaths attributable to melanoma in the group with 1-cm margins, as compared with 105 in the group with 3-cm margins (hazard ratio, 1.24; 95 percent confidence interval, 0.96 to 1.61; P=0.1); overall survival was similar in the two groups (hazard ratio for death, 1.07; 95 percent confidence interval, 0.85 to 1.36; P=0.6). CONCLUSIONS: A 1-cm margin of excision for melanoma with a poor prognosis (as defined by a tumor thickness of at least 2 mm) is associated with a significantly greater risk of regional recurrence than is a 3-cm margin, but with a similar overall survival rate.