Acral lentiginous melanoma: Population-based analysis of incidence and survival in United States from 1993 to 2013.

Abstract

e22108 Background: Acral Lentiginous melanoma (ALM) is a rare form of cutaneous melanoma with aggressive nature. This study investigates the incidence and survival patterns in patients diagnosed with ALM in USA from 1993-2013 using data from the Surveillance, Epidemiology, and End Results (SEER) Registry. Methods: The 18 cancer registries of SEER program were used to identify patients diagnosed with ALM according to international classification of diseases for oncology (ICDO-3) codes. Age adjusted incidence rates in addition to 5 and 10-year relative survival rates were calculated. Results: 2189 patients were included in this retrospective study.The age-adjusted incidence rate of ALM was 2.11 per million person-years.Hispanic whites had highest incidence rates of ALM among all racial subgroups ( 2.58, p = 0.005). Incidence of ALM was higher between 2003-2013 compared to 1993-2003 (2.3 vs 1.9).Median age at diagnosis was 61.68 years. 53.9 % were female. Our study population was dominated by Non-Hispanic Whites (69.2%) followed by Hispanic Whites (13.5%), Blacks (8.2%), Asians or Pacific Islanders (7.3%) and other races (1.8%). stage III was the most frequent (24.7%) followed by stage I (20.9%). In terms of tumor thickness, 43.2 % presented with T3 thickness at the time of diagnosis. The ALM 5 - and 10-year survival rates were highest in age < 40, females, T1, non ulcerated, lymph node negative lesions ( p < 0.05). Among racial subgroups, non Hispanic whites had highest survival rates (83 vs 74 % ). Asian/Pacific Islanders (75.1%vs 49.8%) had lowest survival rates followed Hispanic whites ( 76.4 % vs 63.9 ) and Blacks (74.7 vs 71.5 %) ( p = 0.19). Conclusions: ALM is rare subtype of cutaneous melanoma with increased incidence in people of color. Patients present with increased tumor thickness and advanced stage at the time of diagnosis. Poor survival rates are seen among Asian/Pacific Islanders and Hispanic whites.