Socioeconomic Mediation of Racial Segregation in Pancreatic Cancer Treatment and Outcome Disparities

Objective: To understand the mediating effect of socioeconomic factors on the association between residential segregation and racial disparities in pancreatic cancer (PC). Background: Black patients with PC present at a later stage and have worse mortality than White patients. These disparities have been explained by the level of residential segregation. Methods: Data were obtained from Surveillance, Epidemiology, and End-Results (SEER) and included all Black and White patients who were diagnosed with PC between 2005 and 2015. The primary exposure variable was the Index of Dissimilarity, a validated measure of segregation. County-level socioeconomic variables from the US Census were assessed as mediators. The primary outcomes were advanced stage at diagnosis, surgical resection for localized disease, and overall mortality. Generalized structural equation modeling was used to assess the mediation of each of the socioeconomic variables. Results: Black patients in the highest levels of segregation saw a 12% increased risk [relative risk=1.12; 95% confidence interval (CI): 1.08, 1.15] of presenting at an advanced stage, 11% decreased likelihood of undergoing surgery (relative risk=0.89; 95% CI: 0.83, 0.94), and 8% increased hazards of death (hazard ratio=1.08; 95% CI: 1.03, 1.14) compared with White patients in the lowest levels. The Black share of the population, insurance status, and income inequality mediated 58% of the total effect on the advanced stage. Poverty and Black income immobility mediated 51% of the total effect on surgical resection. Poverty and Black income immobility mediated 50% of the total effect on overall survival. Conclusions: These socioeconomic factors serve as intervention points for legislators to address the social determinants inherent to the structural racism that mediate poor outcomes for Black patients.