Stage-Matched Survival Differences by Ethnicity among Asian Gastric Cancer Patients Treated in the United States

Abstract

Differences have been noted in overall survival (OS) in gastric cancer (GC) between large trials conducted in Western versus Asian countries, questioning the ability to generalize these results to other populations. The National Cancer Database (NCDB) reports outcomes and several patient/disease variables relevant to OS, with robust data on self-reported race/ethnicity. We sought to use the strengths of the NCDB to evaluate this observation in a large American cohort, and hypothesize that additional differences would exist between specific Asian ethnicities. Using NCDB, we identified 89,558 adult patients with squamous cell or adenocarcinoma GC diagnosed 2004-2012 where self-reported race/ethnicity as well as stage and vital status were available. Cox proportional hazard model was used to calculate multivariable hazard ratio (HR) of death with 95% confidence intervals (CI) for GC patients, adjusting for race, ethnicity, age, gender, facility, insurance, co-morbidity score, histology, grade, location, and treatment type with stage interaction. OS analyses were done with Kaplan-Meier method. After adjusting for all variables above, Asian patients (n=6,113) had improved OS as a whole group compared to White patients (HR= 0.74, CI 0.71-0.77). There were differences in OS between specific Asian ethnicities compared to White patients, summarized in the table below. All p-values were <0.0001 except for the HR for OS in Black (p=0.035) and Filipino (p=0.96) patients. When matched for stage, all differences retained significance, with increasing benefit in earlier stages compared to late. This analysis supports improved OS in Asian patients that is independent of stage, treatment, and known patient or disease characteristics in this large US cohort. OS differences between Asian ethnicities suggest ethnogeographic factors influencing outcomes, and should be considered in discussions of prognosis or applying treatment data to patients outside the study population.Abstract SU_12_2118; TableRace/EthnicityMultivariable HR95% CIWhite (n=69,945)Reference-Black (n=13,500)0.980.95-1.00Chinese (n=1,271)0.690.64-0.75Korean (n=1,249)0.700.64-0.75Japanese (n=829)0.840.77-0.91Vietnamese (n=560)0.790.71-0.88Indian (n=492)0.680.61-0.76Filipino (n=415)1.000.89-1.12Other Asian (n=1,297)0.690.64-0.75 Open table in a new tab