Clinicopathologic correlations of gallbladder cancer by ethnicity in New Mexico, 1980-2009.

Abstract

160 Background: Gallbladder cancer (GBCA) is a rare malignancy; however, within the U.S. incidence varies geographically. GBCA has a higher occurrence in the American Indian (AI) population versus non-Hispanic whites (NHW) and Hispanics (H). The goal of the study is to determine if clinicopathologic features correlate with ethnicity. Methods: Incident GBCA diagnosed in New Mexico from 1980-2009 were identified from the population-based New Mexico Tumor Registry. Average age-adjusted incidence rates were calculated by direct method using the United States 2000 standard population. Chi-squared statistic was used to assess ethnicity differences in case distribution at diagnosis by sex, age, stage and grade. Cause-specific survival was calculated by the Kaplan-Meier method and assessed with log-rank statistic. Results: GBCA incidence rates in New Mexico are highest for AI (7.6 per 100,000–95% confidence interval (CI)=6.5-8.9), followed by H (2.8 per 100,000 – 95% CI=2.5-3.2) and NHW (1.0 per 100,000 – 95% CI=0.9-1.1). Females are predominantly affected (Table). Median ages varied among NHW (74 years), H (71 years) and AI (69 years). There are no appreciable differences with respect to stage and tumor grade. Cause-specific survival at 60 months is also similar among NHW (20.25%), H (17.94%), and AI (22.43%) (log-rank p-value=0.7388). Conclusions: GBCA has a higher prevalence in AI. Regardless it shares similar characteristics in all evaluated ethnicities as it is predominantly a disease of older females, with similar tumor grade and stage and with equally poor survival. [Table: see text]