Pancreatic Cancer Treatment and Tumor Biology Differences by Race

A new study explored outcomes in pancreatic ductal adenocarcinoma by race, questioning whether treatment inequity, tumor biology, or both contribute to poorer outcomes among black patients than white patients.

“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 researchers explained. “The role that these differences play remains unknown.”

The study included data on pancreatic ductal adenocarcinoma patients collected from the National Cancer Database, which houses about 70% of all new cancer diagnoses in the U.S., spanning Jan. 1, 2004, through Dec. 31, 2015. The main interest to the study authors was therapy receipt stratified by race, with additional demographic and clinical parameters taken into account in multivariable analyses. Patients who were of a race other than white or black were excluded from analyses. Data were analyzed on Nov. 30, 2018, with a revised analysis completed on June 27, 2019. The main outcome measure was overall survival, which was evaluated with Kaplan-Meier and multivariable Cox proportional hazards regression modeling.

Final analysis included 278,936 patients (137,121 women and 141,815 men) with a mean (SD) age of 68.72 (11.57) years: 243,820 patients (87.4%) were white, and 35,116 patients (12.6%) were black. In unadjusted analyses, median overall survival was longer for white patients than black patients (6.6 months vs. 6.0 months; P<0.001). Black patients were more likely to present at an age younger than 65 years than white patients (15,819/35,116 [45.0%] vs. 83,846/243,820 [34.4%]; P<0.001), and they were more likely to present with more advanced (stage III or IV) disease (20,853/31,600 [66.0%] vs. 135,317/220,224 [61.4%]; P<0.001).

Treatment differed between the groups as well. Black patients with potentially resectable stage II disease, compared to their white counterparts, were less likely to receive operative treatment (4,226/8,097 [52.2%] vs. 39,214/65,124 [60.2%]; P<0.001) and slightly less likely to receive chemotherapy for advanced disease (stage III, 2,756/4,067 [67.8%] vs. 17,296/25,227 [68.6%]; P=0.001; stage IV, 8,208/16,104 [51.0%] vs. 58,603/105,616 [55.5%]; P<0.001).

Upon multivariable analyses controlling for sociodemographic parameters, black patients still had lower survival odds than white patients (hazard ratio [HR]=1.04; 95% confidence interval [CI], 1.02-1.05). When controlling for specific clinical parameters like disease stage and treatment, black patients had a higher survival rate (HR=0.94; 95% CI, 0.93-0.96). Resection was most significantly correlated with overall survival (HR=0.39; 95% CI, 0.38-0.39).

The study’s results were published in JAMA Surgery.

The authors summarized their findings with, “Black patients with [pancreatic ductal adenocarcinoma cancer] 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.”