Abstract

Head and neck radiotherapy is one of the main causes of salivary dysfunction. The salivary glands are extremely sensitive to ionizing radiation, presenting irreversible structural alterations, with alterations in salivary flow and composition. The present study aimed to provide an update on the mechanisms of prevention of the radiotherapy-induced salivary hypofunction through an integrative literature review. Pre-clinical studies in animal models, controlled clinical trials and meta-analysis were selected. Preventive pharmacological methods were approached such as the use of cholinergic agonists (pilocarpine and bethanechol), antioxidant substances, acupuncture, low-level laser therapy (LLLT) and submandibular gland transfer. Studies with bethanechol, pilocarpine and amifostine corroborate the prophylactic effect of these drugs on the salivary glands. However, they have side effects which contraindicate its use in several patients. Researches about acupuncture and LLLT show preservation of salivary flow in oncologic patients with no or little side effects. Patients who undergo the submandibular gland transfer technique previously to radiotherapy also have less incidence of xerostomia. In general, the therapies presented in this review can help to prevent the symptoms caused by the hypofunction of the irradiated salivary glands. Nevertheless, at this point there are no techniques or drugs capable of completely preventing the development of radiotherapy-induced salivary dysfunctions. Controlled clinical trials are still needed in order to find therapeutical methods that preserve the glandular structure undergoing ionizing radiation, thus preventing hyposalivation and xerostomia..

Abbreviations: Salivary gland; Radiotherapy; Radioprotector; Xerostomia; Hyposalivation