Effect Of The First ¹³¹I Therapy On Salivary Gland Function In Patients With Hashimoto’s Thyroiditis Coexisted With Differentiated Thyroid Cancer

Object:To investigate the changes of salivary gland function in patients with differentiated thyroid cancer（DTC）coexisted with Hashimoto’s thyroiditis（HT）after the first course of ¹³¹I treatment,and to compare the effects of different ¹³¹I doses on salivary gland function.Methods:From August 2018 to March 2019,46 patients with DTC who had been hospitalized in the Department of Nuclear Medicine of the First Affiliated Hospital of Guangxi Medical University and had completed one courses of ¹³¹I treatment were selected.Subjects divided into HT and DTC groups:HT group,19cases,were pathologically diagnosed as DTC coexisted with HT.There were 3males and 16 females with an average age of 35.95±14.17 years old in HT group,and the first dose of ¹³¹I was 172.63±22.57 m Ci,and 4.89±1.05 months after the first course of ¹³¹I treatment;27 cases of DTC group which was pathologically diagnosed with DTC only,in which 7 were male and 20 were female with an average age of 35.78±13.74 years old.The first dose of ¹³¹I in DTC group was167.78±34.79 m Ci,and 4.85±1.03 months after the first course of ¹³¹I treatment.In addition,according to the dose of first ¹³¹I treatments,the two groups were divided into a low-dose group（100m Ci≤dosage≤150m Ci）,a medium-dose group（150<dosage<190m Ci）and a high-dose group（≥190m Ci）,respectively.All patients had salivary gland scintigraphy（SGS）before and after the first courses of ¹³¹I treatment.The semi-quantitative parameters of SGS were selected:maximum absorption rate（MAR）reflecting the uptake function of salivary glands,maximum secretion rate（MSR）reflects the excretory function of the salivary glands.The damage of salivary gland function is manifested by the decrease of MAR and MSR values.Paired t-test was used to compare the difference of salivary gland function in HT and DTC group patients before and after ¹³¹I treatment.Independent sample t test was used to compare and analyze the difference of salivary gland function between HT group and DTC group.ANOVA was used to compare the MAR and MSR value of the salivary glands among the low,medium and high-dose subgroups.Results:Before ¹³¹I treatment,the parotid MAR,MSR and submandibular gland MAR,MSR of HT group were 0.89±0.09,0.45±0.31 and 0.54±0.17,0.37±0.18,respectively.After ¹³¹I treatment,the parotid gland MAR,MSR and submandibular gland MAR,MSR of HT group were 0.83±0.27,0.47±0.33 and0.59±0.18,0.40±0.17,respectively.Before ¹³¹I treatment,the parotid MAR,MSR and submandibular gland MAR,MSR of DTC group were 0.84±0.13,0.50±0.30 and 0.56±0.16,0.34±0.19,respectively.After ¹³¹I treatment,the parotid MAR,MSR and submandibular gland MAR,MSR of DTC group are 0.86±0.14,0.36±0.34 and 0.57±0.15,0.32±0.21,respectively.Salivary function comparison result between before and after ¹³¹I treatment:There was no difference in the salivary glands MAR and MSR of HT group before and after ¹³¹I treatment.However,compared with salivary function before ¹³¹I treatment,there was a significant difference in parotid gland MSR of DTC group after ¹³¹I treatment（P<0.05）.Comparison result before ¹³¹I treatment between HT and DTC group:Parotid gland MAR value in HT group was significantly higher than in DTC group.Comparison result after ¹³¹I treatment:There was no significant difference in the MAR and MSR of parotid gland and submandibular gland between HT group and DTC group.Comparison results between subgroups:The low-dose subgroup in HT group had significantly higher parotid and submandibular gland MSR values than those in the low-dose subgroup of DTC group（all P<0.05）.In the HT group,the submandibular gland MAR in the low-dose subgroup was significantly higher than that in the high-dose subgroup,but there was no significant difference in the parotid gland MAR value.Conclusion:The patients with DTC coexisted with HT have not significantly salivary gland dysfunction after 4～6 months of the first course of ¹³¹I treatment,and the salivary gland excretion function may compensatory increase when the first course of ¹³¹I with 100～150m Ci,but when the doses of ¹³¹I are≥190m Ci,uptake function of submandibular gland would be significantly lower than when the dose of ¹³¹I are 100～150m Ci.There is no need to take the effect of HT on salivary glands into the consideration when developing the radioiodine therapy proposal.