Effects of Radioiodine Treatment on Salivary Gland Function in Patients with Differentiated Thyroid Carcinoma: A Prospective Study

Abstract

Complaints of a dry mouth (xerostomia) and sialoadenitis are frequent side effects of radioiodine treatment in differentiated thyroid cancer (DTC) patients. However, detailed prospective data on alterations in salivary gland functioning after radioiodine treatment ( 131 I) are scarce. Therefore, the primary aim of this study was to prospectively assess the effect of high-activity radioiodine treatment on stimulated whole saliva flow rate. Secondary aims were to study unstimulated whole and stimulated glandular (i.e., parotid and submandibular) saliva flow rate and composition alterations, development of xerostomia, characteristics of patients at risk for salivary gland dysfunction, and whether radioiodine uptake in salivary glands on diagnostic scans correlates to flow rate alterations. Methods: In a multicenter prospective study, whole and glandular saliva were collected both before and 5 mo after radioiodine treatment. Furthermore, patients completed the validated xerostomia inventory. Alterations in salivary flow rate, composition, and xerostomia inventory score were analyzed. Salivary gland radioiodine uptake on diagnostic scans was correlated with saliva flow rate changes after radioiodine treatment. Results: Sixtyseven patients (mean age ± SD, 48 ± 17 y; 63% women, 84% underwent ablation therapy) completed both study visits. Stimulated whole saliva flow rate decreased after ablation therapy (from 0.92 [interquartile range, 0.74-1.25] to 0.80 [interquartile range, 0.58-1.18] mL/min, P 5 0.003), as well as unstimulated wholeand stimulated glandular flow rates (P , 0.05). The concentration of salivary electrolytes was similar at both study visits, whereas the output of proteins, especially amylase (P , 0.05), was decreased. The subjective feeling of dry mouth increased (P 5 0.001). Alterations in saliva flow rate were not associated with semiquantitatively assessed radioiodine uptake in salivary glands on diagnostic scans. For the small cohort of patients undergoing repeated radioiodine therapy, we could not demonstrate alterations in salivary parameters. Conclusion: We prospectively showed that salivary gland function is affected after high-activity radioiodine ablation therapy in patients with DTC. Therefore, more emphasis should be placed on salivary gland dysfunction during follow-up for DTC patients receiving high-activity radioiodine treatment.

Early and late adverse effects of radioiodine for pediatric differentiated thyroid cancer

“…3 Dry mouth (xerostomia) and sialoadenitis remain frequent side effects of radioiodine treatment, especially in patients treated with high acitivities. 50 In our study, the number of treatments and the cumulative dose of radioiodine administered are high; this can be explained by the very long period of recruitment (about 35 years), including years when few therapeutic alternatives were available and different guidelines were adopted (e.g., no conservative approach for early stage disease or the absence of some radioiodine alternative options like tyrosine-kinase inhibitors).…”

“…None of these prophylactic measures have yet been formally studied in the pediatric population . Dry mouth (xerostomia) and sialoadenitis remain frequent side effects of radioiodine treatment, especially in patients treated with high acitivities …”

Effects of first radioiodine ablation on functions of salivary glands in patients with differentiated thyroid cancer

“…[31] Furthermore, salivary gland stem cells, which have been proposed to mainly reside in the excretory ducts, [32] may also be affected because of the exposure to β radiation resulting in a reduced regenerative potential. [33] …”

“…For instance, Klein Hesselink et al [8] showed the salivary gland damage varied with the sensitivity of the patients to the radiation and the cumulative dose of 131 I. Some reports demonstrated that acute sialadenitis could happen in as many as 15% of patients.…”

Validating the Xerostomia Inventory in a radiation‐induced xerostomia population in German language

“…All 18 patients suffered from radiation‐induced xerostomia: seven male patients after radioligand therapy of metastasized prostate cancer (tumor‐specific radioligand therapy that binds to prostate‐specific membrane antigen [PSMA], lutetium‐177 PSMA‐617 ‐[LuPSMA]) and 11 (two males and nine females) after radioiodine therapy due to thyroid cancer. Xerostomia is a common side effect of both therapies (Heck et al, ; Klein Hesselink et al, ). Twenty‐one patients with impaired hearing formed the “non‐xerostomia group.” Excluded were patients aged <18 years and those not being fluent in German language.…”