Racial and ethnic differences in melanoma survival in the era of immunotherapy.

Abstract

e21588 Background: Since the introduction of immune checkpoint inhibitors (ICIs) in 2011, mortality in advanced melanoma has been decreasing steadily. Little is known about how sociodemographic factors affect survival in the post-ICI era. Methods: This was a retrospective cohort study of 15,676 patients with advanced melanoma (unresectable Stage III and Stage IV disease) included in the SEER database from 2000 to 2022. Descriptive analyses were conducted and stratified by racial/ethnic group - Non-Hispanic White (NHW), Hispanic (H), Non-Hispanic Black (NHB), and Other. Groups were compared across demographic variables using Fisher’s exact tests. Survival functions were compared using the log-rank test. Cox proportional hazards regression models were then fitted to estimate hazard ratios (HRs) for each group compared with NHWs, with and without adjustment for demographic variables (age, sex, year of diagnosis, marital status, income level, and urbanicity). Extent to which each variable contributed to survival prediction at different follow-up times was quantified by change in Brier score following permutation, with larger increases indicating greater variable importance. Survival analyses were repeated in subgroups diagnosed during 2000–2011 and 2012–2022, respectively. Results: There were 5,026 and 10,650 patients respectively in the pre-ICI (2000-2011) and post-ICI (2012-2022) groups. 14,135 (90.2%) were NHW, 982 (6.3%) H, 240 (1.5%) NHB and 319 (2%) Other. Younger age, female sex, higher income levels and being married consistently conferred a survival benefit (p < 0.05). There was no significant difference in the adjusted overall survival (OS) by racial/ethnic group in the overall time period (2000-2022) (p = 0.288), or in the pre-ICI group (p = 0.666). However, the post-ICI group showed a significant difference in adjusted OS (p = 0.008) with decreased survival in H and NHB patients compared to NHW. Variable importance analyses indicated that age and marital status contributed more to survival prediction than race in both periods. Conclusions: Disparities in survival by racial/ethnic groups after the advent of immunotherapy may indicate barriers in access to treatment. However, marital status played a more influential role in survival prediction than race in the variable importance analysis, highlighting the potential impact of social and demographic factors. Further research is needed to identify and address the underlying mechanisms behind these disparities. OS by racial/ethnic group (2012-2022). Unadjusted OS Adjusted OS HR P-value(compared with ref) Overall P-value HR P-value(compared with ref) Overall P-value NHW Ref Ref Ref Ref Ref Ref H 1.04 (0.94-1.14) 0.481 0.408 1.15 (1.04-1.27) *0.007 *0.08 NHB 1.17 (0.97-1.43) 0.107 0.408 1.23 (1.01-1.49) *0.043 *0.08 Other 1.01 (0.85-1.21) 0.886 0.408 1.12 (0.94-1.34) 0.194 *0.08 *represents statistical significance at p<0.05.