title: Nasolacrimal duct obstruction following radioactive iodine 131 therapy in differentiated thyroid cancers: review of 19 cases.
abstract: 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).
  
  
  CONCLUSIONS
  NLDO is an underestimated complication of (131)I therapy in DTC patients. Clinicians should be aware of this rare complication for prompt intervention.
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, College of Medicine, Advanced Head and Neck Oncology, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Khalid Hussain
authors.initials: KH
authors.lastname: Al-Qahtani
authors.affiliation: Radiation Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia.
authors.forename: Mushabbab
authors.initials: M
authors.lastname: Al Asiri
authors.affiliation: Radiation Oncology, Comprehensive Cancer Center, King Fahad Medical City, Riyadh, Saudi Arabia.
authors.forename: Mutahir A
authors.initials: MA
authors.lastname: Tunio
authors.affiliation: Endocrinology and Thyroid Oncology, King Fahad Medical City, Riyadh, Saudi Arabia.
authors.forename: Naji J
authors.initials: NJ
authors.lastname: Aljohani
authors.affiliation: Radiation Oncology, NCI, Cairo University, Cairo, Egypt.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Bayoumi
authors.affiliation: Nuclear Medicine Sulaiman Al-Habib Hospital, Riyadh, Saudi Arabia.
authors.forename: Iqbal
authors.initials: I
authors.lastname: Munir
authors.affiliation: Clinical Ophthalmology, King Fahad Medical City, Riyadh, Saudi Arabia.
authors.forename: Ayman
authors.initials: A
authors.lastname: AlAyoubi
keywords: differentiated thyroid cancers; nasolacrimal duct obstruction; radioactive iodine 131 therapy