Magnifying endoscopy with narrow band imaging for predicting the invasion depth of superficial esophageal squamous cell carcinoma

The invasion depth of superficial esophageal squamous cell carcinoma is important in determining therapeutic strategy. The aim of this study was to prospectively investigate the clinical utility of magnifying endoscopy with narrow band imaging compared with that of non‐magnifying high‐resolution endoscopy or high‐frequency endoscopic ultrasonography in predicting the depth of superficial esophageal squamous cell carcinoma. The techniques were carried out in 72 patients with 101 superficial esophageal squamous cell carcinomas, which were then resected by either endoscopic mucosal resection or esophagectomy. The histological invasion depth was divided into two: mucosal or submucosal carcinoma. We investigated the relationship between endoscopic staging and histology of tumor depth. Non‐magnifying high‐resolution endoscopy, magnifying endoscopy with narrow band imaging, and high‐frequency endoscopic ultrasonography had overestimation/underestimation rates of 7/5, 4/4 and 8/3%, respectively. The sensitivity rates for the three techniques were 72, 78, and 83%, respectively, and the specificity rates were 92, 95, and 89%, respectively. There were no statistically significant differences among the three endoscopic techniques. Clinical utility of magnifying endoscopy with narrow band imaging does not seem to be significantly different from that of non‐magnifying high‐resolution endoscopy or high‐frequency endoscopic ultrasonography in predicting the depth of superficial esophageal squamous cell carcinoma. Magnifying endoscopy with narrow band imaging may have potential to reduce overestimation risks of non‐magnifying high‐resolution endoscopy or high‐frequency endoscopic ultrasonography.