Serum Thyroglobulin Measurement Following Surgery Without Radioactive Iodine for Differentiated Thyroid Cancer: A Systematic Review

Radioactive Iodine in Differentiated Thyroid Cancer: Effect on Detection of Distant Metastases Comparing 4 Guidelines

Context

Guidelines vary in their recommendations for postoperative radioactive iodine (RAI) in differentiated thyroid cancer (DTC). Omitting RAI reduces overtreatment but poses the possibility of missing distant metastases.

Objective

This study compares 4 guidelines on RAI indications and potentially missed metastases.

Methods

DTC patients were included retrospectively, including 48 patients with distant metastases after first RAI cycle, and 469 without distant metastases. The percentage of distant metastases missed was calculated if RAI had been omitted following the 2015 American Thyroid Association (ATA), 2019 European Society for Medical Oncology (ESMO), 2022 European Thyroid Association (ETA), and 2022 American Society of Nuclear Medicine and Molecular Imaging/European Association of Nuclear Medicine (SNMMI/EANM) guidelines.

Results

In patients without RAI indication, 1.3% to 1.6% of distant metastases may initially be missed with the ATA, ESMO, and ETA guidelines. All these cases had postoperative thyroglobulin (Tg) between 1 and 10 ng/mL or positive Tg antibodies (Tg-abs). In patients for whom RAI should be considered following the ATA, ESMO, and ETA guidelines, 2.6% to 4.0% of distant metastases may initially be missed, with all but 1 case having Tg greater than 10 ng/mL or positive Tg-abs. With the SNMMI/EANM guideline, no distant metastases would be missed, but it resulted in markedly higher RAI use in low-risk patients (82% vs 0%).

Conclusion

Omitting postoperative RAI in low- and intermediate-risk patients, as recommended by the 2015 ATA, 2019 ESMO, and 2022 ETA guidelines, may lead to a small number of initially undetected distant metastases. However, these metastases could potentially be detected later due to the presence of biochemical disease. In contrast, the broader RAI indications endorsed by SNMMI/EANM reduce the likelihood of missed metastases, but substantially increases RAI use, exposing patients to unnecessary treatment and side effects.

Data-driven Thyroglobulin Cutoffs for Low- and Intermediate-risk Thyroid Cancer Follow-up: ITCO Real-world Analysis

CONTEXT

The utility of thyroglobulin (Tg) in the follow-up of patients with differentiated thyroid cancer has been well-documented. Although third-generation immunoassays have improved accuracy, limitations persist (interfering anti-Tg antibodies and measurement variability). Evolving treatment strategies require a reevaluation of Tg thresholds for optimal patient management.

OBJECTIVE

To assess the performance of serum Tg testing in 2 populations: patients receiving total thyroidectomy and radioiodine remnant ablation (RRA) or treated with thyroidectomy alone.

DESIGN

Prospective observational study.

SETTING

Centers contributing to the Italian Thyroid Cancer Observatory database.

PATIENTS

We included 540 patients with 5 years of follow-up and negative anti-Tg antibodies.

INTERVENTIONS

Serum Tg levels assessed at 1-year follow-up visit.

MAIN OUTCOME MEASURE

Detection of structural disease within 5 years of follow-up.

RESULTS

After excluding 26 patients with structural disease detected at any time point, the median Tg did not differ between patients treated with or without radioiodine. Data-driven Tg thresholds were established based on the 97th percentile of Tg levels in disease-free individuals: 1.97 ng/mL for patients undergoing thyroidectomy alone (lower than proposed by the Memorial Sloan Kettering Cancer Center protocol and ESMO Guidelines, yet demonstrating good predictive ability, with a negative predictive value of 98% and 0.84 ng/mL for patients receiving postsurgical RRA. High sensitivity and negative predictive value supported the potential of these thresholds in excluding structural disease.

CONCLUSION

This real-world study provides evidence for the continued reliability of 1-year serum Tg levels. The data-driven Tg thresholds proposed offer valuable insights for clinical decision-making in patients undergoing total thyroidectomy with or without RRA.

Circulating Tfh cells and Tfr cells in papillary thyroid carcinoma and their diagnostic potential

OBJECTIVE

This study aim to explore the alterations of circulating T follicular helper (Tfh) and T follicular regulatory (Tfr) cells in the peripheral blood of patients with papillary thyroid carcinoma (PTC), assess their association with PTC and the influence on B cells, and evaluate their diagnostic potential.

METHODS

Peripheral blood samples were collected from 76 newly diagnosed PTC patients and 21 matched healthy controls between June 2023 and June 2024. Flow cytometry was used to determine the proportions of circulating Tfh and Tfr cells. The relationships between these cell populations and variables such as sex, age, and disease stage were analyzed. The diagnostic performance of circulating Tfh and Tfr cells, individually and in combination, was assessed using receiver operating characteristic (ROC) curves.

RESULTS

Compared to healthy controls, PTC patients exhibited an increased proportion of circulating Tfh cells and a decrease proportion of Tfr cells. While the increase in Tfh cells was not subtype-specific, the proportions of Th1-like and Th17-like Tfr subtypes were significantly altered in the PTC group. The proportion of Tfr cells remained unaffected by sex or age, whereas the increase in Tfh cells was more pronounced in male and elderly patients. Although no significant differences were observed across disease stages, changes in Tfh and Tfr cell proportions correlated with B cell subtypes and certain thyroid-related indicators. ROC plots showed circulating Tfr cells had higher sensitivity and specificity for distinguishing PTC compared to Tfh cells or their combination.

CONCLUSION

PTC patients showed changed circulating Tfh cells and Tfr cells, presenting diagnostic potential.

Pediatric Papillary Thyroid Carcinoma: Outcomes After Surgery Without Adjuvant Radioactive Iodine

CONTEXT

Pediatric papillary thyroid carcinoma (PTC) is usually treated with total thyroidectomy followed by radioactive iodine (RAI). Recently, RAI has been used more selectively based on surgical pathology and postoperative dynamic risk stratification (DRS).

OBJECTIVE

To describe patients with pediatric PTC not initially treated with RAI and their disease outcomes.

METHODS

This was an ambispective study at a tertiary cancer center of patients < 19 years diagnosed from January 1, 1990, to December 31, 2021, with stage 1 PTC who intentionally were not treated with RAI within a year of diagnosis. We assessed clinical characteristics, management, and disease outcomes using DRS.

RESULTS

Of 490 PTC patients, we identified 93 eligible patients (median age at diagnosis 16 years; 87% female), including 46 (49%) with cervical lymph node metastases. Initial management included total thyroidectomy ± neck dissection (n = 69, 75%), lobectomy ± neck dissection (n = 20, 21%), or a Sistrunk procedure for ectopic PTC (n = 4, 4%). After a median follow-up of 5.5 years (range 1-26), most patients (85/93; 91%) remained disease-free with no further therapy. Persistent (n = 5) or recurrent (n = 3) disease was found in 9% of the entire cohort. Four patients ultimately received RAI, of which only 1 clearly benefitted, and additional surgery was performed or planned in 4 patients, 2 of whom had an excellent response at last follow-up.

CONCLUSION

Selected pediatric PTC patients, even those with lymph node metastases, may not require therapeutic 131I and can avoid the unnecessary risks of RAI while still benefitting from the excellent long-term outcomes that are well described for this disease.

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.

Predictive Factors of Athyroglobulinemia After Total Thyroidectomy for Papillary Thyroid Cancer

Background: Thyroglobulin (Tg) is the specific tumor marker for epithelial thyroid cancer. It holds significant value in the postoperative period, and somehow, the goal of surgery in papillary thyroid cancer (PTC) undergoing total thyroidectomy is to achieve undetectable levels of postoperative thyroglobulin (uTg). Methods: This is a retrospective single-center study in which first basal Tg values were evaluated post-surgery in PTC patients undergoing total thyroidectomy. Patients with elevated antithyroglobulin antibodies were excluded. The impact of various demographic, clinical, therapeutic, tumor-stage related, and histopathological variables on the achievement of undetectable thyroglobulin levels (uTg, <1 ng/mL) was studied. A descriptive and logistic regression-based bivariate and multivariate analysis was planned using STATA vs. 16.1. program. The significance level was stated at 0.05. Results: Basal athyroglobulinemia was obtained in 89.6% of 202 patients operated on between January 2015 and June 2023 in a single referral institution. Due to the limited number of cases with detectable Tg, multivariate analysis could not be performed. The main factors that favored its achievement on bivariate analysis were a smaller tumor size (p = 0.003), no need for extended resections due to local invasion beyond the thyroid gland (p = 0.003) or neck dissection (p = 0.039), absence of distant metastases (p = 0.000), and a lower MACIS score (p < 0.000). Conclusions: The achievement of uTg was closely related to factors related to tumor stage (tumor diameter, lymph node spread, and metastatic disease), and it was not influenced by differences in epidemiological data, clinic manifestations, preoperative diagnosis, multifocality, or the presence of aggressive cytological variants.

Thyroid-stimulating hormone suppression in low-risk papillary thyroid cancer: a large-scale retrospective analysis of real-world data

Background

Over 500,000 new cases are diagnosed with papillary thyroid cancer (PTC) globally per year, of whom the vast majority are in the low-risk stratification. Although thyroid-stimulating hormone (TSH) suppression is traditionally recommended for all postoperative PTCs in current guidelines, its necessity remains highly controversial in low-risk patients. Since relevant recommendations in current guidelines are still empirical, we aim to provide a direct, large-scale, real-world evidence.

Methods

This large-scale real-world retrospective study included 11,140 low-risk PTC patients from two Chinese large-volume centers (Fudan University Shanghai Cancer Center [FUSCC] and Cancer Hospital of Chinese Academy of Medical Sciences [CH-CAMS]) treated from January 1, 2000 to June 30, 2022. The mean TSH level was calculated based on postoperative serum TSH values during follow-up. The primary outcome was the association between postoperative TSH level and structural recurrence assessed by Kaplan-Meier, log-rank, multivariate Cox regression analyses and equivalence testing by Two One-Sided Tests (TOST) procedure. Propensity score matching (PSM) was used to adjust for confounders among groups.

Findings

A total of 11,140 patients with low-risk PTC were included with a median follow-up of 70 months. Based on the mean TSH level, we classified these patients into ≤0.5 (n = 1,504, 13.5%), (0.5-1] (n = 4,336, 38.9%), (1-2] (n = 4,285, 38.5%), (2-3] (n = 704, 6.3%) and >3 (n = 311, 2.8%) mU/L groups. After PSM adjusting for age, sex, T and N stage, 8991 patients were included in further analysis, for whom the log-rank analyses showed no significant differences between any two groups (all P > 0.05) in recurrence-free survival (RFS), locoregional recurrence-free survival (LRRFS) and distant metastasis-free survival (DMFS), and suppressed TSH was not associated with tumor recurrence in the multivariate Cox analysis (TSH > 2 group vs TSH ≤ 2 group: HR = 1.30, 95% CI = 0.85-2.01, P = 0.23). Furthermore, the TOST equivalence tests showed that tumor recurrence status of any two TSH groups were statistically comparable (all Bonferroni-corrected P values < 0.005). Subgroup multivariate analyses showed that TSH level did not impact tumor recurrence regardless of age, tumor size, lymph node metastasis, multifocality, surgical extent, biochemical evidence.

Interpretation

Our results suggested that postoperative TSH level was not associated with tumor recurrence in patients with low-risk PTC, for whom deliberate TSH suppression may be exempted to avoid potential secondary complications. Maintaining a TSH level within the normal range may be safe for these patients.

Funding

The study was supported by the National Natural Science Foundation of China (82072951 to Y.W.; 82373008 to X.S.), Shanghai Hospital Development Center (SHDC2020CR6003-001 to Y.W., SHDC2024CRI087 to Y.-J.W.), the Science and Technology Commission of Shanghai Municipality (22Y21900100/23DZ2305600 to Y.W.; 23ZR1412000 to X.S.), the Shanghai Anticancer Association Foundation (SACA-AX202213 to Yu Wang), Shanghai Municipal Health Commission and Shanghai Medicine and Health Development Foundation (WJWRC202302 to X.S.).

Redo Thyroidectomy: Updated Insights

The risk of post-operatory hypothyroidism and hypocalcaemia, along with recurrent laryngeal nerve injury, is lower following a less-than-total thyroidectomy; however, a previously unsuspected carcinoma or a disease progression might be detected after initial surgery, hence indicating re-intervention as mandatory (so-called "redo" surgery) with completion. This decision takes into consideration a multidisciplinary approach, but the surgical technique and the actual approach is entirely based on the skills and availability of the surgical team according to the standard protocols regarding a personalised decision. We aimed to introduce a review of the most recently published data, with respect to redo thyroid surgery. For the basis of the discussion, a novel vignette on point was introduced. This was a narrative review. We searched English-language papers according to the key search terms in different combinations such as "redo" and "thyroid", alternatively "thyroidectomy" and "thyroid surgery", across the PubMed database. Inclusion criteria were original articles. The timeframe of publication was between 1 January 2020 and 20 July 2024. Exclusion criteria were non-English papers, reviews, non-human studies, case reports or case series, exclusive data on parathyroid surgery, and cell line experiments. We identified ten studies across the five-year most recent window of PubMed searches that showed a heterogeneous spectrum of complications and applications of different surgeries with respect to redo interventions during thyroid removal (e.g., recurrent laryngeal nerve monitoring during surgery, other types of incision than cervicotomy, the use of parathyroid fluorescence, bleeding risk, etc.). Most studies addressing novel surgical perspectives focused on robotic-assisted re-intervention, and an expansion of this kind of studies is expected. Further studies and multifactorial models of assessment and risk prediction are necessary to decide, assess, and recommend redo interventions and the most adequate surgical techniques.

Decision Variables for the Use of Radioactive Iodine in Patients with Thyroid Cancer at Intermediate Risk of Recurrence

The use of radioactive iodine (RAI) after total thyroidectomy for patients at the American Thyroid Association (ATA) who are at intermediate risk of recurrence is controversial. This is due to the lack of prospective randomized trials proving a benefit to recurrence or survival of RAI therapy in this group. In the absence of such evidence, clinicians struggle to recommend for or against this therapeutic approach which frequently results in overtreatment. This review describes key elements in the decision-making process that help clinicians more comprehensively evaluate the need for RAI therapy in patients with thyroid cancer at intermediate risk of recurrence. A clear definition of the purpose of RAI therapy should be conveyed to patients. In this sense, adjuvant RAI therapy intends to decrease recurrence, and ablation therapy is used to facilitate surveillance. Better stratification of the intermediate risk category into a low-intermediate subgroup and an intermediate-high-risk subgroup results in less heterogeneity and a more precise prediction of recurrence risk. The evaluation of post-operative thyroglobulin levels may prevent the overtreatment of low-intermediate-risk patients when their thyroglobulin level is <2.5 ng/mL. the integration of tumor genomics (when available) alongside pathologic features can enhance the ability of the clinician to predict iodine concentration in thyroid cancer cells. Finally, a detailed consideration of the adverse effects of RAI, patients' comorbidities, and patient preferences will result in a patient-centered personalized approach. Systematic examination of these variables will ultimately provide a framework for making more educated decisions on the use of RAI in patients at intermediate risk of recurrence that will prevent overtreatment and minimize harm.

Is Stimulated Thyroglobulin Before Radioiodine Therapy a Useful Tool in Predicting Response to Initial Therapy in Patients with Differentiated Thyroid Carcinoma?

Thyroglobulin (Tg) is an important tool to evaluate the persistence and recurrence risk in differentiated thyroid cancer (DTC). We aimed to evaluate the correlation between pre-radioiodine therapy stimulated Tg (pre-RAI Tg) levels and the first response to treatment evaluation, and to establish a cut-off pre-RAI Tg threshold for predicting an initial excellent response. Retrospective cohort study of DTC patients who underwent total thyroidectomy and radioiodine therapy. Response to therapy was evaluated 6 to 24 months after initial therapy, and patients were classified as: excellent response (ER); indeterminate response (IndR) and incomplete response (IncR). Total patients: 166 among which 85.5% female with mean age of 47.6 ± 13 years. The ER had a significantly lower pre-RAI Tg in comparison to IndR (p<0.001) and IncR (p<0.001), and pre-RAI Tg were different between the IndR and IncR (p=0.02). A cut-off pre-RAI Tg value at 7.55ng/ml was obtained by receiver operating characteristics curve for differentiating ER from IndR and IncR. The area under curve was 0.832 (95% CI 0.76-0.91). In multivariate analysis, ATA low-risk (RR 1.61, 95% CI 1.06-2.43, p=0.025) and Tg below 7.55ng/ml (RR 2.17, 95% CI 1.52-3.10, p<0.001) were associated with ER. After a median of 7.4-year follow-up, 124 (74.7%) patients were allocated into ER, 22 (13.2%) into IndR, and 20 (12%) into IncR. In conclusion, pre-RAI Tg predicts first evaluation of treatment response. Pre-RAI Tg cut-off was a key predictor of initial excellent response to therapy and may be an important tool in the follow-up of DTC patients.

Surgical management of papillary thyroid carcinoma coexisting with Hashimoto's disease: a single-center retrospective cohort study

Background

The mechanism and impact of Hashimoto's disease (HT) in patients with papillary thyroid carcinoma (PTC) remains a subject of ongoing debate. The optimal extent of thyroid resection is also controversial in cases of low-risk PTC.

Objective

To investigate the clinical outcomes and prognoses associated with different extents of surgical resection in patients diagnosed with PTC coexisting with HT.

Methods

We retrospectively analyzed data on the clinical features and treatment outcomes of patients with PTC concomitant with HT who underwent lobectomy with isthmusectomy and those who underwent total thyroidectomy at Peking University International Hospital between December 2014 and August 2023.

Results

Twenty-one patients in group A underwent lobectomy with isthmusectomy and prophylactic central neck dissection, whereas twenty patients in group B underwent total thyroidectomy with prophylactic central lymph node (LN) dissection, except one who did not undergo LN dissection. Group A demonstrated shorter surgery time (105.75 min ± 29.35 vs. 158.81 min ± 42.01, p = 0.000), higher parathyroid hormone (PTH) levels on postoperative day 1 [26.96 pg/ml (20.25, 35.45) vs. 9.01 pg/ml (2.48, 10.93), p = 0.000] and a shorter postoperative hospital stay [2.95 d (2.0, 4.0) vs. 4.02 d (3.0, 5.0), p = 0.008] than those of group B, with statistically significant differences. Both groups exhibited similar recovery patterns in terms of PTH [32.10 pg/ml (22.05, 46.50) vs. 20.47 pg/ml (9.43, 34.03), p = 0.192] and serum calcium (2.37 mmol/L ± 0.06 vs. 2.29 mmol/L ± 0.19, p = 0.409) after 1 montsh following the surgery. According to the Kaplan-Meier curves, no significant difference in the 5-year disease-free survival rates were observed between patients in group A (100%) and group B (97.1%) (Log rank test: p = 0.420, Breslow test: p = 0.420).

Conclusion

Lobectomy with isthmusectomy and prophylactic central neck dissection is a safe and feasible treatment option for patients with low-risk PTC coexisting with HT.

Clinical trial registration

http://www.chictr.org.cn, identifier ChiCTR2300079115.

Current Advances in Radioactive Iodine-Refractory Differentiated Thyroid Cancer

BACKGROUND

Differentiated thyroid cancer (DTC) patients have an outstanding overall long-term survival rate, and certain subsets of DTC patients have a very high likelihood of disease recurrence. Radioactive iodine (RAI) therapy is a cornerstone in DTC management, but cancer cells can eventually develop resistance to RAI. Radioactive iodine-refractory DTC (RAIR-DTC) is a condition defined by ATA 2015 guidelines when DTC cannot concentrate RAI ab initio or loses RAI uptake ability after the initial therapy. The RAIR condition implies that RAI cannot reveal new met-astatic foci, so RAIR-DTC metabolic imaging needs new tracers. 18F-FDG PET/CT has been widely used and has demonstrated prognostic value, but 18F-FDG DTC avidity may remain low. Fibroblast activation protein inhibitors (FA-Pi)s, prostatic-specific membrane antigen (PSMA), and somatostatin receptor (SSTR) tracers have been proposed as theragnostic agents in experimental settings and Arg-Gly-Asp (RGD) peptides in the diagnostic trial field. Multi-targeted tyrosine kinase inhibitors are relatively new drugs approved in RAIR-DTC therapy. Despite the promising targeted setting, they relate to frequent adverse-event onset. Sorafenib and trametinib have been included in re-differentiation protocols aimed at re-inducing RAI accumulation in DTC cells. Results appear promising, but not excellent.

CONCLUSIONS

RAIR-DTC remains a challenging nosological entity. There are still controversies on RAIR-DTC definition and post-RAI therapy evaluation, with post-therapy whole-body scan (PT-WBS) the only validated criterion of response. The recent introduction of multiple diagnostic and therapeutic agents obliges physicians to pursue a multidisciplinary approach aiming to correct drug introduction and timing choice.

Stimulated thyroglobulin and diagnostic 131-iodine whole-body scan as a predictor of distant metastasis and association with response to treatment in pediatric thyroid cancer patients

INTRODUCTION

Differentiated thyroid carcinoma (DTC) is a rare oncological disease in the pediatric population, presenting with a more aggressive form. Stimulated thyroglobulin (sTg) and the 131-iodine whole-body scans (WBSs) are known adult markers related to the presence of distant metastasis. Little is known about their roles in the pediatric population.

PURPOSE

To evaluate sTg levels and diagnostic WBS (DxWBS) as predictors of distant metastasis after thyroidectomy and to correlate with the response to treatment at the end of follow-up in pediatric DTC.

MATERIALS AND METHODS

Patients under 19 years old diagnosed with DTC from 1980 to 2022 were retrospectively evaluated. sTg values and WBS were assessed after thyroidectomy and prior radioiodine treatment (RIT) and correlated with the possibility of finding distant metastasis and response to treatment at the end of follow-up.

RESULTS

In a total of 142 patients with a median age of 14.6 (4-18) years who were followed for 9.5 ± 7.2 years and classified according to the ATA risk of recurrence as low (28%), intermediate (16%), and high risk (56%), 127 patients had their sTg evaluated. A sTg value of 21.7 ng/dl yielded a sensitivity of 88% compared to 30% for DxWBS in predicting distant metastasis. Specificity was 60% and 100% respectively. 42% of patients obtained discordant results between DxWBS and RxWBS. In high-risk patients, sTg levels were particularly able to differentiate those who would have distant metastasis with better diagnostic accuracy than the WBSs.

CONCLUSIONS

The sTg level had better performance in detecting distant metastases in pediatric DTC than the DxWBS. DxWBS's low performance suggests that caution should be taken in interpreting their findings in terms of the underdiagnosis for metastatic disease, especially when the sTg level already suggests distant disease.

EndoBridge 2023: highlights and pearls

EndoBridge 2023 took place on October 20-22, 2023, in Antalya, Turkey. Accredited by the European Council, the 3-day scientific program of the 11th Annual Meeting of EndoBridge included state-of-the-art lectures and interactive small group discussion sessions incorporating interesting and challenging clinical cases led by globally recognized leaders in the field and was well attended by a highly diverse audience. Following its established format over the years, the program provided a comprehensive update across all aspects of endocrinology and metabolism, including topics in pituitary, thyroid, bone, and adrenal disorders, neuroendocrine tumors, diabetes mellitus, obesity, nutrition, and lipid disorders. As usual, the meeting was held in English with simultaneous translation into Russian, Arabic, and Turkish. The abstracts of clinical cases presented by the delegates during oral and poster sessions have been published in JCEM Case Reports. Herein, we provide a paper on highlights and pearls of the meeting sessions covering a wide range of subjects, from thyroid nodule stratification to secondary osteoporosis and from glycemic challenges in post-bariatric surgery to male hypogonadism. This report emphasizes the latest developments in the field, along with clinical approaches to common endocrine issues. The 12th annual meeting of EndoBridge will be held on October 17-20, 2024 in Antalya, Turkey.

Dynamic risk assessment in patients with differentiated thyroid cancer

The current approach for patients with differentiated thyroid carcinoma should be individualized according to the risk of recurrence, and this stratification could be used to identify the risk of persistent/recurrent disease in three scenarios: preoperatively, immediately postoperatively, and during long-term follow-up. The initial risk of recurrence will tailor the management of the patient in the preoperative and immediate postoperative settings, while the dynamic risk, which considers the responses to treatment, could guide the decision-making process for remnant ablation and long-term management.This review provides a summary of the existing information regarding the dynamic risk of recurrence and recommended management for patients with differentiated thyroid cancer. The application of this approach is essential to avoid unnecessary treatments for most patients who will have a favorable prognosis. On the other hand, it allows specific therapeutic interventions for those patients at high risk of recurrence. In the future, analysis of tumor biology and prospective studies will surely improve the accuracy of recurrence risk prediction.

One-year Thyroglobulin Levels as a Predictive Measure for Recurrence and Need for Continued Surveillance in Treated Differentiated Thyroid Cancer

PURPOSE

Patients with differentiated thyroid cancer (DTC) undergo posttreatment surveillance for several years. We aim to better define an excellent response to therapy using thyroglobulin (TG) and thyroglobulin antibody (TGab) levels at 1-year to tailor appropriate length of surveillance.

METHODS

Patients with DTC who underwent surgical treatment with or without adjuvant radioiodine therapy were followed with standard American Thyroid Association surveillance. TG and TGab levels at 1-year posttreatment were used to define 3 cohorts: undetectable TG (<0.5 ng/mL), detectable TG (≥0.5 ng/mL), and positive TGab (>1 IU/mL). The rates of structural recurrence and the trends of TG and TGab were compared.

RESULTS

Of the 268 study patients at 1-year, 210 (78%) had undetectable TG, 29 (11%) had detectable TG, and 29 (11%) had positive TGab. The overall structural recurrence rate was 18/268 (7%): undetectable TG at 1 year, 3/210 (1%), detectable TG at 1-year, 11/29 (38%), and positive TGab at 1-year, 4/29 (13%). At the last follow-up, 196/210 (93%) patients with undetectable TG at 1-year continued to have undetectable TG levels. Regarding patients with detectable TG at 1-year, in 11/29 (38%), detectable TG was converted to undetectable TG at the last follow-up without additional treatments. Of those with positive TGab at 1 year, 6/29 (21%) had resolution of TGab and undetectable TG levels at the last follow-up without additional treatments.

CONCLUSION

One year after treatment of DTC, TG levels <0.5 ng/mL, in the absence of TGab, are associated with an exceedingly low risk of recurrence suggesting that further surveillance may not be warranted.

Meta-analysis of the effect and clinical significance of Delphian lymph node metastasis in papillary thyroid cancer

Objective

To investigate the effect and clinical significance of Delphian lymph nodes (DLN) on the factors influencing papillary thyroid cancer (PTC) to provide individualized guidance for the surgical treatment of thyroid cancer.

Methods

Relevant studies from PubMed, Web of Science, the Cochrane Library, Embase, and China National Knowledge Infrastructure databases were searched until February 13, 2023. Stringent selection parameters were used to obtain included data and homogeneous articles. Analyses were performed using Revman 5.4 and SPSS software. A P-value of < 0.05 was considered statistically significant.

Results

Five studies were finally included in this study. The results revealed a higher risk of DLN metastasis (DLNM) in patients with tumor size >1cm, multifocality, and extrathyroidal extension (ETE) of the thyroid. The risk of central lymph node metastasis (CLNM) was 11.25 times higher in DLN-positive patients with PTC than in DLN-negative (OR = 11.25, 95% CI: 8.64-14.64, P < 0.05) patients. The risk of LLNM was 5.57 times higher in DLN-positive patients with PTC than in DLN-negative (OR = 5.57, 95% CI: 4.57-6.78, P < 0.001) patients. The risk of postoperative recurrence in DLN-positive patients with PTC was 3.49 times higher (OR = 3.49, 95% CI: 1.91-6.38, P < 0.001) than in DLN-negative patients with PTC.

Conclusion

Patients with tumor size >1 cm in diameter, multifocality, and ETE have an increased risk for DLN development. DLN-positive patients with central and lateral cervical lymph node metastasis and postoperative recurrence are at higher risk than DLN-negative patients.

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.

Is Multifocality a Predictor of Poor Outcome in Childhood and Adolescent Papillary Thyroid Carcinoma?

CONTEXT

Total thyroidectomy in pediatric papillary thyroid carcinoma (PTC) is recommended in national guidelines because of the high incidence of multifocal disease (MFD).

OBJECTIVE

To determine the incidence of MFD in childhood and adolescent vs adult PTC and whether MFD is a predictor for poorer outcomes in childhood and adolescent PTC.

METHODS

We conducted an institutional review board-approved review of patients with PTC undergoing surgery (1986-2021) at Memorial Sloan Kettering Cancer Center. Clinical and pathological characteristics in patients with unifocal disease (UFD) and MFD were compared using Pearson's χ2 test. Survival outcomes were analyzed using the Kaplan-Meier method and log-rank test. Multivariate analysis assessed the impact of MFD on outcome.

RESULTS

MFD was less common in childhood and adolescent patients with PTC (45%; 127/283) than in adults (54%; 3023/5564; P = .002). Childhood and adolescent patients with UFD and MFD had similar tumor stage and PTC subtype at presentation, with no significant difference in histopathologic features. Median follow-up was 68 months. There was no significant difference in 5-year recurrence-free probability and overall survival was 100% in both groups. There was no significant difference in 5-year contralateral lobe PTC-free probability between patients with UFD and MFD treated with lobectomy. Multivariate analysis showed MFD was not a predictor for recurrence.

CONCLUSION

MFD was less common in childhood and adolescent patients with PTC than adults and was not a predictor of poor outcome on multivariate analysis, with excellent long-term outcomes in all patients with PTC. MFD does not appear to warrant completion thyroidectomy in childhood and adolescent patients selected for lobectomy.

Thyroglobulin and thyroglobulin antibody: an updated clinical and laboratory expert consensus

OBJECTIVE

Thyroglobulin measurement is the cornerstone of modern management of differentiated thyroid cancer, with clinical decisions on treatment and follow-up based on the results of such measurements. However, numerous factors need to be considered regarding measurement with and interpretation of thyroglobulin assay results.

DESIGN

The present document provides an integrated update to the 2013 and 2014 separate clinical position papers of our group on these issues.

METHODS

Issues concerning analytical and clinical aspects of highly-sensitive thyroglobulin measurement will be reviewed and discussed based on an extensive analysis of the available literature.

RESULTS

Thyroglobulin measurement remains a highly complex process with many pitfalls and major sources of interference, especially anti-thyroglobulin antibodies, need to be assessed, considered and, when necessary, dealt with appropriately.

CONCLUSIONS

Our expert consensus group formulated 53 practical, graded recommendations for guidance on highly-sensitive thyroglobulin and TgAb in laboratory and clinical practice, especially valuable where current guidelines do not offer sufficient guidance.

Thyroglobulin Cutoff Values for Detecting Excellent Response to Therapy in Patients With Differentiated Thyroid Cancer

Context

Serum thyroglobulin (Tg) is a biochemical marker for detecting persistent or recurrent differentiated thyroid carcinoma (DTC) post-thyroidectomy. Tg can indicate DTC before structural disease (SD) is visible with imaging procedures.

Objective

This work aimed to evaluate the clinical performance of the Elecsys® Tg II assay at a Tg cutoff of 0.2 ng/mL for ruling out SD in adults with DTC after total/near-total thyroidectomy, with or without radioiodine ablation (RAI).

Methods

Patients were enrolled into 2 cohorts: longitudinal (Tg assessed every 6 months over 2 years under thyroid-stimulating hormone [TSH] suppression therapy following thyroidectomy with or without RAI) and cross-sectional with confirmed SD (Tg assessed once >12 weeks after thyroidectomy). Analyses were performed for both cohorts combined and in the longitudinal cohort.

Results

The study included 530 clinically evaluable samples, the majority (n = 424 samples) from patients who had not received RAI treatment. Following correction for SD prevalence (4.97% in the longitudinal cohort), an Elecsys Tg II cutoff of 0.2 ng/mL ruled out SD with a negative predictive value of 99.9% (95% CI, 99.5%-100%). The assay had excellent sensitivity (98.5%-100%) and acceptable specificity (53.4%-53.5%) for detecting SD (Tg ≥ 0.2 ng/mL) for both cohorts combined and in the longitudinal cohort, with similar findings in RAI-treated and non-RAI-treated subgroups.

Conclusion

In this cohort of DTC patients post-thyroidectomy, a Tg cutoff of 0.2 ng/mL was highly effective for ruling out the presence of SD under TSH-suppressed conditions, including in patients who had not received RAI treatment.

Is radioiodine ablation with 1.1 GBq (30 mCi) 131I necessary in low-risk thyroid cancer patients? Results from a long-term follow-up prospective study

BACKGROUND

In patients with low-risk differentiated thyroid cancer (DTC), remnant ablation with radioiodine (RA) after total thyroidectomy (TT) is controversial. No benefits have been demonstrated in terms of mortality or disease-free survival. Recent evidence found that RA did not improve mid-term outcomes.

PURPOSE

To evaluate initial response to treatment and long-term follow-up status in low-risk DTC patients after TT vs. TT + RA with 131I 1.11 GBq (30 mCi).

METHODS

Prospective multicenter non-randomized study; 174 low-risk DTC that underwent TT were recruited an divided in two groups according to RA (87 ablated and 87 non-ablated). Response to treatment was evaluated at 6-18 months after thyroidectomy and at the end of follow-up with measurements of thyroglobulin, and anti-thyroglobulin antibodies levels, and neck ultrasonography.

RESULTS

Baseline characteristics of both groups were similar. Ablated patients: median age 45.5 years, 84% females, 95.4% papillary thyroid carcinoma (PTC), mean tumor size 16 mm; non-ablated: median age 45 years, 88.5% females, 96.6% PTC, mean tumor size 14 mm. Response to initial treatment was similar between both groups, with < 2% of structural incomplete response. Final status was evaluated in 139 cases (median follow-up of 60 months). Among ablated patients, 82.8% had no evidence of disease (NED), 12% had an indeterminate response (IR) and 5% a biochemical incomplete response (BIR). Non-ablated patients had NED in 90%, IR in 8.7% and BIR in 1.2%. No statistical difference was found between groups (p = 0.29). No patient had evidence of structural disease at the end of follow-up.

CONCLUSIONS

Our findings support the recommendation against routine RA in low-risk DTC patients.

Persistent or recurrent disease in thyroid cancer survivors who have elevated serum anti-thyroglobulin antibodies

OBJECTIVE

Detection of residual differentiated thyroid cancer is important but difficult. A variety of imaging modalities and biochemical markers have been used with moderately good success. We hypothesized that elevated perioperative serum anti-thyroglobulin antibodies (TgAb) would also be a predictive marker for persistent or recurrent thyroid cancer.

METHODS

We performed a retrospective analysis of 277 differentiated thyroid cancer survivors divided into two groups: those with low or normal serum TgAb (TgAb-) and those with elevated serum TgAb (TgAb+). All patients were seen at one major academic medical center. Patients were followed for a median of 7.54 years.

RESULTS

Patients in the TgAb+ group were more likely to have positive lymph nodes at initial surgery, to be assigned to a higher AJCC Stage, and to have significantly higher incidence of persistent/recurrent disease. The higher incidence of persistent/recurrent cancer was significant under univariable and multivariable (including TgAb status, age, and sex) Cox proportional hazards model analysis.

CONCLUSION

We conclude that individuals with elevated serum TgAb at the outset should be followed with a higher index of suspicion for persistent/recurrent thyroid cancer.

Current Controversies in Low-Risk Differentiated Thyroid Cancer: Reducing Overtreatment in an Era of Overdiagnosis

CONTEXT

Low-risk differentiated thyroid cancer (DTC) is overdiagnosed, but true incidence has increased as well. Owing to its excellent prognosis with low morbidity and mortality, balancing treatment risks with risks of disease progression can be challenging, leading to several areas of controversy.

EVIDENCE ACQUISITION

This mini-review is an overview of controversies and difficult decisions around the management of all stages of low-risk DTC, from diagnosis through treatment and follow-up. In particular, overdiagnosis, active surveillance vs surgery, extent of surgery, radioactive iodine (RAI) treatment, thyrotropin suppression, and postoperative surveillance are discussed.

EVIDENCE SYNTHESIS

Recommendations regarding the diagnosis of DTC, the extent of treatment for low-risk DTC patients, and the intensity of posttreatment follow-up have all changed substantially in the past decade. While overdiagnosis remains a problem, there has been a true increase in incidence as well. Treatment options range from active surveillance of small tumors to total thyroidectomy followed by RAI in select cases. Recommendations for long-term surveillance frequency and duration are similarly broad.

CONCLUSION

Clinicians and patients must approach each case in a personalized and nuanced fashion to select the appropriate extent of treatment on an individual basis. In areas of evidential equipoise, data regarding patient-centered outcomes may help guide decision-making.

[Hemithyroidectomy or total thyroidectomy for low-risk papillary thyroid cancer? : Surgical criteria for primary and secondary choice of treatment in an interdisciplinary treatment concept]

The increase in small intrathyroid papillary thyroid cancer (PTC) observed worldwide over the past two decades, with no increase in cancer-specific mortality, has challenged the previous concept of total thyroidectomy as a one-size-fits-all panacea. After exclusion of papillary microcarcinomas, a systematic review of 20 clinical studies published since 2002, which compared hemithyroidectomy (HT) to total thyroidectomy (TT), found comparable long-term oncological outcomes for low-risk papillary thyroid cancer (LRPTC) 1-4 cm in diameter, whereas postoperative complication rates were markedly lower for HT. To refine individual treatment plans, HT should be combined with ipsilateral central lymph node dissection and intraoperative frozen section analysis for staging. Based on recent evidence from studies and in consideration of individual risk factors, patients with LRPTC can be offered the concept of HT as an alternative to the standard TT. A prerequisite for the treatment selection and decision is a comprehensive patient clarification of the possible advantages and disadvantages of both approaches.