In Focus

Diagnosis and management of gastric intestinal metaplasia in the United States


 

Which patients to screen

Understanding this sequence of carcinogenesis offers a potential window for screening and surveillance. Subsequently, early detection of precancerous mucosal changes would be more amenable for endoscopic submucosal dissection (ESD).35,36 Currently, U.S. society guidelines do not specifically address the management of GIM. The American Society for Gastrointestinal Endoscopy (ASGE) guidelines for management of premalignant and malignant conditions of the stomach recommend surveillance in individuals with a family history of gastric cancer or of high-risk ethnic background but with no specific optimal surveillance interval.37 Also, H. pylori treatment is recommended if identified, but empiric treatment in GIM was felt to be controversial. The AGA recently sought comments on a proposed new guideline for the management of GIM. This guideline should be released after the comment period and help address management of GIM in the United States. In April of 2019, the European Society of Gastrointestinal Endoscopy (ESGE) updated the management of epithelial precancerous conditions and lesions in the stomach (MAPS II) guideline.38 The MAPS II guideline identifies atrophic gastritis and intestinal metaplasia as precancerous lesions. In patients with moderate to marked atrophy or GIM affecting both antral and body mucosa, ESGE recommends endoscopic surveillance with high-definition chromoendoscopy, mapping, and guided biopsies or at least two biopsies taken separately at the lesser and greater curvature of the antrum and body. H. pylori eradication was recommended if the patient tested positive.

Furthermore, MAPS II proposed replacing atrophic gastritis (AG) in the Operative Link on Gastritis Assessment (OLGA) staging by GIM (OLGIM) as it is considered a more reliable predictor of an individual’s gastric neoplasia risk, based on the interobserver agreement kappa value 0.6 for AG versus 0.9 for GIM.39 Five biopsies (two from the antrum, two from the corpus, and one from the incisura angularis) are needed for the OLGA/OLGIM score system to be considered an accurate predictor of this risk.39 This is supported by the early findings of gastric atrophy and GIM in the incisura angularis.23 In addition, for patients with GIM only in either the antrum or the body, a family history of gastric cancer, incomplete GIM, autoimmune gastritis, or persistent H. pylori infection was felt to increase the risk to warrant surveillance every 3 years. In those patients with atrophy or GIM in both the antrum and body with a first-degree relative with gastric cancer, surveillance was recommended every 1-2 years. Patients with any dysplasia and a visible lesion should have staging and resection. With no visible lesion, a follow-up endoscopy should be performed in 6 months with high-grade dysplasia and with low-grade dysplasia a repeat in 12 months. Patients with mild to moderate atrophy in the antrum and no intestinal metaplasia were not felt to warrant any further surveillance. (See Figure 1.)

Figure 1. Surveillance recommendations according to MAPS II, April 2019
A recent study explored the cost-effectiveness of noncardia gastric cancer screening in the United States stratified by race or ethnicity with a time horizon of 30 years. The study determined that performing endoscopic screening with mapping biopsies in high-risk patients (non-Hispanic black, Hispanic, and Asian individuals) from 50 years of age with continued surveillance only when indicated would be cost effective compared to a no-screening strategy. These patients had sampling performed via an updated Sydney protocol. If GIM was found, the patients would be enrolled into a 3-year surveillance program. Whereas if dysplasia was present, the patients would undergo endoscopic submucosal dissection or surgical resection and continue a postresection surveillance schedule.40,41

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