Narrow-Band Imaging Detects Lesions Overlooked by White-Light Imaging during Endoscopic Examinations

Helicobacter pylori infection is a well-recognized significant risk factor for developing gastric cancer, making regular screenings for early detection particularly vital in high-prevalence areas. While modern endoscopy techniques allow for the removal of significant neoplasms, the focus is increasingly on the early identification of smaller lesions. Despite these advancements, the detection of subtle epithelial neoplasms, which represent about a quarter of all newly diagnosed small neoplasms, poses a challenge. Now, new research suggests that employing magnifying narrow-band imaging at low magnification (LM-NBI) following routine white-light imaging (WLI) could improve the detection rate of lesions that WLI might miss.

In order to address a research gap regarding the effectiveness of periodic LM-NBI screenings compared to conventional magnifying endoscopy (CE), a study was undertaken at Nagashima Clinic (Yamagata, Japan). This study aimed to ascertain the effectiveness of annual endoscopic exams utilizing LM-NBI for the entire stomach after initial WLI, focusing on identifying gastric neoplasms. In both the LM-NBI and CE groups, the initial endoscopy standardized the baseline, followed by up to five annual endoscopies. The inaugural annual examination for the LM-NBI group occurred between April 2019 and March 2020, and for the CE group, it took place between April 2015 and March 2016. A retrospective examination of medical records was conducted to evaluate gastric tumor detection.

The study's findings showed that among the 388 patients in the LM-NBI group and the 381 in the CE group, 15 and 5 patients, respectively, were diagnosed with gastric neoplasia, excluding one case of mucosa-associated lymphoid tissue lymphoma. Each detected case was classified as epithelial neoplasia. The endoscopic procedures were safely executed without any complications necessitating further intervention. According to the Cox proportional hazards model, there was a hazard ratio of 2.78 (95% CI, 1.01–7.64). Kaplan–Meier analysis (p = 0.039, log-rank test) demonstrated that annual LM-NBI was more effective than CE in detecting gastric neoplasia.

This historical case-control study crucially demonstrates a nearly threefold increase in the detection rate of neoplastic lesions in the stomach through annual LM-NBI following WLI compared to CE. It is the first study to confirm the effectiveness of annual endoscopy using LM-NBI in spotting gastric neoplasms, especially in areas with map-like redness or in atrophic/metaplastic mucosa. The study also emphasizes the value of conducting both WLI and NBI examinations in tandem to ensure thorough lesion detection, acknowledging the tendency of observers to concentrate on color changes in WLI.

“While LM-NBI successfully identified lesions overlooked by WLI, its efficacy in detecting diffuse-type carcinomas remains uncertain, especially for signet ring cell carcinomas,” noted Ryuichi Nagashima, sole author of the study. “Further studies are needed to clarify the superiority of LM-NBI over other image-enhanced endoscopies, such as blue laser imaging bright and linked color imaging, to establish its optimal role in clinical practice.”

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