Abstract 4676: Survival of gastric cancer differs by ethnicity: A population-based experience from British Columbia, Canada

Abstract

Abstract Introduction: Prognostic factors can be classified into three broad groups: i) tumor-related, ii) host-related, and iii) environment-related (health care, treatment, lifestyle) factors. The current study was conducted to examine the effect of ethnicity as a host-related factor for survival of gastric cancer patients in British Columbia, Canada. Methods: Data were obtained from the population-based BC Cancer Registry for patients diagnosed with invasive gastric cancer between 1984 and 2006. The ethnicity of patients was estimated according to their names and categorized as Chinese, South Asian, Iranian or Other (more than 80% of “Other” are British and Western Europeans). Cox proportional hazards regression analysis was used to estimate the effect of ethnicity adjusted for patient sex and age, disease histology, tumor location, disease stage and treatment. Results: Results from this study indicate significantly different survival of gastric cancer patients depending on their ethnic group (p<0.01). When considered separately according to the presence or absence of metastatic disease, significant differences were only found for non-metastatic disease (p<0.01). Furthermore, the association between survival and ethnicity was only significant for patients with non-metastatic disease who received therapeutic surgery (p<0.01). In multivariate analyses adjusting for patient factors, disease factors and treatment, there was a significant difference among ethnic groups. Only Chinese had significantly longer survival compared to the Other ethnicities, but this survival advantage was only seen for non-metastatic disease (HR=0.78, 95% CI=0.64-0.95). Conclusion: The difference observed in patient survival is not likely to be due to healthcare disparities among minority groups, as all BC residents are covered for healthcare through the BC Medical Services Plan (MSP). Ethnicity may represent underlying genetic factors. Such factors could influence host-tumor interactions by altering the tumor's etiology and therefore its chance of spreading. Alternatively, genetic factors may determine response to treatments. Finally, ethnicity may represent non-genetic factors that affect survival. Differences in survival support the importance of ethnicity as a prognostic factor, and may provide clues for the future identification of genetic or lifestyle factors that underlie these observations. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4676. doi:10.1158/1538-7445.AM2011-4676