Purpose: Narrow band imaging (NBI) enhances mucosal vasculature and could help in the identification of recurrences. We assessed the effectiveness of NBI with flexible video-endoscope in the early detection of recurrence after treatment of head and neck squamous cell carcinoma, its diagnostic advantage over high-definition white-light (HD WL) endoscopy, also in relation to recurrence site, and the influence of previous radiotherapy (RT) or chemotherapy (CT). Moreover, we investigated the association between index tumor site and the risk of developing recurrence, and the relation between index tumor site and recurrence site. Methods: From January 2018 to November 2020, 160 patients previously treated with surgery and/or RT ± CT were evaluated using NBI with flexible video-endoscope. Sensitivity, specificity, positive/negative predictive value, and accuracy were calculated for NBI and HD WL, and compared using the McNemar test. The Fisher exact test was used to compare the other associations investigated. Results: The difference between NBI and HD WL sensitivity was statistically significant (p < 0.001). The NBI diagnostic advantage was 62.5%, highest in the hypopharynx (p = 0.05), and was not influenced by previous RT or CT (p = 0.49). Index tumor site statistically related with recurrence site (p < 0.001), but not with the risk of developing recurrence (p = 0.81). Conclusion: NBI with flexible video-endoscope could represent a valid option to detect recurrence early during the follow-up, especially in a difficult-to-visualize site such as the hypopharynx.
