RADIATION-INDUCED XEROSTOMIA - PATHOPHYSIOLOGY, CLINICAL COURSE AND SUPPORTIVE TREATMENT

Xerostomia, or oral dryness, is one of the most common complaints expe rienced by patients who have had radiotherapy of the oral cavity and n eck region, The hallmarks of radiation-induced damage are acinar atrop hy and chronic inflammation of the salivary glands, The early response , resulting in atrophy of the secretory cells without inflammation mig ht be due to radiation-induced apoptosis, In contrast, the late respon se with inflammation could be a result of radiation-induced necrosis, The subjective complaint of a cry mouth appears to be poorly correlate d with objective findings of salivary gland dysfunction. Xerostomia, w ith secondary symptoms of increased dental caries, difficulty in chewi ng, swallowing and speaking and an increased incidence of oral candidi asis, can have a significant effect on tile quality of life. At presen t there is no causal treatment for radiation-induced xerostomia. Tempo rary symptomatic relief can be offered by moistening agents and saliva substitutes, and is the only option for patients without residual sal ivary function. In patients with residual salivary function, oral admi nistration of pilocarpine 5-10 mg three times a day is effective in in creasing salivary flow and improving the symptoms of xerostomia, and t his therapy should be considered as the treatment of choice, Effective ness of sialogogue treatment requires residual salivary function, whic h emphasizes the potential benefit from sparing normal tissue during i rradiation. The hypothesis concerning the existence of early apoptotic and late necrotic effects of irradiation on the salivary glands theor etically offers a way of achieving this goal.