Advances in the Treatment of Head and Neck Cancer: Impact on Swallowing Impairment Thesis Abstract

Chapter one discusses oropharyngeal swallowing impairment due to head and neck cancer (HNC). Its complexity and severity arise from the dual physiological and structural changes to swallowing musculature. Expectations of recovery are difficult to predict due to the variety of treatment modalities, demographic and clinical characteristics, the risk of recurrence, implications of malnutrition, and the progressive nature of radiation fibrosis. The second chapter reported on a systematic review and meta-analysis describing the relationship between radiation dose to critical swallowing structures. The third chapter explores this relationship in the definitive and post-operative setting. Chapter four evaluated swallowing impairment following transoral robotic surgery (TORS) for HNC using fibreoptic endocscopic evaluation of swallowing. A significant deterioration in swallow function, characterised by a heavy secretion load, pharyngeal residue, laryngeal penetration and aspiration was identified in most participants. The fourth chapter evaluated intensity modulated radiation therapy (IMRT) and TORS at 12 months post-treatment for oropharyngeal cancer. A statistically significant advantage for TORS was identified, when adjuvant radiotherapy which involved the primary site could be avoided. This finding correlates with one of the primary purposes for TORS, which was to achieve a deintensification of radiation, known to impair swallowing function as demonstrated in earlier chapters. This thesis describes how technological advances in head and neck cancer treatment have changed the expectations for functional recovery. Both IMRT and TORS represent approaches which are intended to preserve critical swallowing structures in an effort to preserve swallowing function after treatment. While encouraging, results presented here demonstrate significant challenges which impact quality of life. Utilisation of instrumental assessment in this population remains imperative to characterise swallow physiology, particularly in light of high rates of silent aspiration and pharyngeal residue. This information will guide rehabilitation programs