Background: Radiation-induced xerostomia is a common oral complication of patients with head and neck cancer (HNC) undergoing radiotherapy (RT). This can lead to a series of functional oral disorders, particularly dental caries, and ultimately negatively affect their oral health and health-related quality of life (HRQoL).

Aims: The overall aim of this thesis was to understand the living experience of radiation-induced xerostomia and to determine the effects of an integrated supportive program based on multicomponent oral care strategies in Chinese patients with HNC.

Methods: A qualitative descriptive study was conducted to describe how patients (13 men and 7 women) with HNC experienced radiation-induced xerostomia (Ⅰ). A cross-sectional study of patients (n=80) with HNC was conducted to accomplish the validation of the Chinese version of the xerostomia questionnaire (XQ) (Ⅱ). A randomized controlled trial (n=79) was conducted to determine the effect of an integrated supportive program (with a combination of face-to-face health education and coaching sections) on xerostomia, saliva characteristics (Ⅲ), oral health, and HRQoL (IV).

Results: Five categories emerged from the manifest content of the interviews: communication problems, physical problems, psychosocial problems, treatment problems, and relief strategies. The meaning underlying these categories formed a theme, which was the latent content of the interview: Due to lack of information regarding xerostomia, patients had to find their own ways to deal with the problem (Ⅰ). The Chinese version of XQ was a unidimensional scale (1-factor solution explained 75.6 of the total variance) and had good psychometric properties with excellent internal consistency (Cronbach’s α of 0.95), test-retest reliability (intraclass correlation coefficient of 0.92), and good criterion-related validity and content validity (Ⅱ). The integrated supportive program showed significant inter-group differences in xerostomia (P=0.046), unstimulated saliva flow rate (P=0.035), plaque index (P=0.038), Oral Health Impact Profile-14 (P=0.002), and Functional Assessment Cancer Therapy-Head & Neck (P=0.001) over the 12-month follow-up, with better outcomes in the intervention group (Ⅲ & Ⅳ).

Conclusion: This thesis contributes knowledge regarding the experiences of living with xerostomia from a patient perspective, noting that xerostomia has a profound impact on a patient's physical, psychological, and social quality of life. There is lack of assessment tools for xerostomia in the Chinese population, and the Chinese version of XQ proved to be a valid and simple self-administered tool to measure and monitor the xerostomia level in patients with HNC. The integrated supportive program with multicomponent oral care strategies demonstrated positive effects on relieving xerostomia, increasing unstimulated saliva flow rate, and improving their oral health and HRQoL. These findings provide a basis for improvement in the management of xerostomia and oral health of Chinese patients with HNC through the integration of oral care in nursing.