Nasolacrimal Duct Obstruction after Radioactive Iodine Therapy for Thyroid Cancer

Hwang, Moon Won; Lee, Eung; Yang, Jae Wook

Abstract

PURPOSE
To investigate the clinical manifestation of nasolacrimal duct obstruction after radioactive iodine therapy for thyroid cancer.
METHODS
The authors examined 622 patients who were treated with radioactive iodine therapy after the operation for thyroid cancer from January 2009 to December 2011. Fourteen patients (18 eyes) were diagnosed nasolacrimal duct obstruction based on the lacrimal irrigation test, lacrimal probing test and dacryocystography in our oculoplastic clinic. We analyzed the dose of radioactive iodine therapy, number of treatments, clinical manifestation and treatment type by retrospectively reviewing the patients' medical records.
RESULTS
The mean radioactive iodine dose (215.7 +/- 23.1 mCi, p = 0.01) and the mean number of treatments (1.36 +/- 0.50, p< 0.001) were significantly greater in 14 patients who had nasolacrimal duct obstruction than in patients who did not. The average onset of tearing symptoms occurred 10.2 months after radioactive iodine therapy. The mean time between correct diagnosis and therapy was 18.4 months. Three patients (3 eyes) had occlusion at the common cannaliculus and 11 patients (15 eyes) had occlusion at the nasolacrimal duct. Ten patients (13 eyes) underwent endonasal dacryocystorhinostomy for complete obstruction and 4 patients (5 eyes) underwent silicone tube intubation for partial obstruction.
CONCLUSIONS
Nasolacrimal duct obstruction is a rare complication associated with radioactive iodine therapy for thyroid cancer, thus, clinicians should be aware of this complication and refer patients with symptoms of epiphora to the oculoplastic department for specialized evaluation and treatment.