Incidence and risk factors for radioactive iodine-induced sialadenitis.

BACKGROUND: Radioactive iodine (131I) is one of the treatments of hyperthyroidism and differentiated thyroid carcinoma (DTC). Swelling of salivary glands are one of the possible side effects of this treatment, known as radioactive iodine-induced sialadenitis (RAIS). The prevalence of RAIS varies widely and no specific risk ratio has been established. OBJECTIVES: To determine the incidence of RAIS, analysing the epidemiological data and tumour- and treatment-related factors that may influence the development of the disease. MATERIAL AND METHODS: 197 patients who received radioiodine treatment between 2015 and 2017 were studied (76.6% women). The variables studied were age, gender, weight, height, and body mass index; presence of high blood pressure, dyslipidemia, diabetes, and thyroid diseases; cumulative radioiodine dose, presence of sialadenitis, affected salivary gland, and the time of onset. RESULTS: 14 patients developed sialadenitis (78.6% women), all with DTC. The incidence of sialadenitis was 3.4% overall and 6.3% among DTC patients. Furthermore, we found that higher cumulative radioiodine doses confer a greater risk of developing sialadenitis, with a hazard ratio of 1.009 (p = .001). No association was found between the epidemiologic data studied and sialadenitis. CONCLUSIONS: In this series, a dose-dependent relationship was found between radioiodine treatment and sialadenitis.