200 Section - Swallowing Impairment After Treatment in Head and Neck Cancer: Prevalence and Rehabilitation-Relevant Predictors Identified by Videofluoroscopic Swallowing Study

Objectives : To determine the prevalence of dysphagia and to identify rehabilitation-relevant physiological and functional predictors of severe swallowing impairment in patients with head and neck cancer (HNC) following curative-intent treatment.

Design: A retrospective cross-sectional study was conducted using electronic medical records and videofluoroscopic swallowing study (VFSS) data collected between 2017 and 2024 at a tertiary dysphagia rehabilitation clinic, Department of Rehabilitation Medicine, Faculty of Medicine Ramathibodi Hospital. Patients with oral cavity, tongue, pharyngeal, or laryngeal cancer who had completed surgery, radiotherapy, and/or chemotherapy were included. Dysphagia was defined as a Dysphagia Severity Scale (DSS) score ≤ 4. VFSS assessments were analysed using a standardised 4-mL IDDSI Level 2 bolus protocol. Multivariate logistic regression was used to identify independent predictors of severe, function-limiting dysphagia.

Results: Of 295 patients included, 151 (51.2%) demonstrated dysphagia. Multivariate analysis identified three independent predictors of severe dysphagia: lower Functional Oral Intake Scale (FOIS) score (OR = 0.028, p < 0.001), reduced laryngeal elevation (OR = 9.98, p = 0.002), and significant pyriform sinus residue (OR = 7.93, p = 0.024). Surgical involvement of the tongue or oral cavity showed an increased trend toward dysphagia but did not remain statistically significant after adjustment for functional and physiological variables.

Conclusion: Severe dysphagia following HNC treatment is predominantly determined by rehabilitation-modifiable physiological impairments, particularly reduced laryngeal elevation and impaired pharyngeal clearance, rather than by tumour site or treatment modality alone. Functional oral intake (FOIS) closely reflects objective swallowing dysfunction and may serve as a practical rehabilitation outcome measure. These findings support a mechanism-based rehabilitation approach and highlight the importance of long-term swallowing surveillance and targeted intervention to optimise functional recovery in HNC survivors.