Objectives: Salivary gland impairment after high-dose radioiodine (131I) treatment is well recognized. The aim of this study was to determine the protective effect of vitamin E on radiation-induced salivary gland dysfunction in patients undergoing 131I treatment for differentiated thyroid cancer.
Methods: Thirty-six patients with differentiated thyroid carcinoma were enrolled in this study. They were randomly divided into two groups before postsurgical ablation therapy with 3700–5550 MBq 131I: the control group, comprising 17 patients, and the vitamin E group, comprising 19 patients. All 19 patients in the experimental group received vitamin E at a dose of 800 IU/day for a duration of 1 week before to 4 weeks after 131I therapy and the 17 patients in the control group received a placebo for the same duration. Salivary gland function was assessed using salivary gland scintigraphy with intravenous injection of 370 MBq 99mTc-pertechnetate in two phases, one immediately before and the other 6 months after 131I ablative therapy. First-minute uptake ratio, maximum uptake ratio, maximum secretion percentage, and excretion fraction (EF) of each salivary gland were measured and compared between the study phases for the two groups.
Results: There was no significant difference between preablative and postablative salivary scintigraphic indices in the experimental vitamin E group, whereas maximum secretion percentage and EF of the right submandibular gland and EF of the left parotid gland were significantly decreased in the control group. There was also a higher significant decrease in the EF of the left parotid gland in the control group compared with the vitamin E group.