Staging comparison between merkel cell carcinoma and melanoma in black patients

Summary: Abstract Body: Merkel cell carcinoma (MCC) is a rare but highly aggressive skin cancer, with several studies showing an overall higher mortality rate than melanoma. While melanoma has a five-year survival rate exceeding 90% when detected early, MCC's five-year survival rate is significantly lower, with localized cases at 75% and distant metastases at 24%. However, this data across different ethnic groups, especially among black patients, remains underexplored. Therefore, the purpose of this study is to compare the staging between MCC and melanoma in black patients. This retrospective cohort study included black patients diagnosed with MCC and melanoma from 2000 through 2021 in the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program. Variables collected included sex, age, and staging. Two-tailed chi-square was used to assess the association between categorical variables. A proportional relative risk ratio was conducted to determine associations between diagnosis and staging. P-values <0.05 were considered significant. A total of 3,853 cases were identified, of which 315 were diagnosed as MCC. No sex predilection was found in MCC patients (48.2% female), whereas there were more females in the melanoma cohort (56.3%, p<0.001). Patients with MCC were older than melanoma patients with higher percentage of patients aged ≥ 70 years (54.9% and 47.1%, respectively; p<0.001). MCC patients were more likely to present with advanced staging than melanoma patients (i.e. Staging: regional and distant; 141 [52.5%] MCC patients vs 1,134 [42.2%] melanoma patients; RR 1.26; [1.12-1.42]; p<0.001). In comparison to black patients with melanoma, black patients with MCC were diagnosed at older age and with more advanced disease stage, suggesting that MCC may not only be more aggressive than melanoma in black patients but also its diagnosis may be delayed in comparison to black patients with melanoma. This disparity underscores the critical importance of early detection and treatment for MCC. Luis J. Borda¹, H. William Higgins 2nd² 1. Dermatology, UPMC, Pittsburgh, PA, United States. 2. Dermatology, Penn Medicine, Philadelphia, PA, United States. Clinical Research: Epidemiology and Observational Research