CHARACTERISTICS AND ENDOSCOPIC DIAGNOSIS OF HELICOBACTER PYLORI-UNINFECTED GASTRIC CANCER BASED ON TUMOR LOCATION AND BACKGROUND MUCOSA

Abstract

Helicobacter pylori(Hp)-uninfected gastric cancer was previously considered rare, but its incidence is reported to be increasing, reflecting a decline in Hp infection rates. In our case series, we classified Hp-uninfected gastric cancers into four categories: (1) adenocarcinoma of the cardia or esophagogastric junction (EGJ), (2) low grade adenocarcinoma with gastric phenotype predominantly in the fundic gland region, especially in the upper to middle gastric body, (3) signet-ring cell carcinoma predominantly in the gastric antrum, the region between the fundic and pyloric gland, and (4) well-differentiated adenocarcinoma predominantly in the pyloric gland region, sometimes with intestinal phenotypes. Most gastric cardia or EGJ cancers were advanced, whereas cancers located in most other regions were early-stage cancers that could be treated by ESD, suggesting that the progression of these cancers may be slower. In Hp-uninfected stomachs, it is important to make efficient observations based on the morphology and histology of cancers that are predominate in each site and glandular region. Further analysis of the frequency and malignant potential of Hp-uninfected gastric cancer is needed. Risk stratification for appropriate examination intervals of screening endoscopy could also pose a topic for future research.