Objects Although a recent study showed the cancer incidence of Barrett's esophagus (BE) to be 1.2%/year in 251 patient‐years in Japan, the long‐term outcomes remain unclear. The present study estimated the cancer risk of BE in Japan using our original prospective multicenter cohort. Methods A total of 98 patients with BE of maximum length of ≥2 cm were enrolled during the period of 2010–2012 and received at least one follow‐up endoscopy over 5 years thereafter. Cancer incidence rates with 95% confidence interval for occurrence of esophageal adenocarcinoma (EAC) were calculated as the number of events divided by patient‐years of follow‐up and were expressed as %/year. Results Overall, the median endoscopic follow‐up period was 59.9 (first and third quartiles, 48.5–60.8) months, constituting a total of 427 patient‐years of observation. Since two EAC cases developed, the cancer incidence was 0.47% (0.01%–1.81%)/year. The cancer incidence was 0.39% (−0.16% to 2.44%) in 232 patient‐years and 0.31% (−0.13% to 1.95%)/year in 318 patient‐years for 55 cases with specialized intestinal metaplasia and 70 with BE ≥3 cm (maximum), respectively. At the end of follow‐up, 12 of 92 patients (13.0%) died, but none died from EAC. Conclusion This is the largest prospective follow‐up study with endoscopy to investigate the incidence of EAC in unequivocal BE with the maximum length of ≥2 cm in Japan. Although a further large‐scale study will be required to validate our results, the cancer risk of BE in Japan would be lower than previously reported (0.47% vs 1.2%/year).

Background and Objectives: Weakly acidic reflux has been reported as the major cause of symptom occurrence in patients with proton pump inhibitor (PPI)-refractory non-erosive reflux disease (NERD). This study is aimed at clarifying whether the pH value of weakly acidic reflux affects the induction of symptoms. Methods: We retrospectively evaluated the records of combined multichannel intraluminal impedance and pH monitoring in 57 patients with PPI-refractory NERD. Weakly acidic refluxes were divided into 3 categories based on the pH value of the refluxate: pH 4-5, 5-6, and 6-7. Results: A total of 29 patients were positive in the symptom index. The symptom provocation rate in reflux of pH 4-5 (19%) was much higher than in that of pH 5-6 (11%) and pH 6-7 (12%). In the reflux at pH 4-5, the symptom provocation rate in the proximal reflux was higher than that in the distal reflux (p < 0.05), whereas the reflux at pH 5-6 and pH 6-7 was not significantly different in the symptom provocation rate between the proximal and distal refluxes. Conclusion: Reflux at pH < 5 reaching the proximal esophagus was the main factor in the induced symptoms of patients with PPI-refractory NERD.

Background: There has been no study that has directly measured the esophageal reflux factors in Barrett's adenocarcinoma (BA) using 24-h multichannel intraluminal impedance-pH monitoring (24-h MII-pH). We aimed to clarify the esophageal reflux factors in Barrett's esophagus (BE) and BA and the factors that determine the location of BA with 24-h MII-pH. Methods: We performed 24-h MII-pH in 26 patients with superficial BA treated endoscopically (BA group) and 13 patients with BE (BE group) and examined the esophageal reflux factors (esophageal acid exposure time [AET], bolus exposure (acid, weakly acid, and alkaline), and number of reflux episodes. In the BA group, there were 16 cases in which the lesions were localized in an area in contact with the esophagogastric junction (EGJ; EGJ group), and 10 cases in which the lesions were proximal to the BE and separated from the EGJ (non-EGJ group). Results: Total reflux in the bolus exposure in the BA group showed higher values compared to that in the BE group. The total of acid and weakly acid reflux of bolus exposure was significantly higher in the BA group than that in the BE group. The BA group also had greater numbers of total reflux episodes than the BE group. As for the cancer locations in BE, the cases in which the lesions were located proximally and separated from the EGJ had more AET and total reflux and acid reflux indicated by bolus exposure compared to the lesions adjacent to the EGJ. Conclusions: Stronger gastro-esophageal reflux appeared to be an important factor in the development of adenocarcinoma from BE. In addition, the cancer location in BE may be related to the intensity of esophageal reflux.

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Background and Objective: Weakly acidic reflux reaching to the proximal esophagus is closely related to the perception of gastroesophageal reflux in patients with nonerosive reflux disease despite treatment with a proton pump inhibitor (PPI). However, little is known about the involvement of the patients’ mucosal integrity of the proximal esophagus. Methods: We recruited 15 symptomatic nonerosive gastroesophageal reflux disease (GERD) patients with a positive symptom index despite PPI treatment and 11 healthy asymptomatic volunteers as controls. The biopsy specimens obtained from the proximal and distal esophagus were applied to a mini-Ussing chamber system to measure transepithelial electrical resistance (TEER) against a pH 4 weak acid. The esophageal biopsy samples were subjected to quantitative real-time PCR and immunohistochemical analysis. Results: In the proximal esophagus, the weak acid exposure reduced the TEER in the PPI-refractory patients compared to that in the controls. The frequency of the reflux extending to the proximal esophagus had a significant correlation with the reduction in the proximal esophageal TEER in the patients. The reduced TEER in the proximal esophagus was accompanied by an increase in IL-8 and IL-1β mRNA and a decrease in occludin mRNA levels. The proximal esophageal mucosa in the patients presented infiltration of CD3-positive lymphocytes and an increased expression of solute carrier organic anion transporter family member 2A1 (SLCO2A1), a passage gate of reflux symptom-evoking molecules. Conclusions: The reflux perception is related to an impairment of the proximal esophageal mucosal integrity in patients with nonerosive reflux disease despite PPI.