| Objective: Thyroid carcinoma is a common endocrine tumor comprising 1% of all malignant tumors. The well recognized treatment for differentiated thyroid carcinoma (DTC) includes total or near-total thyroidectomy followed by 131I remnant ablation and thyroid hormone suppression of thyroid stimulating hormone (TSH). However, impairment of salivary gland function is a well-recognized side effect following high-dose radioiodine treatment duo to 131I accumulation to a significant amount. It is also observed that the more accumulation of 131I in the salivary glands, the more severe salivary glands dysfunction. Up to date, documents about the damage of salivary gland after first a remnant ablation begets controversy. The objective of this article is to investigate the salivary glands impairment after the first 131I remnant ablation and the radioprotection by amifostine using salivary gland scintigraphy, to present clinicians with the whole and proper information about 131I for DTC and to justify a feasible method against the salivary glands impairment induced by high-dose131I therapy.Methods: Thirty eight thyroidectomy patients were divided into two groups, Groupl: 28 patients received Vit C as protect agent of salivary gland; Group II: 10 patients received amifostine as protect agent of salivary gland. Parameters included the uptake rate at 3Omin(UR.3o) after iv injection, ejection fraction (EF), excretion time and excretion rate (ER) for evaluating quantitatively salivary gland function. Salivary gland function were evaluated before 1311 therapy and 3months after 1311 therapy. The evaluation tables about symptoms of salivary glands dysfunction were designed to record the swelling of salivary glands, dryness, swallowing difficulty, change in taste, oral ulcer. Statistical analysis was performed using the ANOVA and t-test. Results: Dryness and swallowing difficulty was observed in 12 of 28 control patients with DTC 3months after the first 1311 remnant ablation. No discomfort was observed in the other 16 cases. In 10 amifostine-treated patients, dryness was complained in 1 case with no discomfort in the other 9 cases. (1) No significant difference was found in the decrease of UR3o> EF and ER between amifostine-treated patients and vitamine C-treated patients. (2) UR30, EF and ER were significantly decreased in 28 control patients three months after the first 1311 remnant ablation compared with that before 1311 treatment. According to the clinical characteristics of salivary gland impairment, patients were classified into the symptoms-bearing and the systems-free group, respectively. In the symptoms-bearing cases, the functions of parotid and submandibular glands were significantly impaired after the first 1311 treatment. While in the symptoms-free cases, no significant difference was observed before and after the first 1311 treatment. Significant difference of thyroid uptake of radioiodine betweensymptoms-bearing (3.27% ±3.42%) and the symptoms-free groups(13.43% ±8.86%) was founded. (3) UR30, EF, EP and ER insignificantly decreased in amifostine-treated patients after the first 1311 remnant ablation compared with that before 1311 treatment. (4) Significant difference was observed among amifostine-treated group, vitamine C-treated group and Conclusions: Salivary gland functions were damaged after the first 1311 remnant ablation. It was noticed that the remnant of thyroid tissue connected with the salivary glands impairment. It showed that the less residual thyroid tissue and the lower raidoiodine uptake by thyroid tissue, the more uptake by salivary glands and more severe salivary glands impairment. Parotid is more severely damaged than submandibular glands. Parenchymal damage in salivary glands induced by high-dose radioiodine treatment can be significantly reduced by amifostine. In clinics, amifostine may be a good choice for DTC patients with little remnant of thyroid tissue and alower raidoiodine uptake by thyroid tissue. |
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