Effects of first radioiodine ablation on functions of salivary glands in patients with differentiated thyroid cancer

The aim of this study was to evaluate the effects of the first radioactive iodine (131I) therapy on functions of salivary glands in patients with differentiated thyroid carcinoma (DTC). There were 36 consented patients with DTC enrolled in this study, who received 3.7 GBq (100mCi) 131I for ablation after total thyroidectomy. Salivary gland function was assessed using salivary gland scintigraphy in two phases, one 4 hours before and the other 6 months after 131I therapy (both under thyrotropin stimulation condition). Quantitative parameters including uptake fraction (UF), uptake index (UI), excretion fraction (EF), and excretion ratio (ER) were measured and compared. Blood parameters were also compared. Associations between sex and outcome of the first 131I therapy as well as individual salivary gland function were measured. Wilcoxon Signed Rank Sum test and χ2 test were used for statistical analysis. When compared between pre-ablation and post-ablation, UF of bilateral parotid and submandibular glands were significantly increased (all P