Thyroid cancer is the most common malignancy of the endocrine system consisting of several subtypes like papillary carcinoma (accounting for 80% of cases) and follicular carcinoma (accounting for 11% of cases). These are collectively referred to as 'differentiated thyroid cancer'. Treatment with radioactive iodine after surgery (ablation of the thyroid gland or 'thyroidectomy') is important for the detection of metastatic disease and for the destruction of the remaining thyroid tissue with microscopic cancer. After radioactive iodine treatment, adverse effects may happen in the salivary glands and cause salivary gland swelling and pain, usually involving the parotid. The symptoms may develop immediately after a therapeutic dose of radioactive iodine or months later and progress in intensity with time. Secondary complications reported include dry mouth ('xerostomia') and taste alterations.
Amifostine is thought to be a radioprotector of salivary glands used in conjunction with radioiodine therapy. This medication is administered intravenously and was reported to ameliorate the damage of salivary glands caused by radioactive iodine therapy.
We found only two randomised controlled trials in which the effects of amifostine were compared with placebo. The two randomised clinical trials investigated 130 patients treated with high dose radioactive iodine for thyroid cancer. Altogether data from the two trials suggest that amifostine has no obvious protective effects on the salivary glands in these patients. Two patients in one study collapsed after initiation of amifostine therapy and had to be treated by withdrawing the infusion and volume substitution. Both patients recovered without sequelae.
Until better data become available, the use of sour candy or lemon juice to increase salivation might be more appropriate during radioactive iodine treatment for patients with differentiated thyroid cancer. Patients should be well informed of the importance of hydration, acid stimulation and glandular massage after radioactive iodine treatment. In addition, early recognition and treatment of xerostomia may improve outcomes.