Abstract C38: Racial and ethnic disparity in presentation and outcomes in gastric adenocarcinoma: A national study
Authors: Mokdad Ali A. , Wang Sam C. , Porembka Matthew R. 
Published: March 2017

Introduction: Patient presentation, management, and outcomes in gastric cancer are variable. This study explores the impact of race and ethnicity on differences in presentation, treatment utilization, and survival among patients with gastric adenocarcinoma in a national cohort.

Methods: A total of 96,976 adult patients with gastric adenocarcinoma were identified in the National Cancer Data Base between 2006 and 2013. Facility information as well as patient demographics, tumor characteristics, and treatment modalities were compared among whites, African-Americans, Hispanics, and Asians. Risk adjusted treatment utilization, namely operative resection, systemic chemotherapy, neoadjuvant and adjuvant therapy, as well as palliative care, were examined. Overall survival was compared among ethnicities. A Cox proportional hazards model was used to identify predictors of overall survival; the reference group was white patients unless otherwise noted.

Results: The dataset included 60,647 (66%) whites, 14,126 (15%) African-Americans, 10,054 (11%) Hispanics, and 6,275 (7%) Asians. Hispanics presented at an earlier age; 24% were diagnosed before the age of 50. Hispanic patients were more likely to present with metastatic disease (39%, P &lt; 0.01) and high grade cancer (grade 3/4, 74%, P &lt; 0.01). Conversely, Asian patients were more likely to present with early stage disease (Stage I, 25%, P &lt; 0.01), and they were more likely to undergo resection (59%, adjusted odds ratio [OR], 1.2; 95% confidence interval, 1.2-1.3). Administration of neoadjuvant chemotherapy increased over the study period, 14% in 2006-2007 versus 31% in 2012-2013 (P &lt; 0.01, OR, 3.3; 95% CI, 3.0-3.5). Compared to all other ethnicities, white patients were more likely to receive neoadjuvant therapy (27%, OR, 1.4; 95% CI, 1.3-1.5) while African-American, Hispanic, and Asian patients were more likely to receive adjuvant therapy (41%, OR, 1.2; 95% CI, 1.1-1.2). Hispanic and Asian patients survived longer than whites and African-Americans; median survivals were 13, 12, 16, and 25 months, respectively (log-rank P &lt; 0.01). On multivariable analysis, significant predictors of favorable overall survival were treatment at an academic institution, younger age, Asian race, early stage, high income, private insurance, and multimodality treatment.

Conclusions: Race and ethnicity were associated with tumor presentation, treatment utilization, and survival. Disparity in survival among racial and ethnic groups was not completely accounted for by differences in tumor features and treatment.

Citation Format: Ali A. Mokdad, Sam C. Wang, Matthew R. Porembka. Racial and ethnic disparity in presentation and outcomes in gastric adenocarcinoma: A national study. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr C38.