Risk Factors of 131I-Induced Salivary Gland Damage in Thyroid Cancer Patients.

CONTEXT: Sialadenitis and xerostomia are major adverse effects of 131I therapy in thyroid cancer patients. The risk factors for these adverse effects, other than administered activity of 131I, have not been investigated.

OBJECTIVE

The aim of this study is to identify risk factors for 131I-induced salivary gland damage among follicular cell-derived thyroid cancer patients.

DESIGN

We enrolled 216 thyroid cancer patients who visited The Ohio State University Wexner Medical Center between April 2013 and April 2014. Symptoms of xerostomia and sialadenitis were identified via questionnaire and medical record search. To validate the findings in a large cohort, we retrospectively searched for ICD-9/10 codes for sialadenitis, xerostomia, and autoimmune disease associated with Sjögren's syndrome (AID-SS) in our existing database (n = 1507). Demographic and clinical information was extracted from medical records. Multivariate analyses were performed to identify independent predictors for salivary gland damage.

RESULTS

131I treatment associated with higher incidence of xerostomia and sialadenitis. Patients with xerostomia had 46 mCi higher mean cumulative 131I activity and 21 mCi higher mean first-administered 131I activity than patients without xerostomia. Increased age associated with higher incidence of xerostomia, and females had a higher incidence of sialadenitis. Patients who experienced sialadenitis before 131I therapy had higher sialadenitis incidence after 131I therapy. 131I-treated patients diagnosed with AID-SS, whether before or after 131I treatment, had a higher incidence of xerostomia and sialadenitis among 131I-treated patients.

CONCLUSION

Risk factors for 131I-induced salivary gland damage include administered 131I activity, age, gender, history of sialadenitis before 131I treatment, and AID-SS diagnosis.