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.