Abstract 4863: A retrospective study characterizing 1714 cases of epithelioid cell melanoma
Authors: Kurnas Mohammed Al , Wu Xinxin , Mubin Anusha , Silberstein Peter T. 
Published: March 2024

Abstract
Introduction: Epithelioid cell melanoma (ECM) is a variant of cutaneous melanoma (CM) typically characterized by large malignant cells with abundant, glassy cytoplasm and large nuclei. ECMs are aggressive neoplasms and tend to have worse prognosis than other subtypes of CM with a higher risk of metastasis1. Few studies have explored the demographic features of ECM and their effects on outcomes. Using data from the National Cancer Database (NCDB), we hope to fill this gap.
Methods: This is a retrospective study of patients diagnosed with ECM(ICD-8771) between 2004 and 2020 in the National Cancer Database (NCDB) describing demographic features associated with and tumor characteristics of ECM (N = 1714). Descriptive statistics were collected for all patients with ECM and CM (N = 827623) and were compared using Pearson Chi-Square test. Overall survival was determined by the Kaplan-Meier test. Cox regression analysis was used to determine which factors led to decreased survival in ECM. All statistical tests were evaluated for a significance of P &lt; 0.05. Exclusion criteria included missing data.
Results: The cases of ECM were composed mainly of White (96%) males (58.9%), and most had private insurance as the primary payor at diagnosis (50.1%). Greater than half of ECM cases had a primary site of skin on the trunk, upper limbs, or shoulders. Cox regression analysis revealed that patients with ECM treated at integrated network cancer programs had a HR of 0.46 when compared to community centers (95% CI 0.257 - 0.831, P &lt; 0.05). Those with ECM treated at academic programs and comprehensive community cancer programs had hazard ratios of 0.41 (95% CI 0.239 - 0.701, P &lt; 0.05) and 0.49 (95% CI 0.288 - 0.845, P &lt; 0.05) respectively when compared to community programs. Only patients with ECM who had private insurance as primary payor at diagnosis had better outcomes when compared to non-insured with an HR of 0.40 (95% CI 0.225 - 0.714, P &lt; 0.05). In addition, patients with ECM were more likely to be treated at academic centers than patients with CM (55.48% vs 46.95%, P &lt; 0.05). The mean survival of patients with ECM was 12.3 months less than those with CM (141.1 months versus 153.4 months.)
Conclusion: Overall survival for patients was better at academic centers, integrated network cancer programs, and comprehensive community cancer programs when compared to community centers. In addition, only patients who had private insurance were found to have better outcomes than those who were uninsured. These findings help shed light on the effects of certain socioeconomic and factors on outcomes in ECM. We hope this study will be a launching point for further inquiry into the causal relationships these factors have on outcomes in this rare cancer.
1. (Russo A, Avitabile T et al. Iris Melanoma: Management and Prognosis. Appl Sci 2020; 10: 8766).
Citation Format: Mohammed Al Kurnas, Xinxin Wu, Anusha Mubin, Peter T. Silberstein. A retrospective study characterizing 1714 cases of epithelioid cell melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4863.