Salivary gland toxicity after radioiodine therapy for thyroid cancer

AimsSalivary gland toxicity is a common, but not widely appreciated, adverse effect of high-dose radioiodine (¹³¹I). This study was carried out to determine the incidence of symptoms of salivary gland damage after ¹³¹I treatment for differentiated thyroid cancer.Materials and methodsThis was a prospective study of 76 consecutive patients attending thyroid cancer treatment. Symptoms of salivary gland damage (dry mouth, pain and swelling) were assessed during hospital admission and at follow-up visits. Additionally, a retrospective analysis was carried out of patients recorded in our database as having chronic salivary gland swelling after ¹³¹I ablation.ResultsTwenty patients (26%) developed salivary gland toxicity, 11 (15%) had symptoms within the first 48 h, continuing for 12 months in seven of these patients. The onset of toxicity in a further nine (12%) patients with persistent symptoms did not occur until 3 months after therapy. In total, 16 (21%) patients had evidence of chronic toxicity, typically xerostomia, at 12 months. Toxicity was more common after repeated ¹³¹I administration. After searching our thyroid cancer database, we identified an additional five patients to have chronic salivary gland swelling (chronic sialadenitis or pleomorphic adenoma) 20 months to 23 years after ¹³¹I.ConclusionsPain, swelling and dry mouth occurred frequently after ¹³¹I, with some developing symptoms months or years after administration. Early recognition of salivary gland complications may help to reduce morbidity in these patients.