Prevalence of Raspberry-type Gastric Foveolar-type Tumor in Individuals Undergoing Medical Checkups

Vonoprazan as a Long-term Maintenance Treatment for Erosive Esophagitis: VISION, a 5-Year, Randomized, Open-label Study

BACKGROUND & AIMS

Acid secretion inhibitors are associated with hypergastrinemia, which can lead to gastric mucosal changes. Potassium-competitive acid blockers, such as vonoprazan, are more potent than proton pump inhibitors, but long-term safety data are lacking.

METHODS

In this phase IV, randomized trial, patients with erosive esophagitis (EE) received induction therapy (once daily vonoprazan 20 mg or lansoprazole 30 mg; ≤8 weeks). Those with healed EE received maintenance therapy (once daily vonoprazan 10 mg or lansoprazole 15 mg) for 260 weeks (2:1). The primary endpoint was the proportion of patients with malignant epithelial cell alterations, parietal cell hyperplasia, foveolar hyperplasia, enterochromaffin-like (ECL) cell hyperplasia, and G-cell hyperplasia.

RESULTS

Overall, 202/208 patients (vonoprazan, n = 139; lansoprazole, n = 69) achieved healed EE and received maintenance therapy. No malignant alterations or gastric neuroendocrine tumors (NETs) were observed; there was 1 adenoma in each group. At week 260, significantly more patients taking vonoprazan vs lansoprazole had parietal cell hyperplasia (97.1% vs 86.5%) and foveolar hyperplasia (14.7% vs 1.9%); proportions of patients with ECL cell hyperplasia (4.9% vs 7.7%) and G-cell hyperplasia (85.3% vs 76.9%) were similar. Median serum gastrin levels were higher with vonoprazan treatment vs lansoprazole (625 pg/mL vs 200 pg/mL). Incidences of adverse events were comparable for both treatments.

CONCLUSIONS

The exploratory VISION study assessed the safety profile of vonoprazan and lansoprazole over 5 years in Japanese patients with healed EE. Although gastrin concentration, parietal cell hyperplasia, and foveolar hyperplasia were higher in the vonoprazan group, there was no increased risk of malignant epithelial cell alterations and gastric NETs. (ClinicalTrials.gov, NCT02679508).

Spectrum of gastric neoplasms in Helicobacter pylori-naïve patients

Chronic Helicobacter pylori (Hp) infection is the largest etiological factor for gastric cancer, but in recent years the reports of Hp-naïve gastric neoplasms (HpNGNs) have increased as the Hp-infected population in Japan has been declining. The histopathologic spectrum of HpNGNs differs significantly from that of conventional Hp-infected gastric neoplasms. Molecularly, the former harbor considerably fewer genetic and epigenetic abnormalities, reflecting the absence of chronic inflammatory conditions in the gastric mucosa. The majority of HpNGNs fall within several specific histological entities; each arise from particular background mucosa. Most originate from the fundic gland mucosa and have a gastric immunophenotype, as seen in foveolar-type gastric adenoma (FGA), oxyntic gland adenoma (OGA)/gastric adenocarcinoma of fundic gland type (GA-FG), signet-ring cell carcinoma (SRCC), and sporadic fundic gland polyp with dysplasia (FGPD). In contrast, tumors arising from the pyloric or cardiac gland mucosa have a diverse immunophenotype, as seen in intestinal-type gastric dysplasia (IGD) and gastric cardiac carcinoma. FGA, FGPD, SRCC, and IGD are mostly found as small intramucosal lesions. OGA/GA-FG frequently progresses to invasive carcinoma, but only a few have lymph node metastases. Thus, these tumors are regarded as precancerous lesions by Western pathologists, while in Japan they tend to be diagnosed as carcinomas, even in cases of low-grade dysplasia. Gastric cardiac carcinomas, on the other hand, are often found as advanced carcinomas and harbor a high malignant biological potential. A new diagnostic framework for gastric neoplasms is required in the present era of Hp-naïve individuals in Japan.

Prevalence of Gastric Epithelial Tumors in Helicobacter pylori-uninfected Individuals Undergoing a Medical Checkup

Objective This study investigated the prevalence of gastric epithelial tumor in Helicobacter pylori-uninfected subjects who underwent esophagogastroduodenoscopy (EGD) as part of an annual checkup. Methods A total of 20,540 EGD examinations of H. pylori-uninfected individuals (12,917 men, 7,623 women; mean age 51.5±9.2 years old) were performed between April 2016 and March 2023. The prevalence of gastric epithelial tumor discovery and the size and location of each lesion type were analyzed. Results According to 20,540 examinations, 61 gastric epithelial tumors were endoscopically and histologically diagnosed in 58 of the subjects, with a prevalence rate of 0.28%. These tumors included signet-ring carcinoma (n=10, 0.05%), gastric adenocarcinoma of fundic-gland type (n=10, 0.05%), intestinal-type well-differentiated adenocarcinoma (n=2, 0.01%), and raspberry-type gastric foveolar tumors (n=36, 0.18%). One subject had two intestinal-type well-differentiated adenocarcinomas, and two each had two raspberry-type gastric foveolar tumors. The mean sizes of the signet-ring carcinomas, gastric adenocarcinoma of fundic-gland type, intestinal-type well-differentiated adenocarcinomas, and raspberry-type gastric foveolar tumors were 6.4, 4.7, 5.0, and 3.4 mm, respectively. Each lesion was located at a specific site in the stomach characteristic of its type. Conclusion In the present H. pylori-uninfected subjects, the prevalence of gastric epithelial tumors found on an EGD examination was 0.28%. Endoscopic examination should be performed in H. pylori-uninfected individuals to detect such tumors in characteristic locations.

Gastric dysplastic lesions in Helicobacter pylori-naïve stomach: Foveolar-type adenoma and intestinal-type dysplasia

Reports of Helicobacter pylori (Hp)-naïve gastric neoplasm (HpNGN) cases have been rapidly increasing due to the recent increase in the Hp-naïve population in Japan. Most HpNGNs exhibit the gastric immunophenotype and a low malignant potential regardless of histological type. Especially, foveolar-type gastric adenoma (FGA) and intestinal-type gastric dysplasia (IGD) rarely progress to invasive carcinoma. FGA is a foveolar epithelial neoplasm that occurs in the fundic gland (oxyntic gland) mucosa and is classified as the flat type or raspberry type (FGA-RA). The flat type is a large, whitish flatly elevated lesion while FGA-RA is a small reddish polyp. Genomically, the flat type is characterized by APC and KRAS gene mutations and FGA-RA by a common single nucleotide variant in the KLF4 gene. This KLF4 single-nucleotide variant reportedly induces gastric foveolar epithelial tumorigenesis and activates both cell proliferation and apoptosis, leading to its slow-growing nature. IGD consists of an intestinalized epithelial dysplasia that develops in the pyloric gland mucosa, characterized as a superficial depressed lesion surrounded by raised mucosa showing a gastritis-like appearance. Immunohistochemically, it exhibits an intestinal or gastrointestinal phenotype and, frequently, p53 overexpression. Thus, IGD shows unique characteristics in HpNGNs and a potential multistep tumorigenic process.