Racial differences in tumor biology and treatment of gastric cancer in the United States.

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174 Background: Racial disparities for gastric cancer are often identified in the literature. Although patients in Asia consistently demonstrate a survival benefit compared to those in the West, Asian patients in the US still retain this advantage, which suggests that tumor biology may be a major factor. The goal of our study is to identify racial differences in patient demographics, tumor biology and treatment for gastric cancer in the United States. Methods: The National Cancer Database was queried from 2006-2016 for patients with a diagnosis of gastric adenocarcinoma. Patient demographics, tumor characteristics, and treatment patterns were compared by patient ethnicity (White, Black, Hispanic, and Asian) with Kruskal-Wallis test and Pearson’s chi-squared test. Kaplan-Meier survival curves used to assess overall survival, and cox regression used to identify independent prognostic factors for survival. Results: 116,717 patients with gastric cancer identified; 78,066 were White, 17,486 were Black, 8,494 were Asian, and 12,671 were Hispanic. White patients were most likely to be older than 70 and have proximal tumors, and least likely to have diffuse type adenocarcinoma. Hispanic and Black patients were most likely to present with metastases. Asian patients were most likely to receive surgery and least likely to receive chemotherapy or radiotherapy. Stage for stage, Asians had the longest median survival, followed by Hispanic, Black, and White patients. Prognostic factors associated with a survival benefit include Asian ethnicity (HR 0.72, 95% CI 0.68-0.74), Hispanic ethnicity (HR 0.76, 95% CI 0.73-0.79), Black ethnicity (HR 0.95, 95% CI 0.93-0.98), private insurance (HR 0.91, 95% CI 0.87-0.96), higher income (HR 0.85, 95% CI 0.82-0.88), treatment at academic center (HR 0.87, 95% CI 0.83-0.91), higher-volume centers (HR 0.90, 95% CI 0.87-0.93), receiving surgery (HR 0.42, 95% CI 0.41-0.43), chemotherapy (HR 0.56, 95% CI 0.55-0.57), and radiation (HR 0.96, 95% CI 0.93-0.98). Conclusions: Treatment differences between Eastern and Western countries for gastric cancer persist between ethnic groups within the United States, with Asian patients retaining a survival benefit. Black and Hispanic patients present with aggressive disease and unfavorable socioeconomic factors that are detrimental to overall survival.