Cancer Incidence in Japanese Patients With Long‐Segment Barrett's Esophagus—Japan Nationwide 10‐Year Prospective Cohort Study

ABSTRACT Objectives The incidence of esophageal adenocarcinoma (EAC) arising in patients with long‐segment Barrett's esophagus (LSBE) in Japan remains to be elucidated. This study aims to investigate the incidence of EAC in Japanese LSBE cases. Methods This is a multicenter prospective cohort study involving 32 hospitals throughout Japan. Consecutive patients with Barrett's esophagus with a maximal length of ≥ 3 cm were prospectively enrolled. The study was initiated in June 2011, and the eligible cases were scheduled to undergo subsequent annual endoscopies for 10 years, concluding in December 2021. The cancer incidence was calculated with 95% confidence intervals and expressed as %/year of follow‐up. Results The initial registry comprised 343 participants. After excluding 16 cases with prevalent EAC and 60 cases with < 1 year of follow‐up, a total of 267 cases with LSBE were followed up for 1–10 years (58.0 ± 35.5 months), making the total patient‐years 1290.4. During the observation period, 13 new EACs were identified, leading to an estimated EAC incidence of 1.01 (0.57–1.73)%/year. All the incident EAC cases were diagnosed as early cancers. Individuals who developed EAC demonstrated a higher prevalence of ever smoking (76.9% vs. 33.5%, p = 0.002) compared to those who did not. Conclusions This prospective, 10‐year follow‐up study revealed a substantial EAC incidence in Japanese LSBE cases, 1.01 (0.57–1.73)%/year, similar to values reported in Western countries. This result is a significant indicator for developing effective endoscopy surveillance for Japanese LSBE. UMIN000016043.