Saliva Substitute Mouthwash in NPC Survivors With Xerostomia: A Randomized Controlled Trial

Inclusion Criteria: * Patients who have completed radiation therapy or concurrent chemotherapy and radiation therapy for nasopharyngeal carcinoma (clinical staging of tumour based on AJCC staging (8th edition) T1-4, N0-3, M0). * Patients age 20 years old to 85 years old. * Two months has elapsed since last dose of chemotherapy or radiotherapy * Karnofsky performance score more than 70%. * Patients complaining of xerostomia. Exclusion Criteria: * Those contraindicated to using mouthwash (established allergy to lactoperoxidase, lysozyme, glucose oxidase lactoferrin, cetylpyridinium chloride and xylitol) * Patients with residual or recurrent disease. * Patients who received intensity modulated radiation therapy. * Patients with ongoing oral mucositis (WHO Oral Mucositis grading I to IV) * Patients with facial, glossopharyngeal. vagus and hypoglossal nerve palsy/ paresis. * Patients who had any form of concurrent treatment protocols (hormonal, alternative, antiviral, sialogogues or photodynamic therapy) during the study duration. * Patients with autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis and Sjớgren syndrome.