salivary dysfunction after radioiodine treatment

Conditions: Thyroid Cancer

Summary: aim/introduction: the treatment of differentiated thyroid cancer includes generally a total thyroidectomy, followed by a radioiodine (131i)-therapy. due to their ability to concentrate iodine, the salivary glands may present inflammation after administration of 131i, which may be symptomatic, may lead to longer-term chronic abnormalities, resulting in alterations in patients' nutrition and quality of life. the incidence of salivary dysfunctions after 131i-therapy varies considerably between studies due to methodological limitations. also, the occurrence of these dysfunctions may be linked to increased uptake and/or retention of 131i in the salivary glands and/or individual radiosensitivity. however, no clinical or genetic factors have been identified to date to define patients at risk, allowing the delivered activity to be adapted to the expected risk of salivary dysfunctions. the aims of this study are to estimate the incidence of salivary dysfunctions after 131i-therapy, to characterize patients at risk of developing post-treatment dysfunctions using clinical, biomolecular and biochemical factors, and to validate a dosimetric method to calculate the dose received at the salivary gland level in order to analyse the dose response relationship between exposure of salivary glands to 131i and salivary dysfunctions. materials and methods: this prospective cohort aims to include 120 patients, candidates for a 131i-therapy in the context of their differentiated thyroid cancer, treated in the nuclear medicine department of the pitié-salpêtrière hospital (40 and 80 patients in a 1.1gbq and a 3.7gbq dose groups respectively). the follow-up is based on 3 scheduled visits: at inclusion (immediately before 131i therapy), 6months and 18months after treatment. for each visit, questionnaires on salivary disorders (validated french tool), quality of life (had-scale, mos-sf-36), and nutritional status are administered. at inclusion and at t6, saliva samples and individual measurement of the salivary flow, without and with salivary glands stimulation, are performed. external thermoluminescent dosimeters are placed opposite the salivary glands and at the sternal fork on the treatment's day before radioiodine administration and removed 5days after treatment. from dosimeters, a reconstitution of the dose received at the salivary glands will be established using physical and computational phantoms. genetic and epigenetic analyses will be performed to find biomarkers of predisposition to develop salivary disorders after 131i-therapy. expected results inclusion of patients started in september 2020 and are still ongoing. statistical analyses will study the links between salivary dysfunctions and the 131i dose received by the salivary glands, taking into account associated factors. in addition, impacts on the patients' quality of life will be analysed.


Eligibility criteria:
inclusion criteria: * treated for differencied thyroid cancer * aged of 18 and more exclusion criteria: * having been treated by chemiotherapy or radiotherapy * no french language * can't be follow at 6 months after treatment

Keywords: radioiodine salivary dysfunctions genetic polymorphism dosimetry