Acral lentiginous melanoma: incidence and survival patterns in the United States, 1986-2005.

OBJECTIVE: To examine incidence and survival patterns of acral lentiginous melanoma (ALM) in the United States.

DESIGN: Population-based registry study. We used the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute to evaluate data from 17 population-based cancer registries from 1986 to 2005.

PARTICIPANTS: A total 1413 subjects with histologically confirmed cases of ALM. Main Outcome Measure Incidence and survival patterns of patients with ALM.

RESULTS: The age-adjusted incidence rate of ALM overall was 1.8 per million person-years. The proportion of ALM among all melanoma subtypes was greatest in blacks (36%). Acral lentiginous melanoma had 5- and 10-year melanoma-specific survival rates of 80.3% and 67.5%, respectively, which were less than those for all cutaneous malignant melanomas overall (91.3% and 87.5%, respectively; P < .001). The ALM 5- and 10-year melanoma-specific survival rates were highest in non-Hispanic whites (82.6% and 69.4%), intermediate in blacks (77.2% and 71.5%), and lowest in Hispanic whites (72.8% and 57.3%) and Asian/Pacific Islanders (70.2% and 54.1%). Acral lentiginous melanoma thickness and stage correlated with survival according to sex and in the different racial groups.

CONCLUSIONS: Population-based data showed that ALM is a rare melanoma subtype, although its proportion among all melanomas is higher in people of color. It is associated with a worse prognosis than cutaneous malignant melanoma overall. Hispanic whites and Asian/Pacific Islanders have worse survival rates than other groups, and factors such as increased tumor thickness and more advanced stage at presentation are the most likely explanations.