Systematic evaluation of salivary gland damage following I-131 therapy in differentiated thyroid cancer patients by quantitative scintigraphy and clinical follow-up.
OBJECTIVE
Radioiodine therapy is a common adjunct to thyroidectomy in papillary thyroid cancer treatment. However, a variety of associated adverse effects have been reported. In this study, we assessed radioiodine-induced salivary gland dysfunction using quantitative scintigraphy, and evaluated the associated complications.


METHODS
Patients were divided into five groups on the basis of the cumulative I-131 dosage received. Scintigraphic dynamic images of the salivary glands were obtained and converted into clinically relevant parameters: uptake index (UI), maximum secretion rate (%SR), and combined gland function scores. Patients were followed up for 3-66 months and interviewed for side effects including xerostomia, taste alteration, bitter taste, dental caries, xerophthalmia, and pain/swelling.


RESULTS
An increase in I-131 doses resulted in a reduction in the UI and %SR and an increase in the combined scintigraphy score. Parotid glands were more affected than submandibular glands. A cumulative dosage of greater than 600 mCi resulted in complete loss of %SR in the parotid glands. No significant difference in either the UI or the %SR was observed between nontreated patients and patients receiving an I-131 dosage of up to 150 mCi. The occurrence of xerostomia was significantly correlated with the gland scintigraphic score, the number of treatment cycles, and I-131 dosage. The occurrence of pain and swelling was extremely low and only lasted for a short time.


CONCLUSIONS
Although the side effects associated with radioiodine treatment were apparent, they were usually small and temporary. Nevertheless, more consideration should be placed on careful dosing of I-131.
Department of Nuclear Medicine, Zhujiang Hospital Southern Medical University, Guangzhou, China.
Ju-qing
JQ
Wu
Hui-juan
HJ
Feng
Wei
W
Ouyang
Yun-gang
YG
Sun
Pan
P
Chen
Jing
J
Wang
Jia-lang
JL
Xian
Liu-hua
LH
Huang
D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000209:etiology; D011877:Radionuclide Imaging; D012469:Salivary Glands / Q000000981:diagnostic imaging / Q000528:radiation effects*; D013670:Sodium Pertechnetate Tc 99m; D013964:Thyroid Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D014987:Xerostomia / Q000000981:diagnostic imaging / Q000209:etiology
D007457:Iodine Radioisotopes; D013670:Sodium Pertechnetate Tc 99m