Discussion
xerostomia, dry mouth, anxiety
ADVERSE EFFECTS, XEROSTOMIA, ORAL DRYNESS, EVENTS, DRY MOUTH
Up to this date, this is the first RCT showing that trehalose oral spray can improve dry mouth symptoms and xerostomia-related quality of life in a comparable fashion to a CMC spray. Saliva substitutes containing CMC are prescribed to relieve xerostomia and improve quality of life [Though, this study has its own limitations. Subjects did receive different radiotherapy treatment regimens, however, the radiation exposure of the parotid gland (on both sides) to such regimens was similar among all subjects. The radiation exposure was not assessed in the submandibular and sublingual glands. Secondly, polypharmacy may have affected xerostomia levels since a comprehensive medication list could not be collected during this RCT. Thirdly, subjects may have been affected by COVID-19 pandemic and in such cases, they refused to commute to the hospital. To overcome this, questionnaires were performed over the phone, and this may introduce some information bias.Radiation exposure after radiotherapy was evenly distributed between two intervention groups according to parotid gland radiation dose assessments. Mean parotid gland doses were 24–28 Gy in our study participants. Previous studies [Both CMC and trehalose oral sprays improved xerostomia-related quality of life particularly in physical, pain/discomfort, and psychological dimensions. However, major changes in the social dimension were not seen, which could relate to COVID-19 lockdown policies. The number of social events were dramatically reduced during the COVID-19 lockdown, and anxiety levels increased. Some participants avoided or were denied hospital visits for saliva collection, but the post intervention questionnaires were implemented through the phone.The recovery of salivary gland function after radiation is related to radiation dose, radiation technique, concomitant chemotherapy and the involvement of radiation damage to salivary glands. Oral dryness is common, but improves over time in 10–30% of HNC patients [Adverse effects of CMC when taken as a saliva substitute therapy have been reported [