Racial/Ethnic Disparities in Cardia versus Non-Cardia Gastric Cancer Incidence and Survival in the United States

Abstract

Purpose: Gastric cancer is a leading cause of cancer-related deaths worldwide. Recent studies have reported different incidence and survival trends of cardia (CAR) vs. non-cardia gastric cancer (NCAR). While racial/ethnic differences in gastric cancer are known, it is unclear whether these disparities are similar among both CAR and NCAR. The objective of this study is to evaluate racial disparities in incidence and long-term survival of CAR and NCAR. Methods: Using the Surveillance, Epidemiology, and End Results 1992-2009 dataset, race-specific incidence of CAR vs. NCAR was evaluated with stratification by sex, year of diagnosis, tumor stage, and geography. Long-term survival was evaluated using Kaplan-Meier methods, log rank testing, and multivariate Cox proportional hazards models. Results: Overall, men had significantly higher incidence rates than women among both CAR and NCAR. While the incidence of CAR and NCAR were similar among men, the incidence of NCAR among women was more than double that of CAR (2.5 vs. 0.9 per 100,000/year; p<0.001). The significantly higher incidence of NCAR compared to CAR was seen among all race groups with the exception of whites, where the incidence of NCAR and CAR were similar (4.9 vs. 5.0 per 100,000/year; p=0.17). Among patients with CAR, whites had the highest incidence (5.0 per 100,000/year), whereas Asians had the highest incidence among NCAR patients (15.3 per 100,000/year). Overall, 5-year survival for CAR was poorer than NCAR (18.7% vs. 27.2%; p<0.001). The poorer survival of CAR compared to NCAR was seen among both males and females, and among all race groups. However, Asians had the highest 5-year survival compared to all other race groups for both CAR (33.6% vs. 25.3% [white] vs. 25.6% [black] vs. 26.7% [Hispanic]; p<0.001) and NCAR (23.5% vs. 18.4% vs. 17.1% vs. 17.8%, respectively; p<0.001). Multivariate Cox proportional hazards models inclusive of sex, age, race, tumor stage, treatment, year of diagnosis, and geography demonstrated poorer survival in CAR compared to NCAR (HR 1.08; 95% CI 1.05-1.11; p<0.001). Compared to whites, poorer survival was seen among blacks (HR 1.07; 95% CI 1.03-1.11; p<0.001), and higher survival was seen among Asians (HR 0.84; 95% CI 0.81-0.87; p<0.001). Conclusion: Sex-specific and race-specific disparities in CAR and NCAR incidence and survival exist. Women and minorities have significantly higher incidence of NCAR compared to CAR. Whites and Asians had the highest incidence of CAR and NCAR, respectively. In the multivariate Cox model, Asian race was predictive of improved survival, whereas black race predicted poorer survival. Compared to NCAR, CAR was associated with poorer survival.