Surgical excision margin for primary acral melanoma.

BACKGROUND AND OBJECTIVES: This study aimed to evaluate treatment outcomes of acral melanoma (AM) based on the excision margin. METHODS: A retrospective cohort study was conducted for patients with primary AM, analyzing recurrence rates, local and in-transit recurrence-free survival (LITRFS), disease-free survival (DFS), and melanoma-specific survival (MSS). RESULTS: Data from 129 patients of AM were analyzed. In 53 patients with thin AM (thickness ≤1 mm), neither recurrence nor mortality occurred regardless of whether the excision margin was >1 cm or not. Seventy-six patients had thick AM (thickness >1 mm), including 36 treated with a <2 cm excision margin and 40 with a 2 cm margin. Multivariate analyses revealed that a 2 cm margin was associated with a reduced rate of local recurrence (HR, 0.120; P-value = 0.023) and LITR (HR, 0.187; P-value = 0.013) compared with a <2 cm margin. DFS and MSS did not differ between the two groups. CONCLUSIONS: Thin AM were successfully treated with a 1 cm excision margin. For thick AM, a 2 cm excision margin provided improved local control, compared with a <2 cm margin; however, this benefit did not translate into a survival gain. J. Surg. Oncol. 2016;114:933-939. © 2016 Wiley Periodicals, Inc.