Recurrence after low-dose radioiodine ablation and recombinant human thyroid-stimulating hormone for differentiated thyroid cancer (HiLo): long-term results of an open-label, non-inferiority randomised controlled trial

The role of the hypothalamic-pituitary-thyroid axis in thyroid cancer

The hypothalamic-pituitary-thyroid axis plays a crucial role in the pathogenesis, diagnosis, risk stratification, effectiveness of radioiodine therapy, and treatment response evaluation in epithelial thyroid cancer. Supraphysiological doses of levothyroxine are used in patients with intermediate-risk and high-risk thyroid cancer to suppress thyroid-stimulating hormone (TSH) to prevent tumour progression. However, free thyroxine and tri-iodothyronine have also been found to promote tumour growth in thyroid cancer preclinical models. Moreover, current evidence remains inconclusive about the role of TSH suppression in improving survival outcomes and reveals an increased risk of cardiovascular and skeletal adverse events after long-term exposure to excess levothyroxine. Stimulation of the axis with either recombinant human TSH or thyroid hormone withdrawal has been proven equally effective for diagnostic purposes and for facilitating radioiodine uptake for thyroid remnant ablation, but evidence is insufficient for non-inferiority of recombinant human TSH-based vs thyroid hormone withdrawal-based stimulation before radioiodine therapy of distant metastases.

Contribution of neck ultrasonography to patient management in patients with differentiated thyroid carcinoma with excellent response to therapy

PURPOSE

To assess the contribution of intense neck ultrasonography (US) follow-up in the clinical management of differentiated thyroid carcinoma (DTC) patients with the American Thyroid Association (ATA) low-intermediate-risk of recurrence and an excellent response after total thyroidectomy and radioiodine therapy.

MATERIALS AND METHODS

Medical records of patients who underwent serial follow-up neck US examinations between 1996 and 2022 were analyzed retrospectively. The utility of serial US examinations in detecting structural recurrence was assessed in all patients and different subgroups-categorized per the initial risk of recurrence and stimulated thyroglobulin (sTg) level at 1-year response assessment.

RESULTS

Among 2823 US examinations in 296 patients, 2 (0.1%) were categorized as true-positive, 2670 (94.6%) as true-negative, and 151 (5.3%) as false-positive, whereas no false-negative results were observed. Thus, sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy [confidence interval] in all patients were 100% [34.2-100%], 94.7% [93.8-95.4%], 1.3% [0.36-4.6%], 100% [99.9-100%], and 94.7% [93.8-95.4%], respectively. Non-significant higher PPVs were calculated in intermediate-risk patients and patients having sTg ≥0.1 ng/mL, while slightly lower specificity and accuracy were demonstrated in the former group. No recurrence was identified in patients with a low risk of recurrence and those having sTg <0.1 ng/mL.

CONCLUSION

Frequent US examination yields remarkably low PPVs in identifying recurrences in ATA low-intermediate-risk patients with DTC and attaining excellent response after total thyroidectomy and radioiodine ablation. Therefore, US surveillance protocol should be individualized per the initial risk of recurrence and Tg levels at response assessment.

Radioactive Iodine Therapy in Differentiated Thyroid Cancer: Summary of the Korean Thyroid Association Guidelines 2024 from Nuclear Medicine Perspective, Part-II

Thyroid cancer, one of the most common endocrine tumors, generally has a favorable prognosis but remains a significant medical and societal concern due to its high incidence. Early diagnosis and treatment of differentiated thyroid cancer (DTC) significantly affect long-term outcomes, requiring the selection and application of appropriate initial treatments to improve prognosis and quality of life. Recent advances in technology and health information systems have enhanced our understanding of the molecular genetics of thyroid cancer, facilitating the identification of aggressive subgroups and enabling the accumulation of research on risk factors through big data. The Korean Thyroid Association (KTA) has revised the "KTA Guidelines on the Management of Differentiated Thyroid Cancers 2024" to incorporate these advances, which were developed by a multidisciplinary team and underwent extensive review and approval processes by various academic societies. This article summarizes the 2024 KTA guidelines for radioactive iodine (RAI) therapy in patients with DTC, written by the Nuclear Medicine members of the KTA Guideline Committee, and covers RAI therapy as initial management of DTC and RAI therapy in advanced thyroid cancer.

Association of Radioactive Iodine Administration With Outcome Among Patients With Low-Risk Differentiated Thyroid Cancer: A Real-World Data Analysis

OBJECTIVE

Despite the generally favourable long-term prognosis of low-risk differentiated thyroid cancer (DTC), questions remain about disease-free survival (DFS) after initial treatment, particularly regarding the use of radioactive iodine (RAI). Although there are RCT trial confirming that RAI ablation therapy is not superior to follow-up in terms of the 3-year DFS rate in low-risk thyroid cancer, its longer-term prognosis remains to be established. The objective of this study was to assess the impact of RAI ablation on the presence of structural persistent/recurrent disease in patients with low-risk DTC.

METHODS

We retrospectively identified 720 low-risk DTC patients who had undergone total or near-total thyroidectomy (TT) at a tertiary medical centre between January 2008 and July 2018. Propensity scores were calculated using a multivariable logistic regression model that accounted for age, sex, tumour size, neck dissection, multifocality, capsular invasion and lymph node (LN) metastasis. We compared DFS between patients who received RAI and those who did not using log-rank tests and multivariate Cox analyses. Subgroup analyses were also conducted.

RESULTS

Of the total cohort, 180 (25.0%) patients received RAI, while 540 (75.0%) did not before matching. The median follow-up duration was 59.5 months. After matching, the RAI group comprised 135 (39.8%) patients and the non-RAI group comprised 204 (60.2%) patients. In the entire cohort, the 5-year DFS rate was 97.6% for patients receiving RAI compared to 96.8% for those not receiving RAI (p = 0.704). In the matched cohort, the rates were 98.5% and 95.6%, respectively (p = 0.090). Matched multivariate Cox analysis demonstrated that RAI was neither significantly nor independently associated with DFS (hazard ratio [HR] = 0.29; 95% CI 0.06-1.37; p = 0.118). Further subgroup analyses reaffirmed that RAI ablation did not significantly reduce the risk of developing structural persistent/recurrent disease.

CONCLUSION

Administering RAI ablation following TT did not result in improved DFS for low-risk DTC patients. Our findings suggest that decisions regarding RAI should be made judiciously to avoid overtreatment in this clinical scenario.

Thyroidectomy without radioiodine in patients with low-risk thyroid cancer: 5 years of follow-up of the prospective randomised ESTIMABL2 trial

BACKGROUND

ESTIMABL2, a multicentre randomised phase 3 trial in patients with low-risk differentiated thyroid cancer (ie, pT1am or pT1b, N0 [no evidence of regional nodal involvement] or Nx [involvement of regional lymph nodes that cannot be assessed in the absence of neck dissection]), showed the non-inferiority of a follow-up strategy without radioactive iodine (131I) administration compared with a postoperative 131I administration at 3 years post-randomisation. Here, we report a pre-specified analysis after 5 years of follow-up.

METHODS

Patients treated with total thyroidectomy with or without prophylactic neck lymph node dissection, without postoperative suspicious findings on neck ultrasonography, were randomly assigned to the no-radioiodine group or to the radioiodine group (1·1 GBq-30 mCi after recombinant human thyrotropin-stimulating hormone). Follow-up consisted of annual thyroglobulin and thyroglobulin antibody determinations during levothyroxine treatment and neck ultrasonography in odd-numbered years. An event was defined as abnormal foci of 131I uptake on the post-treatment whole-body-scan requiring subsequent treatment, abnormal neck ultrasonography, elevated thyroglobulin levels, increasing titres or appearance of thyroglobulin antibody (using the same laboratory assay), or a combination of these definitions. Non-inferiority of the proportion of patients without an event in one group compared with the other at 5 years after randomisation was shown if this proportion and its CI did not differ by more than -5%. This study was registered on ClinicalTrials.gov (NCT01837745) and is completed.

FINDINGS

Of the 776 patients (n=642 [82·7%] female and n=134 [17·3%] male, median age 52·9 years [IQR 42·6-63·1]) enrolled, 698 were evaluable at 5 years. The proportions of patients without events were 93·2% in the no-radioiodine group and 94·8% in the radioiodine group, for a difference of -1·6% (90% CI -4·5 to 1·4). Events consisted of structural or functional abnormalities (n=11) and biological abnormalities (n=31).

INTERPRETATION

The non-inferiority of a follow-up strategy compared with postoperative 131I administration in low risk differentiated thyroid cancer was confirmed at 5 years. There is no loss of opportunity in following these patients without postoperative ablation.

FUNDING

Programme de Recherche Hospitalier Clinique.

Medium- and long-term recurrence after radioiodine therapy for differentiated thyroid carcinoma with recombinant human thyrotropin: a meta-analysis

Introduction

Radioactive iodine (RAI) is commonly used in the management of differentiated thyroid cancers (DTCs). However, the long-term efficacy and the risk of tumor recurrence associated with it remain unclear. In particular, the comparison between recombinant human thyrotropin (rhTSH) and thyroid hormone withdrawal (THW) in terms of medium- and long-term recurrence rate in DTC patients has not been fully elucidated.

Methods

A systematic search was carried out to identify articles comparing medium- and long-term outcomes (> 2 years) based on treatment with either rhTSH or THW. Ten studies, consisting of six randomized controlled trials (RCTs) and four retrospective studies with a total of 2,833 patients, were included in the analysis.

Results

There was no significant difference in the medium- and long-term recurrence rates between the rhTSH group and the THW group. This was also the case in subgroup analyses of only RCTs or only retrospective studies. The structural incomplete response (SIR) rate was slightly higher in the rhTSH group, but a subgroup analysis of RCTs alone showed no significant difference in SIR between the two groups.

Discussion

rhTSH is comparable to THW in achieving successful ablation of residual disease and maintaining low recurrence rates. However, further RCTs are required to investigate whether rhTSH can increase the risk of SIR.

Long-Term Outcome of Low- and High-Dose Radioiodine for Thyroid Remnant Ablation

OBJECTIVE

We conducted a prospective randomized clinical trial to compare the efficacy of low- and high-dose radioiodine for remnant ablation in patients with low-risk differentiated thyroid cancer (DTC) in China. The first-stage results showed equivalence was observed between the two groups. Here, we report recurrence and survival at 3-5 and 6-10 years and biochemical parameters.

DESIGN, PATIENTS AND METHODS

Between January 2013 and December 2014, adult patients with DTC were enroled. Patients had undergone total or near-total thyroidectomy, with or without cervical lymph node dissection, with tumour stages T1-T3 with or without lymph node metastasis, but without distant metastasis. Patients were randomly assigned to the low-dose (1850 MBq) or high-dose (3700 MBq) radioiodine group. They were then followed up for 3-5 and 6-10 years. Data on biochemical abnormalities, recurrence and survival were analysed using Kolmogorov-Smirnov and χ2 tests.

RESULTS

The data of 228 patients (mean age = 42 years; 70.6% women) were analysed, with 117 patients in the low-dose group and 111 in the high-dose group. There were no significant differences in biochemical abnormalities, recurrence, or survival rates at the 6-10-year follow-up (all p > .05). Nine patients experienced recurrence in the low-dose group (8.7%), while eight patients experienced recurrence in the high-dose group (8.2%). The survival rates were 100% and 98.2% in the low- and high-dose groups, respectively.

CONCLUSIONS

The long-term effectiveness and safety of low-dose (1850 MBq) radioiodine are the same as those of high-dose (3700 MBq) radioiodine for thyroid remnant ablation in Chinese patients with low-risk DTC.

Comparison of 8th and 7th editions of TNM staging in terms of mortality, persistent disease, and response to treatment in patients with differentiated thyroid cancer

OBJECTIVE

To compare the eighth and seventh editions of TNM staging (TNM-8 and TNM-7) on disease-related mortality, persistent disease, and response to treatment in patients with differentiated thyroid cancer (DTC).

METHODS AND MATERIALS

We studied 400 patients (79% female) with DTC with a mean age of 40.93±14.11 years. TNM staging was recorded according to the 7th and 8th editions and patients were followed for at least 1 year and response to therapy was recorded according to ATA response categorization.

RESULTS

The mean follow up time was 42.5±15.24 months. Overall, 108 patients (27%) were down-staged using the TNM-8, mainly due to the changes in the age cut-off (14.5%), N (9.25%), and T categorization (3.25%). All patients in stage III and 82.8% in stage IV were down-staged. The mean Tg levels were significantly higher in stages III and IV in TNM-8 compared to TNM-7. Four disease-related death were recorded during follow up, all in stage IV according to TNM-7, while one was in stage II according to TNM-8. One year after treatment, persistent disease was detected in 12% and 77% of patients in stage III according to the 7th and 8th editions, respectively (P= 0.04). Similarly, biochemical incomplete response one year after treatment was seen in 7.3% and 87% in stage III disease using 7th and 8th editions (P = 0.006) that fell to 2.4% and 22% in the last visit respectively (P = 0.04).

CONCLUSION

Persistent disease and incomplete response to therapy were more common in stages III and IV in TNM-8 compared to TNM-7. The eighth edition was a better predictor of persistent disease in stages III and IV disease.

The Definition of Recurrence of Differentiated Thyroid Cancer: A Systematic Review of the Literature

Background: Recurrence is a key outcome to evaluate the treatment effect of differentiated thyroid carcinoma (DTC). However, no consistent definition of recurrence is available in current literature or international guidelines. Therefore, the primary aim of this systematic review was to delineate the definitions of recurrence of DTC, categorized by total thyroidectomy with radioactive iodine ablation (RAI), total thyroidectomy without RAI and lobectomy, to assess if there is a generally accepted definition among these categories. Methods: This study adhered to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. In December 2023, a systematic literature search in MEDLINE and EMBASE was performed for studies reporting on the recurrence of DTC, from January 2018 to December 2023. Studies that did not provide a definition were excluded. Primary outcome was the definition of recurrence of DTC. Secondary outcome was whether studies differentiated between recurrence and persistent disease. Two independent investigators screened the titles and abstracts, followed by full-text assessment and data extraction. The study protocol was registered in PROSPERO, CRD42021291753. Results: In total, 1450 studies were identified. Seventy studies met the inclusion criteria, including 69 retrospective studies and 1 randomised controlled trial (RCT). Median number of patients in the included studies was 438 (range 25-2297). In total, 17 studies (24.3%) reported on lobectomy, 4 studies (5.7%) on total thyroidectomy without RAI, and 49 studies (70.0%) with RAI. All studies defined recurrence using one or a combination of four diagnostic modalities cytology/pathology, imaging studies, thyroglobulin (-antibodies), and a predetermined minimum tumor-free time span. The most common definition of recurrence following lobectomy was cytology/pathology-proven recurrence (47.1% of this subgroup), following total thyroidectomy with RAI was cytology/pathology-proven recurrence and/or anomalies detected on imaging studies (22.4% of this subgroup). No consistent definition was found following total thyroidectomy without RAI. Nine studies (12.9%) differentiated between recurrence and persistent disease. Conclusion: Our main finding is that there is no universally accepted definition for recurrence of DTC in the current studies across any of the treatment categories. The findings of this study will provide the basis for a future, international Delphi-based proposal to establish a universally accepted definition of recurrence of DTC. A uniform definition could facilitate global discussion and enhance the assessment of treatment outcomes regarding recurrence of DTC.

Assessing radioiodine therapy long-term outcomes in differentiated thyroid cancer using nomograms

This study explored the role of radioiodine therapy (RAI) in low-risk thyroid cancer patients and examined the disease-specific survival (DSS) rates in a large cohort of differentiated thyroid cancer patients (DTC). We obtained patient data from SEER database. Patients who underwent total thyroidectomy were included and categorized into three groups based on histology: classical papillary thyroid carcinoma (C-PTC), follicular type variant carcinoma (FV-PTC), and follicular thyroid cancer (FTC). Patients with distant metastasis, tumor size ≥ 200 mm, chemotherapy, or any type of radiation other than RAI were also excluded. A nomogram was developed and tested for discrimination and calibration. In total, 96,532 thyroid cancer cases were examined, including 59,460 C-PTC, 31,583 FV-PTC, and 5,489 FTC cases. Age > 65 years and male sex were correlated with lower survival rates across the subtypes. In addition, extrathyroidal extension had a worse survival effect in patients with FTC. DSS rates were compared between patients who received RAI and those who did not, with a 3% difference in C-PTC (94% vs. 91%, p < 0.001), 2% in FV-PTC (92% vs. 90%, p < 0.001), and 1% in FTC (89% vs. 88%, p = 0.084) at 15 years. The nomograms for long-term DSS showed high discriminatory abilities with C-indices of 0.815, 0.805, and 0.781 for C-PTC, FV-PTC, and FTC, respectively. The developed nomogram can be used in the treatment plan for patients with DTC. Our study emphasizes the prognostic factors for DTC and highlights the need for personalized treatment plans based on individual risk profiles.

Reducing noise in radioactive iodine activity selection: the utility of an online clinical calculator

Background

Noise, an unwanted variability in judgment, is ubiquitous in medicine, including in the prescription of radioactive iodine (RAI). Building upon our recently developed predictive risk model, we created an online clinical support tool to facilitate the translation of our model into clinical practice. The aim of this study is to assess the utility of an online clinical support tool to reduce noise in the treatment for patients with differentiated thyroid cancer (DTC).

Methods

The tool was accessible via weblink or a QR code. Activity recommendations were applied to the calculator's four risk categories: 0 GBq for very low risk, 1 GBq for low risk, 4 GBq for intermediate risk, and 6 GBq for high risk. The tool was applied prospectively to 103 patients who received RAI at Royal North Shore Hospital between 2021 and 2022 and retrospectively to 393 patients treated with RAI between 2017 and 2021.

Results

A significant difference was observed in administered activity between the 2021-2022 and 2017-2021 cohorts in patients stratified as intermediate risk (median activity 3.95 GBq, interquartile range 2.03-4.04 vs 4 GBq, 4-4) and high risk (4.07 GBq, 3.95-5.7 vs 6 GBq, 6-6) with P-values of 0.01 and <0.01, respectively. No difference was seen in low-risk patients (2.01 GBq, 1.03-3.98 vs 1 GBq, 1-4, P = 0.30). Additionally, no clinically significant recurrence was observed between the two cohorts (6.6% vs 4.5%; P = 0.628).

Conclusion

Optimal risk classification and activity recommendation continue to be established. Our data suggest that providing risk stratification and activity recommendation in an easy-to-access online tool can reduce noise and variability in activity prescription for patients with DTC.

Long-Term Outcome of Patients with Low-Risk Differentiated Thyroid Cancer Treated with Total Thyroidectomy Alone

BACKGROUND

Differentiated thyroid carcinoma (DTC), mainly papillary (PTC), at low risk of recurrence is currently managed with active surveillance strategies or less aggressive surgeries. However, total thyroidectomy with 131I treatment is still performed both if these tumors are diagnosed before or occasionally after surgery. This real-life study aimed to evaluate the rate of biochemical, structural, and functional events in a large series of consecutive DTCs at low risk of recurrence treated by total thyroidectomy, but not with 131I, in a medium-long-term follow-up.

PATIENTS AND METHODS

We evaluated clinical-pathologic data of 383 consecutive patients (2006-2012) with unifocal DTC [T1a/b(s)] at low risk of recurrence, treated with total thyroidectomy but without lymph node dissection and 131I treatment after surgery. We evaluated if structural, biochemical, and functional events were detected during the follow-up.

RESULTS

Females accounted for 75.7% of our study group, and the median age was 50 years. The median tumor dimension was 0.4 cm (range 0.1-1.2). Most of the patients had a unifocal T1a tumor (98.9%), and 73.6% had a classic variant of PTC. We divided the patients according to the absence (group A-n = 276) or presence (group B-n = 107) of interfering TgAb at first control after surgery. After a median follow-up of 10 years, no structural events were detected. Sixteen out of three hundred and eighty-three (4.2%) patients developed biochemical events: 12/276 (4.3%) in group A and 4/107 (3.7%) in group B. The median time elapsed from surgery to detecting a biochemical event was 14.5 and 77.5 months in groups A and B, respectively. No patients performed additional treatments and were followed up with an active surveillance strategy.

CONCLUSIONS

This study confirmed that patients with DTC at low risk of recurrence showed an excellent outcome in a medium long-term follow-up since no structural events were diagnosed. Significant variations in Tg/TgAb were detected in a few cases, all managed with an active surveillance strategy without the need for other treatments. Therefore, a relaxed follow-up with neck ultrasound and Tg/TgAb measurement is enough to early identify those very unusual cases of recurrence.

Epigenetics in thyroid cancer: a bibliometric analysis

Background

Epigenetics, which involves regulatory modifications that do not alter the DNA sequence itself, is crucial in the development and progression of thyroid cancer. This study aims to provide a comprehensive analysis of the epigenetic research landscape in thyroid cancer, highlighting current trends, major research areas, and potential future directions.

Methods

A bibliometric analysis was performed using data from the Web of Science Core Collection (WOSCC) up to 1 November 2023. Analytical tools such as VOSviewer, CiteSpace, and the R package 'bibliometrix' were employed for comprehensive data analysis and visualization. This process identified principal research themes, along with influential authors, institutions, and countries contributing to the field.

Results

The analysis reveals a marked increase in thyroid cancer epigenetics research over the past two decades. Emergent key themes include the exploration of molecular mechanisms and biomarkers, various subtypes of thyroid cancer, implications for therapeutic interventions, advancements in technologies and methodologies, and the scope of translational research. Research hotspots within these themes highlight intensive areas of study and the potential for significant breakthroughs.

Conclusion

This study presents an in-depth overview of the current state of epigenetics in thyroid cancer research. It underscores the potential of epigenetic strategies as viable therapeutic options and provides valuable insights for researchers and clinicians in advancing the understanding and treatment of this complex disease. Future research is vital to fully leverage the therapeutic possibilities offered by epigenetics in the management of thyroid cancer.

Radioactive iodine therapy for thyroid cancer coexisting with Hashimoto's thyroiditis: a systematic review and meta-analysis

OBJECTIVES

To investigate the clinical character of differentiated thyroid cancer (DTC) coexisting with Hashimoto's thyroiditis (HT) and provide state-of-art evidence for personalized radioactive iodine-131 therapy (RAIT) for patients coexisting with HT.

METHODS

From January 2000 to January 2023, PubMed, Embase, and Web of Science databases were searched for relevant original articles that published in English on the RAIT efficacy for DTC with HT. RevMan 5.4 and Stata 17.0 were used for data analysis.

RESULTS

Eleven studies involving 16 605 DTC patients (3321 with HT) were included. HT was more frequent in female (OR: 2.90, 95% confidence interval [CI]: 1.77-4.76, P < .00001). The size of tumour (MD: -0.20, 95% CI: -0.30 to -0.11), extrathyroidal extension rate (OR: 0.77, 95% CI: 0.67-0.90), and metastasis rate (OR: 0.18, 95% CI: 0.08-0.41) were less in HT, but tumour, node, metastasis (TNM) stage had no significant difference among HT and non-HT group. Disease-free survival (DFS) rate (OR: 1.96, 95% CI: 1.57-2.44, P < .00001), 5-year DFS (OR: 1.73, 95% CI: 1.04-2.89, P = .04), and 10-year DFS (OR: 1.56, 95% CI: 1.17-2.09, P = .003) were higher in HT group. The recurrent (OR: 0.62, 95% CI: 0.45-0.83, P = .002), RAIT dosage (MD = -38.71, 95% CI: -60.86 to -16.56, P = .0006), and treatment (MD: -0.13, 95% CI: -0.22 to -0.03, P = .008) were less in HT group.

CONCLUSIONS

DTC coexisting with HT was associated with less invasion. DFS of HT group was higher than non-HT group after RAIT. Low-dose treatment did not impair the efficacy of RAIT in DTC with HT.

ADVANCES IN KNOWLEDGE

Hashimoto's thyroiditis is a risk for DTC, but it minimalizes the progression of cancer and enhance the efficacy of RAIT, which should be considered in personalizing RAIT.

Ablation Rates and Long-Term Outcome Following Low-Dose Radioiodine for Differentiated Thyroid Cancer in the West of Scotland: A Retrospective Analysis

OBJECTIVE

Low-dose radioiodine is an accepted means of remnant ablation in patients with low- to intermediate-risk differentiated thyroid cancer (DTC) based on the results of several phase III trials. We evaluated the rate of ablation success and long-term recurrence outcomes in the first 3 years of implementing this practice at our institution.

METHODS

Patients who received 1.1 to 1.2 gigabecquerel (30 millicurie) were identified retrospectively from the radionuclide database, January 1, 2012, to December 31, 2014, inclusive. Successful ablation was defined as Iodine-131uptake <0.1% on diagnostic scan and Tg level <2.0 ng/mL at 6 to 8 months after treatment. Follow-up was conducted annually for 10 years and relapse rates were determined based on the available clinical, radiological, and biochemical information.

RESULTS

We identified 114 patients, 109 of whom had dual response assessment. The median age was 43 years (range, 14 to 80 years). Almost 70% had T1 or T2 tumors, with T3 and T4 tumors recorded in 27% and 2.5% of patients, respectively. Nodal staging was performed in just over 30% and involved lymph nodes were detected in 21% (N1a 8% and N1b 13%). Ablation success based on diagnostic scan alone was 94.7% (108/114), Tg alone 94.7% (108/114), and on both modalities was 90.4% (103/114).

CONCLUSION

Remnant ablation was achieved in >90%, and the corresponding clinical recurrence rate was only 1.8% despite the inclusion of patients with locally advanced disease. Low-dose radioiodine is effective and may be suitable for a proportion of patients with higher-risk DTC.

Comparison of Recombinant Human Thyroid-Stimulating Hormone and Thyroid Hormone Withdrawal for 131 I Therapy in Patients With Intermediate- to High-Risk Thyroid Cancer : A Systematic Review and Meta-analysis

BACKGROUND

This meta-analysis and systematic review aimed to evaluate the therapeutic efficacy and advantages associated with the use of recombinant human thyroid-stimulating hormone (rhTSH) for radioactive iodine (RAI) therapy in patients with intermediate- to high-risk differentiated thyroid cancer.

PATIENTS AND METHODS

MEDLINE, EMBASE, and Cochrane databases were searched to identify relevant articles reporting clinical outcomes of rhTSH compared with thyroid hormone withdrawal (THW) in patients with intermediate- to high-risk differentiated thyroid cancer published between January 2012 and June 2023. Meta-analyses were performed (PROSPERO registration number: CRD42022340915) to assess the success rate of radioiodine remnant ablation (RRA) in patients with intermediate to high risk and determine the disease control rate among patients with distant metastases, evaluated using the RECIST criteria.

RESULTS

Thirteen studies involving 1858 patients were included in the meta-analysis. Pooled analyses revealed significantly higher overall RRA success rate in the rhTSH group compared with the THW group, with a risk ratio (RR) of 1.12 (95% confidence interval [CI], 1.01-1.25). However, in the subgroup analysis of high-risk patients, pooled analyses showed no significant differences in RRA success rate between the rhTSH group compared with the THW group with a pooled RR of 1.05 (95% CI, 0.88-1.24). In patients with distant metastases, there were no significant differences in the disease control rate between groups, with a pooled RR of 1.06 (95% CI, 0.78-1.44).

CONCLUSIONS

rhTSH for RAI therapy is a practical option for RAI therapy in patients with intermediate- to high-risk thyroid cancer, including those with distant metastases.

Practice patterns in management of differentiated thyroid cancer since the 2014 British Thyroid Association (BTA) guidelines

BACKGROUND

The updated 2014 BTA guidelines emphasised a more conservative, risk adapted model for the management of low-risk differentiated thyroid cancer (DTC). In comparison to historical approach of total thyroidectomy combined with radioactive iodine, treatment de-escalation is increasingly supported.

AIMS

To evaluate the impact of the updated BTA guidelines on the management of DTC cases at regional UK centre.

METHODS

All DTC patients were retrospectively identified from regional thyroid MDT database between Jan2009-Dec2020. Oncological treatment and clinico-pathological characteristics were analysed.

RESULTS

623 DTC cases were identified; 312 (247 female: 65 male) between 2009 and 2014 and 311 (225 female: 86 male) between 2015 and 2020. Median age is 48 years (range 16-85). By comparing pre- and post-2015 cohorts, there was a significant drop in total thyroidectomy (87.1% vs 76.8%, p = 0.001) and the use of radioactive iodine (RAI) (73.1% vs 62.1%, p = 0.003) in our post-2015 cohort. When histological adverse features were analysed, extra-thyroidal extension (4.2% vs 17.0%, p=< 0.001), lymphovascular invasion (31.4% vs 50.5%, p=<0.001) and multi-centricity (26.9% vs 43.4%, p = 0.001) were significantly increased in the post 2015 cohort. Nonetheless, total thyroidectomy (TT) remains the treatment choice for low risk T1/2 N0 M0 disease in 65.3% (124/190) in post-2015 cohort for several reasons. Reasons include adverse histological features (50.8%), benign indications (32.5%), contralateral nodules (11.7%), patient preference (2.5%), and diagnostic uncertainty (2.5%).

CONCLUSION

Our study confirms a move towards a more conservative approach to patients with low-risk DTC in the UK, which is in keeping with the BTA 2014 guideline and international trends, but total thyroidectomy remains prevalent for low risk T1/2 N0 M0 disease for other reasons.

HIF-1α regulates the cell viability in radioiodine-resistant papillary thyroid carcinoma cells induced by hypoxia through PKM2/NF-κB signaling pathway

The curative treatment options for papillary thyroid cancer (PTC) encompass surgical intervention, radioactive iodine administration, and chemotherapy. However, the challenges of radioiodine (RAI) resistance, metastasis, and chemotherapy resistance remain inadequately addressed. The objective of this study was to investigate the protective role of hypoxia-inducible factor-1α (HIF-1α) in 131 I-resistant cells and a xenograft model under hypoxic conditions, as well as to explore potential mechanisms. The effects of HIF-1α on 131 I-resistant BCPAP and TPC-1 cells, as well as the xenograft model, were assessed in this study. Cell viability, migration, invasion, and apoptosis rates were measured using Cell Counting Kit-8, wound-healing, Transwell, and flow cytometry assays. Additionally, the expressions of Ki67, matrix metalloproteinase-9 (MMP-9), and pyruvate kinase M2 (PKM2) were examined using immunofluorescence or immunohistochemistry assays. Sodium iodide symporter and PKM2/NF-κBp65 relative protein levels were detected by western blot analysis. The findings of our study indicate that siHIF-1α effectively inhibits cell proliferation, cell migration, and invasion in 131 I-resistant cells under hypoxic conditions. Additionally, the treatment of siHIF-1α leads to alterations in the relative protein levels of Ki67, MMP-9, PKM2, and PKM2/NF-κBp65, both in vivo and in vitro. Notably, the effects of siHIF-1α are modified when DASA-58, an activator of PKM2, is administered. These results collectively demonstrate that siHIF-1α reduces cell viability in PTC cells and rat models, while also mediating the nuclear factor-κB (NF-κB)/PKM2 signaling pathway. Our findings provide a new rationale for further academic and clinical research on RAI-resistant PTC.

Outcomes of ATA Low-Risk Pediatric Thyroid Cancer Patients Not Treated With Radioactive Iodine Therapy

CONTEXT

The American Thyroid Association (ATA) Pediatric Guidelines recommend patients not receive radioactive iodine therapy (RAIT) for differentiated thyroid cancer (DTC) confined to the thyroid. Since publication, there is ongoing concern whether withholding RAIT will result in a lower rate of remission.

OBJECTIVE

This study explores whether ATA low-risk patients treated with and without RAIT achieved similar remission rates.

METHODS

Medical records of patients <19 years old diagnosed with DTC and treated with total thyroidectomy between 2010 and 2020 were reviewed. Multivariate logistic regression was performed to evaluate factors influencing RAIT administration and remission rate.

RESULTS

Ninety-five patients with ATA low-risk DTC were analyzed: 53% (50/95) and 47% (45/95) were treated with and without RAIT, respectively. RAIT was used to treat 82% of patients before 2015 compared with 33% of patients after 2015 (P < .01). No significant difference in 1-year remission rate was found between patients treated with and without RAIT, 70% (35/50) vs 69% (31/45), respectively. With longer surveillance, remission rates increased to 82% and 76% for patients treated with and without RAIT, respectively. Median follow-up was 5.8 years (IQR 4.3-7.9, range 0.9-10.9) and 3.6 years (IQR 2.7-6.6; range 0.9-9.3) for both cohorts. No risk factors for persistent or indeterminate disease status were found, including RAIT administration, N1a disease, and surgery after 2015.

CONCLUSION

Withholding RAIT for pediatric patients with ATA low-risk DTC avoids exposure to radiation and does not have a negative impact on remission rates. Dynamic risk stratification at 1-year after initial treatment is a suitable time point to assess the impact of withholding RAIT for these patients.

Radioiodine versus no radioiodine outcomes in low-risk differentiated thyroid cancers: A propensity-score matched analysis

OBJECTIVE

The 2015 American Thyroid Association guidelines recommend against radioiodine (RAI) ablation for patients with low-risk papillary microcarcinoma. However, its role in other low-risk differentiated thyroid cancer (DTC) patients remains controversial. Here, we compare long-term outcomes with RAI versus no-RAI in a large cohort comprising all low-risk DTCs.

METHODS

Patients with low-risk, histologically-proven DTC post-thyroidectomy, treated with RAI or kept on follow-up without RAI, between 1990 and 2019 were included. The main outcomes included recurrence rate and recurrence-free survival (RFS), and were validated by propensity-score matching analysis.

RESULTS

Of the 2074 low-risk DTC patients (median age: 35 years), 1686 patients underwent RAI-ablation (RAI group), while 388 patients underwent no-RAI follow-up (NOI group). Over a median follow-up of 8 years (range: 3-29), the recurrence rates were similar between the RAI and NOI groups (2.0% vs. 3.3%, p = .161). The 5- and 10-year RFS probabilities were 99.2% and 97.4%, respectively in RAI group versus 98.4% and 96.2%, respectively, in NOI group (p = .055). Subgroup regression analyses showed that patients with age <55 years (p = .044), male sex (p = .015), papillary histology (p = .043), pT3a tumours (p = .049) and postoperative thyroglobulin ≥5 ng/mL (p = .002) had significantly better RFS with RAI compared to NOI follow-up. Propensity-score matching generated 776 matched pairs with no significantly different outcomes between the two groups.

CONCLUSIONS

In low-risk DTC patients post-thyroidectomy, RAI ablation does not confer significant survival advantage over no-RAI follow-up. Further studies are required to demonstrate any long-term benefit with RAI, specifically in patients with tumour size >4 cm and elevated postoperative thyroglobulin.

Normal organ dosimetry for thyroid cancer patients treated with radioiodine as part of the multi-centre multi-national Horizon 2020 MEDIRAD project

PURPOSE

Dosimetry is rarely performed for the treatment of differentiated thyroid cancer patients with Na[131I]I (radioiodine), and information regarding absorbed doses delivered is limited. Collection of dosimetry data in a multi-centre setting requires standardised quantitative imaging and dosimetry. A multi-national, multi-centre clinical study was performed to assess absorbed doses delivered to normal organs for differentiated thyroid cancer patients treated with Na[131I]I.

METHODS

Patients were enrolled in four centres and administered fixed activities of 1.1 or 3.7 GBq of Na[131I]I using rhTSH stimulation or under thyroid hormone withdrawal according to local protocols. Patients were imaged using SPECT(/CT) at variable imaging time-points following standardised acquisition and reconstruction protocols. Whole-body retention data were collected. Dosimetry for normal organs was performed at two dosimetry centres and results collated.

RESULTS

One hundred and five patients were recruited. Median absorbed doses per unit administered activity of 0.44, 0.14, 0.05 and 0.16 mGy/MBq were determined for the salivary glands of patients treated at centre 1, 2, 3 and 4, respectively. Median whole-body absorbed doses for 1.1 and 3.7 GBq were 0.05 Gy and 0.16 Gy, respectively. Median whole-body absorbed doses per unit administered activity of 0.04, 0.05, 0.04 and 0.04 mGy/MBq were calculated for centre 1, 2, 3 and 4, respectively.

CONCLUSIONS

A wide range of normal organ doses were observed for differentiated thyroid cancer patients treated with Na[131I]I, highlighting the necessity for individualised dosimetry. The results show that data may be collated from multiple centres if minimum standards for the acquisition and dosimetry protocols can be achieved.

Controversies in the Radioiodine Treatment of Patients With Differentiated Thyroid Cancer

The use of radioiodine (I-131) in the management of patients suffering differentiated thyroid cancer (DTC) has changed little in the past 40 years. The use of a standardized approach has served the majority of patients well over that time. However, there have been recent doubts concerning this approach in some low risk patients and if so, how can these patients recognized and which patients who may need more intensive treatment. A number of clinical trials have questioned the paradigms used in the treatment of DTC including what activity of I-131 should be used for ablation and which low risk patients should be treated with I-131 especially as there remains some doubts as to the long-term safety of I-131. Should a dosimetric approach be used to optimize the use of I-131 even though at present this approach has not been shown to improve outcomes in a formal clinical trial. The era of precision oncology represents a challenge and opportunity to nuclear medicine with a move away from a regime of standard care to one of highly individualized care based on the genetic profiling of the patient and their cancer. The treatment of DTC with I-131 is about to become very interesting.

Initial results of the INSPIRE clinical trial-investigating radiation dosimetry for differentiated thyroid cancer patients

Introduction

The optimal strategy for differentiated thyroid cancer (DTC) patients treated with radioiodine (RAI) following thyroidectomy remains controversial. Multi-centre clinical studies are essential to identify strategies to improve patient outcomes while minimising treatment-induced toxicity.

Materials and Methods

The INSPIRE clinical trial (ClinicalTrials.gov Identifier: NCT04391244) aims to investigate patient-specific dosimetry for DTC patients and to determine the range of absorbed doses delivered to target and non-target tissues and their relationship with treatment outcome and toxicity.

Results

We report here initial results of the first 30 patients enrolled onto the INSPIRE trial. A large range of absorbed doses are observed for both thyroid remnants and salivary glands, with median values of 4.8 Gy (Range 0.2 - 242 Gy) and 0.3 Gy (Range 0.1 to 1.7 Gy), respectively.

Discussion

The preliminary study results are encouraging and could help to improve our understanding of absorbed doses to thyroid remnants and normal organs following RAI therapy. Such knowledge could potentially enable patient-specific treatment planning with improved clinical outcomes and quality-of-life of patients.

Post-Surgical Indications to Radioiodine Treatment and Potential Risk Factors for Post-Treatment Recurrence in Patients with Intermediate-Risk Differentiated Thyroid Carcinoma

In this multicentric retrospective observational study, we investigated the potential risk factors for radioiodine (RAI) indication and the post-treatment recurrence of intermediate-risk differentiated thyroid cancer (DTC) 1 and 3 years from diagnosis. We included 121 patients who underwent thyroidectomy for intermediate-risk DTC. The 92 patients (76.0%) who underwent RAI treatment had a higher prevalence of extra-thyroid micro-extension (mETE) (p = 0.03), pT3 staging (p = 0.03) and recourse to therapeutic central (p = 0.04) and lateral (p = 0.01) neck dissection, as well as higher numbers (p = 0.02) and greater dimensions (p = 0.01) of lymph node metastases, compared with untreated patients. Relapse was observed in 18.1% and 20.7% of cases 1 and 3 years from diagnosis, respectively, with no significant differences between groups. A lower age at diagnosis (p = 0.03) and higher levels of stimulated thyroglobulin (Tg) (p = 0.04) emerged as the only independent risk factors for tumour relapse at 1 year. Tumour relapse at 3 years was only independently predicted by the presence of tumour relapse at 1 year (p = 0.04). In conclusion, mETE, pT3 and the presence of large, multiple or clinically evident lymph node metastases represent the main indicators for referring patients to RAI treatment. Early recurrence may be considered the most relevant factor when planning further surveillance.

Conservative management of low-risk papillary thyroid carcinoma: a review of the active surveillance experience

The detection of low-risk thyroid carcinoma has increased in recent decades, although disease-specific mortality remained without changes. The high prevalence of occult carcinomas in autopsy studies, and hence the underlying indolent course of this entity, prompted the emergence of active surveillance as an alternative approach to these tumors. This strategy aims to recognize the minority group of patients who will develop clinical progression and probably benefit from deferred surgery. Experience around the world has shown that during active surveillance these tumors are mostly unchanged in size, with very-slow growth and even a decrease in diameter. Moreover, the rates of lymph node metastases were low and easily handled by rescue surgery, and distant metastases have not been reported. Given the high prevalence of small thyroid carcinomas and the excellent outcomes for observation, active surveillance provides a safe and feasible alternative in properly selected patients with low-risk thyroid cancer.

The role of BRAF V600E mutation in post-surgical 131I therapy in papillary thyroid carcinoma: a study based on SPECT-CT uptake analysis

BACKGROUND

The BRAF V600E mutation (BRAF mut) in papillary thyroid cancer (PTC) has been associated with poor response to therapy with ¹³¹I in patients with metastases but the results in postsurgical treatment are controversial. Our main objective is to investigate the impact of the mutation on the biokinetics of the administered ¹³¹I therapy after surgery.

METHODS

A prospective study was designed, from July 2015 to January 2018 which included patients with PTC receiving ¹³¹I therapy after surgical treatment. To study the biokinetics of the radioiodine in postoperative thyroid remnants, SPECT-CT images were acquired so as to obtain the following variables: percentage of remnant uptake at 2 and 7 days post-administration, effective half-life and time-integrated activity coefficient. All of them were compared depending on the mutational diagnosis and other clinical features and pathological variables.

RESULTS

Sixty-one patients, and in total 103 thyroid remnants, were included. About 59% of patients were BRAF mutated. The mutation was associated with classic variant (88.5% vs. 11.5%; P=0.0001), desmoplastic reaction (85.7% vs. 14.3%; P=0.002), smaller tumor size (1.5 vs. 2.1 cm; P=0.024), nodal disease (3.3 vs. 1; P=0.001) and advanced stages (76.9% vs. 23%; P=0.014). The BRAFmut group had a lower percentage of ¹³¹I uptake at 2 days (0.17% vs. 0.47%; P=0.001) and at 7 days (0.02% vs. 0.1%; P=0.013); and a lower time-integrated activity coefficient (0.05h vs. 0.17 h; P=0.002). In univariate analysis, in addition to the mutation, the histological variant was significant but only for time-integrated activity coefficient (P=0.04). In multivariate analysis, only mutation determined the 2-day uptake (P<0.001) and the time-integrated activity coefficient (P<0.001).

CONCLUSIONS

The BRAF V600E mutation is associated with lower ¹³¹I uptake in thyroid remnants. Furthermore, it is an independent factor that decreases the effect of post-surgical ¹³¹I therapy, and therefore, it could be used as a potential tool to optimize the treatment of PTC.

Recombinant or endogenous thyroid-stimulating hormone for radioactive iodine therapy in thyroid cancer: state of knowledge and current controversies

For patients undergoing radioiodine therapy (RIT) of differentiated thyroid carcinoma (DTC), thyroid-stimulating hormone (TSH) stimulation prior to RIT can be achieved using thyroid hormone withdrawal (THW) or administration of recombinant human TSH (rhTSH). As THW can lead to nausea, headaches, vomiting, fatigue, and dizziness secondary to transient acute hypothyroidism, rhTSH could be a good alternative. Recombinant human TSH has been administered in patients in order to stimulate TSH for RIT since 2005. According to the Martinique criteria formulated by the leading professional societies involved in care of patients with DTC, rhTSH can be applied in 3 settings: for remnant ablation, adjuvant treatment, and treatment of known disease. Numerous studies have investigated the effects of rhTSH as a method of TSH stimulation on the thyroid cell, the systemic effects, biokinetics, and clinical outcomes; however, no consensus has been reached about many aspects of its potential use. Recombinant human TSH is able to stimulate sufficient TSH levels (>30 mIU L-1) and is hypothesized to decrease risks of tumor cell proliferation. As rhTSH-use avoids the transiently impaired renal function associated with THW, radioiodine excretion is faster with the former, leading to a lower iodine-131 uptake and a difference in fractional remnant uptake, effective half-life, mean residence time, and dose to the blood. Differences between rhTSH and THW were observed in radioiodine genotoxic effects and endothelial-dependent vasodilation and inflammation. For thyroid remnant ablation, THW and rhTSH lead to similar remnant ablation rates. For adjuvant therapy and treatment of known disease, insufficient trials have been conducted and future prospective studies are recommended. The current review provides a state-of-the-science overview on the issues and debates surrounding TSH stimulation through either rhTSH adminsitration orendogenous TSH production after levothyroxin withdrawal.

Pros and cons of an aggressive initial treatment with surgery and radioiodine treatment in minimally invasive follicular thyroid carcinoma

BACKGROUND

Currently, surgery alone is the gold standard treatment for minimally invasive follicular thyroid cancer (mi-FTC).

CASE PRESENTATION

A case of a mi-FTC diagnosed in 1994 was treated with total thyroidectomy and radioiodine (RAI) ablation, according to the therapeutic algorithm used at that time. Nevertheless, he had a recurrence with distant metastasis after 24 years from the initial treatment.

CONCLUSION

Total thyroidectomy and RAI ablation might have delayed the development of distant metastasis but they were not sufficient to avoid disease recurrence. Certainly, remnant ablation simplified the follow-up and the monitoring of serum thyroglobulin allowed the early detection of the biochemical recurrence, but didn't change the outcome of the disease. Moreover, because of this early detection the patient was exposed to useless biochemical and imaging examinations. The aim of this report is to discuss the pros and cons of an aggressive treatment of a patient with mi-FTC.

The effect of thyroid hormone withdrawal performed to evaluate the success of I-131 ablation on quality of life and psychological symptoms in female patients with low-risk differentiated thyroid cancer

Aim: There is a need to evaluate the treatment response in patients who have undergone radioiodine treatment (RIT) for differentiated thyroid cancer. Diagnostic tests that are used for this purpose include radioiodine whole-body scan (WBS) and serum thyroglobulin (Tg) measurement, which are most accurate during thyroid-stimulating hormone (TSH) stimulation. However, temporary discontinuation of thyroid hormone therapy to increase TSH (withdrawal) may be associated with the morbidity of hypothyroidism. The study aimed to show the effects of thyroid hormone withdrawal (THW) on quality of life and psychological symptoms in female patients with low-risk, well-differentiated papillary thyroid cancer. Methods: We applied the short form-36 (SF-36) and Symptom Checklist-90-R (SCL-90-R) questionnaires to the patients in the euthyroid state who have referred a median of 9 months (6-13 months) after RIT to perform a dWBS and to evaluate stimulated Tg. We applied the same questionnaire again when thyroid-stimulating hormone (TSH) was > 30 μIU/mL 4 weeks after THW (hypothyroid state). Results: 52 patients were evaluated (median age 48 years, range 23-65 years). There was a statistically significant worsening in anxiety, psychosis, additional items, and general symptoms of the SCL-90-R questionnaire, physical functioning, role limitation due to physical health, energy/fatigue, emotional well-being, social function, and general health change in the SF-36 questionnaire. Conclusions: THW worsened the patients’ psychological symptoms and quality of life. To reduce the side effects of hypothyroidism, treatment response assessment with TSH stimulation should be used only in a selected group of patients with a higher risk of recurrence.

Patient Preparation and Radiation Protection Guidance for Adult Patients Undergoing Radioiodine Treatment for Thyroid Cancer in the UK

Radioactive iodine is a highly effective treatment for thyroid cancer and has now been used in clinical practice for more than 80 years. In general, the treatment is well tolerated. However, it can be logistically quite complex for patients due to the need to reduce iodine intake and achieve high levels of thyroid-stimulating hormone prior to treatment. Radiation protection precautions must also be taken to protect others from unnecessary radiation exposure following treatment. It has been well documented by thyroid cancer patient support groups that there is significant variation in practice across the UK. It is clear that some patients are being asked to observe unnecessarily burdensome restrictions that make it more difficult for them to tolerate the treatment. At the instigation of these support groups, a multidisciplinary group was assembled to examine the evidence and generate guidance on best practice for the preparation of patients for this treatment and the management of subsequent radiation protection precautions, with a focus on personalising the advice given to individual patients. The guidance includes advice about managing particularly challenging situations, for example treating patients who require haemodialysis. We have also worked together to produce a patient information leaflet covering these issues. We hope that the guidance document and patient information leaflet will assist centres in improving our patients' experience of receiving radioactive iodine. The patient information sheet is available as Supplementary Material to this article.

Effect of recombinant human thyroid stimulating hormone on long-term salivary gland dysfunction in thyroid cancer patients treated with radioactive iodine. A systematic review

Adjuvant radioactive iodine (RAI) is administered to thyroid cancer patients following thyroidectomy for remnant tissue ablation and metastatic disease management. Patients are prepared with thyroid hormone withdrawal (THW) or recombinant human thyroid stimulating hormone (rhTSH). Long-term salivary gland dysfunction (LT-SGD) is a common, dosage-dependent, RAI adverse effect. Although rhTSH preparation seems to reduce LT-SGD, this effect could be due to lower RAI activity generally used in rhTSH-prepared patients. Therefore, this meta-analysis investigated the effect of preparation type on LT-SGD development. Literature search (PubMed, Medline, EmBase, Cochrane, Web of Science, LILACS, Google Scholar) was performed four times (January-November 2022) and studies reporting LT-SGD incidence ≥1 year after RAI in patients prepared with rhTSH/THW were identified. The LT-SGD risk ratio (RR) was estimated with various models considered for sensitivity analysis (fixed-effect, random-effects, study-quality adjusted, publication-bias adjusted, individual-patient-data meta-analysis adjusted for RAI). Subgroup analysis according to RAI activity (<3.7/≥3.7 GBq) also was performed. Literature search resulted in five studies (321 rhTSH, 632 THW patients). The pooled RRs according to various models were 0.65 (95% confidence interval -95CI, 0.49-0.86; fixed-effect); 0.62 (95CI, 0.38-1.02; random-effects); 0.72 (95CI, 0.54-0.96; quality adjusted); 0.76 (95CI, 0.58-0.99; publication-bias adjusted); 0.0.80 (95CI, 0.55-1.14; individual-patient-data meta-analysis). The pooled RRs stratified for RAI activity were 0.26 (95CI, 0.05-1.30) for <3.7 GBq; 0.75 (95CI, 0.57-0.98) for ≥3.7 GBq. The number of patients needed to be prepared with rhTSH to prevent one case of LT-SGD ranged between seven and thirty-seven. There is moderate-quality scientific evidence that rhTSH preparation may consistently protect salivary gland function.

Differentiated thyroid carcinoma: An update

Differentiated thyroid carcinoma (DTC) is the most common endocrine cancer. Particularly the incidence of small clinically indolent tumors has been increasing significantly during the last decades because of increased diagnostic scrutiny, while the DTC-related mortality remained unchanged. In light of the increased awareness of the significant risk of detecting clinically indolent tumors and the potential harm and burden associated with overly diagnosis and the treatment, the approach towards management of DTC recently underwent a critical appraisal. The focus lays on reducing the unnecessary burden for patients with very low risk DTC and the correct identification of those who require treatment that is more intensive and/or follow-up. Management of DTC includes a range of different modalities, making multidisciplinary collaboration expedient. In this review, we elaborate on the recent developments in diagnosis, staging and management of DTC with specific focus on the more individualized risk assessment-based approach.

Role of 131I in low-risk differentiated thyroid cancer

Differentiated thyroid cancer (DTC) is the most frequent endocrine neoplasm, with an increase in recent decades. Papillary carcinoma is the most frequent histological subtype and a large number of cases are related to tumors of small size and with little clinical repercussion, detected incidentally or as a consequence of the availability of diagnostic techniques. The "good prognosis" of the majority of cases has maintained for years the controversy in the approach to these patients, especially in two basic aspects of the therapeutic protocol: surgery and the administration of radioiodine. While in metastatic and high-risk patients, the administration of ¹³¹I therapy is widely accepted, in intermediate-low risk patients its use is highly questioned. In this paper we review the available evidence on radioiodine therapy in low-risk patients.

Risk Reassessment of Differentiated Thyroid Cancer in Ahvaz, Iran: A Cross-sectional Retrospective Study

BACKGROUND

Accurate evaluation of response to treatment in differentiated thyroid cancer (DTC) is the sine qua non of preventing over-treatment in low-risk patients and implementing appropriate interventions in high-risk individuals.

OBJECTIVES

This study aimed to assess the response to therapy in DTC patients based on dynamic stratification method.

METHODS

In this cross-sectional study, 154 medical records of subjects with DTC (with at least 6 months after total thyroidectomy) and referred to endocrinology clinics in Ahvaz, Iran, from April 2020 to May 2021 were examined. Patients were stratified according to a dynamic risk stratification system (informed by their specific clinical, histopathological, and ultrasonography findings, and other diagnostic imagines) into four groups: Excellent response (ER), indeterminate response (IR), biochemical incomplete response (BIR), and structural incomplete response (SIR).

RESULTS

For a mean follow-up period of 28.59 months, excellent response to treatment was observed in 92 patients (59.7%), indeterminate response to treatment was found in 32 patients (20.8%), biochemical incomplete response was detected in 2 patients (1.3%), and structural incomplete response was seen in 28 patients (18.2%). In the group with low risk of recurrence, ER and IR were observed in 79.2% and 15.6% of the patients, respectively (P < 0.0001). In the group with an intermediate risk of recurrence, ER was found in 32% of the patients, while IR and SIR + BIR were seen in 34% and 34% of the patients, respectively (P < 0.0001). No cases of ER or IR were observed in the group with high risk (P = 0.001).

CONCLUSIONS

In sum, response to treatment significantly varied based on dynamic risk stratification, with ER being highest in the low-risk group, less likely in moderate risk group, and undetected in the high-risk group.

Is conservative management of the indeterminate thyroid nodule [Thy3f or Bethesda category IV] safe?

PURPOSE

The histological diagnosis after diagnostic thyroidectomy for indeterminate thyroid nodules is often non-malignant and some cancers detected are considered 'indolent'. The safety and effectiveness of conservative management in these patients are unclear. The aim of this study was to determine the safety of conservative management of indeterminate thyroid nodules and to explore association between clinical features and pathology in patients undergoing surgery.

METHODS

This is a retrospective cohort study of patients presenting to a single centre over a 4-year period (2013-2016) with thyroid nodules that were considered indeterminate (thy3f in the UK RCPath classification) on cytology. Demographic data, ultrasound features, follow-up details (in those undergoing conservative management) and histology details (in those undergoing surgery) were collected.

RESULTS

Of 164 patients that had Thy3f cytology, 34 were initially managed conservatively; however, 4 of these eventually had surgery (due to patient preference). No patient on conservative management had significant disease progression on ultrasound at a median (interquartile range) of 27 (16-40) months. Of the 134 patients that underwent surgery, 26 had thyroid malignancy. The BTA 'U' classification, gender and age (> 55) were not associated with malignancy in these nodules, but larger nodules (> 40 mm) were more likely to be malignant (p = 0.042).

CONCLUSIONS

Conservative management of indeterminate (Thy3f or Bethesda stage IV) thyroid nodules is safe in the short term and may be indicated in selected cases after appropriate discussion of risks and benefits of surgery.

Treatment strategies for low-risk papillary thyroid carcinoma: a position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM)

Increasingly sensitive diagnostic methods, better understanding of molecular pathophysiology, and well-conducted prospective studies have changed the current approach to patients with thyroid cancer, requiring the implementation of individualized management. Most patients with papillary thyroid carcinoma (PTC) are currently considered to have a low risk of mortality and disease persistence/recurrence. Consequently, current treatment recommendations for these patients include less invasive or intensive therapies. We used the most recent evidence to prepare a position statement providing guidance for decisions regarding the management of patients with low-risk PTC (LRPTC). This document summarizes the criteria defining LRPTC (including considerations regarding changes in the TNM staging system), indications and contraindications for active surveillance, and recommendations for follow-up and surgery. Active surveillance may be an appropriate initial choice in selected patients, and the criteria to recommend this approach are detailed. A section is dedicated to the current evidence regarding lobectomy versus total thyroidectomy and the potential pitfalls of each approach, considering the challenges during long-term follow-up. Indications for radioiodine (RAI) therapy are also addressed, along with the benefits and risks associated with this treatment, patient preparation, and dosage. Finally, this statement presents the best follow-up strategies for LRPTC after lobectomy and total thyroidectomy with or without RAI.

Strategies for Radioiodine Treatment: What’s New

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

Assessment of Different Radioiodine Doses for Post-ablation Therapy of Thyroid Remnants: A Systematic Review

The determination of radioiodine remnant ablation (RRA) dosage in post-operation thyroid residual tissues resection has been largely subject of discussion, yet no concise conclusion is released through systematic review studies. In this study, we conducted a systematic review of comparative experiments to evaluate and compare the efficacy of different prescribed dosages of radioiodine in post-op thyroid residual tissues resection among low, intermediate, and high-risk patients to approve the common method. Using automated searches, studies were collected from PubMed, Google Scholar, Elsevier, Scopus, and UpToDate, all until April 2021. Alongside the aforementioned sources, comparative experiments were added in for further investigation. Overall, 4000 patients with papillary thyroid cancer, differentiated thyroid carcinoma (DTC), metastasized and non-metastasized thyroid cancer took part in twenty-one trials are assessed. We discovered no significant difference in successful thyroid residual tissues excision between low-activity and high-activity radioiodine treatment in people with low and intermediate risk. In these individuals, there was no significant difference between the high therapeutic dose of 3700 MBq and the lesser dose of 1850 MBq for RRA. However, high-dose treatment usually yielded superior results. Low activity RRA causes fewer adverse effects in metastasis-free patients than high-activity 3.7 GBq. There was no significant therapeutic difference regarding treatment efficacy in patients with low and moderate risks. However, in patients with high-risk status, applying a high-dose regimen of RRA produced a significantly better response.

Thyroidectomy without Radioiodine in Patients with Low-Risk Thyroid Cancer

BACKGROUND

In patients with low-risk differentiated thyroid cancer undergoing thyroidectomy, the postoperative administration of radioiodine (iodine-131) is controversial in the absence of demonstrated benefits.

METHODS

In this prospective, randomized, phase 3 trial, we assigned patients with low-risk differentiated thyroid cancer who were undergoing thyroidectomy to receive ablation with postoperative administration of radioiodine (1.1 GBq) after injections of recombinant human thyrotropin (radioiodine group) or to receive no postoperative radioiodine (no-radioiodine group). The primary objective was to assess whether no radioiodine therapy was noninferior to radioiodine therapy with respect to the absence of a composite end point that included functional, structural, and biologic abnormalities at 3 years. Noninferiority was defined as a between-group difference of less than 5 percentage points in the percentage of patients who did not have events that included the presence of abnormal foci of radioiodine uptake on whole-body scanning that required subsequent treatment (in the radioiodine group only), abnormal findings on neck ultrasonography, or elevated levels of thyroglobulin or thyroglobulin antibodies. Secondary end points included prognostic factors for events and molecular characterization.

RESULTS

Among 730 patients who could be evaluated 3 years after randomization, the percentage of patients without an event was 95.6% (95% confidence interval [CI], 93.0 to 97.5) in the no-radioiodine group and 95.9% (95% CI, 93.3 to 97.7) in the radioiodine group, a difference of -0.3 percentage points (two-sided 90% CI, -2.7 to 2.2), a result that met the noninferiority criteria. Events consisted of structural or functional abnormalities in 8 patients and biologic abnormalities in 23 patients with 25 events. Events were more frequent in patients with a postoperative serum thyroglobulin level of more than 1 ng per milliliter during thyroid hormone treatment. Molecular alterations were similar in patients with or without an event. No treatment-related adverse events were reported.

CONCLUSIONS

In patients with low-risk thyroid cancer undergoing thyroidectomy, a follow-up strategy that did not involve the use of radioiodine was noninferior to an ablation strategy with radioiodine regarding the occurrence of functional, structural, and biologic events at 3 years. (Funded by the French National Cancer Institute; ESTIMABL2 ClinicalTrials.gov number, NCT01837745.).

Can ultrasensitive thyroglobulin immunoassays avoid the need for ultrasound in thyroid cancer follow-up?

PURPOSE

Differentiated thyroid cancer (DTC) is the most common endocrine neoplasm, with a rising incidence and a long life expectancy. It has recently been suggested that patients with low- and intermediate-risk DTC with a good response to treatment at one year could be followed up using only highly sensitive immunoassays for thyroglobulin (Tg). The aim of this study was to examine the serum Tg levels in a series of DTC patients with histologically proven persistent or recurrent diseases.

METHODS

The study involved 50 consecutive patients being routinely followed up at our center, whose clinical, histological, and biochemical data were retrospectively collected.

RESULTS

The false-negative rate of ultrasensitive serum Tg assay was 14.3% (5/35) overall, and limited to anti-thyroglobulin autoantibodies (TgAb)-negative patients. Among them, only one patient had an excellent response to treatment at one-year follow-up and was diagnosed with a 4 mm recurrence, after more than seven years of periodic ultrasounds. The size of the neck lesion documented in the histological report was slightly larger in patients with detectable as opposed to negative Tg values (P < 0.05).

CONCLUSIONS

Serum highly sensitive Tg is undetectable in a proportion of patients with a proven persistent or recurrent DTC. The reasons behind this phenomenon are still unknown. However, in low/intermediate-risk patients cured at one-year follow-up, highly sensitive Tg without neck US seems an appropriate strategy for patients' management.

Initial Evaluation of Therapy Response after Adjuvant Radioiodine Therapy in Patients with Early-Stage Papillary Thyroid Cancer-Does Time Matter?

BACKGROUND

The aim was to assess ablation success after initial radioiodine (RAI) therapy in early-stage PTC patients and compare outcomes of first diagnostic control after 6 and 9 months (6m/9m-DC) to examine whether time could possibly avoid unnecessary overtreatment.

METHODS

There were 353 patients who were matched regarding age, sex, and tumor stage and divided in two groups depending on time of first DC (6m- and 9m-DC). Therapy response was defined as thyroglobulin level <0.5 ng/mL, no pathological uptake in the diagnostic I-131 whole-body scintigraphy (WBS), and no further RAI therapy courses. The 6m-DC group was further divided into endogenously and exogenously stimulated TSH before RAI therapy and compared regarding outcome.

RESULTS

No significant differences were found between 6m-DC vs. 9m-DC regarding I-131 uptake in WBS (p = n.s.), Tg levels (p = n.s.), re-therapy rates (p = n.s.), and responder rates (p = n.s.). Significantly less relevant pathological I-131 uptake was found in WBS (p = 0.006) in endogenously compared to exogenously stimulated 6m-DC patients, resulting in lower re-therapy (p = 0.028) and higher responder rates (p = 0.001).

CONCLUSION

DC at 6 months after RAI therapy and stimulation with recombinant human thyroid-stimulating hormone (rhTSH) represent the most balanced solution. Particularly regarding quality of life and mental relief of patients, early DC with rhTSH represents sufficient and convenient assessment of ablation success.

Radiotheranostics - Precision Medicine in Nuclear Medicine and Molecular Imaging

'See what you treat and treat what you see, at a molecular level', could be the motto of theranostics. The concept implies diagnosis (imaging) and treatment of cells (usually cancer) using the same molecule, thus guaranteeing a targeted cytotoxic approach of the imaged tumor cells while sparing healthy tissues. As the brilliant late Sam Gambhir would say, the imaging agent acts like a 'molecular spy' and reveals where the tumoral cells are located and the extent of disease burden (diagnosis). For treatment, the same 'molecular spy' docks to the same tumor cells, this time delivering cytotoxic doses of radiation (treatment). This duality represents the concept of a 'theranostic pair', which follows the scope and fundamental principles of targeted precision and personalized medicine. Although the term theranostic was noted in medical literature in the early 2000s, the principle is not at all new to nuclear medicine. The first example of theranostic dates back to 1941 when Dr. Saul Hertz first applied radioiodine for radionuclide treatment of thyroid cells in patients with hyperthyroidism. Ever since, theranostics has been an integral element of nuclear medicine and molecular imaging. The more we understand tumor biology and molecular pathology of carcinogenesis, including specific mutations and receptor expression profiles, the more specific these 'molecular spies' can be developed for diagnostic molecular imaging and subsequent radionuclide targeted therapy (radiotheranostics). The appropriate selection of the diagnostic and therapeutic radionuclide for the 'theranostic pair' is critical and takes into account not only the type of cytotoxic radiation emission, but also the linear energy transfer (LET), and the physical half-lives. Advances in radiochemistry and radiopharmacy with new radiolabeling techniques and chelators are revolutionizing the field. The landscape of cytotoxic systemic radionuclide treatments has dramatically expanded through the past decades thanks to all these advancements. This article discusses present and promising future theranostic applications for various types of diseases such as thyroid disorders, neuroendocrine tumors (NET), pediatric malignancies, and prostate cancer (PC), and provides an outlook for future perspectives.

Radioactive Iodine for Papillary Thyroid Carcinoma

Radioactive iodine is given after total thyroidectomy for remnant ablation or treatment of residual/metastatic disease. The decision and dose of radioactive iodine should be in a personalized and patient-specific approach, taking account the clinical-pathological features, risk stratification, patient's preference, and facilities of the institutions. We review the principles and use of radioactive iodine in differentiated thyroid cancer.

Long noncoding RNA SNHG6 promotes papillary thyroid cancer cells proliferation via regulating miR-186/CDK6 axis

Background

Papillary thyroid cancer (PTC) is a common endocrine malignancy, and its incidence rate has been increasing in recent years. Long noncoding RNAs (lncRNAs) participate in cell biological processes through a variety of regulatory ways, and play an essential role in tumor development.

Methods

This study explored the expression of lncRNA small nucleolar RNA host gene 6 (SNHG6) in PTC by bioinformatics analysis, and quantitative real-time PCR (qRT-PCR). Cell counting kit-8 (CCK-8) assay, colony formation assay, and 5-ethynyl-2'-deoxyuridine (EdU) assay were used to study the effect of SNHG6 on the proliferation of PTC cells. Luciferase reporter gene assay and western blot were used to study the mechanism.

Results

SNHG6 was highly expressed in PTC tissue samples and cell lines. In vitro, overexpression of SNHG6 promoted the proliferation of PTC cells, while silencing SNHG6 inhibited the proliferation of PTC cells. miR-186 is the downstream target of SNHG6. SNHG6 regulates the proliferation of PTC cells through miR-186. In addition, CDK6 is the target gene of miR-186, which can inhibit the expression of CDK6 protein. SNHG6 can promote the expression of CDK6 by regulating miR-186.

Conclusions

SNHG6 is highly expressed in PTC and can promote the proliferation of PTC cells by regulating the miR-186/CDK6 axis, which is expected to become a potential therapeutic target for PTC.

Dynamic risk allows us to adequately select patients with differentiated thyroid cancer who do not require radioiodine treatment

OBJECTIVE

The treatment of patients with differentiated thyroid cancer (DTC) was modified in the last decade towards a more individualized approach according to the risk of recurrence (RR). We compared the outcomes of patients with low and intermediate RR (LRR and IRR) who received or did not receive radioiodine remnant ablation (RRA) after assessing the dynamic risk.

METHODS

We included 307 DTC patients with LRR and IRR submitted to total thyroidectomy. All patients were reclassified according to the dynamic risk stratification (low or high). Patients with high dynamic risk received RRA (141 patients).

RESULTS

LRR patients who received RRA presented a frequency of structural incomplete response (SIR) of 5% at the end of the follow-up, compared to 2% in those who did not receive it (p=0.353). IRR patients treated with RRA had a frequency of SIR of 22%, compared to 5% in patients without RRA (p=0.008).

CONCLUSION

This study demonstrates the usefulness of dynamic risk assessment to decide RRA in a cohort with a long-term follow-up. The lower prevalence of SIR at the end of the follow-up in patients who did not receive RRA highlights the adequate selection of those who would not benefit from RRA, even with an intermediate risk of recurrence.