Original articleAcral lentiginous melanoma: Who benefits from sentinel lymph node biopsy?

BackgroundThere are significant clinicopathological, genetic, and biological differences between acral lentiginous melanoma (ALM) and other types of melanoma.ObjectiveWe sought to investigate the use of sentinel lymph node (SLN) biopsy for patients with ALM.MethodsThis was a retrospective review of 116 patients with primary ALM. Melanoma-specific and disease-free survival were estimated using the Kaplan-Meier method, together with multivariate analyses using the Cox proportional hazards regression model.ResultsAll patients were Japanese (48 male and 68 female). Metastases in SLN were noted in 13 of 84 patients who underwent SLN biopsy. No patients with thin ALM (≤1 mm) and only 2 patients with nonulcerated ALM had tumor-positive SLN. Patients with positive SLN had significantly shorter melanoma-specific survival (5-year survival rate, 37.5% vs 84.3%; P < .0001) and disease-free survival (5-year survival, 37.5% vs 77.9%; P = .0024). Among patients with thick (>1 mm) ALM, the influence of SLN positivity on melanoma-specific survival was increased (5-year survival, 22.7% vs 80.8%; P = .0005).LimitationsThis was a retrospective study and had a small sample size.ConclusionsSLN biopsy should be considered for patients with thick or ulcerated ALM. For patients with thin or nonulcerated ones, it may be of limited importance.