The development of image-enhanced endoscopy has dramatically improved the qualitative and quantitative diagnosis of gastrointestinal tumors. In particular, narrow band imaging (NBI) has been widely accepted by endoscopists around the world in their daily practice. In 2009, Yao et al. proposed vessel plus surface (VS) classification, a diagnostic algorithm for early gastric cancer using magnifying endoscopy with NBI (ME-NBI), and in 2016, Muto et al. proposed a magnifying endoscopy simple diagnostic algorithm for early gastric cancer (MESDA-G) based on VS classification. In addition, the usefulness of ME-NBI in the differential diagnosis of gastric cancer from gastritis, diagnosis of lesion extent, inference of histopathological type, and diagnosis of depth has also been investigated. In this paper, we narrative review the basic principles, current status, and future prospects of NBI.

Both endoscopic and surgical approaches are employed in the treatment of early gastric cancer (EGC). The aim of this study was to establish appropriate treatment strategies for early gastric cancer.

Background: The indications for endoscopic submucosal dissection (ESD) for gastric cancer are based on preoperative histological assessment; however, examination of tissue biopsy is not always reliable as only a limited portion of the lesion can be obtained. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are markers of inflammatory response and are potentially associated with the grade of malignancy in gastric cancer. We aimed to investigate the association between NLR and PLR and the histology of gastric cancer. Methods: This study included 218 patients who underwent ESD for gastric cancer. The relationship between NLR/PLR and histological diagnosis was investigated. Results: Patients with adenocarcinomas showed significantly higher NLR and PLR than those with adenomas (p < 0.001 and p < 0.05, respectively). Further, patients with undifferentiated adenocarcinoma showed a significantly higher NLR (p < 0.05) than those with differentiated adenocarcinoma. Conclusion: This study suggests that NLR could be a useful marker for assessing early gastric cancer.

Endoscopic submucosal dissection (ESD) and en bloc resection of stomach and colon tumors have become common. However, mucosal defects resulting from ESD may cause delayed bleeding and perforation. To prevent adverse events, we developed a new clip closure technique, namely, the loop and open–close clip closure method (LOCCM), and aimed to examine its efficacy after ESD for stomach and colon tumors. The LOCCM uses loop and open–close clips. Here, the open–close clip was used to grasp the loop to bring it to the edge of the post-ESD mucosal defect. Another clip with a loop was then inserted into the opposite edge and clipped to the contralateral mucosa to pull both edges together. Once apposed, additional clips facilitated complete closure. The LOCCM was performed in 19 patients after ESD at Tottori University between October 2020 and March 2021. The outcomes retrospectively analyzed were the LOCCM success and adverse event rates. The complete closure rate using LOCCM was 89.5% and none of the patients had post-ESD bleeding or perforation. The results show that LOCCM is an effective and safe closure technique for mucosal defects after stomach and colon ESD to prevent bleeding and perforation.

Although the recent development and widespread use of image-enhanced endoscopy and magnifying endoscopy have improved endoscopic diagnosis of gastric cancer, it is somewhat complicated, requires a higher level of expertise, and is still subjective. Photodynamic endoscopic diagnosis (PDED) is based on the fluorescence of photosensitizers that accumulate in tumors, which enables objective evaluation independent of the endoscopist’s experience, and is useful for tumor detection. The objective of this work was to perform a narrative review of PDED for gastric tumors and to introduce our approach to PDED in gastric tumors in our hospital. In our review there have been case reports of PDED for gastric cancer, but its usefulness has not been established because no prospective studies evaluating its usefulness have been performed. In our previous study, 85.7% (42/49) of gastric tumors exhibited fluorescence in PDED. PDED may be useful in the diagnosis of early gastric cancer. Our previous studies were pilot studies in cancer patients; therefore, future prospective studies are required to verify the usefulness of PDED.