Unique prognostic factors in acral lentiginous melanoma

Background This study was performed to identify clinicopathologic factors associated with survival in acral lentiginous melanoma. Methods A post hoc analysis of a prospective clinical trial and local database was performed in all patients with acral lentiginous melanomas. Multivariate analyses of factors associated with a tumor-positive sentinel lymph node (SLN) biopsy, disease-free survival (DFS), overall survival (OS), and local and in-transit recurrence-free survival (LITRFS) were performed. Kaplan–Meier survival analyses were performed. Results Eighty-five patients were identified. Age younger than 59 years and Breslow thickness (BT) of 2.0 mm or greater were independent risk factors for a positive SLN. SLN status was the only independent risk factor for DFS and LITRFS on multivariate analysis. A BT of 2.0 mm or greater was the only independent risk factor for OS. SLN status distinguished differences in DFS, OS, and LITRFS on Kaplan–Meier analysis. Conclusions SLN status is the dominant factor for recurrence and survival in acral lentiginous melanoma. BT and ulceration are less important in this histologic subtype.