Salivary and lacrimal gland dysfunction (sicca syndrome) after radioiodine therapy

Salivary gland dysfunction has been described in patients undergoing radioiodine therapy but associated lacrimal gland dysfunction (sicca syndrome) has never been reported. We conducted a prospective cohort study with follow-up for up to 3 y in a tertiary care university center to determine the prevalence of sicca syndrome in patients after high-dose radioiodine treatment. Methods: From January 1990 to December 1995, all patients undergoing radioiodine therapy (n = 79) with a standard dose of 925 MBq to 18.5 GBq (25-500 mCi) were interviewed using a standardized questionnaire to determine subjective ocular and oral dryness and were examined for objective lacrimal and salivary gland dysfunction. Results: After radioiodine treatment, 32.9% of the patients reported subjective xerostomia and 25.3% reported subjective xerophthalmia in the first year of follow-up. Xerostomia persisted to the second year of follow-up in 20.3% of cases and was still present >3 y after the last dose of radioiodine in 15.2% of cases. Xerophthalmia persisted to the second year of follow-up in 17.7% of cases and was still present in the third year of follow-up in 13.9% of cases. Severe xerostomia occurred in 4 patients. Reduced salivary and lacrimal gland function was documented in 40 (50.6%) and 14 (17.7%) of the 79 cases, respectively, in the first year of followup. Objective xerostomia persisted in 13.9% of cases to the second year of follow-up and was still present in all patients >3 y after the last radioiodine application. Keratoconjunctivitis sicca persisted in 11 patients (13.9%) to the second year of follow-up but was only present in 6 patients (7.6%) >3 y after the last radioiodine application. Additionally, 28/79 patients (35.4%) who had a normal salivary gland scintigraphy previously showed reduced salivary gland function in the third year of follow-up. No significant dependence on cumulative treatment was found for objective xerostomia or xerophthalmia, but doses >11.1 GBq (300 mCi) were related to stage 3 dysfunction on salivary gland scintigraphy, Conclusion: Salivary and lacrimal gland dysfunction (sicca syndrome) is relatively frequent after radioiodine therapy. In most cases this is a transient side effect, but in some patients it may persist for a long period or appear late.