Acral lentiginous melanoma: who benefits from sentinel lymph node biopsy?

There are significant clinicopathological, genetic, and biological differences between acral lentiginous melanoma (ALM) and other types of melanoma.

We sought to investigate the use of sentinel lymph node (SLN) biopsy for patients with ALM.

This 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.

All 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).

This was a retrospective study and had a small sample size.

SLN biopsy should be considered for patients with thick or ulcerated ALM. For patients with thin or nonulcerated ones, it may be of limited importance.