The visibility and diagnostic accuracy of early gastric cancer (EGC) after Helicobacter pylori (HP) eradication have been reported to improve using image-enhanced endoscopy (IEE) compared with white light imaging (WLI). The present study clarified the appropriate IEE for the detection and diagnosis of EGC in clinical settings. This prospective and cross-sectional study evaluated the visibility of EGC and endoscopic findings of gastric mucosa after successful HP eradication (n = 31) using videos with WLI and IEE. Three endoscopists evaluated high-definition videos in a randomized order. The mean visibility scores (MVSs) on linked color imaging (LCI) for atrophic border, intestinal metaplasia, map-like redness, and EGC were the highest among each modality (3.87 ± 0.34, 3.82 ± 0.49, 3.87 ± 0.50, and 3.35 ± 0.92, respectively). The MVSs with blue laser imaging (BLI) were highest for magnifying view of the demarcation line (DL), microsurface pattern (MSP), and microvascular pattern (MVP) for EGC (3.77 ± 0.49, 3.94 ± 0.25, and 3.92 ± 0.34, respectively). LCI had the highest visibility among findings of gastric mucosa and EGC after HP eradication, and BLI had the highest visibility of MVP, MSP, and DL in magnifying observation. These results suggest that LCI observation in the entire stomach and further magnifying BLI are the best methods for detecting and diagnosing EGCs after HP eradication, respectively.

Background: Vacuolar ATPase (V-ATPase) is involved in cancer development. The use of proton pump inhibitors (PPIs) as V-ATPase inhibitors has been reported to enhance the effectiveness of chemotherapy in certain cancers. This study aimed to evaluate the effect of PPIs on chemotherapy for esophageal cancer. Methods: To investigate the effects of PPIs on esophageal cancer cells, human KYSE50 and 70 cells were plated and 3 PPIs (lansoprazole, esomeprazole, vonoprazan) were added at various concentrations with 5-Fluorouracil (5-FU) to the corresponding cells for a cell viability assay. To investigate the effects of PPI treatment on patients undergoing 5-FU-based therapy in the clinical setting, we retrospectively analyzed the clinical outcomes and chemotherapy-related adverse events in 40 esophageal cancer patients who received 5-FU chemotherapy in our hospital between May 2013 and April 2017. Results: In the viability assays, all PPIs significantly enhanced the cytotoxic effect of 5-FU on the two esophageal cancer cell lines. In the clinical study, PPI-treated patients showed better overall survival (OS) than patients managed without PPI treatment. A multivariate analysis revealed that PPI treatment was independently associated with OS (p = 0.009, HR, 0.33; 95% CI, 0.12–0.76). Conclusions: PPI treatment may safely enhance chemosensitivity in esophageal cancer patients.