An Approach to the Primary and Secondary Prevention of Gastric Cancer in the United States

Abstract

Background & aims: Gastric cancer (GC) remains a leading cause of mortality among certain racial, ethnic, and immigrant groups in the United States (US). The majority of GCs are diagnosed at advanced stages, and overall survival remains poor. There exist no structured national strategies for GC prevention in the US.

Methods: On March 5-6, 2020 a summit of researchers, policy makers, public funders, and advocacy leaders was convened at Stanford University to address this critical healthcare disparity. After this summit, a writing group was formed to critically evaluate the effectiveness, potential benefits, and potential harms of methods of primary and secondary prevention through structured literature review. This article represents a consensus statement prepared by the writing group.

Results: The burden of GC is highly inequitably distributed in the US and disproportionately falls on Asian, African American, Hispanic, and American Indian/Alaskan Native populations. In randomized controlled trials, strategies of Helicobacter pylori testing and treatment have been demonstrated to reduce GC-specific mortality. In well-conducted observational and ecologic studies, strategies of endoscopic screening have been associated with reduced GC-specific mortality. Notably however, all randomized controlled trial data (for primary prevention) and the majority of observational data (for secondary prevention) are derived from non-US sources.

Conclusions: There exist substantial, high-quality data supporting GC prevention derived from international studies. There is an urgent need for cancer prevention trials focused on high-risk immigrant and minority populations in the US. The authors offer recommendations on how strategies of primary and secondary prevention can be applied to the heterogeneous US population.

Keywords: Disparity; Gastric Intestinal Metaplasia; Helicobacter pylori; Screening.

Figure 1.

Top panels, age-standardized incidence rates of gastric cancer in the United States among individuals 50 and older, by race/ethnicity and sex in 2010-2017. Source: SEER Research Data. Bottom panels, incidence rates of non-cardia gastric cancer among individuals 50 and older. Source: California Cancer Registry, 2011-2015. Data adapted from Shah et al. (2020). NHW, non-Hispanic White; NHB, non-Hispanic Black.

Figure 2:

Green line: percentage of gastric cancers diagnosed at early stage in South Korea between 2001 and 2016. Red line: percentage of gastric cancers diagnosed at localized stage (using American Joint Committee on Cancer staging) in the United States from 2004 to 2016. Data adapted from Huang et al. (2020).

Figure 3:

Forest plot of randomized controlled trials of Helicobacter pylori eradication therapy: Effect on subsequent occurrence of gastric cancer (modified intention-to-treat analysis). Hp, Helicobacter pylori. Data adapted from Ford et al. (2020).

Figure 4:

Pooled analysis of the association between endoscopic screening and gastric cancer mortality from published cohort and case-control studies. Reproduced with permission from Gastroenterology, Volume No. 155, Issue No. 2, Zhang X et al., Endoscopic Screening in Asian Countries Is Associated With Reduced Gastric Cancer Mortality: A Meta-analysis and Systematic Review, Copyright (2018), with permission from the AGA Institute and Elsevier.

Figure 5:

Secular trends in gastric cancer incidence and number of endoscopic screening exams in South Korea (2002-2012). Data from the Korean Statistical Information Service.