Optimizing exercise programs for chronic radiation-associated dysphagia in head and neck cancer survivors

Abstract

Persistent dysphagia is a common and debilitating sife effect in head and neck cancer (HNC) survivors treated with (chemo)radiotherapy. Radiation exposure can affect not only the tumour but also the surrounding swallowing muscles and cranial nerves that are essential for safe and efficient swallowing. Consequently, patients may develop oropharyngeal muscle weakness, fibrosis, and impaired swallowing function, leading to reduced oral intake, an increased risk of aspiration, and a substantial decline in quality of life. The HIT-CRAD (Home-based Intensive Treatment of Chronic Radiation-Associated Dysphagia) study was designed to identify the most effective rehabilitation approach for chronic radiation-associated dysphagia (CRAD). In this multicenter randomized controlled trial, 54 HNC survivors with CRAD were allocated to one of three intervention groups: intensive oropharyngeal strength training , sequential strength and skill-based swallowing training combined with sham neuromodulation, or sequential strength and skill-based swallowing training combined with active neuromodulation. The study demonstrated high feasibility and acceptability of all intervention programmes. Overall adherence remained above 75% throughout the eight-week intervention period. Both the exercise programmes and the neuromodulation procedure were safe and well tolerated. All treatment groups showed significant improvements in swallowing function, oropharyngeal muscle strength, and functional oral intake. However, the sequential combination of strength and skill-based swallowing training resulted in the greatest improvements in oral intake and quality of life. No additional benefit of neuromodulation was observed beyond the effects of the exercise interventions. At baseline, patients in the HIT-CRAD cohort who were more than 5 years after (chemo)radiotherapy exhibited more pronounced swallowing difficulties and reduced tongue strength compared to those who were treated more recently. Importantly, meaningful improvements were found irrespective of the time elapsed since cancer treatment, indicating that intensive dysphagia rehabilitation remains beneficial even many years after (chemo)radiotherapy. An additional exploratory retrospective analysis offered preliminary insights into the impact of primary C/RT on the biomechanical aspects of swallowing. A valuable next step will be to tailor rehabilitation programs accordingly. In conclusion, the results of this PhD provide strong evidence that a sequential strength-and-skill training programme is the most effective rehabilitation strategy for improving oral intake and quality of life in HNC survivors with CRAD, regardless of the time elapsed since cancer treatment.