Narrow Band Imaging Endoscopy of the Nasopharynx for Malignancy: An Inter- and Intraobserver Study

Abstract

Objective: To assess interobserver agreement and intraobserver reproducibility when assessing the nasopharynx for malignancy under white light and narrow band imaging endoscopy because the decision to biopsy hinges on the examiner's perceived chance of malignancy.

Methods: An interobserver and intraobserver agreement study utilizing white light and narrow band endoscopic images of the nasopharynx. The setting was an academic referral hospital. Participants were 156 adults with suspected nasopharyngeal carcinoma who underwent white light and narrow band imaging endoscopy and biopsy. Images of the nasopharynges were subsequently scored for malignancy by four otolaryngologists. The nasopharynx was scored on 4-point scales under white light and narrow band imaging endoscopy for the likelihood of malignancy or abnormality, respectively.

Results: Intraclass correlation coefficients for intraobserver agreement for nasopharyngeal malignancy for four observers under white light were 0.86, 0.89, 0.79 and 0.88 (mean 0.855), respectively; and under narrow band imaging they were 0.64, 0.68, 0.64, and 0.66 (mean 0.655), respectively (all P values < 0.001). The coefficient for interobserver reliability under white light was 0.79 (95% confidence interval [CI] 0.76-0.82; P < 0.001), which indicated strong agreement. The coefficient for interobserver reliability under narrow band imaging was 0.56 (95% CI 0.50-0.61; P < 0.001), which indicated moderate agreement.

Conclusions: Intraobserver and interobserver agreement for nasopharyngeal malignancy was strong on white light endoscopy but only moderate on narrow band imaging endoscopy. Agreement may be improved by adopting a standard set of assessment guidelines, including an objective detailed morphological analysis under white light and vasculature analysis under narrow band imaging.

Level of evidence: 2a Laryngoscope, 129:1374-1379, 2019.

Keywords: Nasopharyngeal carcinoma; endoscopy; narrow band imaging; observer variation.