UC San Diego

Anatomic subsite risk factors for gastric cancer differ substantially, and subsite-specific distribution of risk factors (such as Helicobacter pylori) can vary by race and ethnicity and neighborhood socioeconomic status (nSES). We examined differences in gastric cancer incidence by subsite, stratified by race and ethnicity and nSES, using Surveillance Epidemiology and End Results Program 2000-2014 data for 77,881 incident gastric cancer cases (cardia, n = 23,651; non-cardia, n = 35,825; overlapping or unspecified, n = 18,405). Compared with non-Hispanic whites, cardia cancer multivariable-adjusted incidence rate ratios were 35%-47% lower for blacks, Hispanics, Asian or Pacific Islanders, and American Indian or Alaska Natives; conversely, non-cardia incidence rate ratios were 1.7- to 3.9-fold higher for blacks, Hispanics, Asian or Pacific Islanders, and American Indian or Alaska Natives. Higher adjusted incidence rate ratios with decreasing nSES (lowest vs highest nSES quintile) were observed for all gastric (1.3-fold) and non-cardia (1.3-fold) cancers but were borderline significant for cardia cancers (1.1-fold). In conclusion, non-cardia cancer incidence is higher in minorities and varies by nSES, but cardia cancer incidence is higher in non-Hispanic whites and does not vary substantially by nSES. Clarifying reasons for higher cardia risk in non-Hispanic whites and targeted interventions to address non-cardia cancer risk in minorities could lessen the burden of gastric cancer.