Prognosis of acral melanoma: a series of 281 patients.

BACKGROUND: Acral melanoma (AM) is an unusual malignancy with poor survival. This study defines a cohort of patients, treated at a single institution, and the factors associated with survival and comparison with nonacral cutaneous melanoma (NACM).
METHODS: All patients with AM presenting from 1995 to 2010 were identified from a prospectively maintained database. Analysis of clinicopathologic features of AM associated with disease-specific survival (DSS) was performed. A stratified, stage-matched survival analysis compared the outcome of 281 acral to 843 extremity NACM patients.
RESULTS: A total of 281 AM patients (170 volar, 111 subungual) were identified. Pathologic stage (p < 0.001), ulceration (p < 0.001), Breslow thickness (p < 0.001), and a positive sentinel lymph node (p < 0.001) were found to be poor prognostic indicators associated with DSS. In stage-matched analysis, AM had a worse DSS compared with NACM (hazard ratio 1.8; 95 % CI 1.2-2.7; p < 0.01).
CONCLUSIONS: This study represents the largest, single-institution series describing the characteristics and outcomes of AM. AM tumors exhibit aggressive histopathologic features associated with a poorer survival outcome. AM patients have an inferior survival than extremity NACM when matched for stage, perhaps reflecting inherent alterations in tumor biology. This warrants further investigation into the differences between acral and cutaneous melanoma.