Age and ethnicity predict overall survival in patients with metastatic gastric cancer

Abstract

15500 Background: Patients diagnosed with metastatic gastric cancer have dismal outcome. There was a lack of established regimens to improve their survival. The prognostic role of gender, age and ethnicity on survival for patients with metastatic gastric cancer has not been determined in the U.S. It has been shown that Asians treated in Asia have overall a significant better outcome than Caucasians treated in Western world. The etiology of gastric cancer may differ among the different ethnic groups. These different etiologies include environmental factors, H.pylori infection and dietary factors which may lead to different genetic profiles of gastric cancer associated with different clinical outcome. Methods: Extracting data from the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registries, we compared overall survival for patients with metastatic gastric cancer by gender, age and ethnicity using multivariate Cox proportional hazards models. 15,228 patients (≥ 18 years) were identified from the years 1988- 2003. The ages of the males and females were categorized with <45, 45- 54, 55- 64, 65–74, and ≥75 years. Patients who were Native Americans, African Americans, Asians, Caucasians, and Hispanics were included. The models were adjusted for potential confouders including marital status at diagnosis, tumor site, treatment with radiation and/or surgery, and histology, and stratified by SEER registry sites and years of diagnosis. Results: Overall survival was decreased with age (p<0.001, Cox model). The median overall survival was 6 months in patients of ≤ 44 years compared to 2 months in patients who were ≥75 years. The difference of overall survival by ethnicity significantly was varied by sex (P for interaction = 0.01). Among males, Asian patients had longer overall survival, and African American patients had shorter overall survival compared to Caucasian patients (p=0.023). No significant difference in overall survival across ethnicity was found among females. Conclusions: This is the largest study of metastatic gastric cancer from SEER registries to show that age was a significant prognostic factor for overall survival in patients with metastatic gastric cancer. The influence of ethnicity on overall survival was dependent on sex. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Bristol-Myers Squibb, Genentech™ BioOncology, ImClone Systems Incorporated, Merck, Pfizer Oncology, Response Genetics Genentech™ BioOncology, Merck, Pfizer Oncology, Roche, sanofi-aventis Dhont Family Foundation, NCI, NIH