Dysfunction of the salivary and lacrimal glands after radioiodine therapy: 6-month follow-up results of a self-controlled study in France

Abstract: Following radioiodine therapy (RAI) of differentiated thyroid cancer, salivary and lacrimal glands may be injured, leading to dysfunctions. The incidence of these dysfunctions after RAI is poorly known, and no risk factors have been identified to date to define at-risk patients. The aims of this study are to characterize the dysfunction of salivary and lacrimal glands after RAI, and to identify risk factors of such dysfunctions.START (Salivary dysfuncTion After Radioiodine Treatment) is a prospective study launched in 2020, including 139 thyroid cancer patients, candidates for a RAI (45 and 94 patients received 1.1GBq and 3.7GBq 131I activity, respectively) in Pitié-Salpêtrière hospital, Paris, France. Follow-up was based on 3 scheduled visits: immediately before RAI (T0), 6 months (T6) and 18 months (T18) later. At each visit, questionnaires on salivary disorders (validated French tool), dry eye (OSDI© Questionnaire), and anxiety/depression symptoms (HAD scale) were administered. At T0 and T6, individual salivary flow measurements (with and without salivary gland stimulation) were performed. The doses to the salivary glands were evaluated through a dosimetric reconstruction based on recordings from thermoluminescent dosimeters directly positioned on the patients. In the present work, data for the T0 and T6 visits were analysed based on descriptive analyses and random-effects logistic and linear regressions.Complete information was provided for 136 patients (71% women, mean age=47.1 (±14.1) y). Mean doses to the salivary glands were 0.7 (±0.2) and 2.3 (±0.9) Gy for the 1.1GBq and 3.7GBq 131I-activity groups, respectively. At T6, 18% and 22% of the study population without any symptoms at T0 reported dry eye and/or dry mouth feeling, respectively. Stimulated saliva flow rate significantly decreased from T0 to T6 (2.14 (±0.86) and 1.93 (±0.78) mL/min, p