Endoscopic diagnosis of early neoplasia of the esophagus with narrow band imaging: Correlations among background coloration and iodine staining findings

Background and Aim It was previously reported that high‐grade intraepithelial neoplasia of the esophagus turns pink within a few minutes after iodine staining (pink‐color sign; PCS); however, iodine staining is uncomfortable. By using narrow band imaging (NBI), color change in the area between the intraepithelial papillary capillary loop (background coloration; BGC) is often observed within the brownish area. The diagnostic usefulness of BGC findings for differentiating high‐grade intraepithelial neoplasia from low‐grade intraepithelial neoplasia was evaluated. Methods In a prospective observational study from September 2010 to August 2012, 285 patients who were in a high‐risk group for esophageal squamous cell carcinoma underwent endoscopic examination. Lesions with both endoscopic findings of dilated intraepithelial papillary capillary loop on NBI and iodine‐unstained areas were studied, in which endoscopic biopsy or endoscopic resection was subsequently performed. The esophageal background mucosa was also evaluated on the basis of the iodine staining pattern (uniform type: Group U, scattered type: Group S). Results One hundred three esophageal lesions in 87 patients were studied. When BGC was used as the differentiation index, sensitivity was 93.8%, specificity was 88.2%, and accuracy was 91.3%. When PCS was used, sensitivity was 97.9%, specificity was 88.2%, and accuracy was 93.2% (P = 0.79). In Group U (n = 54), BGC had an accuracy of 93.8%, and PCS had an accuracy of 92.3% (P = 1.0). On the other hand, in Group S (n = 33), BGC had an accuracy of 86.8%, while PCS had an accuracy of 94.7% (P = 0.27). Conclusions Diagnosis using BGC on NBI may substitute for diagnosis based on PCS in many patients.