Low-Risk Melanoma Lesions Can Be Excised Safely with 5 mm Margin

Sun C, Lim A, De’Ambrosis B, et al. Recurrence Rate of Small Melanoma in Situ on Low-Risk Sites Excised With 5-mm Excisional Margin. JAMA Dermatol. 2024;160(8)874–877.

Zitelli JA. Recurrence Rate of Melanoma in Situ Excised with a 5-mm Excisional Margin. JAMA Dermatol. 2024;160(8)803–804.

Melanoma in situ (MIS) is treated with lesion excision at a recommended margin of 5–10 mm. Sun and coauthors reported MIS recurrence rates over 5 years of follow-up following excision with a confirmed 5 mm margin (n = 351 lesions in 292 patients).

Lesions were primarily located on the trunk and extremities and lesion length and width were 10 mm or less. Recurrence occurred in 0.9% of patients and no metastases were diagnosed.

The authors noted that these melanomas were small and occurred in low-risk body sites. They concluded that low-risk lesions could be safely excised with a 5 mm margin.

In the editorial that accompanied the article, Zitelli stressed that the main strength of this study is the 5-year follow-up of the included patients. However, these results may not provide data to support use of 5 mm margins in higher risk lesions. Five mm margins may not be safe for patients with MIS lesions located in areas such as the head and neck. Lesions larger than 10 mm in length and/or width may carry a higher risk of recurrence, and the 5 mm margin would be too small for these lesions. Proper choice of margin width will depend on lesion location, lesion size, and risk assessment.