Nasolacrimal duct obstruction following radioactive iodine 131 therapy in differentiated thyroid cancers: review of 19 cases

BACKGROUND Radioactive iodine 131 ((131)I) therapy has long been used in the treatment of differentiated thyroid cancers (DTC). While salivary and lacrimal glandular complications secondary to (131)I therapy are well documented, there is little in the literature addressing nasolacrimal duct obstruction (NLDO). We aimed to evaluate the frequency of (131)I therapy-acquired NLDO, its correlation to (131)I therapy doses, and the surgical treatment outcome of this rare side effect. METHODS From 2000-2012, a retrospective review of 864 among 1,192 patients with confirmed DTC who were treated with (131)I therapy was performed to examine the frequency of NLDO, its causative factors, as well as imaging, surgical intervention, and outcomes. RESULTS Nineteen (2.2%) patients were identified with NLDO. The mean age was 51.9±10.5 years (range: 39-72 years). Fifteen (78.9%) were female and four were male (21.1%). The mean individual (131)I doses were 311.1±169.3 millicurie (mCi) (range: 150-600 mCi). The mean duration between the date of (131)I therapy and the occurrence of NLDO was 11.6±4.1 months (range: 6.5-20). Fourteen (73.7%) patients had bilateral epiphora. Computed tomography dacryography allowed for the detection of all NLDO. Eighteen (94.7%) patients underwent dacryocystorhinostomy. Complete recovery was obtained in 14 (73.7%) patients. Age >45 years and (131)I therapy doses >150 mCi were significantly correlated with NLDO (P=0.02 and P=0.03, respectively). CONCLUSION NLDO is an underestimated complication of (131)I therapy in DTC patients. Clinicians should be aware of this rare complication for prompt intervention.