Diagnostic Ability of Magnifying Endoscopy Compared to Biopsy Examination for Early Gastric Cancer prior to Endoscopic Submucosal Dissection.

Introduction: Biopsy-specimen examination is the gold standard for the preoperative histological diagnosis of early gastric cancer (EGC). However, few studies have compared the diagnostic accuracies of biopsy and magnifying endoscopy with narrow-band imaging or blue laser imaging (ME-NBI/BLI). Thus, we compared the diagnostic accuracy of biopsy specimens and ME-NBI/BLI to evaluate whether ME-NBI/BLI is a feasible preoperative diagnostic tool for EGC.

Methods: This retrospective single-center study enrolled 185 patients who underwent gastric endoscopic submucosal dissection (ESD) between January and December 2018. The sensitivity and positive predictive value (PPV) of the histological diagnosis of ME-NBI/BLI and biopsy were evaluated. Logistic regression analysis was used to assess the risk factors for the misdiagnosis of biopsy specimens and ME-NBI/BLI.

Results: In total, 158 patients with EGC were analyzed. Sensitivities of biopsy and ME-NBI/BLI were 1 and 0 for adenomas (p = 0.333), 0.693 and 0.971 for differentiated adenocarcinomas (p < 0.001), and 0.688 and 0.625 for undifferentiated adenocarcinomas (p > 0.999), respectively. PPVs of biopsy and ME-NBI/BLI were 0.077 and 0 for adenomas (p > 0.999), 0.960 and 0.958 for differentiated adenocarcinomas (p > 0.999), and 0.750 and 0.750 for undifferentiated adenocarcinomas (p > 0.999), respectively. The underdiagnosis rate for differentiated adenocarcinomas was significantly higher in biopsy examination than in ME-NBI/BLI (27.9% vs. 0%, respectively, p < 0.001).

Conclusion: ME-NBI/BLI had a higher sensitivity than biopsy examination for the preoperative diagnosis of differentiated adenocarcinomas. Therefore, performing ME-NBI/BLI for these lesions may be preferable regardless of their diagnosis as noncancerous lesions from biopsy specimens.