Worsening trends in disparities of stage of presentation in acral lentiginous melanoma: A national cohort study

Summary: Abstract Body: Acral lentiginous melanoma (ALM), the most common histology seen in Black patients, presents with more advanced disease compared to other melanoma microscopic subtypes. The reasons are likely multifactorial and may include decreased awareness of this subtype by both patients and clinicians. We sought to study whether there has been improvement in early detection and presentation stage for ALM over time. This retrospective cohort study used the National Cancer Database to identify melanoma cases from 2010 to 2021, excluding those without staging information. Joinpoint regression was used to determine annual percent change (APC) in the proportion of patients with ALM vs non-ALM who presented with metastatic (AJCC stage III or IV) disease, and, in an independent analysis, the proportion with tumors thicker than 1 mm (T2 or greater). Of 424,903 total cutaneous melanoma patients, 6,543 (1.5%) had ALM and the remaining 418,360 (98.5%) had non-ALM. The median overall age was 64 years; 97.7% of patients were White. The percentage of ALM patients presenting with metastatic disease (Stage III/IV) increased over the study period (24.8% in 2010 to 33.9% in 2021, APC 0.67, p<0.001), as did the proportion of patients with T2 disease or greater (64.2% to 70.5%, APC 0.51, p=0.003). By comparison, for non-ALM patients over the same time period, there was a smaller increase in the proportion of patients with Stage III/IV (12.4% to 15.9%, APC 0.38, p=0.001) or with T2 or greater disease (41.5% to 45.1%, APC 0.28, p=0.001). ALM trends towards worse disease in more recent years seem to outpace overall melanoma trends. These findings underscore the need for effective methods for increasing awareness of and implementation of screening for ALM. Neha Shafique¹, Gracia M. Vargas¹, Mohammad S. Farooq¹, Michael E. Ming², John T. Miura¹, Giorgos C. Karakousis¹ 1. Surgery, Penn Medicine, Philadelphia, PA, United States. 2. Dermatology, Penn Medicine, Philadelphia, PA, United States. Minoritized Populations and Health Disparities Research