Does sentinel lymph node status have prognostic significance in patients with acral lentiginous melanoma?

Abstract

The prognostic benefit of sentinel lymph node biopsy (SLNB) and factors predictive of survival specifically in patients with acral lentiginous melanoma (ALM) are unknown. The SEER database was queried for ALM cases that underwent SLNB from 1998 to 2013. Clinicopathological factors were correlated with SLN status, overall survival (OS), and melanoma-specific survival (MSS). Median age for the 753 ALM study patients was 65 years, and 48.2% were male. Median thickness was 2 mm with 38.1% of cases having ulceration. SLN metastases were detected in 194 of 753 cases (25.7%). Multivariable analysis showed that thickness, Clark level IV-V, and ulceration significantly predicted for SLN metastasis (P < 0.05). For patients with positive SLN, 5-year OS and MSS were significantly worse at 48.1% and 58.9%, respectively, compared with 78.7% and 88.5%, respectively, for patients with negative SLN (P < 0.0001). On multivariable analyses, older age, male gender, increasing thickness, ulceration, and a positive SLN significantly predicted for worse OS and MSS (all P < 0.05). This study confirms the important role of SLNB in ALM. SLN metastases are seen in 25.7% of ALM cases, providing significant prognostic information. In addition, thickness, ulceration status, and SLNB status significantly predict survival in patients with ALM.