Association of Treatment Inequity and Ancestry with Pancreatic Ductal Adenocarcinoma Survival

Importance: Pancreatic ductal adenocarcinoma (PDAC) has a higher incidence and worse outcomes among black patients than white patients, potentially owing to a combination of socioeconomic, biological, and treatment differences. The role that these differences play remains unknown. Objectives: To determine the level of survival disparity between black and white patients in a modern PDAC cohort and whether treatment inequity is associated with such a disparity. Design, Setting, and Participants: This cohort study used data on 278936 patients with PDAC with database-defined race from the National Cancer Database from January 1, 2004, to December 31, 2015. The median follow-up for censored patients was 24 months. The National Cancer Database, comprising academic and community facilities, includes about 70% of new cancer diagnoses in the United States. Race-stratified receipt of therapy was the primary variable of interest. Multivariable analyses included additional demographic and clinical parameters. Data analysis was initially completed on November 30, 2018, and revised data analysis was completed on June 27, 2019. Main Outcomes and Measures: Overall survival was the primary outcome, analyzed with Kaplan-Meier and multivariable Cox proportional hazards regression modeling. Results: The cohort included 278936 patients (137121 women and 141815 men; mean [SD] age, 68.72 [11.57] years); after excluding patients from other racial categories, 243820 of the 278936 patients (87.4%) were white and 35116 of the 278936 patients (12.6%) were black. Unadjusted median overall survival was longer for white patients than for black patients (6.6 vs 6.0 months; P <.001). Black patients presented at younger ages than white patients (15819 of 35116 [45.0%] vs 83846 of 243820 [34.4%] younger than 65 years; P <.001) and with more advanced disease (20853 of 31600 [66.0%] vs 135317 of 220224 [61.4%] with stage III or IV disease; P <.001). Black patients received fewer surgical procedures than white patients for potentially resectable stage II disease (4226 of 8097 [52.2%] vs 39214 of 65124 [60.2%]; P <.001) and slightly less chemotherapy for advanced disease (2756 of 4067 [67.8%] vs 17296 of 25227 [68.6%] for stage III disease [P =.001]; 8208 of 16104 [51.0%] vs 58603 of 105616 [55.5%] for stage IV disease [P <.001]). Decreased survival for black patients persisted in multivariable modeling controlled for sociodemographic parameters (hazard ratio, 1.04 [95% CI, 1.02-1.05]). Conversely, modeling that controlled specifically for clinical parameters such as disease stage and treatment revealed a modest survival advantage (hazard ratio, 0.94 [95% CI, 0.93-0.96]) among black patients. Resection was the factor most strongly associated with overall survival (hazard ratio, 0.39 [95% CI, 0.38-0.39]). Conclusions and Relevance: Black patients with PDAC present at younger ages and with more advanced disease than white patients, suggesting that differences in tumor biology may exist. Black patients receive less treatment stage for stage and fewer surgical procedures for resectable cancers than white patients; these findings may be only partly associated with socioeconomic differences. When disease stage and treatment were controlled for, black patients had no decrease in survival.