JMIR Publications

ABSTRACT

Background:

Following radioiodine (131I) therapy of differentiated thyroid cancer, salivary glands may become inflamed, leading to dysfunctions, then leading to decreases in patients’ nutrition and quality of life. The incidence of these dysfunctions after 131I-therapy is poorly known, and 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.

Objective:

This prospective cohort aims to include patients for whom a 131I-therapy is indicated within the treatment of their differentiated thyroid cancer in a Paris hospital (40 and 80 patients in a 1.1 GBq and a 3.7 GBq groups respectively). The follow-up is based on 3 scheduled visits: at inclusion (T0, immediately before 131I-therapy), 6 months (T6) and 18 months (T18) after treatment. For each visit, questionnaires on salivary dysfunctions (validated French tool), quality of life (HAD-scale, MOS-SF-36), and nutritional status are administered by a trained clinical research associate. At T0 and at T6, saliva samples and individual measurement of the salivary flow, without and with salivary glands stimulation, are performed. External thermoluminescent dosimeters are positioned on the skin opposite the salivary glands and at the sternal fork immediately before radioiodine administration and removed 5 days after treatment. From dosimeters, an estimation of the dose received at the salivary glands will be performed using physical and computational phantoms. Genetic and epigenetic analyses will be performed in order to look for potential biomarkers of predisposition to develop salivary dysfunctions after 131I-therapy.

Methods:

START (Salivary dysfuncTion After Radioiodine Treatment) is a prospective study including 139 patients, candidates for a 131I-therapy in the context of their differentiated thyroid cancer (45 and 94 patients in 1.1GBq and 3.7GBq groups respectively). The follow-up is based on 3 scheduled visits: immediately before 131I-therapy (T0), 6-month(T6) and 18-month after (T18). At each visit, questionnaires on salivary disorders (validated French tool) and dry eye (OSDI© Questionnaire) were administered, and individual salivary flow measurements (without and with salivary gland stimulation) were performed. Descriptive analyses and paired comparisons tests between T0 and T6 were computed. This prospective cohort aims to include patients for whom a 131I-therapy is indicated within the treatment of their differentiated thyroid cancer, at the Nuclear Medicine department of the Pitié-Salpêtrière hospital (40 and 80 patients in a 1.1 GBq and a 3.7 GBq groups respectively). The follow-up is based on 3 scheduled visits: at inclusion (T0, immediately before 131I-therapy), 6 months (T6) and 18 months (T18) after treatment. For each visit, questionnaires on salivary dysfunctions (validated French tool), quality of life (HAD-scale, MOS-SF-36), and nutritional status are administered by a trained clinical research associate. At T0 and at T6, saliva samples and individual measurement of the salivary flow, without and with salivary glands stimulation, are performed. External thermoluminescent dosimeters are positioned on the skin opposite the salivary glands and at the sternal fork immediately before radioiodine administration and removed 5 days after treatment. From dosimeters, an estimation of the dose received at the salivary glands will be performed using physical and computational phantoms. Genetic and epigenetic analyses will be performed in order to look for potential biomarkers of predisposition to develop salivary dysfunctions after 131I-therapy.

Results:

139 patients (71% women, mean age=47.4 (±14.3) years old) were included between September 2020 and April 2021 (45 and 94 patients in 1.1GBq and 3.7GBq groups respectively). The 6-months follow-up is still ongoing, and the 18-months follow-up will start in February 2022. Statistical analyses will study the links between salivary dysfunctions and absorbed doses to the salivary glands, taking into account associated factors. In addition, impacts on the patients' quality of life will be analyzed.

Conclusions:

To our knowledge, this study is the first to investigate the risk of salivary dysfunctions (using both objective and subjective indicators) in relation to organ (salivary glands) doses, based on individual dosimeter records and dose reconstructions. The results will allow the identification of patients at risk of salivary dysfunctions, and thus to propose to clinicians a more adapted follow-up and/or countermeasures to adverse effects. Clinical Trial: ClinicalTrials.gov NCT04876287; https://clinicaltrials.gov/ct2/show/NCT04876287