Silent aspiration and swallowing physiology after radiotherapy in patients with nasopharyngeal carcinoma.

Background: There is a paucity of knowledge on dysphagia in patients with nasopharyngeal carcinoma postradiotherapy (NPC post-RT). The purpose of this study was to establish silent aspiration occurrence, safe bolus consistency, and their relationship with swallowing physiology in patients with dysphagic NPC post-RT.

Methods: Eighty-five patients with dysphagic NPC post-RT were assessed across 4 bolus consistencies. We compared penetration-aspiration scores against 4 swallowing physiology impairments.

Results: Silent aspiration occurred in 65.9% of patients with dysphagia, with 64.7% on thin fluids, 35.3% on thick fluids, 11.8% on pureed diet, and 5.9% on soft diet. Multivariate analysis of variance (MANOVA) indicated pharyngeal contraction and swallowing response had significant effect on thick fluids (p = .002), thin fluids (p = .017), and soft diet (p = .031).

Conclusion: Silent aspiration of thin fluids is a common occurrence in dysphagic NPC post-RT, with least aspiration noted on soft diet. Considering the high incidence of silent aspiration, instrumental assessment in this cohort is crucial.