Objective: To compare the real-time diagnostic accuracy of conventional white-light imaging (WLI) endoscopy with that of narrow-band imaging (NBI) endoscopy in patients at high risk for nasopharyngeal carcinoma (NPC).
Design: Prospective study.
Setting: A university tertiary care center.
Patients: From July 28 through October 27, 2009, a total of 211 consecutive patients at high risk for NPC were enrolled. A high-performance endoscopic system equipped with WLI and NBI modes was used for a detailed examination of the nasopharynx during the same endoscopy.
Main outcome measures: Diagnostic efficacies of WLI and NBI were compared with pathologic findings. Lesions were classified according to the detailed morphologic epithelial microvessel observations during NBI.
Results: A total of 285 lesions were detected, including 66 cancerous lesions. The sensitivity and negative predictive values of NBI in NPC screening were significantly higher than those of WLI (93.9% vs 71.2%, P = .001; and 98.1% vs 91.7%, P = .003; respectively); specificity and positive predictive value were not significantly different. During NBI, the presence of superficial, distorted, irregularly shaped microvessels indicated malignant lesions; 53 of 55 lesions (96.4%) with type IV intrapapillary capillary loops were confirmed on histologic testing as malignant. The false-negative and false-positive rates for NBI were 4.5% and 3.6%, respectively.
Conclusions: Narrow-band imaging endoscopy is a promising tool to differentiate nonmalignant from malignant nasopharyngeal lesions on the basis of the morphologic findings of mucosal capillary vessels in vivo. In addition, NBI may increase the diagnostic value of endoscopy in populations at high risk for NPC.