A new model of gastric cancer screening suggests that, for Asian Americans, endoscopic screening alongside colonoscopy and follow-up surveillance of gastric preneoplasia is a cost-effective strategy. Incremental cost-effectiveness ratios (ICERs) were lowest for Chinese, Japanese, and Korean Americans. The model simulated results for asymptomatic 50-year-old subjects.
Gastric cancer risk is highest in Asian Pacific, Latin American, and Eastern European countries. Asia Pacific countries alone represent about half of all new cases. Helicobacter pylori–related gastritis is the strongest known risk factor for intestinal-type noncardia gastric adenocarcinoma (NCGA), which is the most common gastric cancer, and this chronic inflammation can lead to gastric intestinal metaplasia (GIM). Individuals with GIM have a 0.16% increased annual risk of NCGA, which makes them good candidates for endoscopic screening that could catch new cancers at an early stage.
In a previous study (), researchers at Vanderbilt University Medical Center in Durham, N.C., at Boston University School of Medicine, and at the University of Pennsylvania in Philadelphia showed that, in asymptomatic 50-year-old Asian Americans, Hispanic patients, and non-Hispanic Black patients, performing a single esophagogastroduodenoscopy (EGD) concomitantly with a colonoscopy, followed by screening EGDs if indicated (such as for a GIM diagnosis), is a cost-effective strategy. They found ongoing screening was not cost effective if the original results were normal.
In the new study published in, the researchers followed up this finding with an attempt to tease out the cost-effectiveness of screening in different subgroups, as well as by sex. They built a Markov decision model focusing on the six most common Asian groups in the United States: Chinese, Filipino, Southeast Asian, Vietnamese, Korean, and Japanese Americans.
Model inputs were based on the published literature, and the outputs were compared with data from the Surveillance, Epidemiology, and End Results (SEER) data for disaggregated Asian Americans between 2001 and 2014 and separately with the California Cancer Registry (2011-2015). The model produced a good fit to the epidemiological data.
The model then compared cost-effectiveness of three hypothetical screening strategies in asymptomatic 50-year-old Asian Americans: one-time upper EGD with biopsies conducted at the time of colonoscopies for colorectal cancer screening, followed by EGDs every 3 years if GIM was detected (or other appropriate management of higher-grade pathology); EGD with biopsy at a colonoscopy for CRC screening followed by EGD biennially regardless of initial findings; and no endoscopy screening.
The one-time EGD strategy was the most cost-effective, regardless of sex, with an ICER of $75,959 per quality-adjusted life-year (QALY) in males and $74,329/QALY in females. The lowest ICER was found for Chinese Americans (males and females, $68,256/QALY), followed by Japanese Americans (males, $69,011/QALY; females, $73,748/QALY), and Korean Americans (males, $70,739/ QALY; females, $70,236/QALY). The highest ICERs were among Filipino American males and females, but the strategy was still cost-effective at the predetermined willingness-to-pay threshold of $100,000 ($83,732/QALY).
In all ethnic groups, the biennial screening strategy produced more harm than good and was costlier.
The authors believe that the strategy could be applied to other ethnic groups that come from countries with populations at higher relative risk of gastric cancer, such as Central and Latin American countries.
Asked to comment on the study, Mimi Tan, MD, an assistant professor of gastroenterology at Baylor College of Medicine in Houston, suggested that the estimates of precancerous lesions used in the Markov model were quite high because they were based on pathology databases. These sources tend to be biased toward symptomatic individuals since these are the patients typically referred for upper endoscopy biopsies. “Therefore, these probabilities may not represent true probability of these precancerous lesions among asymptomatic screening populations,” Dr. Tan said in an interview. She also questioned whether the study represented the true risk in female populations since the literature for women is sparse.
Dr. Tan suggested that a more cost-effective screening strategy might be one-time H. pylori immunoglobulin G testing in Asian Americans. The Houston Consensus Conference on Testing for H. pylori Infection already recommends testing for first-generation immigrants from high prevalence areas and Latino and African American racial or ethnic groups (). “Future studies should compare cost-effectiveness of one-time upper endoscopy, which is more costly but able to detect premalignant lesions, to one-time H. pylori testing,” said Dr. Tan.
SOURCE: Shah SC et al. Clin Gastroenterol Hepatol. 2020 July 21. .