Salivary and lacrimal dysfunction after radioactive iodine for differentiated thyroid cancer: American Head and Neck Society Endocrine Surgery Section and Salivary Gland Section joint multidisciplinary clinical consensus statement of otolaryngology, ophthalmology, nuclear medicine and endocrinology

Abstract

Background: Postoperative radioactive iodine (RAI) administration is widely utilized in patients with differentiated thyroid cancer. While beneficial in select patients, it is critical to recognize the potential negative sequelae of this treatment. The prevention, diagnosis, and management of the salivary and lacrimal complications of RAI exposure are addressed in this consensus statement. Methods: A multidisciplinary panel of experts was convened under the auspices of the American Head and Neck Society Endocrine Surgery and Salivary Gland Sections. Following a comprehensive literature review to assess the current best evidence, this group developed six relevant consensus recommendations. Results: Consensus recommendations on RAI were made in the areas of patient assessment, optimal utilization, complication prevention, and complication management. Conclusion: Salivary and lacrimal complications secondary to RAI exposure are common and need to be weighed when considering its use. The recommendations included in this statement provide direction for approaches to minimize and manage these complications.

Strategies for Radioiodine Treatment: What’s New

“…In fact, in addition to the thyroid gland, the presence of sodium/iodine symporter (NIS) has been shown in several organs, allowing significant iodine uptake, but also leading to an increased susceptibility to adverse events (AEs) during RAI treatments [ 128 ]. The most frequently involved non-thyroidal tissues are the salivary and nasolacrimal glands, but potential toxicity on gastrointestinal tissues, bone marrow, and gonads has also been described during the course of succeeding radioiodine administrations [ 128 , 129 , 130 , 131 , 132 , 133 ]. The real incidence of RAI-related AEs varies, according to the studies and the detection methods.…”

“…Considering the high rate of salivary gland AEs, several preventive strategies have been investigated in pre-clinical and clinical settings [ 131 , 161 ]. Pre-clinical studies explored the efficacy of various agents, including antioxidants (i.e., Vitamin E) and nutraceutics (i.e., Curcuma longa , Ocimum sanctum , and zinc), showing potential benefits in non-human subject tests [ 161 ].…”

Hyperparathyroidism subsequent to radioactive iodine therapy for Graves' disease

“…To better characterize the possible relationship and mechanism of RAI‐induced PHPT, larger prospective studies would be needed. RAI is known to have a number of potential side effects and it is possible that the risk of developing PHPT should be added as a potential consideration 27 …”

“…RAI is known to have a number of potential side effects and it is possible that the risk of developing PHPT should be added as a potential consideration. 27 As the literature on this topic is limited, the clinical presentation of these patients remains unclear. The latency period from the time of RAI treatment to the development of PHPT is not well studied.…”

Disease-Induced Changes in Salivary Gland Function and the Composition of Saliva

“…A substantial proportion of thyroid cancer sufferers are treated with radioactive iodine (RAI), which is also concentrated in parotid and submandibular glands by expressed sodium iodide membrane symporter proteins. Acute salivary gland hypofunction is seen in the first week following treatment and chronic sialadenitis from 3 mo onward, associated with ductal strictures and obstructive disease, which causes pain and associated salivary gland dysfunction, usually determined by salivary gland scintigraphy (Singer et al 2020).…”