Xerostomia Following Radiotherapy of the Head and Neck Affects Vocal Function

To investigate whether xerostomia induced by wide-field radiotherapy (RT) of the head and neck affects vocal function. We conducted a retrospective cohort study comparing 20 patients with early glottic cancer treated by limited RT of the larynx to 20 patients receiving wide-field RT of the primary tumor site and the lymphatic system of the entire head and neck, including the salivary glands. Salivary and vocal functions, as well as responses to questionnaires on xerostomia and quality of life were compared between groups. Twenty healthy volunteers matched for age, sex, and smoking status were included as controls. The wide-field RT patients showed high xerostomia-related symptom scores and significantly lower values of whole salivary flow rate compared to the limited RT and healthy patients (P < .001). Subjective vocal dysfunction and stroboscopic abnormality were observed in the wide-field RT group (P < .05), but acoustic or aerodynamic profiles showed no significant difference among groups (P > .05). Subjective and objective salivary gland hypofunction was significantly correlated to vocal dysfunction. Our results suggest that xerostomia following extensive RT of the head and neck can affect vocal function. In the treatment of head and neck malignancies, efforts to prevent post-RT xerostomia would be anticipated to contribute to the preservation of vocal function.