Diagnostic performance of magnifying blue laser imaging versus magnifying narrow-band imaging for identifying the depth of invasion of superficial esophageal squamous cell carcinoma.

Identifying the depth of invasion (DOI) of superficial esophageal squamous cell carcinoma (SESCC) is crucial to determine the indication for endoscopic resection. This retrospective, single-center study aimed to evaluate the diagnostic efficacy of magnifying blue laser imaging (M-BLI) compared with white-light imaging (WLI) or magnifying narrow-band imaging (M-NBI) for identifying the DOI of SESCC. A total of 160 consecutive patients with SESCCs who underwent endoscopic submucosal dissection were enrolled in this study. Still images of the lesion were obtained using WLI, M-BLI and M-NBI prior to endoscopic submucosal dissection. Three endoscopists retrospectively evaluated the DOI using WLI according to non-magnifying findings and using M-BLI and M-NBI images according to the magnifying endoscopic classification of the Japan Esophageal Society. The diagnostic accuracy of each modality was compared using the chi-square test. The DOIs in 160 SESCCs evaluated pathologically were as follows: invasion to the epithelium or lamina propria mucosa in 130, invasion to the lamina muscularis mucosa or submucosa to a depth ≤ 200 μm in 18, and invasion to the submucosa to a depth > 200 μm in 12. The overall diagnostic accuracy rates of WLI, M-BLI, M-NBI, WLI with M-BLI (WLI + M-BLI), and WLI with M-NBI (WLI + M-NBI) were 86.9, 91.2, 90.6, 95.6 and 94.4%, respectively. Significant differences were found between WLI and WLI + M-BLI or WLI + M-NBI (P = 0.006 and P = 0.021, respectively). The concordance of intrapapillary capillary loops between M-BLI and M-NBI was 91.2%. The kappa coefficients for interobserver variability of the three endoscopists for M-BLI and M-NBI were 0.728/0.649/0.792 and 0.729/0.666/0.791, respectively, while those for intraobserver variability were 0.919/0.746/0.778 and 0.736/0.720/0.745, respectively. Similar to M-NBI, M-BLI was useful in predicting the DOI of SESCCs.