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.

Sialadenitis as a complication of radioiodine therapy in patients with thyroid cancer: where do we stand?

PURPOSE

This study aims to elaborate on the current knowledge concerning the mechanism, frequency, clinical manifestations, diagnostic procedures, prevention, and management of radioactive iodine (RAI)-induced sialadenitis in patients receiving treatment for differentiated thyroid cancer (DTC).

METHODS

A review of the literature was carried out through the " www.ncbi.nlm.nih.gov/pubmed " database focusing on the results of the past decade.

RESULTS

The high concentration of RAI in the salivary glands results in high beta radiation exposure of the striated duct cells and stem cells. This exposure leads to acute and/or chronic sialadenitis with obstructive symptoms and progressive loss of salivary gland function and xerostomia, with severe impact on patients' quality of life. No standard diagnostic method has been established. As far as prevention is concerned, many approaches have been proposed, such as sialogogues, local massage, vitamin E, and amifostine administration. Although there is no unanimity as to their effectiveness, the use of sialogogues is recommended. Treatment includes conservative drug therapy and sialendoscopy when necessary.

CONCLUSION

RAI-induced sialadenitis has a major impact on patients' quality of life. Due to the good prognosis of DTC, the reduction of sialadenitis and its prognosis, prevention, and treatment constitute a priority for the overall treatment of these patients. Further studies that will establish a coherent treatment protocol for this condition are necessary.

Clinical Management of End-Stage Renal Disease Patients on Dialysis Receiving Radioactive Iodine Treatment

PURPOSE

Radioactive iodine (RAI) is used to treat thyroid cancer patients with a clear paradigm for most patients. End-stage renal disease (ESRD) patients pose several challenges when undergoing RAI treatment, primarily due to the lack of renal clearance. We retrospectively report our experience with RAI treatment in a cohort of patients with ESRD and provide a set of recommendations on aspects such as the need for adjusted dose activity, balancing scheduling between RAI therapy and dialysis, and radiation safety precautions.

PATIENTS AND METHODS

In this study, we report on 5 patients (6 cases), with ESRD on dialysis, treated with RAI for thyroid cancer. Retention measurements to determine individual biological clearance of RAI from the patient's body before and after dialysis sessions were assessed using external exposure dose rates measured at 1 m.

RESULTS

Delayed biological clearance of RAI, after the first hemodialysis session, resulted in a longer RAI effective half-life as a consequence of longer retention periods, consistent with observations reported in scientific literature. To achieve a much closer radiation exposure compared with a nondialysis patient, one would recommend administering ~20%-30% of the dose activity normally administered to a thyroid cancer patient based on their medical history, histopathology, and uptake with the appropriate dialysis schedule.

CONCLUSIONS

Special precautions should be taken with the administration of RAI in ESRD patients by adjusting the prescribed dose activity, dialysis sessions, and paying special attention to wastes. Pooling data from multiple centers may be useful to build a consensus and substantiated recommendations.

Clinical impact of radioactive iodine dose selection based on the number of metastatic lymph nodes in patients with papillary thyroid carcinoma: A multicenter retrospective cohort study

OBJECTIVE

The aim of this study is to investigate whether the number of metastatic lymph nodes (LNs) could be used as a basis in the radioactive iodine (RAI) dose selection for patients with papillary thyroid carcinoma (PTC).

PATIENTS

A total of 595 patients with PTC who received first RAI therapy after total or near-total thyroidectomy and had no evidence of disease in treatment response assessment were retrospectively enroled from five hospitals. The patients were classified into two subgroups based on the number of metastatic LNs (>5). The multivariate Cox-proportional hazard model was performed to identify the significant factors for recurrence prediction in each group as well as all enroled patients.

RESULTS

Overall, 22 (3.7%) out of 595 patients had the recurrent disease during the follow-up period. The number of metastatic LNs (>5) was only a significant factor for recurrence prediction in all enroled patients (odds ratio: 7.834, p < .001). In the subgroup with ≤5 metastatic LNs, the presence of extrathyroidal extension was only associated with recurrence (odds ratio: 7.333, p = .024) in multivariate analysis. RAI dose was significantly associated with recurrence rate in which the patients with high-dose RAI (3.7 GBq or higher) had less incidence of recurrence than those with low-dose RAI (1.11 GBq) in the subgroup with more than five metastatic LNs (odds ratio: 6.533, p = .026).

CONCLUSIONS

High-dose RAI (≥3.7 GBq) therapy significantly lowered the recurrence rate in patients with more than five metastatic LNs. Therefore, RAI dose should be determined based on the number of metastatic LNs as well as conventional risk factors.

Metastatic Medullary Thyroid Cancer: The Role of 68Gallium-DOTA-Somatostatin Analogue PET/CT and Peptide Receptor Radionuclide Therapy

CONTEXT

Metastatic medullary thyroid cancer (MTC) is a rare malignancy with minimal treatment options. Many, but not all, MTCs express somatostatin receptors.

OBJECTIVE

Our aim was to explore the role of 68Ga-DOTA-somatostatin analogue (SSA) positron emission tomography (PET)/computed tomography (CT) in patients with metastatic MTC and to determine their eligibility for peptide receptor radionuclide therapy (PRRT).

METHODS

We retrospectively identified patients with metastatic MTC who had 68Ga-DOTA-SSA PET/CT at 5 centers. We collected characteristics on contrast-enhanced CT, 68Ga-DOTA-SSA and 18F-FDG PET/CT. The efficacy of PRRT was explored in a subgroup of patients. Kaplan-Meier analysis was used to estimate time to treatment failure (TTF) and overall survival (OS).

RESULTS

Seventy-one patients were included (10 local recurrence, 61 distant disease). Of the patients with distant disease, 16 (26%) had ≥50% of disease sites with tracer avidity greater than background liver, including 10 (10/61, 16%) with >90%. In 19 patients with contemporaneous contrast-enhanced CT, no disease regions were independently identified on 68Ga-DOTA-SSA PET/CT. Thirty-five patients had an 18F-FDG PET/CT, with 18F-FDG positive/68Ga-DOTA-SSA negative metastases identified in 15 (43%). Twenty-one patients had PRRT with a median TTF of 14 months (95% CI 8-25) and a median OS of 63 months (95% CI 21-not reached). Of the entire cohort, the median OS was 323 months (95% CI 152-not reached). Predictors of poorer OS included a short calcitonin doubling-time (≤24 months), strong 18F-FDG avidity, and age ≥60 years.

CONCLUSIONS

The prevalence of high tumor avidity on 68Ga-DOTA-SSA PET/CT is low in the setting of metastatic MTC; nevertheless, PRRT may still be a viable treatment option in select patients.

Delayed Initial Radioiodine Adjuvant Therapy Does Affect Biochemical Response in Intermediate- to High-Risk Differentiated Thyroid Cancer

Background

There are no definite recommendations on the optimal time of initiating radioactive iodine (RAI) therapy for differentiated thyroid cancer (DTC) patients in current relevant guidelines. This study aimed to investigate the relationship between the timing of initiating radioiodine adjuvant therapy (RAT) and the clinical outcomes based on dynamic follow-ups and assessments in intermediate- to high-risk DTC patients.

Methods

A total of 206 patients with intermediate- to high-risk DTC receiving RAT of 150 mCi were retrospectively reviewed. According to the time interval (TI: between thyroidectomy and initial RAT), the patients were divided into 2 groups: Group 1: TI < 3 months (n=148), and Group 2: TI ≥ 3 months (n=58). The RAT therapy response was evaluated as excellent response (ER), indeterminate response (IDR), biochemical incomplete response (BIR), structural incomplete response (SIR). The univariate and multivariate analyses were conducted to screen out factors associated with incomplete response (IR= BIR+SIR). Finally, the prognostic nomogram was used to explain IR rates as a valuable tool in clinical practice.

Results

Response to initial RAT was significantly different between 2 groups during dynamic follow-ups (all P<0.05). Group 2 had significantly lower ER rates (37.9 vs 63.5, 52.0 vs 73.9, 64.4 vs 80.3, all P<0.05, respectively) and higher IR rates (39.7 vs 14.9, 36.0 vs 9.7, 12.2 vs 3.9, all P<0.05, respectively) than group 1 during dynamic follow-ups. By univariate and multivariate analyses, prolonged TI (HR: 6.67, 95%CI: 2.241-19.857, P=0.001), soft tissue invasion (HR: 7.35, 95%CI: 1.624-33.296, P=0.010), higher sTg (HR: 7.21, 95%CI: 1.991-26.075, P=0.003) were manifested to be independent risk factors for IR. The nomogram showed that soft tissue invasion, sTg, and TI were the top 3 contributors to the IR.

Conclusions

Early RAT is associated with greater biochemical response but has no impact on SIR. Delayed initial RAT (≥3 months after thyroidectomy) related to IR in intermediate- to high-risk DTC.

Patterns of radioiodine use for differentiated thyroid carcinoma in Brazil: insights and a call for action from a 20-year database

OBJECTIVE

This study aimed to explore the patterns of radioactive iodine (RAI) use for differentiated thyroid cancer (DTC) in Brazil over the past 20 years.

METHODS

A retrospective analysis of the DTC-related RAI prescriptions, from 2000 to 2018, retrieved from the Department of Informatics of the Unified Health System (Datasus) and National Supplementary Health Agency (ANS) database was performed. RAI activities prescriptions were re-classified as low (30-50 mCi), intermediate (100 mCi), or high activities (>100 mCi).

RESULTS

The number of DTC-related RAI prescriptions increased from 0.45 to 2.28/100,000 inhabitants from 2000 to 2015, declining onwards, closing 2018 at 1.87/100,000. In 2018, population-adjusted RAI prescriptions by state ranged from 0.07 to 4.74/100,000 inhabitants. Regarding RAI activities, in the 2000 to 2008 period, the proportion of high-activities among all RAI prescriptions increased from 51.2% to 74.1%. From 2009 onwards, there was a progressive reduction in high-activity prescriptions in the country, closing 2018 at 50.1%. In 2018, the practice of requesting high-activities varied from 16% to 82% between Brazilian states. Interestingly, variability of RAI use do not seem to be related to RAI referral center volume nor state socio-economic indicators.

CONCLUSION

In recent years, there has been a trend towards the lower prescription of RAI, and a reduction of high-activity RAI prescriptions for DTC in Brazil. Also, significative inter-state and inter-institutional variability on RAI use was documented. These results suggest that actions to advance DTC healthcare quality surveillance should be prioritized.

Outcomes after radioiodine ablation in patients with thyroid cancer: Long-term follow-up of a Chinese randomized clinicaltrial

OBJECTIVE

Two large randomized trials of patients with differentiated thyroid cancer (DTC) reported recently (HiLo and ESTIMABL1) found that the recurrence rate among patients who underwent 1.1 GBq radioactive iodine (RAI) ablation was not higher than that of patients who underwent 3.7 GBq radioactive iodine (RAI) ablation. However, no similar studies have been conducted in China. We aimed to report clinical outcomes in Chinese patients with low/intermediate risk of recurrence DTC after long-term follow-up, and evaluate the risk factors that influence the presence or absence of incomplete response at the final follow-up.

DESIGN

A long-term follow-up of a Chinese randomized clinical trial (October 2014 and February 2021) was conducted.

PATIENTS

A total of 506 DTC patients at low/intermediate risk of recurrence who were randomized into two groups to receive 1.1 (n = 251) or 3.7 GBq (n = 255) RAI ablation following thyroid hormone withdrawal were followed on levothyroxine treatment for a median of 4.5 years (range: 1.6-6.3).

MEASUREMENTS

Suppressed serum thyroglobulin (Tg) and anti-thyroglobulin antibody (TgAb) levels were determined, and neck ultrasonography was performed.

RESULTS

At the final follow-up, 499 (98.6%) patients showed an excellent response. The other seven patients (two patients underwent 1.1 GBq and five patients underwent 3.7 GBq RAI ablation, respectively) showed either structural incomplete response (lymph node metastasis, n = 1), biochemical incomplete response (increased serum Tg ≥ 1 ng/ml, or increased positive TgAb levels, n = 5), or indeterminate response (stable positive TgAb levels, n = 1). The risk of incomplete response at the final follow-up was significantly increased in patients with stimulated serum Tg ≥ 10 ng/ml at ablation (p = .003) and in patients with unsuccessful ablation (p = .008).

CONCLUSION

Our findings indicated that there was no difference in the long-term outcomes with RAI ablation using either 1.1 or 3.7 GBq in patients with low/intermediate risk of recurrence DTC, and 1.1 GBq RAI might be suitable for patients who are recommended for ablation.

Life after thyroid cancer: the role of thyroglobulin and thyroglobulin antibodies for postoperative follow-up

INTRODUCTION

Differentiated thyroid carcinomas (DTCs) are treated with (near-)total thyroidectomy and radioiodine therapy. Recently, the use of highly sensitive thyroglobulin (hsTg) assays has simplified DTC follow-up and improved patients' quality of life. More limited approaches are currently applied in low-risk patients requiring interpretations of Tg results in different clinical scenarios. Finally, Tg assays are hampered by interference from thyroglobulin autoantibodies (TgAb).

AREAS COVERED

The role of Tg measurement in DTC patients treated with complete thyroid ablation, thyroidectomy alone, or lobectomy is summarized. The management of patients carrying positive TgAb is also addressed.

EXPERT OPINION

Patients with undetectable hsTg after total thyroid ablation are safely managed by periodic hsTg measurement, combined with selective use of imaging procedures in few cases. Serum hsTg trend remains informative in patients treated without radioiodine ablation. However, reliable reference values are urgently needed in this setting. The role of hsTg is debated in patients who have undergone lobectomy due to the amount of Tg released by a functioning thyroid lobe. The evaluation of TgAb trend over time (i.e. surrogate tumor marker) is recommended in patients with positive TgAb and potentially interfering Tg results.

131I Ablation of an Entire Thyroid Gland in Locally Invasive Differentiated Thyroid Cancer Without Surgery

ABSTRACT

A 79-year-old man with locally metastatic papillary thyroid cancer to left-sided cervical lymph nodes was referred for radioiodine therapy. He was considered unfit for thyroidectomy due to extensive local involvement and severe interstitial lung disease requiring continuous oxygen. The patient was treated with low doses of radioiodine (approximately 30 mCi) every 6 months with corticosteroid cover for 3 years with good effect. Sequential 131I scanning and serum thyroglobulin levels confirmed virtual complete ablation of the thyroid gland. The patient remained well on thyroid hormone replacement.

68Ga-FAPI PET/CT Versus 18F-FDG PET/CT for Detecting Metastatic Lesions in a Case of Radioiodine-Refractory Differentiated Thyroid Cancer

ABSTRACT

18F-FDG PET/CT is a useful imaging modality for detecting disease recurrence and metastases in patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC). However, the sensitivity of 18F-FDG PET/CT in RAIR-DTC is not very satisfactory. 68Ga-FAPI is a promising PET tracer that allowed imaging of various types of cancer. In this case, 68Ga-FAPI showed a far better signal-to-background ratio than 18F-FDG for detecting the RAIR-DTC metastatic lesions, especially for detecting the small pulmonary metastases. Therefore, 68Ga-FAPI may be a promising alternative to 18F-FDG for detecting tumor recurrence and metastases in RAIR-DTC. It could also be used for guiding FAP-targeted radionuclide therapy.

Prognostic factors for incomplete response in thyroid microcarcinoma: an analysis of initial response to therapy in 517 patients

OBJECTIVE

Although thyroid microcarcinoma (TMC) usually has a favorable prognosis, some patients present a higher risk of disease recurrence or persistence. Thus, we aimed at identifying possible risk factors associated with an incomplete response to therapy in TMC.

METHODS

This was a retrospective study of 517 patients with TMC treated with total thyroidectomy, with or without radioactive iodine (RAI) therapy, reclassified after 1.1 ± 0.4 years according to the response to treatment into "favourable" (excellent/indeterminate) or "unfavorable" (biochemical/structural incomplete) responses. We evaluated participants' age, sex, tumor size, histological variants, multifocality, presence of vascular/lymphatic/perineural invasion, extrathyroidal extension, metastatic lymph nodes (LN), and distant metastasis. The effect of RAI therapy on the response range was analyzed in a given subgroup.

RESULTS

The mean age observed was 46.4 ± 12.0 years, and 89.7% were female. We noted 97.5% with papillary carcinoma, 27.8% with multifocality and 11.2% with LN metastasis. Although the majority of patients had a low risk of recurrence/persistence (78%), 75% were submitted to RAI therapy. Incomplete response (20.7%) was associated with multifocality (p=0.041; OR=1.619) and metastatic LN (p=0.041; OR=1.868). These variables were strongly correlated (p=0.000; OR=3.283). No cut-off of tumor size was identified as a predictor of incomplete response by the receiver operating curve analysis. RAI treatment did not influence the response of patients with multifocality or LN metastasis.

CONCLUSION

Multifocality and LN metastasis are independent risk factors for incomplete response in TMC patients and are strongly correlated. Additional RAI therapy was not associated with a more favorable response in these subgroups.

Long-term male fertility after treatment with radioactive iodine for differentiated thyroid carcinoma

CONTEXT

Whilst radioactive iodine (RAI) is often administered in the treatment for differentiated thyroid carcinoma (DTC), long-term data on male fertility after RAI are scarce.

OBJECTIVE

To evaluate long-term male fertility after RAI for DTC, and to compare semen quality before and after RAI.

DESIGN, SETTING, AND PATIENTS

Multicenter study including males with DTC ≥2 years after their final RAI treatment with a cumulative activity of ≥3.7 GBq.

MAIN OUTCOME MEASURE(S)

Semen analysis, hormonal evaluation, and a fertility-focused questionnaire. Cut-off scores for 'low semen quality' were based on reference values of the general population as defined by the World Health Organization (WHO).

RESULTS

Fifty-one participants had a median age of 40.5 (interquartile range (IQR): 34.0-49.6) years upon evaluation and a median follow-up of 5.8 (IQR: 3.0-9.5) years after their last RAI administration. The median cumulative administered activity of RAI was 7.4 (range: 3.7-23.3) GBq. The proportion of males with a low semen volume, concentration, progressive motility, or total motile sperm count did not differ from the 10th percentile cut-off of a general population (P = 0.500, P = 0.131, P = 0.094, and P = 0.500, respectively). Cryopreserved semen was used by 1 participant of the 20 who had preserved semen.

CONCLUSIONS

Participants had a normal long-term semen quality. The proportion of participants with low semen quality parameters scoring below the 10th percentile did not differ from the general population. Cryopreservation of semen of males with DTC is not crucial for conceiving a child after RAI administration but may be considered in individual cases.

Prognostic Implications of Preablation Stimulated Tg: A Retrospective Analysis of 2500 Thyroid Cancer Patients

CONTEXT

The risk of persistent and recurrent disease in patients with differentiated thyroid cancer (DTC) is a continuum that ranges from very low to very high, even within the 3 primary risk categories. It is important to identify independent clinicopathological parameters to accurately predict clinical outcomes.

OBJECTIVE

To examine the association between pre-ablation stimulated thyroglobulin (ps-Tg) and persistent and recurrent disease in DTC patients and investigate whether incorporation of ps-Tg could provide a more individualized estimate of clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

Medical records of 2524 DTC patients who underwent total thyroidectomy and radioiodine ablation between 2006 and 2018 were retrospectively reviewed.

MAIN OUTCOME MEASURE

Ps-Tg was measured under thyroid hormone withdrawal before remnant ablation. Association of ps-Tg and clinical outcomes.

RESULTS

In multivariate analysis, age, American Thyroid Association (ATA) risk stratification, distant metastasis, ps-Tg, and cumulative administered activities were the independent predictive factors for persistent/recurrent disease. Receiver operating characteristic analysis identified ps-Tg cutoff (≤10.1 ng/mL) to predict disease-free status with a negative predictive value of 95%, and validated for all ATA categories. Integration of ps-Tg into ATA risk categories indicated that the presence of ps-Tg ≤ 10.1 ng/mL was associated with a significantly decreased chance of having persistent/recurrent disease in intermediate- and high-risk patients (9.9% to 4.1% in intermediate-risk patients, and 33.1% to 8.5% in high-risk patients).

CONCLUSION

The ps-Tg (≤10.1 ng/mL) was a key predictor of clinical outcomes in DTC patients. Its incorporation as a variable in the ATA risk stratification system could more accurately predict clinical outcomes.

Outcomes of Thyrotropin Alfa Versus Levothyroxine Withdrawal-Aided Radioiodine Therapy for Distant Metastasis of Papillary Thyroid Cancer

Background: Thyrotropin alfa (rhTSH) is not currently approved by the Food and Drug Administration or European Medicines Agency for the preparation of radioactive iodine therapy (RAIT) in patients with distant metastatic papillary thyroid cancer (PTC). There are only a few studies comparing rhTSH with levothyroxine withdrawal (LTW) in this context. Our main aim was to compare the two methods of RAIT preparation in terms of avidity and structural/biochemical response in distant metastatic PTC. We also intended to evaluate whether the two methods of RAIT preparation represented independent prognostic factors for progression-free survival (PFS) and disease-specific survival (DSS) in this subset of patients. Methods: We performed a retrospective analysis of all patients with PTC treated with RAIT for distant metastatic disease between 2006 and 2018. We included 95 PTC patients-27 (28.4%) had LTW and 68 (71.6%) had rhTSH for RAIT. Results: The two groups presented similar clinicopathological characteristics, except for median age at PTC diagnosis, which was higher in the rhTSH group (p = 0.001), but the median age at first RAIT for distant metastatic disease was not different between the two methods of preparation, 63 years old (interquartile range [IQR] 23) in the LTW group versus 70 (IQR 26.75), p = 0.06. Avidity was similar between the two groups (p = 0.973). Median estimate PFS (p = 0.076) and DSS (p = 0.084) were also similar between LTW and rhTSH. Regarding RAIT-related side effects, only 1 (3.7%) patient and 5 (7.4%) patients in the LTW and rhTSH groups, respectively, reported sialadenitis (p = 0.670). Conclusions: There were no differences between the two methods of RAIT preparation regarding avidity and clinical response. rhTSH may be used as an alternative method of preparation for RAIT in patients with known distant lesions, as it presents similar clinical outcomes to LTW and a good safety profile.

Effect of TSH stimulation protocols on adequacy of low-iodine diet for radioiodine administration

Low-iodine diet (LID) is a crucial preparation for radioactive iodine (RAI) treatment or scan in thyroid cancer. The aim of this study is to analyze the influence of thyroid stimulating hormone (TSH) stimulation protocols and other clinical factors on LID adequacy. Thyroid cancer patients who underwent LID for RAI scan or treatment were retrospectively analyzed. Patients were guided to have LID for 2 weeks before RAI administration and urine iodine/creatinine ratio (UICR, μg/g Cr) was measured. TSH stimulation was conducted using either thyroid hormone withdrawal (THW) or recombinant human TSH (rhTSH) injection. Adequacy of LID was classified by UICR as ‘excellent (< 50)’, ‘adequate (50–100)’, ‘inadequate (101–250)’ and ‘poor (> 250)’. A total of 1715 UICR measurements from 1054 patients were analyzed. UICR was significantly higher in case of rhTSH use than THW (72.4 ± 48.1 vs. 29.9 ± 45.8 μg/g Cr, P < 0.001). In patients who underwent LID twice using both TSH stimulation protocols alternately, UICR was higher in case of rhTSH than THW regardless of the order of method. Among clinical factors, female, old-age, and the first LID were significant factors to show higher UICR. Although the adequacy of LID was ‘adequate’ or ‘excellent’ in most patients, multivariate analysis demonstrated that THW method, male, young age, and prior LID-experience were significant determinants for achieving ‘excellent’ adequacy of LID. In conclusion, UICR was higher and the proportion of ‘excellent’ LID adequacy was lower with rhTSH than with THW. UICR was higher also in women, old-age, and LID-naïve patients. Further researches are required to suggest effective methods to reduce body iodine pool in case of rhTSH use and to validate the efficacy of such methods on outcomes of RAI treatment.

Redifferentiation-facilitated radioiodine therapy in thyroid cancer

Based on experimental data, the inhibition of the MAPkinase pathway in patients with radioiodine-refractory thyroid cancer was capable of inducing a redifferentiation. Preliminary data obtained in a small series of patients were encouraging and this strategy might become an alternative treatment in those patients with a druggable mutation that induces a stimulation of the MAP kinase pathway. This is an active field of research to answer many still unresolved questions.

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.

Assessing potential impact of 2015 American Thyroid Association guidelines on community standard practice for I-131 treatment of low-risk differentiated thyroid cancer: case study of Jordan

OBJECTIVES

The 2015 American Thyroid Association (ATA) guidelines called for significantly more selective ¹³¹I therapy in patients with low-risk differentiated thyroid cancer (DTC). We hypothesized that application of these guidelines would significantly reduce the ¹³¹I activity utilized by an academic tertiary hospital in Jordan.

METHODS

All DTC patients managed at Jordan University Hospital (JUH) between 1/2009 and 6/2019 were classified according to the 2015 ATA risk category and ¹³¹I activity was assigned accordingly. The actual ¹³¹I activity administered was compared with that recommended by the 2015 ATA guidelines.

RESULTS

In total, 135/182 DTC patients (74.2%) managed at JUH underwent ¹³¹I therapy. Of those, 58 (43%) had ATA low-, 58 (43%) intermediate-, and 19 (14%) high-risk disease. The low-, intermediate-, and high-risk DTC patients received an average (±SD) initial ¹³¹I activity of 3.53 ± 0.95, 4.40 ± 1.49, and 5.06 ± 2.52 GBq, respectively. Withholding ¹³¹I therapy altogether in the 2015 ATA low-risk patients would result in decreasing the ¹³¹I activity in the overall patient population by 37%. Withholding ¹³¹I therapy only in low-risk papillary thyroid microcarcinomas while administering 1.11 GBq of ¹³¹I to other low-risk patients would result in 28% reduction of ¹³¹I.

CONCLUSION

This study demonstrates a significant reduction in ¹³¹I therapeutic activity that would be given to DTC patients in an academic tertiary setting in Jordan, following acceptance of the 2015 ATA recommendations. Institutions that adopted the 2015 ATA guidance should measure outcomes in comparison to their historical controls and report those findings, while long-term results of randomized controlled trials are forthcoming.

Late toxicities burden in patients with radioiodine-refractory differentiated thyroid cancer treated with lenvatinib

PURPOSE

Radioactive-iodine (RAI)-resistant differentiated thyroid cancer (DTC) patients benefit from multi-kinase inhibitors (MKIs), such as lenvatinib. Incidence of treatment-related (TR) late toxicities has been not yet described.

METHODS

From January 2015 to June 2019 we retrospectively reviewed clinical records of patients with RAI-resistant DTC treated with lenvatinib at Istituto Nazionale dei Tumori (Milan, Italy). New side effect of any grade, appeared after 12 months of lenvatinib, was defined as late adverse event (AE). Descriptive analyses were performed. Survival curves were estimated with Kaplan-Meier method and compared with log-rank test.

RESULTS

Thirty-seven patients were included, 65% had ≥65 years and 68% were female. Thirty patients received lenvatinib for >12 months. Lenvatinib was started at ≤20 mg/daily in 59% of patients, 64% were ≥65 years. The frequency of late AEs was 80% and cardiovascular toxicity was the most common (57%). There was no difference in the incidence of late AEs between younger/older population (77% and 82%, respectively). Median lenvatinib treatment duration (TD) was 39.96 months (95% CI 21.64-NR): 39.96 months for patients <65 years (95% CI: 13.25-NR) and 37.53 months for those ≥65 years, respectively (95% CI: 15.85-NR). Median overall survival (OS) was 39.96 months (95% CI: 21.84-NR), no statistically differences in OS was observed between younger (<65 years) and older patients (≥65 years) (HR 1.013; 95% CI 0.963-1.065; p = 0.62).

CONCLUSION

Late toxicity burden of lenvatinib is not negligible. Cardiovascular toxicity remains the principal side effect even after a prolonged lenvatinib exposition.

The role of adjuvant radiation therapy for locoregionally recurrent papillary thyroid carcinoma

Objectives:

To evaluate the role of adjuvant radiation therapy in patients with locoregionally recurrent (rpT4/N1b) papillary thyroid carcinoma (PTC).

Methods:

The medical records of patients with rpT4/N1b PTC who were treated between January 2001 and December 2016 were reviewed. A total of 57 patients were analyzed, of which 24 patients were treated with adjuvant radiation therapy, and 33 patients did not receive adjuvant radiation therapy. Survival outcomes were compared between the 2 treatment groups. The primary endpoint was locoregional recurrence-free survival rate.

Results:

The median follow-up period for all patients was 10.3 years (range, 2.8-19.2 years). The 15-year locoregional recurrence-free survival rate was 80.5% for those who received adjuvant radiation therapy and 28.1% for those who did not (p<0.001). The 15-year distant metastasis-free survival rate was 48.8% for those who received adjuvant radiation therapy and 33.4% for those who did not (p=0.906). The 15-year overall survival rate was 69.7% for those who received adjuvant radiation therapy and 53.1% for those who did not (p=0.921).

Conclusions:

Adjuvant radiation therapy ensured favorable locoregional recurrence-free survival in patients with rT4/N1b PTC and might contribute to improving patients’ quality of life by reducing the need for additional salvage surgery and the economic burden of other salvage treatments, such as surgery or radioactive iodine therapy.

Application of Pet-CT Fusion Deep Learning Imaging in Precise Radiotherapy of Thyroid Cancer

This article explores the value of wall F-FDG PET/Cr imaging in the diagnosis of thyroid cancer, studies its ability to distinguish benign and malignant thyroid lesions, and seeks ways to improve the accuracy of diagnosis. The normal control group selected 40 patients who came to our center for physical examination. In the normal control group, the average value of the standard uptake value of both sides of the thyroid was used as the SUV of the thyroid gland and the highest SUV value of the patient's lesion (SUV max) represented the SUV of the lesion. After injection of imaging agent 18F-FD1G, routine imaging was performed at 1h, time-lapse imaging was performed at 2.5 h, and the changes with conventional imaging were compared to infer the benign and malignant lesions. We used SPSS software to carry out statistical analysis, respectively, carrying out analysis of variance, paired t-test, independent sample t-test, and linear correlation analysis. In the thyroid cancer group, 87.5% of the delayed imaging SUV was higher than the conventional imaging SUV, while 83.33% of the benign disease group had a lower SUV than the conventional imaging SUV. 18F-FDG PET/CT imaging has higher sensitivity and specificity for the diagnosis of recurrence or metastasis in patients with Tg positive. However, it has lower sensitivity and specificity for the diagnosis of 131I-Dx-WBS negative DTC and 18F-FDG PET/CT. The specificity increases with the increase of serum Tg level. The above results confirm that 18F-FDG PET/CT imaging is of great significance for the diagnosis of recurrence or metastasis in patients; with PET/CT imaging, the results changed 16.13% of the Tg-positive and 131I-Dx-WBS negative DTC patients' later treatment decision. The decision-making and curative effect evaluation have certain value.

High thyroglobulin and negative whole-body scan: no long-term benefit of empiric radioiodine therapy

PURPOSE

Around 10-27% of patients will present elevated thyroglobulin (Tg) levels and negative diagnostic whole-body scan (dxWBS) during differentiated thyroid cancer (DTC) follow-up. Empiric radioactive iodine (RAI) therapy in this context is controversial due to the lack of good quality studies in the context. The main purpose of this study is to compare long-term response to therapy status and overall survival between empiric RAI treated and untreated DTC patients.

METHODS

A retrospective study comparing differentiated thyroid cancer patients with negative diagnostic whole-body scan and elevated thyroglobulin levels submitted or not to empiric radioactive iodine therapy in a thyroid cancer referral center. The main outcome measures were ATA Response to Therapy Stratification at 6-12 months after RAI ablative dose, at 6-18 months after negative dxWBS and last follow-up visits.

RESULTS

Overall, 120 DTC patients with stimulated Tg >10 ng/ml and negative dxWBS were included in this study. Overall, 53 patients were submitted to empiric RAI and 67 were in the control group. No difference was observed in ATA Response to Therapy Stratification after RAI ablation or at the end of follow-up between groups. Also, no difference was found in terms of Tg changes response. After more than 10 years of follow-up, 17 patients died (13 from treated and 4 from untreated group).

CONCLUSIONS

Empiric RAI treatment was not associated with better long-term ATA response to therapy status or overall survival.

Correlation of Performance Status and Neutrophil-Lymphocyte Ratio with Efficacy in Radioiodine-Refractory Differentiated Thyroid Cancer Treated with Lenvatinib

Background: Radioiodine-refractory differentiated thyroid cancer (RR-DTC) has a low 10-year patient-survival rate and is challenging to treat. Lenvatinib is a multikinase inhibitor approved for the treatment of RR-DTC. This study aims to assess Eastern Cooperative Oncology Group performance status (ECOG PS) and neutrophil-to-lymphocyte ratio (NLR) as prognostic markers for patients with RR-DTC treated with lenvatinib. Methods: In this retrospective analysis of the Study of (E7080) LEnvatinib in Differentiated Cancer of the Thyroid (SELECT), patients randomly assigned to receive lenvatinib were classified according to baseline ECOG PS (0 or 1) or baseline NLR (≤3 or >3). The effects of baseline ECOG PS and NLR on progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) were evaluated. In addition, the effects of baseline ECOG PS on the change in diameter of target lesions and correlations between baseline NLR and the sums of the diameters of target lesions were calculated. Results: Among patients who received lenvatinib, patients with a baseline ECOG PS of 0 had statistically improved PFS (hazard ratio [HR] 0.52; 95% confidence interval [CI 0.35-0.77]; p = 0.001), OS (HR 0.42 [CI 0.26-0.69]; p = 0.0004), and ORR (odds ratio [OR] 3.51 [CI 2.02-6.10]; p < 0.0001) compared with patients with a baseline ECOG PS of 1. Patients who received lenvatinib with a baseline NLR ≤3 also had improved PFS (HR 0.43 [CI 0.29-0.65]; p < 0.0001) and OS (HR 0.48 [CI 0.29-0.78]; p = 0.0029) versus patients with a baseline NLR >3. Moreover, patients with a baseline NLR ≤3 had a trend toward increased ORR (OR 1.57 [CI 0.94-2.64]; p = 0.08) compared with patients with a baseline NLR >3. Treatment-emergent adverse events were generally similar among patients who received lenvatinib, irrespective of patients' ECOG PS at baseline. Conclusion: Lower ECOG PS and NLR may provide prognostic value for improved efficacy in patients with RR-DTC. ClinicalTrials.gov no. NCT01321554.

Recombinant human thyroid-stimulating hormone versus thyroid hormone withdrawal preparation for radioiodine ablation in differentiated thyroid cancer in children, adolescents and young adults

OBJECTIVE

Recombinant human TSH (rhTSH) is commonly used to prepare patients for postoperative radioiodine (I-131) ablation after surgery for differentiated thyroid cancer (DTC). In adults, rhTSH is associated with equivalent oncologic efficacy in comparison to thyroid hormone withdrawal (THW), but its use has not been well studied in children. We aimed to measure time to disease progression after rhTSH stimulation vs. THW in paediatric patients under the age of 21 with DTC following total thyroidectomy.

DESIGN

Retrospective cohort study (March 2001-July 2018).

PATIENTS

Sixteen children and adolescents (75% female, median age, 17.4 years) who received rhTSH were compared to 29 historical controls (72% female, median age, 18.5 years) prepared with THW, followed for a median of 2.4 years (range, 0.5-14).

MEASUREMENTS

Stimulated serum TSH concentrations prior to I-131 ablation and time to disease progression, as determined by a component outcome variable encompassing both structural and biochemical disease persistence/recurrence.

RESULTS

No differences were observed in tumour characteristics and I-131 dose (median 2.3 [1.8-2.90] mCi/kg rhTSH) between groups. Patients who received rhTSH achieved a similar median stimulated TSH level (163 [127-184] mU/L), compared to those who underwent THW (136 [94.5-197] mU/L; p = .20). Both groups exhibited similar time to progression (p = .13) and disease persistence/recurrence rates (rhTSH 31% vs. THW 59%, p = .14).

CONCLUSION

In this cohort of children and adolescents with DTC, we observed similar time to disease progression among those who received rhTSH or underwent THW prior to postoperative I-131 ablation.

The effect of I-131 therapy on pregnancy outcomes after thyroidectomy in patients with differentiated thyroid carcinoma: a meta-analysis

PURPOSE

Studies on the effects of I-131 therapy on pregnancy outcomes after differentiated thyroid carcinoma (DTC) surgery showed inconsistent findings. The purpose of the study was to investigate the association between I-131 therapy and pregnancy outcomes in female DTC patients.

METHODS

PubMed, Embase, Cochrane Library, CNKI, and VIP were searched until November, 2020. Keywords included differentiated thyroid cancer, thyroid carcinoma, thyroid neoplasm, radioiodine, I-131, ¹³¹I, pregnancy outcomes, reproduction, fertility, abortion, preterm birth, and congenital malformation. Studies that provided the pregnancy outcomes in DTC patients who received I-131 therapy and those who did not receive I-131 therapy were included. Meta-analysis was performed in Stata/SE 12. A random or fixed effects model was adopted according to the result of heterogeneity test.

RESULTS

Seven observational studies were eligible, involving 125,591 participants and 13,811 pregnancies. It showed that postoperative I-131 therapy for DTC had no significant effect on spontaneous abortion (OR = 1.05, P = 0.701), induced abortion (OR = 1.06, P = 0.859), abortion (OR = 1.07, P = 0.098), premature birth (OR = 1.02, P = 0.756), stillbirth (OR = 1.58, P = 0.364), and congenital malformation(OR = 1.00, P = 0.986). Cumulative RAI dose >3.7 GBq or <3.7 GBq had no significant effect on abortion (OR = 0.94, P = 0.252) and congenital malformation (OR = 1.05, P = 0.752).The group in which interval time between last I-131 therapy and pregnancy >1 year had significant lower risk of abortion than with interval <1 year (OR = 0.60, P = 0.000).

CONCLUSIONS

Pregnancy is not recommended for DTC patients within 1 year after I-131 therapy.

Occupational exposure and radiobiological risk from thyroid radioiodine therapy in Saudi Arabia

Worldwide, thyroid cancer accounts for some 10% of total cancer incidence, most markedly for females. Thyroid cancer radiotherapy, typically using 131I (T1/2 8.02 days; β- max energy 606 keV, branching ratio 89.9%), is widely adopted as an adjunct to surgery or to treat inoperable cancer and hyperthyroidism. With staff potentially receiving significant doses during source preparation and administration, radiation protection and safety assessment are required in ensuring practice complies with international guidelines. The present study, concerning a total of 206 patient radioiodine therapies carried out at King Faisal Specialist Hospital and Research Center over a 6-month period, seeks to evaluate patient and occupational exposures during hospitalization, measuring ambient doses and estimating radiation risk. Using calibrated survey meters, patient exposure dose-rate estimates were obtained at a distance of 30-, 100- and 300 cm from the neck region of each patient. Occupational and ambient doses were measured using calibrated thermoluminescent dosimeters. The mean and range of administered activity (AA, in MBq) for the thyroid cancer and hyperthyroidism treatment groups were 4244 ± 2021 (1669-8066), 1507.9 ± 324.1 (977.9-1836.9), respectively. The mean annual occupational doses were 1.2 mSv, that for ambient doses outside of the isolation room corridors were found to be 0.2 mSv, while ambient doses at the nursing station were below the lower limit of detection. Exposures to staff from patients being treated for thyroid cancer were less compared to hyperthyroidism patients. With a well-defined protocol, also complying with international safety requirements, occupational exposures were found to be relatively high, greater than most reported in previous studies.

Pregnancy Does not Affect the Prognoses of Differentiated Thyroid Cancer Patients With Lung Metastases

CONTEXT

Pregnancy-related hormones may stimulate thyroid cancer growth, but whether pregnancy affects the prognoses of patients with lung metastases from differentiated thyroid cancer (DTC-LM) after surgery and radioiodine therapy is unclear.

OBJECTIVE

To assess the impact of pregnancy on DTC-LM through the comparison of prognoses between female patients with DTC-LM who did and did not become pregnant after surgery and radioiodine therapy.

METHODS

We retrospectively analyzed the records of 124 female patients aged 16 to 35 years who underwent surgery and radioiodine therapy for DTC-LM. These patients were divided into pregnancy group (n = 37) and nonpregnancy group (n = 87) according to whether they became pregnant after surgery and radioiodine therapy, regardless of whether they had a pregnant history before treatment.

RESULTS

The 5- and 10-year progression-free survival rates were 94.52% and 63.22% in pregnancy group versus 89.82% and 58.13% in nonpregnancy group. The 5- and 10-year cumulative overall survival rates of pregnancy group were 97.30% and 85.77% versus 93.50% and 81.95% in nonpregnancy group (all P > 0.05). The median time of follow-up in the pregnancy and nonpregnancy groups was 82 months (25-136 months) and 68 months (13-133 months), respectively. Non-radioiodine-avid LM and primary tumors needing repeated resection were independent predictors of poor progression-free survival for patients in pregnancy group.

CONCLUSION

Pregnancy does not affect the prognoses of patients with DTC-LM after surgery and radioiodine therapy. Non-radioiodine-avid LM and repeated primary tumor surgeries are independent risk factors for poor prognoses of pregnant patients.

Simultaneous measurements of single gamma ray of 131I and annihilation radiation of 18F with Compton PET hybrid camera

In internal 131I therapy for thyroid cancer, a decision to continue treatment is made by comparing 131I scintigraphy and [18F]FDG-PET. However, with current SPECT and PET systems, simultaneous imaging of diagnostic PET nuclides and therapeutic 131I nuclides has not been achieved so far. Therefore, we demonstrated that the recently developed Compton PET hybrid camera with Ce:Gd3(Al,Ga)5O12 (GAGG)- Silicon Photomultiplier(SiPM) scintillation detectors can be used to simultaneously image 131I Compton image and 18F PET image.

Clinicopathological features and treatment outcome of paediatric differentiated thyroid cancer treated with Radioactive Iodine-131 therapy in Hospital Kuala Lumpur, Malaysia

BACKGROUND

Radioactive iodine ¹³¹I (RAI) therapy is one of the definitive treatments for paediatric differentiated thyroid cancer (DTC) initiated at nuclear medicine departments. In Malaysia, there is a need to identify the standardisation of treatment regimes to align with international standards. We aimed to evaluate the clinicopathological features and the patient response to RAI therapy among paediatric DTC cases at Hospital Kuala Lumpur (HKL), Malaysia.

METHODS

A retrospective, longitudinal study was conducted among paediatric DTC patients treated with RAI in HKL and followed up between 2000-2016. Sixty-five patients were studied (mean period: 58.8±36 months). The clinicopathological data of the patients was recorded, and descriptive analysis was made. The association between categorical and continuous data with disease status was assessed using chi-square and Kruskal-Wallis tests, p-value <0.05 taken as statistically significant.

RESULTS

Most patients were female (78.5%), and adolescents comprised 89.2%. Pre-pubertal age, those presenting with cervical nodal involvement, extra-thyroidal extension and lymphovascular invasion were significantly associated with distant metastases at presentation. There was no mortality reported during the follow-up period. Sixty per cent of patients achieved remission, while 40% had persistent disease. The persistent disease was significantly correlated with distant metastasis at presentation (p=0.025).

CONCLUSIONS

Paediatric DTC manifests with a more extensive disease burden at presentation and requires multiple RAI doses. Despite this, it carries an excellent overall prognosis.

Favorable outcomes of papillary thyroid microcarcinoma concurrent with Graves' disease after radioactive iodine therapy

Graves' disease (GD) may coexist with papillary thyroid microcarcinoma (PTMC). The main purpose of this study was to evaluate whether treatment with radioactive iodine (RAI) may cause acute exacerbation of PTMC concurrent with GD or not. From the medical records of 10,257 GD patients who underwent RAI therapy between 2000-2017, 12 subjects with concurrent PTMC were retrieved. Further, 49 patients with concurrent GD and PTMC who underwent no RAI administration throughout their clinical course were enrolled as controls. Size of the PTMC nodules was evaluated based on maximal diameter and tumor volume-doubling rate (TV-DR). Among the 12 subjects who underwent RAI therapy (median dose, 13 mCi), 2 showed tumors >10 mm in maximal diameter with slow growth for more than 10 years, while the other 10 showed tumors with maximal diameter ≤10 mm. No subject showed any clinical findings of nodal or distant metastasis during the follow-up periods (0.4-11.5 years) before surgery or during active surveillance. No significant differences were observed in the TV-DR values (median, 0.044/year; range, -0.81-1.40) between the study subjects and controls (median, 0.025/year; range, -0.70-1.29; p = 0.69). When comparing the TV-DR before and after RAI administration in 3 individuals in particular, in whom PTMC were cytologically confirmed before RAI administration and whose prospective follow-up data were available, tumor progression was observed to be stable or decreased after RAI administration. There were no acute exacerbations or unfavorable outcomes of concurrent PTMC and GD after low-dose RAI administration.

Dependency of the remnant 131I-NaI biokinetics on the administered activity in patients with differentiated thyroid cancer

PURPOSE

To study the dependency of the effective half-life on the administered activity and the correlation between the time-integrated activity and the remnant uptake at 2d and 7d in patients treated for DTC with 1.11 GBq, 3.7 GBq or 5.55 GBq of ¹³¹I-NaI.

METHODS

Ninety-two patients undergoing total thyroidectomy and lymph node removal were included. If cancer had not spread to lymph nodes, patients received 1.11 GBq of ¹³¹I-NaI when the lesion maximal diameter was smaller than 4 cm, and 3.7 GBq for bigger sizes. If cancer had spread to lymph nodes patients received 5.55 GBq. There were 30, 49 and 13 patients respectively treated with 1.11 GBq(Group 1), 3.7 GBq(Group 2) and 5.55 GBq(Group 3). Two SPECT/CT scans were performed at 2d and 7d after radioiodine administration for each patient to determine the thyroid remnant activities and effective half-lives of the radioiodine.

RESULTS

Statistical analysis showed significant differences (p < 0.05) in the effective half-life among patients treated with 1.11 GBq, 3.7 GBq and 5.55 GBq. A high positive correlation (ρ > 0.95) was found between the time-integrated activity and the remnant activity at 2d for the three groups of patients.

CONCLUSIONS

There were significant differences in the effective half-life of the radioiodine in remnants of patients treated with activities of 1.11 GBq, 3.7 GBq or 5.55 GBq. The high positive linear correlation found between the time-integrated activity and the remnant activity at 2d for the three groups of patients indicate that the time-integrated activity could be estimated from one time-point.

The Value of Stimulated Thyroglobulin Before the First Radioactive Iodine Treatment in Metastasis for Differentiated Thyroid Carcinoma

BACKGROUND

To evaluate the value of preablative stimulated thyroglobulin (ps-Tg) before the first radioactive ablation iodine (RAI) treatment to predict the postoperative metastasis of DTC.

METHODS

A total of 235 DTC patients, who underwent total thyroidectomy and neck lymph node dissection, were enrolled. On the basis of the presence or absence of metastasis, all patients were divided into metastasis (M1) and non-metastasis (M0) groups. Besides, the patients in the M1 group were further divided into two subgroups according to sites of metastasis. These groups included cervical lymph node metastasis and distant metastasis groups. Subsequently, the level of serum ps-Tg was measured 3 - 4 days before the first RAI ablation treatment, whereas 131I whole-body imaging and SPECT/CT tomography were performed 5 - 7 days after radio ablation. Subsequently, the Mann Whitney U test was used to compare the different levels of ps-Tg between the two groups. Additionally, the relationship between ps-Tg and the metastasis of DTC was analyzed through correlation analysis, regression analysis, and the ROC curve.

RESULTS

The ps-Tg level in the M1 group was higher than that in the M0 group. Further analysis discovered that the ps-Tg in the distant metastasis group was higher than that in the cervical lymph node metastasis and non-metastasis groups. Also, the ps-Tg level was positively correlated with distant metastasis (r = 0.599, p = 0.000). Besides, the results of multivariate logistic regression analysis outlined that the level of ps-Tg was an independent risk factor for the development of distant metastasis (OR = 1.008, p = 0.018). Subsequently, the results from the ROC analysis also showed a good diagnostic performance for ps-Tg in treating distant metastasis (AUC = 0.964, p = 0.000), and the optimal cutoff value was 61.87 ng/mL.

CONCLUSIONS

The ps-Tg in patients with DTC before the first RAI ablation treatment is an independent risk factor and a meaningful indicator in predicting postoperative distant metastasis.

Radioactive Iodine Treatment for Children and Young Adults with Thyroid Cancer in South Korea: A Population-based Study

PURPOSE

This study investigated radioactive iodine treatment (RAIT) patterns and the secondary cancer incidence among children and young adults receiving RAIT after thyroidectomy for thyroid cancer.

METHODS

This population-based cohort study used the Health Insurance Review and Assessment database of South Korea to identify a total of 18 617 children and young adults (0-29 years) who underwent thyroidectomy for thyroid cancer between 2008 and 2018. We recorded age at surgery, sex, the interval from surgery to RAIT, the doses of RAI, the number of RAIT sessions, and secondary cancer incidence.

RESULTS

A total of 9548 (51.3%) children and young adults underwent 1 or more RAIT sessions. The initial dose of RAIT was 4.35 ± 2.19 GBq. The overall RAIT frequency fell from 60.9% to 38.5%, and the frequency of high-dose RAIT (>3.7 GBq) fell from 64.2% to 36.5% during the observational period. A total of 124 cases of secondary cancer developed during 120 474 person-years of follow-up; 43 (0.5%) in the surgery cohort and 81 (0.8%) in the RAIT cohort. Thus, the RAIT cohort was at an increased risk of secondary cancer (adjusted hazard ratio 1.52 [95% confidence interval 1.03-2.24], P = 0.035).

CONCLUSION

The proportion of children and young adults receiving RAIT, and the RAI dose, fell significantly over the observational period. RAIT was associated with secondary cancers. This is of major concern in the context of child and young adult thyroid cancer survivors.

Posttraumatic Scab on 131I Whole-Body Scan-A False-Positive Finding

ABSTRACT

131I scan plays a crucial role in the management of patients with differentiated thyroid cancer for the evaluation of remnant thyroid tissue, residual/recurrent metastatic disease, posttherapy tracer distribution, and response assessment to high-dose 131I therapy. Different causes secondary to physiological, pathological, and anatomical variations have been described for false-positive findings in the whole-body planar images. This case report of a patient of differentiated thyroid cancer with undocumented trauma to the left knee region a day before receiving the high-dose radioiodine therapy showed an interesting image finding of tracer uptake at unusual site in the posttherapy whole-body 131I scan.

Radioiodine therapy reduces the frequency of circulating tumour cells in patients with differentiated thyroid cancer

OBJECTIVE

The aim of the study was the quantification of circulating tumour cells (CTCs) in differentiated thyroid cancer (DTC) patients before and 6 weeks after radioiodine therapy (RIT).

CONTEXT

Circulating tumour cells (CTCs) were described more recently in cancer patients, mostly correlating with poor outcome and advanced metastases.

DESIGN

Peripheral blood for identification and quantification of CTC before RIT or/and 6 weeks after RIT was provided by 55 DTC patients that received RIT for remnant tissue ablation.

PATIENTS

13 follicular thyroid cancer (FTC) patients, 31 papillary thyroid cancer (PTC) patients and 11 patients having the follicular variant PTC (FV-PTC) were included.

MEASUREMENTS

Peripheral blood mononuclear cells (PBMCs) were isolated and EpCAM-positive CTCs were counted by immune fluorescent staining.

RESULTS

A CTC positivity of 31.8% before RIT could be observed. Six weeks after RIT, the CTC positivity was reduced to 13.6%. Paired data at both time points of blood sampling could be gathered for n = 33 DTC patients. These patients had significantly higher CTC numbers before RIT than 6 weeks afterwards (0.27 ± 0.47 vs 0.05 ± 0.15, P = .0215). Additionally, significantly reduced CTC numbers were also demonstrated in pre-RIT CTC-positive patients (0.88 ± 0.43 vs 0.05 ± 0.16, P = .0039).

CONCLUSION

Our results indicate a reducing effect on the number of CTCs by RIT. Therefore, CTC enumeration should be considered as efficient tool for treatment monitoring during RIT.

Perioperative diagnostics of patients referred for radioiodine therapy of differentiated thyroid carcinoma: referral center experience in an iodine-insufficient country

PURPOSE

The interdisciplinary "Martinique-Principles" of four international professional societies concerned with the patient management of differentiated thyroid cancer (DTC) patients were agreed upon. Differences in perioperative diagnostics can lead to differences in clinical decision founding regarding the treatment of thyroid carcinoma. Our aim was to analyze the perioperative diagnostics of patients referred for postoperative I-131 therapy of DTC.

METHODS

We retrospectively examined the data of 142 patients who were referred to our center for the first course of postsurgical I-131 therapy. We extracted data on perioperative diagnostics.

RESULTS

Fine-needle biopsy (FNB) was performed in 27/142 patients. In 17 patients, FNB yielded findings suspicious of malignancy, in 3 patients a follicular lesion was reported. An intraoperative frozen section analysis was performed in 79/142 patients. 5/63 patients showed already a cytologically proven malignancy. In 10/79 patients, the frozen section had a nonmalignant result, although DTC was found on final assessment. In 2/79 patients, frozen section analysis was indecisive, although the final report confirmed DTC. In the remaining 67 patients, frozen section yielded DTC.

CONCLUSIONS

There is room for improvement in perioperative diagnostics surrounding thyroid surgery, currently many procedures are performed without adequate information on potential presence of thyroid cancer. More frequent use of FNB might be able to decrease the number of unnecessary thyroid surgeries, increased use of frozen section might decrease the number of second operations and might contribute to less discordance between experts in the field of DTC treatment.

Intermediate-risk thyroid carcinoma: indicators of a poor prognosis

OBJECTIVE

The intermediate-risk (IR) category includes tumors with different degrees of aggression. We aimed to identify the risk factors associated with unfavorable response to initial treatment and compare the effect of low/high radioactive iodine (RAI) therapy.

METHODS

A total of 614 IR patients were selected from a database, during 1972-2015. All patients underwent total thyroidectomy and RAI therapy and were reclassified after 12-18 months into the favorable (complete/indeterminate) response group and the unfavorable (biochemical/incomplete structural) response group. A total of 92 patients were assessed for late response (mean: 9.19 ± 5.73 years). Age, gender, tumor size, histology, multifocality, vascular invasion, extrathyroidal extension, presence and number of lymph node metastasis, and stimulated thyroglobulin at ablation (sTg) were evaluated.

RESULTS

Mean age at diagnosis was 41.47 ± 15.81 years, and 83.6% of the patients were female. Within 12-18 months after initial therapy, unfavorable response was detected in 41.2% of the patients and was associated, in multivariate analysis, with lymph node metastasis (p = 0.041; odds ratio [OR] = 1.9), presence of more than five metastatic lymph nodes (p = 0,017; OR = 2.6), and sTg > 10 ng/mL (p = 0.005; OR = 10.0). For patients with a longer follow-up, sTg >10 ng/mL was associated with unfavorable response (p = 0.002; OR = 6.8). A higher RAI dose was not related to better prognosis at the end of the follow-up.

CONCLUSION

A sTg level of >10 ng/mL and lymph node metastasis were associated with an unfavorable response 12-18 months after initial treatment. A RAI dose below 150 mCi was proven sufficient to treat IR patients.

Multilevel Factors Associated With More Intensive Use of Radioactive Iodine for Low-Risk Thyroid Cancer

CONTEXT

The use of radioactive iodine (RAI) for low-risk thyroid cancer is common, and variation in its use exists, despite the lack of benefit for low-risk disease and potential harms and costs.

OBJECTIVE

To simultaneously assess patient- and physician-level factors associated with patient-reported receipt of RAI for low-risk thyroid cancer.

METHODS

This population-based survey study of patients with newly diagnosed differentiated thyroid cancer identified via the Surveillance Epidemiology and End Results (SEER) registries of Georgia and Los Angeles County included 989 patients with low-risk thyroid cancer, linked to 345 of their treating general surgeons, otolaryngologists, and endocrinologists. We assessed the association of physician- and patient-level factors with patient-reported receipt of RAI for low-risk thyroid cancer.

RESULTS

Among this sample, 48% of patients reported receiving RAI, and 23% of their physicians reported they would use RAI for low-risk thyroid cancer. Patients were more likely to report receiving RAI if they were treated by a physician who reported they would use RAI for low-risk thyroid cancer compared with those whose physician reported they would not use RAI (adjusted OR: 1.84; 95% CI, 1.29-2.61). The odds of patients reporting they received RAI was 55% lower among patients whose physicians reported they saw a higher volume of patients with thyroid cancer (40+ vs 0-20) (adjusted OR: 0.45; 0.30-0.67).

CONCLUSIONS

Physician perspectives and attitudes about using RAI, as well as patient volume, influence RAI use for low-risk thyroid cancer. Efforts to reduce overuse of RAI in low-risk thyroid cancer should include interventions targeted toward physicians, in addition to patients.

Multimodal treatments and outcomes for anaplastic thyroid cancer before and after tyrosine kinase inhibitor therapy: a real-world experience

BACKGROUND

Anaplastic thyroid cancer (ATC) has dismal prognosis and there is no effective treatment. We aimed to evaluate the efficacy of tyrosine kinase inhibitor (TKI) therapy in real-world clinic and to suggest the most effective treatment modality according to the combination of treatments.

METHODS

This retrospective study evaluated clinical outcomes and cause of death with multimodal treatments in patients with ATC at Samsung Medical Center.

RESULTS

A total of 120 patients received anti-cancer treatment for ATC. Seventy-seven (64.2%) patients underwent surgery, 64 (53.3%) received radiotherapy, 29 (24.2%) received cytotoxic chemotherapy, and 19 (15.8%) received TKI therapy. In the TKI therapy group, eight achieved partial response (three with lenvatinib and five with dabrafenib plus trametinib), and two patients with lenvatinib showed stable disease. Median progression-free survival (PFS) of the TKI therapy group was 2.7 months (range: 0.1-12.7) and their median overall survival (OS) was 12.4 months (range: 1.7-47.7). Patients who received surgery or radiotherapy for local control showed superior OS than those who did not. In a multivariate analysis, surgery, TKI therapy, younger age, and no distant metastasis were associated with favorable OS. The combination of surgery, radiotherapy, and TKI therapy (median OS: 34.3 months, 6-month survival rates: 77.8%) was the most effective. Compared to the era without TKI therapy, distant metastasis has recently become the major cause of death in ATC over airway problems.

CONCLUSIONS

Multimodality treatment including TKI therapy demonstrated prolonged survival with dabrafenib plus trametinib as the most effective therapeutic option demonstrated for BRAF mutant ATC patients.

Patient Perspectives on the Extent of Surgery and Radioactive Iodine Treatment for Low-Risk Differentiated Thyroid Cancer

OBJECTIVE

To understand patient perspective regarding recommended changes in the 2015 American Thyroid Association (ATA) guidelines. Specifically, in regard to active surveillance (AS) of some small differentiated thyroid cancer (DTC), performance of less extensive surgery for low-risk DTC, and more selective administration of radioactive iodine (RAI).

METHODS

An online survey was disseminated to thyroid cancer patient advocacy organizations and members of the ATA to distribute to the patients. Data were collected on demographic and treatment information, and patient experience with DTC. Patients were asked "what if" scenarios on core topics, including AS, extent of surgery, and indications for RAI.

RESULTS

Survey responses were analyzed from 1546 patients with DTC: 1478 (96%) had a total thyroidectomy, and 1167 (76%) underwent RAI. If there was no change in the overall cancer outcome, 606 (39%) of respondents would have considered lobectomy over total thyroidectomy, 536 (35%) would have opted for AS, and 638 (41%) would have chosen to forego RAI. Moreover, (774/1217) 64% of respondents wanted more time with their clinicians when making decisions about the extent of surgery. A total of 621/1167 of patients experienced significant side effects with RAI, and 351/1167 of patients felt that the risks of treatment were not well explained. 1237/1546 (80%) of patients felt that AS would not be overly burdensome, and quality of life was the main reason cited for choosing AS.

CONCLUSION

Patient perspective regarding choice in the management of low-risk DTC varies widely, and a large proportion of DTC patients would change aspects of their care if oncologic outcomes were equivalent.

Efficacy of 131I therapy and its influencing factors in children and adolescents with differentiated thyroid carcinoma

PURPOSE

We aimed to explore the efficacy and safety of iodine-131 (131I) therapy in children and adolescents with differentiated thyroid carcinoma (DTC), and to analyze the possible factors affecting the efficacy.

METHODS

A retrospective analysis was performed on the clinical data of 94 children and adolescent DTC patients aged ≤21 years old, who received 131I therapy. The efficacy was assessed, and the levels of serum thyroglobulin (Tg) and Tg antibody (TGAb), and adverse reactions were observed. Besides, the possible influencing factors for the efficacy were explored.

RESULTS

There were 79 cases of overall response (84.0%) and 15 cases of no response (16.0%). Besides, the initial 131I ablation of thyroid remnants was efficacious in 61 (64.9%) patients, but not in 33 (35.1%) patients who continued to receive the subsequent 131I therapy. As of June 2019, 18 (54.5%) patients reached remission, whereas the other 15 (45.5%) patients failed to reach remission. Of 23 patients with distant metastases in the lungs, there were 8 cases of lesion elimination, 12 cases of improvement or stable disease and 3 cases of no response or progressive disease after 131I therapy. Among 44 patients with only lymph node metastasis, 28 patients were negative for the whole-body 18F-FDG tumor imaging. Moreover, the whole-body 18F-FDG tumor imaging was positive in 16 patients. Furthermore, the clinical tumor stage and pre-treatment Tg and RAIU were found to be the independent influencing factors for the efficacy of 131I therapy.

CONCLUSION

131I therapy is exactly effictive in treating DTC in children and adolescents, and the clinical tumor stage and pre-treatment Tg and RAIU are the major factors affecting the efficacy.

Impact of age on survival in radioiodine refractory differentiated thyroid cancer patients

OBJECTIVE

The objectives of our study were to analyze the influence of age on the survival of patients with RAIR-DTC and to determine their prognostic factors according to age.

METHODS

This single-center, retrospective study enrolled 155 patients diagnosed with RAIR-DTC. The primary end point was overall survival (OS) according to different cutoff (45, 55, 65, 75 years). Secondary endpoints were progression free survival (PFS) and prognostic factors in patients under and over 65 years.

RESULTS

Median OS after RAIR diagnosis was 8.2 years (95% IC: 5.3-9.6). There was no difference according to age with a 65 (P = 0.47) and 55 years old cutoff (P = 0.28). Median OS improved significantly before 45 years old (P = 0.0043). After 75 years old, median OS significantly decreased (P = 0.0008). Median PFS was 2.1 years (95% CI: 0.8-3) in patients < 65 years old, and 1 year in patients ≥ 65 years old (95% CI: 0.8-1.55) with no statistical difference (P = 0.22). There was no impact of age on PFS with any cutoff. In both groups, progressive disease despite 131I treatment reduced OS. In patients < 65 years old, an interval of less than 3 years between the initial diagnosis and the diagnosis of RAIR metastatic disease was predictive of poor survival. In patients > 65 years old, the presence of a mediastinum metastasis was a significant factor for mortality (HR: 4.55, 95% CI: 2.27-9.09).

CONCLUSION

In RAIR-DTC patients, a cut-off age of 65 years old was not a significant predictive factor of survival. Forty-five and 75-years-old cutoff were predictive for OS but not PFS.

The Effect of Radioactive Iodine Therapy on Ovarian Function and Fertility in Female Thyroid Cancer Patients: A Systematic Review and Meta-Analysis

Introduction: Thyroid cancer is one of the most common carcinomas diagnosed in adolescents and young adults, with a rapidly rising incidence for the past three decades. Surgery is the standard treatment for patients with differentiated thyroid carcinoma (DTC), and when indicated, followed by radioactive iodine (RAI) treatment. The aim of this study was to evaluate the possible effects of RAI therapy on ovarian function and fertility in women. Methods: The PubMed, Embase, and Web of Science databases were systematically searched up to January 2020. In addition, a meta-analyses were performed for anti-Mullerian hormone (AMH) levels after RAI, comparison of AMH levels prior and 1 year after RAI, and pregnancy rates in patient with thyroid cancer receiving RAI compared with patients with thyroid cancer who did not receive RAI. Results: A total of 36 studies were eligible for full-text screening and 22 studies were included. The majority of the studies had a retrospective design. Menstrual irregularities were present in the first year after RAI in 12% and up to 31% of the patients. Approximately 8-16% of the patients experienced amenorrhea in the first year after RAI. Women who received RAI treatment (median dose 3700 MBq [range 1110-40,700 MBq]); had menopause at a slightly younger age compared with women who did not receive RAI treatment, 49.5 and 51 years, respectively (p < 0.001). Pooled AMH of the seven studies reporting AMH concentrations after RAI was 1.79 ng/mL. Of these, four studies reported AMH concentrations prior and 1 year after RAI. The mean difference was 1.50 ng/mL, which was significant. Finally, meta-analysis showed that patients undergoing RAI were not at a decreased risk of becoming pregnant. Conclusions: Most of the studies indicate that RAI therapy for DTC is not associated with a long-term decrease in pregnancy rates although meta-analyses show a significant decrease in AMH levels after RAI therapy. Prospective studies are needed to confirm these results. We recommend counseling patients about the possible effects of ¹³¹I and incorporate today's knowledge in multidisciplinary counseling.

Selective Use of Radioactive Iodine Therapy for Papillary Thyroid Cancers With Low or Lower-Intermediate Recurrence Risk

CONTEXT

Current guidelines recommend a selective use of radioiodine treatment (RAI) for papillary thyroid cancer (PTC).

OBJECTIVE

This work aimed to determine how policy changes affect the use of RAI and the short-term outcomes of patients.

METHODS

A retrospective analysis of longitudinal data was conducted in an academic referral center of patients with nonaggressive PTC variants; no extrathyroidal invasion or limited to soft tissues, no distant metastases, and 5 or fewer central-compartment cervical lymph node metastases. In cohort 1, standard treatments were total thyroidectomy and RAI (May 2005-June 2011); in cohort 2 decisions on RAI were deferred for approximately 12 months after surgery (July 2011-December 2018). Propensity score matching was used to adjust for sex, age, tumor size, lymph node status, and extrathyroidal extension. Intervention included immediate RAI or deferred choice. Main outcome measures were responses to initial treatment during 3 or more years of follow-up.

RESULTS

In cohort 1, RAI was performed in 50 of 116 patients (51.7%), whereas in cohort 2, it was far less frequent: immediately in 10 of 156 (6.4%), and in 3 more patients after the first follow-up data. The frequencies of structural incomplete response were low (1%-3%), and there were no differences between the 2 cohorts at any follow-up visit. Cohort 2 patients had higher rates of "gray-zone responses" (biochemical incomplete or indeterminate response).

CONCLUSION

Selective use of RAI increases the rate of patients with "uncertain" status during early follow-up. The rate of structural incomplete responses remains low regardless of whether RAI is used immediately. Patients should be made aware of the advantages and drawbacks of omitting RAI.

Improved Patient Dosimetry at Radioiodine Therapy by Combining the ICRP Compartment Model and the EANM Pre-Therapeutic Standard Procedure for Benign Thyroid Diseases

Radioactive iodine is commonly used for the treatment of different thyroid conditions since the 1940s. The EANM has developed a standard pre-therapeutic procedure to estimate patient specific thyroid uptake at treatment of benign thyroid diseases. The procedure which models the time dependent fractional thyroid uptake is based on a two-compartment fitting system, one representing the thyroid and the other the blood. The absorbed dose is however only estimated for the thyroid and not for any other organ in the body. A more detailed biokinetic model for iodine is given by the ICRP and includes an iodide transport in the whole body. The ICRP model has 30 different compartments and 48 transfer coefficients to model the biokinetics of iodide and to model different transfer for inorganic iodide and organic iodine. The ICRP model is a recirculation iodine model, and the optimization is performed on the whole model and not exclusively on the thyroid as in the EANM procedure. Combining the EANM method and the ICRP model gives both patient specific estimations of thyroid uptake and retention and include most organs in the body. The new software gives both an improved patient specific dosimetry for the thyroid and an estimation of the absorbed dose to non-target organs and tissues like kidneys, urinary bladder, stomach wall, and uterus. Using the method described in this paper, the repercussions on the daily routines will be minimal.

123I Scan With Whole-Body Retention Measurement at 48 Hours for Simplified Dosimetry Before 131I Treatment of Metastatic Thyroid Cancer

ABSTRACT

A previously published model (Atkins) allows for calculation of 131I maximum tolerated activity on the basis of 48-hour whole-body retention of 131I on a pretherapy diagnostic scan. Our practice uses iodine 123I for diagnostic imaging of metastatic thyroid cancer for staging before 131I therapy, with images typically acquired 24 hours after administration of the radiopharmaceutical. We explored the feasibility of an additional 123I whole-body scan and retention measurement at 48 hours, with application of the model to estimate maximum tolerated activity of radioiodine before 131I treatment of metastatic thyroid cancer.

Least Significant Changes and Reproducibility of 131I Uptake Test

ABSTRACT

Radioactive iodine uptake (RAIU) is one of the important tests performed in the departments of nuclear medicine, testing thyroid function by measuring the amount of 131I uptake after oral administration. A RAIU value measured 4 and 24 h after administration has been widely used for differential diagnosis of thyroid function and for the calculation of treatment dose. This study was performed to define practical methods for reproducibility and least significant change (LSC) values replicating thyroid measurements. In the study were 119 patients referred to the nuclear medicine department for examination of thyroid gland function with the diagnosis of Graves' disease (60), toxic multinodular goiter (29), thyroiditis (10), thyroid cancer (6), and unknown etiology (14). The level of thyroid stimulating hormone (TSH) among the patients was 2.07 ± 6.74 μIU mL-1. RAIU measurements were carried out by two different technicians, who have performed an equal number of measurements from each diagnosis in reference to the clinical diagnosis. Measurement of each patient was performed twice at 4 and 24 h after the administration under stable geometry and counting conditions using a standard procedure. Data were evaluated using statistical methods. For assessment of the reproducibility, three parameters were used: reproducibility coefficient (RC), the root-mean-square standard deviation (SDRMS), and the least significant change values. The average RAIU values of the first and second measurements were found as 23.71 ± 16.52% and 23.94 ± 16.64% at 4 h (p >0.05), and 35.33 ± 19.22% and 35.49 ± 19.19% at 24 h (p >0.05), respectively. For thyroid uptake values repeated at 4 and 24 h after radioiodine administration, the mean difference was found to be -0.24 ± 0.62% [limits of agreement (%); -1.44 to 0.97] at 4 h and -0.16 ± 0.44% [limits of agreement (%); -1.02 to 0.70] at 24 h. Confidence intervals were within the limits of agreement (d̅-1.96 SD and d̅+1.96 SD). When the correlation between the repeated RAIU measurements was examined taking the differences and averages into account, there was a negative correlation between 4-h measurement pairs (r=-0.203, p <0.05). On the other hand, a significant correlation was not found between the 24-h measurement pairs (r=0.074, p >0.05). RC, SDRMS, and LSC were calculated as 0.70%, 0.46%, and 1.29% for the 4 h measurements and 0.54%, 0.33%, and 0.91% for the 24-h measurements, respectively. Although there was a minor difference between measurement pairs at 4 and 24 h post-administration, the difference appeared to be insignificant without an apparent effect in the clinical settings.

Clinical outcomes of a conservative approach in cervical lymph node metastases of thyroid cancer

CONTEXT

Lymph node metastases (LNM) can be present in 35% of patients with differentiated thyroid cancer (DTC), and the management of persistent/recurrent nodal disease has been controversial. Watchful waiting may be a reasonable approach in selected patients, but uncertainty about clinical outcomes remains a concern.

OBJECTIVE

To investigate the outcomes of patients with DTC with recurrent/persistent confirmed LNM under surveillance.

METHODS

Patients with LNM from DTC were selected from databases of needle washout thyroglobulin measurements and fine-needle aspiration biopsies performed in our institution. Patients with confirmed metastases, in whom active surveillance was initially proposed, were selected. Main clinical outcomes were analysed.

RESULTS

We found 89 patients with LNM under surveillance. Classic papillary was the most frequent variant (44%). During a median follow-up of 3 (0.5-17.2) years, different treatments were needed in 35 (39.3%) patients: radioactive iodine (RAI) in 23 (25.8%), surgery in 9 (10.1%) and radiotherapy (RT) in 3 (3.4%). From those submitted initially to RAI, progression of disease was observed in 8 patients, 4 requiring other treatment modalities: surgery (n = 2), RT (n = 1) and RAI (n = 1). The remaining 54 (60.7%) patients maintained surveillance. In this group, progression of disease was observed in 26 (48.1%), due to increase in the number and/or volume of metastases, but further treatments were not required.

CONCLUSION

In a group of patients with cervical LNM under active surveillance, only 16.9% (n = 15) required invasive intervention (surgery or RT).

Do Molecular Profiles of Primary Versus Metastatic Radioiodine Refractory Differentiated Thyroid Cancer Differ?

Management of metastatic radioiodine refractory differentiated thyroid cancer (DTC) can be a therapeutic challenge. Generally, little is known about the paired molecular profile of the primary tumor and the metastases and whether they harbor the same genetic abnormalities. The present study compared the molecular profile of paired tumor specimens (primary tumor/metastatic sites) from patients with radioiodine refractory DTC in order to gain insight into a possible basis for resistance to radioiodine. Twelve patients with radioiodine refractory metastases were studied; median age at diagnosis of 61 years (range, 25-82). Nine patients had papillary TC (PTC), one had follicular TC (FTC), and two had Hürthle cell TC (HTC). Distant metastases were present in the lungs (n = 10), bones (n = 4), and liver (n = 1). The molecular profiling of paired tumors was performed with a panel of 592 genes for Next Generation Sequencing, RNA-sequencing, and immunohistochemistry. Digital microfluidic PCR was used to investigate TERT promoter mutations. The genetic landscape of all paired sites comprised BRAF, NRAS, HRAS, TP53, ATM, MUTYH, POLE, and NTRK genes, including BRAF and NTRK fusions. BRAF V600E was the most common point mutation in the paired specimens (5/12). TERT promoter mutation C228T was detected in one case. PD-L1 expression at metastatic sites was highly positive (95%) for one patient with HTC. All specimens were stable for microsatellite instability testing, and the tumor mutation burden was low to intermediate. Therefore, the molecular profile of DTC primary and metastatic lesions can show heterogeneity, which may help explain some altered responses to therapeutic intervention.