Radioiodine therapy effects on salivary gland function in patients with differentiated thyroid cancer [Persian]

Salivary gland involvement is one of the radioiodine therapy complications. Salivary gland scintigraphy in quantitative mode can accurately evaluate salivary gland function. Methods: Salivary gland scintigraphy was performed with Tc-99m Pertechnetate, at the time of iodine therapy as a basic study and then 3 weeks and 3 months afterwards. Ejection Fraction (EF) of parotid and submandibular glands was obtained at each stage of the study. Results: 36 patients (10 male, 16 female) were studied. Mean of EF 3 weeks and 3 months following radioiodine therapy was reduced. There was no significant involvement in 12 patients (33.3%). With increase in radioiodine dose, more salivary gland involvement was noted in 3 weeks (P=0.07), but not after 3 months (P=0.5). No difference was noted between two sexes (P=0.6). Parotid gland involvement was more than submandibular gland (P<0.05), confirming more radiosensitivity of parotid gland. No meaningful relation was noted between salivary gland involvements with age (P=0.1). Parotid gland dysfunction was not related to radioiodine dose, but in submandibular gland, with dosage increase, more involvement was noted (P=0.02). Clinical symptoms were not reliable in evaluating salivary gland dysfunction.