Evaluation of gastric cancer diagnosis using new ultrathin transnasal endoscopy with narrow‐band imaging: Preliminary study

BACKGROUND AND AIM: The new developed ultrathin transnasal endoscope, the GIF-XP290N, makes possible a resolving power similar to the GIF-H260 at a distance of 3 mm. In this study, using the GIF-XP290N, we evaluated whether endoscopic diagnosis (discrimination between benign and malignant) of gastric lesions is possible using nonmagnified narrow-band imaging (NBI) endoscopy. METHODS: The subjects were 255 consecutive patients who underwent screening of the gastrointestinal tract using new ultrathin transnasal endoscopy. Their average age was 65.2 ± 11.4 years. The male-female ratio was 2.5:1. All cases were examined using conventional white-light imaging (WLI) and nonmagnified NBI. When a depressed lesion was detected in the stomach, it was examined using WLI, then NBI close examination (at about 3 mm). We observed the mucosal structure of the lesion using close visualization with NBI. Concerning mucosal structural changes, we looked for a clear demarcation line between the lesion and the surrounding mucosa, and loss, irregularity, or nonuniformity of the lesion mucosal microsurface pattern. RESULTS: A total of 52 depressed lesions were examined. The histological diagnosis was cancer for 8 lesions, and noncancer for 44 lesions. WLI examination yielded a sensitivity of 50.0% (4/8), specificity of 63.6% (28/44), and accuracy 61.5% (32/52). On the other hand, NBI close examination yielded a sensitivity of 87.5% (7/8), specificity of 93.2% (41/44), and accuracy of 92.3% (48/52), significantly higher. CONCLUSION: NBI close examination using ultrathin transnasal endoscopy enables mucosal diagnosis even without magnification and was considered to be an effective technique for improving endoscopic diagnosis.