Examination protocol
gastrointestinal tumors, ESCCs
GASTROINTESTINAL TUMORS
The examination protocol consisted of detection by non-ME with NBI, characterization by ME with NBI, and biopsy of detected lesions (Fig. 
Flowchart of the examination protocolAI, artificial intelligence; ME, magnifying endoscopy; NBI, narrow band imagingThe endoscopic procedures were performed using the following equipment: GIF-H290Z, GIF-H260Z, GIF-Q240Z, GIF-XZ1200, or GIF-EZ1500 endoscopes (Olympus, Tokyo, Japan) with an EVIS X1 system (Olympus, Tokyo, Japan). Five endoscopists who had been routinely diagnosing gastrointestinal tumors performed all endoscopic procedures. These five endoscopists were board-certified fellows of the Japan Gastroenterological Endoscopy Society or had equivalent qualifications, and all had diagnosed over 300 cases of ESCCs with endoscopic images. The five endoscopists had a median endoscopy experience of 8 years (range 6–26 years) and the median number of esophagogastroduodenoscopies performed was 4500 (range 3000–25,000).