The Protection of Salivary Glands by Amifostine and Vitamin C in Radioiodine Treatment

Objectives: To investigate salivary gland protection of Amifostine and vitamin C in Radioiodine Treatment (RIT) of patients with differentiated thyroid cancer(DTC). Patients and Methods: 32patients who with DTC and total thyroidectomy were divided into two groups, experimental group 13 patients who were treated with 400mg amifostine intravenously before RIT and 100mg/2h vitamin C tablets mouth meltingly after RIT for 7days and 19 patients served as control group , who were treated with vitamin C alone, methods ibid. All patients took a dose of 100mCi radioiodine orally to ablate thyroid remnants completely . Parenchymal function was assessed by quantitative salivary gland scintigraphy one day before RIT and six months after RIT, respectively. Xerostomia was graded according to World Health Organization (WHO) criteria. Remedial whole body scan(Rx-WBS) and ¹³¹I SPECT/CT were used to estimate the success rate of ¹³¹I ablation for thyroid remnant.

Results: ①Compared parenchymal function before and after RIT in experimental patients , there was not significantly altered (P>0.05) in the uptake ratio of technetium-99m ( ^99mTc)-pertechnetate of 20min (UR20) , excretion fraction (EF) , time interval from stimulation to minimum count (T_min) , excretion ratio (ER) in parotid and submandibular glands, and one developed grade I xerostomia. ②In control patients, there was also not significantly altered (P>0.05) in UR20 , EF , T_min and ER in parotid , so do submandibular in UR20 and EF , but T_min and ER was significantly altered (P<0.05), namely after RIT the T_min significantly lengthenedandER obviously decreased. Five control patients developed grade I xerostomia . ③Compared the difference value(ΔP) before and after ¹³¹I treatment of the two groups , we found no significant difference inΔPUR20 , ΔPEF , ΔPT_min and ΔPER in parotid , so do submandibular inΔPUR20 , ΔPEF , but there was significant difference (P<0.05) inΔPT_min and ΔPER . ④We didn’t find any significant difference (P=0.833) in success rate of ¹³¹I ablation for thyroid remnant between the two groups .

Conclusion: The side effects of RIT to salivary gland can significantly be reduced by amifostine and vitamin C, especially the combination of the two drugs , which may improve the long-term quality of life of patients with DTC . Key words: salivary glands; radioiodine therapy; amifostine; vitamin C