The diagnostic utility of narrow band imaging magnifying endoscopy in clinical practice in a population with intermediate gastric cancer risk.

OBJECTIVE: Narrow band imaging (NBI) and NBI-magnifying endoscopy (ME) have been reported to facilitate the diagnosis of intestinal metaplasia (IM) and early gastric cancer (EGC) in high-risk populations. This study aimed at comparing the detection rate of focal gastric lesions by NBI against white light endoscopy (WLE), and examined the utility of NBI-ME in differentiating gastric mucosal pathology in a population with intermediate gastric cancer risk.

METHODS: Chinese patients aged 35-70 years undergoing diagnostic gastroscopy (GIF FQ260Z) by six experienced endoscopists were enrolled prospectively. The sequence of endoscopic evaluation was WLE followed by NBI. Focal lesions were re-examined by NBI-ME. The incremental diagnostic yield of NBI over WLE and ability of NBI-ME to differentiate gastric mucosal pathology were analyzed.

RESULTS: Over a 30-month period, 458 patients (mean age: 52 years; men: 53.7%; Helicobacter pylori positive: 20.1%) were recruited. WLE detected a focal gastric lesion in 43.7% (200/458). WLE made a definitive diagnosis in 148 out of 200 patients (147 benign lesions and one gastric cancer), whereas NBI-ME correctly clarified the nature of the remaining 52 lesions (benign: 51; EGC: one). NBI detected an additional 69 out of 458 lesions (type 0_IIa: 91.3%; type 0_IIb: 8.7%) missed by WLE; the diagnoses based on NBI-ME were IM (67/69), EGC (1/69), and benign lesion (1/69). Interobserver agreement study revealed a κ statistic of 0.71.

CONCLUSION: NBI detected IM missed by WLE. NBI-ME was useful in differentiating the pathology of focal gastric mucosal lesions.