Asian Ethnicity–Related Differences in Gastric Cancer Presentation and Outcome Among Patients Treated at a Canadian Cancer Center

Abstract

Purpose: Differences in stage-stratified survival have been reported between Asian and Western populations with gastric cancer. This study examines differences in presentation and outcomes among Asian and non-Asian patients evaluated and treated at a Canadian institution. Patients and Methods: We reviewed 2,043 patients (159 Asians and 1,884 non-Asians) with gastric adenocarcinoma treated between 1978 and 1997. Overall survival was examined by the Kaplan-Meier method, and multivariable analysis by Cox proportional hazards was used to identify whether Asian ethnicity had independent prognostic significance for survival. Results: Median survival was 13.1 months for Asians and 11.1 months for non-Asians (P = .0016). Asian patients were younger and had a greater proportion of signet ring cell histology but were less likely to have proximal disease. Signet ring cell histology did not adversely affect survival. By multivariable analysis, proximal location, poor differentiation, and extent of disease were independently associated with worse survival. Survival was improved with curative resection, palliative resection, and palliative chemotherapy. Asian ethnicity was not independently associated with survival (hazard ratio, 0.89; 95% confidence interval, 0.74 to 1.08). Although a similar proportion of patients underwent curative resection, an interaction was observed between Asian ethnicity and efficacy of resection, with Asians achieving a greater benefit as compared with non-Asians even when adjusted for age and location. Conclusion: The disparity between Eastern and Western gastric cancer survival is not explained by the hypothesis of ethnicity-related differences in tumor biology. Although it is not an independent predictor of survival, Asian ethnicity is associated with distinct characteristics at presentation and more favorable outcomes after curative surgery.