Is blue light imaging without magnification satisfactory as screening for esophageal squamous cell carcinoma? Post-hoc analysis of multicenter randomized controlled trial

Objectives: Narrow light observation is currently recommended as an alternative to Lugol chromoendoscopy (LCE) to detect esophageal squamous cell carcinoma (ESCC). Studies revealed little difference in sensitivity between the two modalities in expert settings; however, these included small numbers of cases. We aimed to determine whether blue light imaging (BLI) without magnification is satisfactory for preventing misses of ESCC. Methods: This was a post-hoc analysis of a multicenter randomized controlled trial targeting patients at high risk of ESCC in expert settings. In this study, BLI without magnification followed by LCE was performed. The evaluation parameters included: (i) the diagnostic abilities of ESCC; (ii) the endoscopic characteristics of lesions with diagnostic differences between the two modalities; and (iii) the color difference between cancerous and noncancerous areas in BLI and LCE. Results: This study identified ESCC in 49 of 699 cases. Of these cases, nine (18.4%) were missed by BLI but detected by LCE. In per-patient analysis, the sensitivity of BLI was lower than that of LCE following BLI (83.7% vs. 100.0%; P = 0.013), whereas the specificity and accuracy of BLI were higher (88.2% vs. 81.2%; P < 0.001 and 87.8% vs. 82.5%; P < 0.001, respectively). No significant endoscopic characteristics were identified, but the color difference was lower in BLI than in LCE (21.4 vs. 25.1; P = 0.003). Conclusion: LCE following BLI outperformed BLI in terms of sensitivity in patients with high-risk ESCC. Therefore, LCE, in addition to BLI, would still be required in screening esophagogastroduodenoscopy even by expert endoscopists.