Magnifying Endoscopic Classification for Early Barrett's Neoplasia.

[BACKGROUND] Barrett's esophagus (BE) is becoming increasingly prevalent in both Western countries and Japan. Early diagnosis of Barrett's neoplasia remains challenging. Traditionally, the Seattle protocol, a four-quadrant random biopsy method, has been recommended in Western guidelines. However, this approach has several limitations, including sampling errors, poor adherence, and a high procedural burden. Therefore, magnifying endoscopy has gained attention as a valuable tool for detecting and characterizing neoplastic lesions in patients with BE.

[SUMMARY] This review outlines historical and current developments in magnifying endoscopic classification systems for BE, with a focus on narrow-band imaging (NBI) and acetic acid chromoendoscopy in both Western countries and Japan. Although various NBI-based classifications have been proposed, their complexity and poor reproducibility have limited their widespread clinical adoption. Recently, simplified and standardized classification systems, including the Barrett's International NBI Group classification in the West and the Japan Esophageal Society-Barrett's esophagus classification in Japan, have been introduced. These systems adopt a binary framework, categorizing mucosal and vascular patterns as "regular" (non-neoplastic) or "irregular" (neoplastic). They are easy to apply and have demonstrated high diagnostic accuracy and substantial interobserver agreement. Further simplification and practical refinement are required for broader clinical implementation.

[KEY MESSAGES] Compared with other gastrointestinal cancers, the magnifying endoscopic diagnosis of Barrett's neoplasia remains technically demanding. However, based on a growing body of evidence, endoscopists should be encouraged to actively challenge this area. Continued efforts to simplify and validate the classification systems are essential for their widespread clinical use in BE surveillance.