Incidence and risk factors for radioactive iodine-induced sialadenitis

Diagnosis and Treatment of Radioactive Iodine-Induced Sialadenitis: A 10-Year Endoscopic Experience

OBJECTIVES

The aim of this study was to explore the endoscopic characteristics of radioactive iodine-induced sialadenitis (RAIS), and to evaluate the treatment outcomes of endoscopic intervention for RAIS.

STUDY DESIGN

Retrospective case series.

METHODS

Eighty-two consecutive patients (11 males and 71 females) diagnosed as RAIS from Nov. 2012 to Sep. 2023 were retrospectively included. All patients underwent endoscopic exploration and intervention of the affected glands. The endoscopic features were collected, and treatment outcomes were followed-up and evaluated through post to pre-operative comparisons of gland status.

RESULTS

Overall, endoscopic procedures were undertaken for 162 parotid glands (PGs) and 62 submandibular glands (SMGs). Endoscopy showed severe lumen stricture (49.3%) and ductal atresia (23.5%) in PGs, as well as severe stenosis of the anterior duct and ectasia of the proximal duct (59.7%) in SMGs. During a median six months' follow-up, the treatment outcomes of PGs were evaluated as "improvement" in 23.4%，"lesion maintenance" in 45.1% and "lesion aggravation" in 31.5% of the glands. As for SMGs, the treatment outcomes were scored as "improvement"in 29.0%，"lesion maintenance"in 54.8%, and"lesion aggravation"in 16.1% of the glands. No significant differences of treatment outcomes were found relative to RAI treatment sessions and cumulative dosage.

CONCLUSION

RAIS is characteristic of severe lumen stricture and ductal atresia in PGs, and stenosis of the distal duct and ectasia of the proximal duct in SMGs. Endoscopy can alleviate clinical symptoms of RAIS and help to preserve the gland function.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:4506-4513, 2024.

Ultrasound Changes in Salivary Glands after Radioactive Iodine Treatment in Benign Diseases and Differentiated Cancer of Thyroid Glands in Consideration of Dose and Time Dependency

PURPOSE

To assess ultrasound (US) features observed in salivary glands after radioactive iodine treatment (RAIT) in relation to the dose and time interval after RAIT.

MATERIALS AND METHODS

A retrospective analysis of US findings regarding the salivary glands of patients presenting after RAIT due to thyroid cancer (Group 1, n=99) or benign thyroid diseases (Group 2, n=25). The control group consisted of randomly selected patients (no RAIT, Group 3, n=100). Groups were compared regarding RAIT dose, symptoms, and US findings (duct dilation, hypoechoic/heterogeneous parenchyma, parenchymal loss). The association of the presence of US parameters after RAIT with various dose levels (2000-15000MBq) and time intervals (24, 60, 120 months) and the differences between the groups was evaluated.

RESULTS

Significant differences between US parameters were noted when comparing Group 1 with Group 2 or 3. Nothing of relevant significance was noted when Groups 2 and 3 were compared. US features indicating a slight or moderate sialadenitis showed the most significant associations with doses <4000MBq and time intervals <24 months after RAIT. US changes indicating a serious sialadenitis or even gland atrophy showed the most significant association at doses between >7000-9000MBq and when US was performed >60 months after RAIT.

CONCLUSION

Our results point to a dose and time dependency of pathologic US findings in RAIT-induced effects on the major salivary glands. Based on the US findings, a better estimation of the current impact of RAIT on the salivary glands and the further prognosis appears possible.

Epidemiologic, radiologic, and sialendoscopic aspects in chronic obstructive sialadenitis

PURPOSE

Chronic obstructive sialadenitis (COS) is a recurring inflammation of the salivary gland. To date, there are no known predisposing factors for COS. Given the advances seen in radiology and sialendoscopy, we must update our knowledge of COS, analyzing factors that can favor its development.

METHODS

We prospectively analyzed 333 patients who underwent sialendoscopy between 2012 and 2021. Epidemiologic, radiologic, and sialendoscopy-related factors were correlated. Suspected diagnosis was established based on the clinical and radiologic data. The final diagnosis was determined on the basis of sialendoscopic findings.

RESULTS

The most common etiology of COS was stricture (40.8%). Lack of papilla distensibility (LPD) was also described as an etiology. COS was related to patient gender and age. Submandibular gland involvement was significantly more associated with lithiasis and LPD, while COS of the parotid gland was most frequently caused by stricture. Radioiodine sialadenitis and Sjögren's syndrome were significantly associated with stricture. MR sialography (MR-Si) showed the best overall sensitivity and specificity.

CONCLUSION

In our series, stricture was the most common cause of COS. We describe LPD as a frequent cause of COS in this series; ours is the first study to report this finding. There was a significant association between the salivary gland involved, patient sex and age, and the cause of COS. MR-Si showed the greatest diagnostic yield.

Strategies for Radioiodine Treatment: What’s New

Radioiodine treatment (RAI) represents the most widespread and effective therapy for differentiated thyroid cancer (DTC). RAI goals encompass ablative (destruction of thyroid remnants, to enhance thyroglobulin predictive value), adjuvant (destruction of microscopic disease to reduce recurrences), and therapeutic (in case of macroscopic iodine avid lesions) purposes, but its use has evolved over time. Randomized trial results have enabled the refinement of RAI indications, moving from a standardized practice to a tailored approach. In most cases, low-risk patients may safely avoid RAI, but where necessary, a simplified protocol, based on lower iodine activities and human recombinant TSH preparation, proved to be just as effective, reducing overtreatment or useless impairment of quality of life. In pediatric DTC, RAI treatments may allow tumor healing even at the advanced stages. Finally, new challenges have arisen with the advancement in redifferentiation protocols, through which RAI still represents a leading therapy, even in former iodine refractory cases. RAI therapy is usually well-tolerated at low activities rates, but some concerns exist concerning higher cumulative doses and long-term outcomes. Despite these achievements, several issues still need to be addressed in terms of RAI indications and protocols, heading toward the RAI strategy of the future.

Prevention of salivary gland dysfunction in patients treated with radioiodine for differentiated thyroid cancer: A systematic review of randomized controlled trials

INTRODUCTION

Salivary gland dysfunction (e.g., sialadenitis and xerostomia) is the most common complication of radioactive iodine (RAI) therapy for differentiated thyroid cancer (DTC). Several methods have been used to reduce/prevent this adverse effect. We aimed to systematically review the effectiveness of non-pharmacological and pharmacological interventions in preventing RAI-induced salivary gland dysfunction in patients with DTC.

METHODS

A systematic review was conducted, according to PRISMA guidelines. The protocol was registered (PROSPERO: CRD42022295229). PubMed, Embase, Scopus, and the Cochrane Library electronic databases were searched from inception to November 2021. Inclusion criteria were randomized controlled trials of DTC patients who were older than 18 years and underwent RAI after thyroidectomy in which at least one studied group received an intervention to prevent salivary gland dysfunction.

RESULTS

Twelve studies (a total of 667 participants) were included. Among DTC patients who were treated with RAI, nonpharmacological treatment such as parotid gland massage and aromatherapy ameliorated salivary gland dysfunction. Antioxidants such as vitamin E and selenium demonstrated radioprotective effects on the salivary gland, while other antioxidants did not show radioprotective benefits. Vitamin C showed no significant effects on preventing salivary gland dysfunction. Amifostine had inconsistent outcomes among studies. Among cholinergic agonists, pilocarpine did not demonstrate the radioprotective effect on parotid glands, while bethanechol lowered salivary gland dysfunction. However, the negative results from pilocarpine may be explained by the strong sialorrheic effect of the Cincinnati regimen in both study arms.

CONCLUSION

Among non-pharmacological and pharmacological methods, parotid gland massage, aromatherapy, vitamin E, selenium, amifostine, and bethanechol may have benefits in minimizing RAI-induced salivary gland dysfunction in patients with DTC. The results are limited by a small number of patients and should be confirmed in future larger randomized controlled trials.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=295229, PROSPERO, identifier CRD42022295229.

Differences between radioactive iodine-induced sialadenitis and chronic obstructive parotitis

The purpose of this study was to clarify the differences in the diagnosis and treatment outcomes between radioactive iodine-induced sialadenitis (RAIS) and chronic obstructive parotitis (COP). The study cohort comprised 47 consecutive patients diagnosed with RAIS and 50 patients with COP. All patients were treated by interventional endoscopy. Clinical, sialography, and endoscopy characteristics and treatment outcomes were compared between the two groups. Compared with the COP group, the RAIS group included more females (male:female ratio 1:8.4 vs 1:2.1; P = 0.011) and had a younger onset age (42 vs 50 years; P = 0.001) and shorter disease duration prior to hospital visit (5.4 vs 34.8 months; P < 0.001). In the RAIS group, sialography revealed obliteration of the main duct (20.4% vs 0%; P < 0.001), non-visualization of the main gland (23.7% vs 0%; P < 0.001), and incomplete contrast filling of the main gland (19.4% vs 6.4%; P = 0.008), which were scarcely observed in the COP group. Endoscopy revealed a higher percentage of duct atresia in RAIS compared to COP (20.4% vs 0%; P < 0.001). During follow-up, a higher percentage of RAIS patients had duct atresia and gland atrophy (49.5% vs 1.1%, P < 0.001). Compared with COP, RAIS more commonly involves younger females and has a shorter disease duration. Atresia of the main duct and atrophy of the gland parenchyma occur more often despite the use of interventional endoscopy.