Physiology of the Swallow and the Impact of Thickened Liquids in Post-radiation Head and Neck Cancer Patients

There is an increasing prevalence of head and neck cancers (HNC) in Canada and the United States, with approximately 52,000 new cases every year, and approximately 9,500 deaths annually due to the disease in the United States alone. In Canada, there are approximately 220 new diagnoses of oropharyngeal cancer and an estimated 120 deaths resulting from this cancer type per annum. Patients with oropharynx cancers commonly are undergo radiation treatment for their disease, which has good results in terms of tumor control. While survival is improving, patients are left suffering from radiation-induced toxicities. Dysphagia (swallowing impairment) is one of the side effects that can become a long-term, pervasive issue. Individuals with dysphagia are at risk for aspiration (food/liquid entering into the airway). Aspiration is estimated to occur in 30-69% of HNC patients after radiation treatment (range of 1-12 months) and is often silent (i.e. with no overt symptoms). Thickened liquids are commonly used to reduce aspiration in the neurogenic dysphagia population but there is a gap in our knowledge with regards to the impact that viscosity and texture modification have on swallowing in the head and neck cancer population. The studies in this dissertation will examine the potential of thickened liquids to reduce aspiration in patients who present with unsafe swallowing onthin liquids after the completion of radiation treatment (post-3-6 months) for cancers focal to the oropharynx.Ph.D