Ultrasound and Sialendoscopy Findings in Radioactive Iodine-Induced Sialadenitis: Comparative Analysis and Possible Impact on Management

BACKGROUND

To assess the correlation/association between ultrasound and sialendoscopy findings in radioactive iodine therapy-induced sialadenitis (RAIS).

METHODS

Patients presenting with RAIS were investigated with ultrasound and sialendoscopy. Four pathologic ultrasound parameters and seven pathologic sialendoscopy parameters were retrospectively assessed. Correlations/associations between ultrasound and sialendoscopy findings and associations between the changes between the first and last ultrasound and sialendoscopy findings were assessed separately for the parotid (PG) and submandibular glands (SMG).

RESULTS

Sixty-seven patients were included. In the first examination, 107 glands were investigated (PGs 88.8%, SMGs 11.21%), and in the last examination, 64 glands were investigated (90.6% PGs, 9.4% SMGs). Highly significant positive associations were observed between the severity or category of ultrasound and sialendoscopy findings for first and last examinations for PGs (both p = 0.0001) and SMGs (p = 0.002; p = 0.037). Duct dilation had a significant negative association with the sialendoscopy findings for PGs in the first and last examinations (both p = 0.0001), but not for SMGs. Comparison of changes in the ultrasound and sialendoscopy findings between the first and last examinations showed a significant positive association for PGs (p = 0.0001) but not for SMGs.

CONCLUSIONS

Ultrasound and sialendoscopy findings for the parenchyma and duct system in RAIS showed significant associations/correlations and can be useful for effective management in RAIS.

Evaluation and management of dry mouth and its complications in rheumatology practice

INTRODUCTION

The symptom of dry mouth has multiple potential etiologies and can be a diagnostic clue to the presence of common systemic diseases encountered in rheumatology practice. The presence of decreased saliva flow (i.e. salivary hypofunction) defines a subset of dry mouth patients in whom there may be reversible drug effects, an iatrogenic insult such as head and neck irradiation, or a disease that directly involves the salivary glands (e.g. Sjögren's disease). The assessment of salivary hypofunction includes sialometry, salivary gland imaging, salivary gland biopsy, and an assessment for relevant systemic diseases. Optimal management of dry mouth requires accurate definition of its cause, followed by general measures that serve to alleviate its symptoms and prevent its complications.

AREAS COVERED

Through a literature search on xerostomia and salivary hypofunction, we provide an overview of the causes of dry mouth, highlight the potential impact of salivary hypofunction on oral and systemic health, detail routine evaluation methods and treatment strategies, and emphasize the importance of collaboration with oral health care providers.

EXPERT OPINION

Our Expert Opinion is provided on unmet needs in the management of dry mouth and relevant research progress in the field.

Bethanechol used to prevent salivary gland dysfunction in patients submitted to radioactive iodine therapy: A double blind, placebo-controlled, randomized study

Symptoms related to salivary gland damage are one of the most frustrating complications after radioactive iodine (¹³¹I) therapy. To the best of our knowledge, this is the first study that aimed to evaluate the prophylactic effect of Bethanechol on the radioiodine content of salivary gland. Fifty patients who were referred to ¹³¹I therapy were randomized into Bethanechol and placebo groups. Patients received Bethanechol or Placebo (25 mg, 2 times daily), starting 2 h after ¹³¹I therapy to 1-month.  Both groups were compared at baseline, 10, 30 and 90 days after ¹³¹I therapy based on the following: symptoms related to salivary gland damage; unstimulated whole saliva (UWS) and quality of life using University of Washington Quality of Life 4 questionnaire. Bethanechol group presented significantly lower complaints of dry mouth on 10 (p = 0.047) and 30 (p = 0.003) days compared with placebo. Salivary gland pain and swelling were more frequent among placebo patients at 10 days (p = 0.047). Comparison of the two groups by UWS, no statistical difference was found. Placebo group presented worse score related to activity (p = 0.034), saliva (p = 0.05) and humor (p = 0.05) at 10 days; palate (p = 0.05) and saliva (p = 0.05) at 1 month. Interestingly, Bethanechol patients who received ¹³¹I dose > 125mCi, showed better xerostomia indices when compared to the Placebo with same dose. Bethanechol during ¹³¹I therapy was found to be effective in decreasing the acute salivary gland damage with impact on patients' quality of life.

Progressive changes in the major salivary gland after radioiodine therapy for differentiated thyroid cancer: a single-center retrospective ultrasound cohort study

This study aimed to determine the prevalence of radioiodine-induced salivary gland damage by evaluating progressive changes in salivary glands using ultrasound. Four hundred forty-six patients with differentiated thyroid carcinoma who underwent total or near-total thyroidectomy and postoperative radioiodine therapy were retrospectively reviewed. From the first to the fifth follow-up visits, the positive rate of major salivary gland changes on ultrasound gradually increased from 2.0% to 33.0% (P<0.001) and possibly stabilized at the fifth visit (approximately 36 months). The first positive result was detected at an average of 20.78±8.72 months. Only 21 of the 161 positive cases eventually achieved negative ultrasound results (Fisher's test, P<0.001), and the 21 cases simply showed a coarse echotexure. In conclusion, ultrasound changes appeared late, and most of these changes were not reversed.

Disorders of Dental Hard Tissues Induced by Radioiodine-131 (I-131) Therapy Used in Differentiated Thyroid Cancer: An In Vitro Study

This study aimed to evaluate, in vitro, the effects of I-131 on enamel and dentin in healthy human incisive permanent maxillary teeth. Our in vitro model analogue with the in vivo conditions of differentiated thyroid carcinoma patients treated with I-131, consisted in a solution of I-131 dissolved in artificial saliva. A total of 48 teeth were divided into eight groups (n = 6): control, irradiation groups at 3, 6, 12, 24, 36, 48, and 192 h, respectively. At the end of radiation exposure, radioiodine activity of specimens was assessed. Fine microstructure, nanostructure, surface roughness, and hidroxyapatite (HAP) crystallite diameter were investigated by atomic force microscopy (AFM) to both enamel and dentin structures. There is a constant increase of radioactivity in dental structures at 3, 6, 12, 24 h, due to progressive retention and I-131 migration, with a maximum at 36 h. Enamel showed notable alterations, which was correlated with the increase of the treatment time. A relevant visible distance between the HAP prisms was observed after 24 h. The surface suffered a loss in its compact structure. I-131 acts in the same way on HAP crystallites in dentin as in those in enamel. It was noticed that their morpho-dimensional changes occurred only after 12 h of treatment. Radioiodine-131 determines degradation of enamel and dentin by starting from the alteration of the crystalline network of HAP prisms, transforming them from compact materials into an agglomeration of rocky submicron structures.

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

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.

Clinical and Sialographic Imaging Features of 131I Radiation-induced Submandibular Gland Sialadenitis

PURPOSE

¹³¹I radiation-induced sialadenitis is the most frequent complication of ¹³¹I treatment for papillary thyroid carcinoma, but little is known about ¹³¹I radiation-induced submandibular gland sialadenitis. The purpose of this study was to compare and contrast the clinical and sialographic imaging features of ¹³¹I radiation-induced submandibular gland sialadenitis to ¹³¹I radiation-induced parotitis.

PATIENTS AND METHODS

This retrospective cross-sectional study included patients with ¹³¹I radiation-induced submandibular gland sialadenitis and parotitis. Clinical records and sialographic image features were evaluated. The predictor variables included age at the time of diagnosis, gender, course of the disease, site of symptoms, and sialographic image grades. The outcome variable was the location of sialadenitis. A student t-test was conducted to analyze the associations between predictor variables and the outcome.

RESULTS

The sample was composed of 4 patients with submandibular gland sialadenitis (100% female), 28 with parotitis (85.7% female), and 1 with submandibular gland sialadenitis and parotitis (P < .05). The occurrence of bilateral glands dysfunction was less often in submandibular glands (SMG: 1/4; PG: 19/28). The age and course of disease were not different between submandibular gland sialadenitis and parotitis (Age, SMG: 46.00 ± 13.59 years; PG: 50.04 ± 10.71 years, P > .05; Course of the disease, SMG: 11.00 ± 16.69 months; PG: 6.96 ± 11.18 months, P > .05). Radiographically, 7 of 16 patients with parotitis were identified as grade 2 and 9 patients as grade 3. In 3 patients with submandibular gland sialadenitis, 1 patient was identified as grade 2 and 2 patients as grade 3. The postoperative pathological results showed that the proliferation of glandular tissue from the hilum of the submandibular gland caused duct stenosis.

CONCLUSION

The results suggest ¹³¹I radiation-induced submandibular gland sialadenitis has a lower incidence compared with parotitis and ¹³¹I radiation-induced submandibular gland sialadenitis might be related to duct stenosis caused by proliferative glandular tissue after ¹³¹I radiation treatment.

Clinical, Pathological, and Molecular Profiling of Radioactive Iodine Refractory Differentiated Thyroid Cancer

Background: Six to 20% of thyroid cancer (TC) patients develop distant metastases, and one-third become radioiodine refractory (RAIR). Available targeted therapies increase progression-free survival but are associated with toxicities. This study aims to characterize clinical, pathological, and molecular profiles of patients with RAIR TC. Methods: Data of TC patients seen during 2013-2017 at two tertiary care centers were retrospectively analyzed. Patients were considered RAIR according to American Thyroid Association guidelines. The control cohort was sex matched and age matched and had either regression or stable disease (by Response Evaluation Criteria in Solid Tumors) on follow-up at least three years after initial therapy. Molecular profiles on a subset of RAIR patients were reviewed. Results: Compared with 22 matched controls, 54 RAIR patients had an average age of 57 years (standard deviation [SD] = 13), 56% were male (41% in the control group); the average tumor size was 4 cm (SD = 2.5); tumors were multifocal in 54%, with involved surgical margins in 42%, focal invasion in 79%, and extrathyroidal extension (ETE) in 61%. Sixty-six percent had distant metastases at initial presentation with metastases to the lungs in 85%, bone in 56%, both sites in 43%, brain in 9%, and liver in 4%. There were no statistically significant differences between RAIR and controls in tumor size, focal invasion, ETE, and histology. The RAIR group received a higher cumulative radioactive iodine (RAI) dose and number of therapies compared with the controls (518 mCi vs. 302 mCi, p = 0.002 and 2.2 vs. 1.3 treatments, p = 0.001). Overall, patients >46 years had 4.5 times higher odds ratio (OR) of being RAIR; white race/ethnicity was associated with a reduced OR of RAIR disease (OR 0.33, p = 0.079). Molecular profiling data in the RAIR subgroup indicated that 50% of patients harbored mutations in the RAS/RAF pathway (11/22). Among 19 patients with a more extensive molecular panel, median tumor mutational burden was 5 megabase (range 3-16) and 26% (5/19) exhibited strong PD-L1 positivity. Conclusion: Among patients with metastatic differentiated thyroid carcinomas, patients with RAIR have similar histopathological and clinical characteristics as patients with RAI avid cancer. The risk of having RAIR TC is increased at age ≥46 and reduced in Caucasians.

Assessment of Parotid and Submandibular Glands With Shear Wave Elastography Following Radioactive Iodine Therapy for Papillary Thyroid Carcinoma

OBJECTIVES

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Radioactive iodine (RAI) therapy is used for remnant ablation following thyroidectomy. Side effects such as dysphagia, xerostomia, and sialoadenitis may occur. We aimed to determine the differences in the parotid and submandibulary glands between healthy patients and patients with PTC who had undergone RAI therapy and have dry mouth symptoms using both shear wave elastography and ultrasonography.

METHODS

We enrolled 30 patients with PTC who had undergone RAI therapy following surgery and 30 healthy controls. Ultrasonography and shear wave elastography of submandibular and parotid glands were performed. The volume of the submandibular glands and the thickness of parotid glands were determined. Ten independent measurements were obtained from each gland, with the region of interest placed at different points on the glands. The mean shear wave velocities (SWVs) were calculated and compared between the patients and controls.

RESULTS

In the PTC group, there was a significant reduction in the volume of the submandibular glands (P < .05) and in the thickness of the parotid glands (P < .05) compared with the control group. The mean SWVs of the parotid glands and submandibular glands were significantly higher in the PTC group compared with the control group (P < .0001). The SWVs of the parotid glands were higher than the SWVs of the submandibular glands (P < .0001).

CONCLUSIONS

Shear wave elastography could be a noninvasive and easy assessment method of parotid and submandibular glands in patients who had undergone RAI therapy and experience dry mouth.

Salivary evaluation in radioactive I131 treated patients with thyroid carcinoma

BACKGROUND AND OBJECTIVE

radioiodine treatment (I¹³¹) used to treat thyroid carcinomas produces side effects (sialadenitis, xerostomia, dysphagia and caries susceptibility) reflecting in a poor patient quality of life. This study aimed to evaluate the effect of I¹³¹ on salivary function and possible oral impairment.

MATERIAL AND METHODS

Thirty-seven patients undergoing I¹³¹ were submitted to oral examination, answer questions regarding xerostomia/hyposalivation and collect saliva at three moments (M1: 30-45 days before I¹³¹, M2: 1-2 days after I¹³¹ and M3: 7-10 days after treatment). Saliva was assayed for flow rate and calcium/phosphate concentrations.

RESULTS AND CONCLUSIONS

significant difference in calcium/phosphate concentration was shown between M1 and M2, with evident decrease at M2. Flow rate reduced right after treatment with 41% of patients returning to previous rate at M3 (no statistical difference). A higher number of patients related xerostomia and difficulty in swallowing food at M2. The results showed that xerostomia/hyposalivation, dysphagia and calcium/phosphate concentration decrease may be considered early radioiodine side effects.

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

The aim of this study was to evaluate the effects of the first radioactive iodine (I) therapy on functions of salivary glands in patients with differentiated thyroid carcinoma (DTC).There were 36 consented patients with DTC enrolled in this study, who received 3.7 GBq (100mCi) I for ablation after total thyroidectomy. Salivary gland function was assessed using salivary gland scintigraphy in two phases, one 4 hours before and the other 6 months after I therapy (both under thyrotropin stimulation condition). Quantitative parameters including uptake fraction (UF), uptake index (UI), excretion fraction (EF), and excretion ratio (ER) were measured and compared. Blood parameters were also compared. Associations between sex and outcome of the first I therapy as well as individual salivary gland function were measured. Wilcoxon Signed Rank Sum test and χ test were used for statistical analysis.When compared between pre-ablation and post-ablation, UF of bilateral parotid and submandibular glands were significantly increased (all P < .01). UI of both submandibular glands were significantly increased (P < .05). This seemingly increased uptake function after the first I therapy was actually compensatory mechanism of salivary gland, which indicated a possible intermediate state after radiation. But salivary glands' secretory function had not changed significantly except for left submandibular gland; we demonstrated that only left submandibular gland showed significantly decreased ER (P < .05). Thyroglobulin and thyroglobulin antibody significantly decreased after I therapy (P < .05). There were no sex differences on therapeutic outcome and salivary gland dysfunctions after the first I therapy. Salivary gland of both males and females could be affected by I therapy.The first I ablative therapy may impair the salivary uptake and secretory function of patients with DTC. There was no association between sex and salivary gland dysfunction.

Diagnostic Utility of Acoustic Structure Quantification for Evaluation of Radiation Sialadenitis after Radioactive Iodine Therapy

Acoustic structure quantification (ASQ) software was used to analyze statistical information on acquired echo signals, to determine the ability of ASQ to distinguish normal salivary glands of asymptomatic patients from glands of patients with radiation sialadenitis (RS) after radioactive iodine therapy. The ASQ values of 192 salivary glands were compared by multinomial logistic regression analysis, and receiver operating characteristic curves were constructed. Between-observer agreement was assessed by calculating the intra-class correlation coefficient. The mean ASQ values of patients with chronic RS or asymptomatic patients who had undergone radioactive iodine therapy were greater than those of patients with normal glands (p < 0.001). The ratio was associated with the highest odds ratio in patients with chronic RS compared with normal patients. Diagnostic performance was moderate; the intra-class correlation coefficient between observers was very good. ASQ can objectively differentiate RS-affected tissue from normal salivary tissue and is thus valuable for clinically diagnosing RS after radioactive iodine therapy.

Non-contrast-enhanced computed tomography attenuation in the parotid glands before radioiodine therapy for thyroid carcinoma could be a predictor of radiovulnerability

OBJECTIVE

This study aimed to determine a predictive factor for the effect of radioiodine therapy (RIT) on salivary gland dysfunction through a multiple regression analysis.

METHODS

We retrospectively assessed 40 patients with thyroid carcinoma, including 13 men (age range, 21-80 years) and 27 women (age range, 28-75 years), who underwent total thyroidectomy and were treated with RIT. We used multiple regression analysis to evaluate whether factors such as age, sex, dose number, prescintigraphy grade, computed tomography (CT) attenuation, and CT volume of the salivary glands affected the postscintigraphy grade. Receiver operating characteristics analysis was performed for predicting worsening scintigraphy grade of the parotid glands in 20 patients after RIT.

RESULTS

The postscintigraphy grade of the parotid glands was positively associated with the dose number and prescintigraphy grade and negatively associated with CT attenuation (β=0.48, P<0.01; β=0.47, P<0.01; and β=-0.26, P<0.05, respectively; adjusted R2=0.50, P<0.05). In the submandibular glands, the postscintigraphy grade was only positively correlated with dose number (β=0.58, P<0.01; adjusted R=0.32, P<0.01). Area under the curve was 0.775 (P<0.05) and the cutoff CT attenuation was -18.8 HU (sensitivity 0.714 and specificity 0.846).

CONCLUSION

The RIT dose number, prescintigraphy grade, and CT attenuation may be important predictors of parotid gland dysfunction after RIT, whereas the dose number alone may be a significant predictor of submandibular gland dysfunction.

Effects of Salivary Secretion Stimulation on the Treatment of Chronic Radioactive Iodine-Induced Sialadenitis

BACKGROUND

The aim of this prospective study was to investigate the effect of salivary stimulation therapy using pilocarpine (a cholinergic agent) on chronic radioactive iodine (RAI)-induced sialadenitis.

METHODS

Sixty-one patients with a diagnosis of chronic RAI-induced sialadenitis after thyroidectomy and RAI therapy were enrolled in this prospective study. Patients received salivary stimulation therapy with pilocarpine (5 mg, 3 times daily) over a 3-month period. Subjective symptom scores were assessed using self-reported questionnaires. Salivary flow rates (SFRs) were measured and salivary gland scintigraphy (SGS) was performed to evaluate objective salivary gland functions.

RESULTS

After salivary stimulation therapy, subjective symptom scores were significantly improved (p=0.002), but posttreatment unstimulated and stimulated SFRs did not differ significantly from pretreatment values. SGS parameters, that is, uptake ratio (UR), maximum accumulation (MA), Tmin, and maximum secretion (MS) of parotid and submandibular glands were nonsignificantly different after salivary stimulation therapy.

CONCLUSION

The study shows that salivary stimulation therapy may reduce the subjective symptoms of RAI-induced chronic sialadenitis but does not significantly induce functional restoration.

Salivary gland dysfunction after radioactive iodine (I-131) therapy in patients following total thyroidectomy: emphasis on radioactive iodine therapy dose

PURPOSE

The purpose of this study was to retrospectively evaluate symptoms, images of salivary gland dysfunction, and related clinical factors in thyroid cancer patients with total thyroidectomy followed by radioiodine therapy (RIT).

METHODS

We included 164 patients who underwent thyroid ultrasonography or contrast-enhanced neck computed tomography more than 6 months later after RIT. Correlation between subjective symptoms and various RIT doses was also evaluated.

RESULTS

Swelling and decreased salivary volume were the most common symptoms and images. RIT dose was the only factor with a positive correlation (P<.001).

CONCLUSION

The dose of RIT should be carefully determined to minimize gland dysfunction.

Nasal symptoms after radioiodine therapy: a rarely described side effect with similar frequency to lacrimal dysfunction

BACKGROUND

Salivary and lacrimal side effects of radioiodine therapy have been carefully described. However, nasal side effects are rarely described. The objective of this study was to document the frequency of nasal side effects in comparison to the already well-documented lacrimal side effects and to determine contributing risk factors.

METHODS

A retrospective review of the medical records of 807 patients with differentiated thyroid cancer who received care at an academic medical center was conducted. Four hundred eleven patients who received treatment with radioactive iodine (RAI) were identified and included in the analysis. The frequency of both nasal and lacrimal side effects was ascertained. Factors that may have contributed to patients sustaining nasal damage after RAI therapy were also documented. These factors included radioactive iodine dose, method of preparation for receiving RAI therapy, and patient characteristics.

RESULTS

The mean dose of RAI administered was 109 mCi. Forty-three patients (10.5%) and 40 patients (9.7%) developed nasal and lacrimal side effects, respectively, following RAI treatment. The mean time of onset of nasal symptoms was 11 days, compared with 10 months for lacrimal symptoms. Radioiodine dose and body mass index were significantly positively and negatively correlated, respectively, with sustaining nasal side effects (p values of 0.04 and 0.01, respectively). Similarly, both RAI dose and body mass index were significantly correlated, positively and negatively, respectively, with sustaining lacrimal side effects (p values of 0.02 and 0.01). Preparation for treatment using a withdrawal protocol was associated with increased risk of both nasal and lacrimal side effects, compared with a recombinant human thyrotropin (rhTSH) protocol (p values of <0.01 and 0.01). The odds ratios (95% confidence interval [CI]) for nasal and lacrimal side effects with recombinant rhTSH preparation were 0.22 [0.11-0.44] and 0.37 [0.18-0.76], respectively. Instructions to maintain adequate hydration and development of lacrimal symptoms were only associated with nasal symptoms in unadjusted analyses.

CONCLUSIONS

Both nasal and lacrimal dysfunction occurred at an approximately 10% frequency. Although it cannot be determined whether acute nasal side effects are followed by long-term ramifications, these consequences of RAI could potentially add to the reasons to carefully evaluate the benefits and risks of RAI therapy on an individual basis.

Appropriate dosing of adjuvant radioactive iodine for differentiated thyroid cancer

PURPOSE OF REVIEW

The incidence of well differentiated thyroid cancer (WDTC) is increasing in the US population and is now a major public health concern. Although surgery is the mainstay of treatment, radioactive iodine (RAI) is routinely used for adjuvant therapy, remnant ablation, and for the treatment of metastatic disease. Despite excellent prognosis and stable mortality rates, the use of RAI is increasing in many low and intermediate risk WDTC patients without clear indication that it changes the outcome. As a result, the current treatment paradigm has shifted towards a risk-stratified approach.

RECENT FINDINGS

Although there is widespread acceptance that RAI improves overall and recurrence-free survival in patients with metastatic disease, controversy remains regarding radioactive remnant ablation use in low and intermediate risk patients. Additional studies have shown that reduced doses of RAI can provide similar rates of remnant ablation and adjuvant therapy in low and intermediate risk patients without adversely affecting the recurrence rates and mortality.

SUMMARY

Recent studies suggest potential new paradigms in radioactive remnant ablation dosing and indications for use. Risk stratification is important in determining the proper use and dosing of RAI.

A randomized controlled trial for the use of thymus honey in decreasing salivary gland damage following radioiodine therapy for thyroid cancer: research protocol

AIM

To test the effectiveness of thymus honey as a complementary intervention for decreasing the salivary gland damage due to Radioiodine ((131) I) therapy.

BACKGROUND

Radioiodine is the treatment of choice in people diagnosed with thyroid cancer following total thyroidectomy. Although its value has been acknowledged in eradicating remnant thyroid tissue and treating residual disease in patients with visible, inoperable, iodine-avid metastases, it has been associated with various salivary gland side effects.

DESIGN

This is a randomized controlled trial with a 2 × 3 mixed between-within subjects design.

METHODS

In total, 120 participants of postsurgical differentiated thyroid cancer, who will be referred to this centre for (131) I therapy to ablate the remnant thyroid tissue or to treat metastatic tumour, will be prospectively studied under varying regimens of lemon candy (standard treatment) and thymus honey mouthwashes (experimental intervention). Patients will be randomized in four equally numbered groups based on the assumptions and hypothesis of the study. The recruiting process will be informed by predefined inclusion and exclusion criteria. Mixed statistical modelling will be adopted taking into consideration between and within subjects' effects and repeated measures.

DISCUSSION

The recommended intervention protocol is expected to improve the comprehensive management of salivary gland-related side effects induced by the radioiodine treatment in people diagnosed with thyroid cancer. Through the methodological approach chosen, the ideal intervention protocol in terms of the time to initiate the intervention and the frequency of the intervention to acquire optimal results in minimizing salivary glands damage will be tested.

Radioprotective agents for the prevention of side effects induced by radioiodine-131 therapy

Radioiodine 131 (131I) has been used worldwide for the ablation of remnant thyroidal tissue after surgery or as the first-line treatment for Graves’ disease. Although the use of 131I is becoming increasingly prevalent, there is evidence suggesting that this treatment is associated with side effects such as salivary gland dysfunction and an increased risk of leukemia. This article aims to review the potential use of radioprotective agents and the side effects induced by 131I therapy. Several synthetic and natural compounds have been investigated in preclinical and clinical studies. The protective agents reduced the toxicity of 131I, mainly in the salivary glands, and mitigated the genetic damage through different mechanisms. There are limited clinical studies evaluating the use of radioprotective agents in patients undergoing radioiodine therapy. However, lemon candies, lemon juice and sugarless chewing gum have been proposed to be beneficial for minimizing the side effects of radioiodine within the salivary glands.

Modulation of sodium/iodide symporter expression in the salivary gland

BACKGROUND

Physiologic iodide-uptake, mediated by the sodium/iodide symporter (NIS), in the salivary gland confers its susceptibility to radioactive iodine-induced damage following (131)I treatment of thyroid cancer. Subsequent quality of life for thyroid cancer survivors can be decreased due to recurrent sialoadenitis and persistent xerostomia. NIS expression at the three principal salivary duct components in various pathological conditions was examined to better our understanding of NIS modulation in the salivary gland.

METHODS

NIS expression was evaluated by immunohistochemistry in human salivary gland tissue microarrays constructed of normal, inflamed, and neoplastic salivary tissue cores. Cumulative (123)I radioactivity reflecting the combination of NIS activity with clearance of saliva secretion in submandibular and parotid salivary glands was evaluated by single-photon emission computed tomography/computed tomography imaging 24 hours after (123)I administration in 50 thyroid cancer patients.

RESULTS

NIS is highly expressed in the basolateral membranes of the majority of striated ducts, yet weakly expressed in few intercalated and excretory duct cells. The ratio of (123)I accumulation between parotid and submandibular glands is 2.38±0.19. However, the corresponding ratio of (123)I accumulation normalized by volume of interest is 1.19±0.06. The percentage of NIS-positive striated duct cells in submandibular salivary glands was statistically greater than in parotid salivary glands, suggesting a higher clearance rate of saliva secretion in submandibular salivary glands. NIS expression in striated ducts was heterogeneously decreased or absent in sialoadenitis. Most ductal salivary gland tumors did not express NIS. However, Warthin's tumors of striated duct origin exhibited consistent and intense NIS staining, corresponding with radioactive iodine uptake.

CONCLUSIONS

NIS expression is tightly modulated during the transition of intercalated to striated ducts and striated to excretory ducts in salivary ductal cells. NIS expression in salivary glands is decreased during inflammation and tumor formation. Further investigation may identify molecular targets and/or pharmacologic agents that allow selective inhibition of NIS expression/activity in salivary glands during radioactive iodine treatment.

The results of selective use of radioactive iodine on survival and on recurrence in the management of papillary thyroid cancer, based on Memorial Sloan-Kettering Cancer Center risk group stratification

BACKGROUND

The American Thyroid Association guidelines recommend the routine use of radioactive iodine for remnant ablation (RRA) in all T3 or greater primary tumors, and selective use in patients with intrathyroidal disease >1 cm, or evidence of nodal metastases. The guidelines recognize that there is conflicting and inadequate data to make firm recommendations for most patients. The aim of this study was to analyze our institutional experience of the use of RRA in the management of papillary thyroid cancer, with a particular focus on outcomes for those patients selected not to receive RRA.

METHODS

We retrospectively reviewed 1129 consecutive patients who underwent total thyroidectomy at the Memorial Sloan-Kettering Cancer Center between 1986 and 2005. Of these, 490 were pT1-2 N0, 193 pT1-2 N1, and 444 pT3-4. Details on recurrence and disease-specific survival were recorded by the Kaplan-Meier method and compared using the log-rank test.

RESULTS

The five-year disease-specific survival and recurrence-free survival in the pT1/T2 N0, pT1-2 N1, and pT3-4 were 100% and 92%, 100% and 92%, and 98% and 87% respectively. Low-risk patients who were managed without RRA (who tended to have limited primary disease, pT1-2, and low-volume metastatic disease in the neck, pT1-2 N1-fewer than five nodes, all <1 cm greatest dimension) had five-year recurrence-free survival of >97%. In the group with advanced local tumors (pT3-4), those patients who did not receive RRA (who tended to have pT3 N0 disease) had five-year recurrence-free survival of >90%.

CONCLUSION

Following appropriate surgical management, the majority of patients with low-risk local disease and even some patients with more advanced-stage (pT3) tumors or regional metastases have low rates of recurrence and high rates of survival when managed without RRA.

Assessment of salivary gland dysfunction after radioiodine therapy for thyroid carcinoma using non-contrast-enhanced CT: the significance of changes in volume and attenuation of the glands

BACKGROUND AND PURPOSE

Although radiation induced damage to the salivary gland is a known complication of radioactive iodine ((131)I) therapy for thyroid carcinoma, prediction of the severity and reversibility of sialoadenitis is difficult. Our aim was to correlate the extent of salivary dysfunction assessed by salivary gland scintigraphy with changes in the volume and attenuation of salivary glands on nonenhanced CT in postoperative patients with thyroid cancer treated with RIT.

MATERIALS AND METHODS

Forty patients with thyroid carcinoma, 13 men (age range, 21-80 years) and 27 women (age range, 28-75 years) who underwent a total thyroidectomy and were treated with RIT were assessed retrospectively. On CT, the percentage of volume reduction and the difference in attenuation of the parotid and submandibular glands after RIT were determined and correlated with the extent of radiation-induced salivary dysfunction on scintigraphy.

RESULTS

The salivary gland volume significantly decreased with an increase in the dysfunction grade on scintigraphy for both the parotid and submandibular glands (P < .001). The attenuation significantly increased with an increase in the dysfunction grade on scintigraphy for the parotid gland (P < .001), but not for the submandibular gland. The cutoff value of volume reduction to diagnose severe gland dysfunction was 19.5% (sensitivity, 86.0%; specificity, 100%) for the parotid gland and 31.0% (sensitivity, 100%; specificity, 97.0%) for the submandibular gland, and that of the attenuation change was 9.8 HU (sensitivity, 81.0%; specificity, 95%) for the parotid gland.

CONCLUSIONS

The reduction in volume of the parotid and submandibular glands and the increase in attenuation of the parotid gland on nonenhanced CT can be indicators of the grade of RIT-induced salivary dysfunction.

Salivary gland malignancy and radioiodine therapy for thyroid cancer

BACKGROUND

The risk of second primary malignancies in patients with well-differentiated thyroid cancer is of special interest because of the common use of radioactive iodine (RAI) ablation and/or treatment of these patients and the theoretical risk of subsequent nonthyroid malignancies associated with the radiation exposure. This brief report focuses specifically on the occurrence of second primary malignancies of the salivary glands. RAI residency within salivary tissues is known to have both acute and chronic consequences on salivary function, but secondary neoplasia is quite unusual.

SUMMARY

We present a very rare case of a patient with papillary thyroid cancer treated with 600 mCi of RAI, who subsequently developed salivary gland cancer.

CONCLUSIONS

We recommend salivary gland protection to diminish potential side effects after the exposure to radioiodine. On the basis of our experience we suggest administration of sialogogues (such as lemon juice) continuously, every 30-60 minutes for 24 hours, after RAI administration.

RETRACTED ARTICLE: Radiation sialadenitis induced by high-dose radioactive iodine therapy

Radioactive iodine ((131)I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, (131)I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the (131)I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of (131)I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of (131)I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with (131)I-induced sialadenitis that is unresponsive to medical treatment.

Role of sialoscopy in the treatment of Stensen's duct strictures

OBJECTIVES

The origin of strictures of Stensen's duct often remains unclear, but chronic recurrent parotitis may be one associated disease. Failure of conservative therapy leads to a recommendation of parotidectomy in a high percentage of cases. Nowadays, development of new, minimally invasive methods may lead to a fundamental change in the treatment regimen.

METHODS

We retrospectively evaluated 39 patients who presented with symptomatic strictures of Stensen's duct from 2002 to 2005. Sialoscopy was performed with semirigid endoscopes. Therapy consisted of irrigation and intraductal infusion of cortisone. If possible, interventional sialoscopy was carried out as the first-line procedure. If indicated, operative procedures of the duct were performed.

RESULTS

After irrigation and intraductal medication, 17.9% of the patients were free of symptoms. Interventional sialoscopy was carried out in 74.4%, with a success rate of 75.9%. Operative duct procedures (extended papillotomy or resection of papilla stricture with duct reinsertion) were carried out in 23% of cases. In 5.1% of the total cases, parotidectomy was unavoidable.

CONCLUSIONS

Sialoscopy-based methods play a central role in gland-preserving treatment of strictures of Stensen's duct. Sialoscopy has proven to be a fast, useful, and relatively safe therapeutic tool with a high success rate. Parotidectomy is the last choice in symptomatic cases.

False-positive xerostomia following radioactive iodine treatment: case report

Radioactive iodine (131I), used in the treatment of differentiated thyroid carcinoma, is known to cause both short-term and long-term radiation damage to the salivary glands. The injury appears as glandular swellings and/or decreased salivation with 131I dosage and passage of time playing significant roles. A case report is presented to alert the profession to the existence of patients who have received 131I therapy and who complain shortly thereafter of xerostomia, but following a thorough examination are found to represent a group of false-positives. Emphasis is placed on the diagnostic techniques used in the differential diagnosis.

Sialadenitis following radioiodine therapy – a new diagnostic and treatment modality

OBJECTIVES

To explore the usage of salivary gland endoscope technique as a diagnostic tool as well as a novel treatment modality for sialadenitis following radioiodine therapy.

SUBJECTS AND METHODS

Fifteen patients suffering from sialadenitis of the major salivary glands after I131 therapy for thyroid carcinoma underwent a single procedure of sialoendoscopy under local anesthesia.

RESULTS

All the patients were free of sialadenitis after one sialoendoscopy procedure with no complications accompanied.

CONCLUSIONS

Sialoendoscopy is an efficient technique with low morbidity as well as a relatively simple surgical method for diagnosing and treating sialadenitis induced by radioiodine therapy for thyroid cancer patients.

Radioactive iodine and the salivary glands

Radioactive iodine ((131)I) targets the thyroid gland and has been proven to play an effective role in the treatment of differentiated papillary and follicular cancers. Simultaneously, this radioisotope hones in on the salivary glands where it is concentrated and secreted into the saliva. Dose related damage to the salivary parenchyma results from the (131)I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of (131)I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, stomatitis, candidiasis, and neoplasia. Prevention of the (131)I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Recently, amifostine has been advocated to prevent the effects of irradiation. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration.