Nasolacrimal Drainage System Obstruction from Radioactive Iodine Therapy for Thyroid Carcinoma

Ophthalmic complications of 131I therapy, including ocular dryness, have been recently investigated and described. However, nasolacrimal drainage system obstruction (NDSO), complicating 131I therapy, has not been previously well appreciated or characterized. One of our patients developed bilateral complete nasolacrimal duct obstruction after 131I therapy that prompted awareness of this potential complication. Over 16 months, 423 patients with epithelial-derived thyroid cancer were provided routine clinical care; 390 of these patients had received 131I ablation or therapy, and 10 patients subsequently reported epiphora. All had evidence of NDSO disease after a mean cumulative 131I dose of 17,279 ± 2,923 MBq (467 ± 79 mCi), with a mean individual 131I dose of 6,660 ± 555 MBq (180 ± 15 mCi). Symptoms appeared 6.5 ± 1.4 (range, 3–16) months after the last 131I dose, whereas the mean time from symptom onset to correct diagnosis was 18 ± 5 months. A causal relationship between 131I administration and NDSO is strongly suspected. Patients reporting epiphora should be evaluated promptly by an oculoplastic surgeon.