Epidemiology of Noncardia Gastric Adenocarcinoma in the United States

OBJECTIVES: Adenocarcinomas of the cardia (International Classification of Diseases (ICD)-9 code 151.0) and stomach (ICD-9 codes 151.1-151.9) are frequently grouped together in epidemiologic statistics, but are clearly distinct diseases. The objective of this study was to describe the current epidemiology of noncardia gastric cancer (noncardia gastric adenocarcinoma (NCGA)) in the United States. METHODS: Rates of NCGA in the United States from 1997 to 2008 were analyzed in three national databases: the Surveillance, Epidemiology, and End Results registry was used for incidence, the Healthcare Costs and Utilization Project for hospitalizations, and the Compressed Mortality File for mortality. Population-based rates were calculated and age-adjusted to the US 2000 population using direct standardization. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated and adjusted for confounders with the Mantel-Haenszel method. RESULTS: Annually, NCGA was associated with 18,873 incident cases, 17,284 hospitalizations for principal discharge diagnoses, 31,354 hospitalizations for all-listed diagnoses, and 11,562 deaths. Incidence was greater in men (OR = 1.56, CI = 1.53-1.59) and non-White races (OR = 2.38, 2.33-2.43). Hospitalization was more common in men (1.82, 1.81-1.83) and non-White races (2.13, 2.10-2.15). Mortality was more common in men (1.83, 1.81-1.86) and non-White races (2.23, 2.20-2.26). NCGA rates showed a marked age-dependent rise (P < 0.001). Hospitalization and mortality were greatest in the Northeast region of the United States (P < 0.001). CONCLUSIONS: Epidemiologic patterns of NCGA were congruent in three national databases. Older age, male gender, non-White race, and residence in the Northeast region were associated with increased risk. These patterns may reflect the underlying variations in Helicobacter pylori, lifestyle, and environmental exposures.