Age-Specific Trends in Incidence of Noncardia Gastric Cancer in US Adults

Abstract

Gastric cancer is the fourth most common type of cancer and the second most common among cancer deaths worldwide.¹ While tumors of the cardia, the upper part of the stomach adjoining the esophagus, may be related to gastroesophageal reflux, the majority of noncardia gastric cancers are attributable to chronic mucosal infection by the bacterium Helicobacter pylori.² The presumed mechanism of carcinogenesis is the induction of inflammation and consequent gastritis, the initial lesions in a multistage process.³ In both high- and low-prevalence populations, H pylori infection is commonly acquired in childhood and generally not later. In the United States, prevalence of infection increases with age, reflecting improvements in hygienic conditions and decreased crowding during childhood for younger generations.⁴ Prevalence also varies by race, socioeconomic status, and geographic region,⁵ contributing to population differences in gastric cancer risk.⁶