Acral Melanomas Represent a Rare but Potentially Aggressive Form of Melanoma

Hensin Tsao, MD, PhD

Unlike other more common forms of melanoma, AMs occur in all ethnic groups.

Acral melanoma (AM) is the least common of four subtypes of cutaneous melanoma (approximately 2% to 10% of all melanoma cases). It is however, the most common cutaneous melanoma in dark-skinned patients. To characterize factors associated with the poor survival outcomes in patients with AM, investigators at a single cancer center compared 281 patients with AM and 843 patients with other nonacral cutaneous melanomas (NACMs) of the extremities (14% and 0% nonwhite, respectively).

The 5-year survival rate was 70% in AM patients and 83% in NACM patients. Breslow thickness, Clark level, positive margin status, sentinel lymph node (SLN) positivity, higher pathologic stage, and ulceration were all significantly associated with reduced disease-specific survival (DSS). To examine whether delayed diagnosis was responsible for worse survival in AM patients, AM patients were matched by stage with extremity NACM patients. Median Breslow thickness and positive SLN were nearly identical in the matched groups, but AM was associated with worse DSS (hazard ratio 1.8; 95% CI 1.2–2.7; P<0.01).

Citation(s):

Bello DM et al. Prognosis of acral melanoma: A series of 281 patients. Ann Surg Oncol 2013 Oct; 20:3618.