Available online 13 August 2022

RAI dose correlates with nasolacrimal & increased intranasal I-131 activity on WBS

Increased intranasal WBS activity is a RAI dose-dependent correlative factor of NLDO

Having >1 lifetime RAI treatment is a RAI dose-dependent correlative factor of NLDO

Nasolacrimal WBS activity is a RAI dose-independent correlative factor of NLDO

RAI associated sialadenitis is a RAI dose-independent correlative factor of NLDO

Identify factors associated with radioactive iodine (RAI)-acquired nasolacrimal duct obstruction (NLDO).

Retrospective chart review and telephone surveys were conducted of patients who received RAI therapy for thyroid carcinoma at an academic institution. Telephone surveys were used to screen for post-RAI NLDO diagnoses. Databases were reviewed for documented NLDO, demographics, RAI dose, total number of RAI treatments, and sialadenitis. Routine post-RAI whole body scintigraphy (WBS) images were analyzed for the presence or absence of 131I sodium iodide (I-131) in the nasolacrimal duct. Intranasal I-131 activity was graded as none, low, moderate, and high; those with moderate or high activity were considered to have “increased” activity. Logistic and ordinal logistic regression models were used to evaluate the associations with NLDO while adjusting for I-131 dose.

Of the 209 patients who completed the survey, 7% (15/209) had NLDO diagnoses. Increased intranasal I-131 activity on WBS, presence of nasolacrimal I-131 WBS activity, presence of documented post-RAI sialadenitis, and history of >1 RAI treatment were associated with the development of NLDO from univariate analyses (p≤0.013). After adjusting for the administered dose of I-131, the presence of sialadenitis and nasolacrimal I-131 activity on WBS were the remaining two factors significantly associated with NLDO development (p<0.001 and p=0.01, respectively).

The presence of sialadenitis and nasolacrimal I-131 activity on WBS are I-131 dose-independent correlative factors for RAI-associated NLDO. Patients with these characteristics should be counseled on their increased risk of NLDO after RAI therapy for thyroid carcinoma.

nasolacrimal duct obstruction

radioactive iodine

thyroid cancer

epiphora

sialadenitis

whole body scintigraphy

© 2022 Published by Elsevier Inc. on behalf of the AACE.