矢野 智則

Gastric endoscopic mucosal resection is challenging due to the slippery mucosa, abundant blood vessels, and the presence of mucus. We developed gel immersion endoscopy to secure the visual field, even in a blood-filled gastrointestinal lumen in 2016. Clear gel with appropriate viscosity, instead of water, can prevent rapid mixture with blood and facilitate identification of the culprit vessel. We further optimized the gel for endoscopic treatment, and the resultant product, Viscoclear (Otsuka Pharmaceutical Factory) was first released in Japan in 2020. The viscosity of this gel has been optimized to maximize endoscopic visibility without compromising the ease of its irrigation. The aim of this study is to clarify the effectiveness of gel immersion endoscopic mucosal resection for small-sized early gastric neoplasms. Seven lesions in seven patients were treated by gel immersion endoscopic mucosal resection. The size of all lesions was under 10 mm. The median procedure time was 4.5 min. Intraoperative bleeding occurred in four of seven lesions immediately after snare resection and was easily controlled by endoscopic hemostatic forceps during the gel immersion endoscopy. The R0 resection rate was 100%. In conclusion, gel immersion endoscopic mucosal resection may be a straightforward, rapid, and safe technique for resecting superficial gastric neoplasms <10 mm in diameter.

Gastric mucosal changes associated with long-term potassium-competitive acid blocker and proton pump inhibitor (PPI) therapy may raise concern. In contrast to that for PPIs, the evidence concerning the safety of long-term potassium-competitive acid blocker use is scant. Vonoprazan (VPZ) is a representative potassium-competitive acid blocker released in Japan in 2015. In order to shed some comparative light regarding the outcomes of gastric mucosal lesions associated with a long-term acid blockade, we have reviewed six representative gastric mucosal lesions: fundic gland polyps, gastric hyperplastic polyps, multiple white and flat elevated lesions, cobblestone-like gastric mucosal changes, gastric black spots, and stardust gastric mucosal changes. For these mucosal lesions, we have evaluated the association with the type of acid blockade, patient gender, Helicobacter pylori infection status, the degree of gastric atrophy, and serum gastrin levels. There is no concrete evidence to support a significant relationship between VPZ/PPI use and the development of neuroendocrine tumors. Current data also shows that the risk of gastric mucosal changes is similar for long-term VPZ and PPI use. Serum hypergastrinemia is not correlated with the development of some gastric mucosal lesions. Therefore, serum gastrin level is unhelpful for risk estimation and for decision-making relating to the cessation of these drugs in routine clinical practice. Given the confounding potential neoplastic risk relating to H. pylori infection, this should be eradicated before VPZ/PPI therapy is commenced. The evidence to date does not support the cessation of clinically appropriate VPZ/PPI therapy solely because of the presence of these associated gastric mucosal lesions.

BACKGROUND/AIMS: Underwater endoscopic mucosal resection (UEMR) is the standard resection method for superficial non-ampullary duodenal tumors (SNADETs). We developed a novel UEMR technique that creates an anchor by protruding the distal fold with a saline injection (UEMR-A). The aim of this study was to clarify the usefulness of UEMR-A compared to conventional UEMR (UEMR-C). METHODS: This retrospective observational study included patients who underwent UEMR for SNADETs. RESULTS: A total of 141 patients were included and divided into UEMR-A (n=54) and UEMR-C (n=87) groups. Lesion resection was performed significantly more frequently by an expert endoscopist in the UEMR-C group compared to the UEMR-A group (p<0.001). The procedure time for UEMR-A was significantly shorter than that for UEMR-C (p=0.018), despite the additional time required for submucosal injection. The R0 resection rate was significantly higher in the UEMR-A group than in the UEMR-C group (p=0.004). The horizontal margins were significantly clearer in the UEMR-A group than in the UEMR-C group (p=0.018). Multivariate analysis revealed that the use of UEMR-A was the only significant positive factor for R0 resection. CONCLUSIONS: The UEMR-A technique for SNADETs appears to improve R0 resection rates and reduce procedure times compared to the UEMR-C technique.

BACKGROUND AND AIM: Peutz-Jeghers syndrome (PJS) and juvenile polyposis syndrome (JPS) are autosomal dominant diseases associated with high cancer risk. In Japan, knowledge about the prevalence and incidence of PJS and JPS is lacking despite being crucial for providing appropriate medical support. We aimed to determine the prevalence and incidence of these diseases. METHODS: In 2022, a nationwide questionnaire survey was conducted to determine the number of patients with PJS or JPS by sex and the number of newly confirmed cases from 2019 to 2021. The target facilities included gastroenterology, pediatrics, and pediatric surgery departments, which were stratified into seven classes on the basis of the total number of beds. We randomly selected target facilities using different extraction rates in each class, resulting in 1748/2912 facilities (extraction rate: 60%) as the final sample. We calculated the estimated number of patients using the response and extraction rates. RESULTS: A total of 1077 facilities responded to the survey. The estimated numbers of patients with PJS and JPS were 701 (95% confidence interval [CI]: 581-820) and 188 (95% CI: 147-230), respectively. The 3-year period prevalences of PJS and JPS were 0.6/100000 and 0.15/100000, whereas the incidences in 2021 were 0.07/100000 and 0.02/100000, respectively. Male patients constituted 53.5% and 59.6% in the PJS and JPS groups, respectively. CONCLUSIONS: We determined the prevalence and incidence of PJS and JPS in Japan for the first time. Further research is needed to obtain more detailed information, including the clinical differences and outcomes in Japan.