Clinical and Demographic Characteristics of Tearing in Patients after Radioiodine Ablation for Differentiated Thyroid Cancer.

Background: Radioiodine ablation is a frequent procedure for the management of thyroid cancer. In several cases, this treatment is followed by secondary acquired nasolacrimal duct obstruction (SALDO). Risk factors for the development of SALDO are not defined yet.Aim - to provide clinical and demographic characteristics of tearing in patients after radioiodine treatment.Materials and methods: Material was obtained by a phone survey of 588 patients who underwent radioiodine treatment. Age and gender of the respondent, strength of administered medication, and time since the end of treatment were taken into account. Patients were asked if they had dry mouth and/or tearing at the time of the survey. Differences in values were found using parametric and nonparametric criteria, Pearson's χ2 test. Differences were considered statistically significant at p ≤ 0.05.Results: Severe tearing was reported by 8.8% of patients after single-dose radioiodine treatment and 23.9% of patients after repeated one. The age of patients with severe tearing and without it showed statistically significant difference in patients after single-dose radioiodine treatment and no statistically significant difference in patients after repeated radioiodine treatment. Administration of 4 GBq or more in patients aged 61-71 years results in 4-fold increase of the risk of severe tearing. Dry mouth causes 3.6-fold increase of the risk of developing severe tearing.Conclusion: Finding risk factors for SALDO development after radioiodine therapy in the future will contribute to an individualized approach to the prevention of this complication. Development of preventive measures is one of the tasks facing researchers.