Ultrasonographic Features of Salivary Glands after Radioiodine Therapy in Patients with Thyroid Cancer

Objective Chronic sialadenitis is the most common complication of radioactive iodine (RAI) treatment. The aim of the study was to ascertain sonographic features of the major salivary glands in patients with papillary thyroid cancer (PTC) treated with RAI. Methods The database of a tertiary medical center was retrospectively searched for consecutive patients who underwent total thyroidectomy for PTC in 2011-2020 with ultrasound follow-up after 1 year. Changes in ultrasound features of the major salivary glands were compared between patients treated or not treated with RAI postoperatively. Results The cohort included 158 patients, of whom 109 (69%) were treated postoperatively with RAI (mean dose, 131 mCi) and 49 were not (control group). Sonographic changes were observed in the major salivary glands in 43% of the study group and 18% of the control group (p = 0.002), including coarse echotexture, decreased echogenicity, fibrosis, and atrophy. Higher RAI doses were significantly correlated with the prevalence and severity of glandular changes (p < 0.0001). Conclusion RAI treatment following thyroidectomy is associated with a dose-response effect and adverse changes in the major salivary glands and should be prescribed carefully. Level of Evidence 4 Laryngoscope, 2022