Prospective Single-Arm Study of Radioprotection by Amifostine in High Dose Radioactive Iodine Therapy for Thyroid Cancer

Purpose: Xerostomia, sialoadenitis, taste dysfunction and nausea are well known toxicities following high dose radioactive iodine (RAI) treatment for well-differentiated thyroid cancer. This prospective study sought to determine the incidence rates for RAI adverse effects and to determine, whether the radioprotector, amifostine could decrease the duration of the adverse effects in single treatment patients. Materials and methods: Patients with differentiated thyroid cancer received 150 mCi RAI after total thyroidectomy. All patients were pretreated with 1 mg granisetron and 4 mg dexamethasone. Patients in the amifostine arm (n = 27) were prospectively enrolled and received 500 mg amifostine subcutaneously. Adverse effects were scored based on the CTCAE at 1 month, 6 months, and yearly intervals using a physician administered questionnaire. The results were compared with a retrospective no amifostine cohort (n = 22) for whom data was collected with the identical questionnaire. Results: The overall incidence of xerostomia, sialadenitis, taste dysfunction and nausea in the treatment group was 26, 22, 52 and 26% respectively. Only grades 1 and 2 adverse effects were observed. The mean duration (days) of xerostomia (control vs treatment)—37.3 vs 21.9 (F test, p = 0.016), taste dysfunction—45.5 vs 23.5 (F test, p = 0.001), sialadenitis— 16.8 vs 7.5 and nausea—18.7 vs 5.1. Conclusion: In patients treated once with high dose RAI, who develop xerostomia, sialoadenitis, taste dysfunction, and/or nausea, the duration of symptoms appears to be reduced by pretreatment with 500 mg of subcutaneous amifostine without significant treatment related adverse effects.