Racial and ethnic differences in the clinical presentation and outcomes of acral lentiginous melanoma

Funding sources: none. Conflicts of interest: The authors declare they have no conflicts of interest. Dear Editor, Acral lentiginous melanoma (ALM) is one of the four major subtypes of cutaneous melanoma (CM) and occurs on the palms, soles and nailbeds. CM has often been associated with sun exposure,1 but ALM occurs in generally unexposed anatomical sites. While the aetiology remains largely unknown, melanocytic naevi, trauma, pressure, ultraviolet radiation and gene mutations have been postulated in ALM development.2 ALM represents about 2–3% of all melanomas but represents a much higher proportion of CM in darker‐skinned individuals.3 Racial and ethnic differences have been shown in CM.4 Due to its rarity, few studies have closely examined racial differences in ALM.3 Our study aims to investigate racial and ethnic differences in the clinical presentation and outcomes in patients with ALM. We searched the US National Cancer Database (NCDB) for patients with ALM of the upper and lower extremities from 2004 to 2016. Only cases that were histologically confirmed to be ALM and where ALM was the primary malignancy were included. We performed Pearson’s χ2‐test and Kruskal–Wallis test, Kaplan–Meier curves, log‐rank tests and Cox proportional‐hazards models to analyse the characteristics and survival outcomes of the 4139 cases that met our criteria. Race and ethnicity were categorized as white (not Hispanic), black (not Hispanic), Asian (not Hispanic), Hispanic and other/unknown. The study included no patient identifiers and was exempt from institutional review board approval.