RACE, ETHNICITY, SOCIOECONOMIC STATUS AND ANATOMIC SUBSITESPECIFIC RISK FOR GASTRIC CANCER

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