MANAGEMENT OF DIFFERENTIATED THYROID CANCER: THE STANDARD OF CARE

Nanobody-Based PET Imaging of CD47 Expression in Thyroid Carcinoma

Thyroid cancer is the most common malignant tumor in the endocrine system. A significant correlation has been established between elevated CD47 expression and the progression of thyroid carcinoma. This study aims to evaluate the diagnostic potential of immuno-positron emission tomography (immunoPET) utilizing CD47-targeting nanobodies in thyroid cancer tumor models. Immunohistochemistry (IHC) was employed to evaluate CD47 expression in patients with thyroid cancer, as well as in anaplastic thyroid carcinoma (ATC) xenograft tumor (OCUT-2C) and differentiated thyroid cancer (DTC) xenograft tumors (TPC-1 and BCPAP). Two nanobodies, C2 and its albumin-binding derivative (ABDC2), specifically targeting CD47 were labeled with 68Ga. The tracers were evaluated using immunoPET imaging in models of thyroid cancer. IHC revealed that CD47 was highly expressed in 34.69% of the tumor tissues from patients with thyroid cancer. Additionally, high levels of CD47 expression were observed in OCUT-2C, TPC-1, and BCPAP tumor tissues. Micro-PET imaging using [68Ga]Ga-NOTA-C2 and [68Ga]Ga-NOTA-ABDC2 demonstrated clear visualization of OCUT-2C tumors. Notably, the tumor uptake of [68Ga]Ga-NOTA-ABDC2 was significantly higher than that of [68Ga]Ga-NOTA-C2 at each imaging time point. Additionally, [68Ga]Ga-NOTA-ABDC2 exhibited specific uptake in the TPC-1 and BCPAP models. This study confirmed that [68Ga]Ga-NOTA-ABDC2 as a innovative PET imaging radiotracer targeting CD47 presented specific and higher tumor uptake to accurately identify CD47 expression and diagnose thyroid cancer. The clinical application of these imaging strategies may aid in selecting patients for CD47-targeted therapies and evaluating their subsequent responses.

PET imaging of differentiated thyroid cancer with thyrotropin-alfa

Thyrotropin-alfa is an FDA approved recombinant human TSH agonist. This study represents a preclinical evaluation of thyrotropin-alfa as a thyroid-stimulating hormone receptor (TSHR)-targeted PET radiopharmaceutical, [89Zr]Zr-thyrotropin-alfa. [89Zr]Zr-thyrotropin-alfa was synthesized by conjugating p-SCN-Bn-deferoxamine (DFO) to thyrotropin-alfa in a molar ratio of 3:1 (DFO:thyrotropin-alfa) and radiolabeling with 89Zr (t1/2 = 78.4 h, β+ = 22.7%) at a molar activity of 25.9 MBq/nmol. [89Zr]Zr-thyrotropin-alfa uptake was assessed in THJ529T and FTC133 cells stably transduced with the TSHR and compared to their low-expressing wild-type. Studies included a combination of in vitro cell uptake, in vivo PET imaging, and ex vivo biodistribution on Days 1-3 post-injection in male and female mice. In vitro uptake was significantly higher (P < 0.0001) in TSHR + THJ529T (6.6 ± 1.3% bound/mg) and FTC133 (3.5 ± 0.5% bound/mg) cells over low-expressing wild-type counterparts (2.9 ± 1.3% bound/mg and 2.0 ± 0.4% bound/mg, respectively). Blocking uptake with excess DFO-thyrotropin-alfa showed specificity for TSHR (P < 0.0001). In vivo PET imaging showed the highest uptake in TSHR + xenografts on Day 1 post-injection. Ex vivo biodistribution demonstrated significantly higher uptake in the TSHR + female FTC133 xenograft model (P < 0.0001) and TSHR + male FTC133 xenograft model (P < 0.0001) compared to TSHR- xenografts. Uptake of [89Zr]Zr-thyrotropin-alfa supports continued preclinical optimization and potential studies in clinical trials.

External validation of a predictive model for post-treatment persistent disease by 131I whole-body scintigraphy in patients with differentiated thyroid cancer

PURPOSE

We performed an external validation of a predictive model for persistent/metastatic disease in patients with differentiated thyroid cancer (DTC) at post-treatment 131I whole-body scintigraphy (WBS).

METHODS

Our study population included 836 patients (median age 44 years, 78% women) with DTC referred from 1994 to 2021 at our center. Age, sex, histology, T stage, N stage, American Thyroid Association risk classes, thyroid-stimulating hormone, radioactive iodine (RAI) activity, and thyroglobulin (Tg) levels were considered potential predictors of post-treatment WBS results. For the external validation, N stage and Tg levels were put into the decision tree (DT) model using its same Tg cut-off values.

RESULTS

Ninety-nine patients (12%) had positive post-treatment WBS. The area under receiver operating characteristic (ROC) curve for predicting WBS findings through the external validation was 0.60 (95% confidence interval, CI, 0.56-0.64), and positive and negative predictive values were 58% (95% CI, 41-74%) and 90% (95% CI, 88-92%). We also developed an internal model including the independent predictors of WBS findings (i.e., Tg levels, T stage, N stage, and RAI activity). For this model the area under ROC curve was 0.75 (95% CI, 0.69-0.81), and positive and negative predictive values were 90% (95% CI, 68-99% and 88-92%).

CONCLUSIONS

The external validation of the proposed DT model has a limited value for predicting post-treatment 131I-WBS findings in our patients. The internal model including also T stage and RAI activity demonstrates higher predictive value.

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.

Is second 131I treatment necessary for differentiated thyroid cancer patients and who could not benefit from it? A real-world retrospective study in China

BACKGROUND

The efficacy of a second radioactive iodine-131 (131I) treatment in patients with differentiated thyroid cancer (DTC) who did not achieve an excellent response (ER) following initial 131I therapy remains controversy and the population that would derive limited benefit from it is currently unclear.

OBJECTIVES

The aim of this retrospective study was to assess the efficacy of the second 131I treatment in DTC patients with non-ER after the initial 131I therapy, and to identify potential risk factors associated with non-benefit of the second 131I treatment.

METHODS

127 DTC patients who underwent two 131I treatments following thyroidectomy were included in this study, and the therapeutic response was evaluated after each 131I treatment. Beneficial treatment was defined as an improvement in therapy response grade (e.g. from indeterminate response to ER) after the second 131I treatment, while unbeneficial treatment was defined as no change or a downgrade in therapy response grade. The potential risk factors associated with the non-benefit of the second 131I treatment were identified using univariate and multivariate logistic regression models.

RESULTS

Following the second 131I treatment, therapy responses of 55.12% (70/127) of patients were reclassified to a better grade indicating treatment benefit, while 44.88% (57/127) showed no change or were reclassified to a worse grade suggesting no benefit from treatment. The non-benefit of the second 131I treatment was significantly associated with potential risk factors including stimulated thyroglobulin (sTg) level ≥ 11.46 ng/mL before the second 131I treatment, primary tumor size > 2 cm, status T2 or higher, N1b status and ATA high risk.

CONCLUSIONS

The study results demonstrated that more than half of DTC patients could potentially benefit from a second 131I therapy. However, over 40% of patients exhibited no benefit in response to the second 131I treatment, suggesting potential overtreatment for this subgroup. Therefore, clinicians should exercise meticulous and precise decision-making based on identified risk factors when considering the necessity of a second 131I treatment.

PET/CT imaging of differentiated and medullary thyroid carcinoma using the novel SSTR-targeting peptide [18F]SiTATE - first clinical experiences

PURPOSE

The novel 18F-labeled somatostatin receptor (SSTR)-directed radiotracer [18F]SiTATE demonstrated promising results for the imaging of various SSTR-expressing tumor types. Although thyroid carcinomas (TC) express SSTR, data on [18F]SiTATE PET/CT imaging in TC are lacking. This study explores the use of [18F]SiTATE PET/CT in a patient cohort with histologically proven TC.

METHODS

As part of a prospective observational study at a single tertiary cancer center, 21 patients with TC (10 medullary (MTC) and 11 differentiated (DTC)) who underwent at least one [18F]SiTATE PET/CT were included (37 scans in total). Mean SUVmax and SUVmean of tumoral lesions, mean total-tumor-volume (TTV), and whole-body (WB)-SUVmax and WB-SUVmean on PET with their standard deviations (SDs) were determined. PET parameters were correlated to clinical parameters including tumor marker levels (thyroglobulin for DTC, calcitonin for MTC).

RESULTS

89 lesions were included in the analysis. Metastases were localized in the bone, lymph nodes, lung, soft tissue, and thyroid bed. Osseous (31 lesions; SUVmax 8.6 ± 8.0; SUVmean 5.8 ± 5.4) and nodal (37 lesions; SUVmax 8.7 ± 7.8; SUVmean 5.7 ± 5.4) metastases showed the highest uptake. The MTC disease burden on PET significantly correlated with the calcitonin tumor marker level (e.g., TTV: r = 0.771, r2 = 0.594, p = 0.002). For DTC, no such correlation was present.

CONCLUSION

Our data demonstrate high feasibility of [18F]SiTATE PET/CT in a small cohort of patients with MTC and DTC. The use of [18F]SiTATE may overcome logistical disadvantages of 68Ga-based tracers and facilitate SSTR-targeted PET/CT imaging of thyroid carcinoma.

Influence of Tumor Laterality and Focality on Clinical Implications and Tumor Advancement in Well-Differentiated Thyroid Cancer

BACKGROUND

The accurate preoperative diagnosis of TC plays a very important role in the selection of an appropriate treatment strategy. In addition to the hypoechogenicity of thyroid lesions on ultrasound and the presence of microcalcifications or high cell atypia on FNAB, highlighting the features of laterality and focality and ascertaining their influence (alone or combined) on TC staging and appropriate treatment are crucial.

MATERIALS AND METHODS

A retrospective analysis of the clinical data of 697 patients admitted to the study center between 2008 and 2023 was conducted. Preoperative data (age, sex, type of surgery, ultrasound, and FNAB data) and postoperative histopathological data indicating TC advancement (pTNM, extrathyroidal extension, vascular invasion) were collected and analyzed. Patients presenting well-differentiated TCs (papillary TC and follicular TC) were isolated for better clinical evaluation. Finally, patients were divided into four groups according to their laterality and focality features, and the influences of combinations of these features on TC advancement were analyzed.

RESULTS

The largest group included patients with unilateral and solitary TC (n = 461). This group had the lowest rate of negative prognostic features: extrathyroidal extension, lymph node invasion, distant metastases, and vascular invasion (25.81%, 19.96%, 3.69%, and 26.46%, respectively). In contrast, the group with bilateral and multifocal TC (n = 40) presented the highest percentages of the mentioned features (82.50%, 82.50%, 7.50%, and 77.50%, respectively). All the results were statistically significant (p < 0.0001).

CONCLUSIONS

Laterality and focality features may be important parameters in the management of TC and should be accurately determined. These features should be combined and a more aggressive treatment method should be selected to reduce the reoperation rate.

A homogeneous electrochemiluminescence immunoassay platform based on carbon quantum dots and magnetic beads enrichment for detection of thyroglobulin in serum

Considering the high probability of recurrence or metastasis after thyroidectomy, it is meaningful to develop a rapid, sensitive and specific method for monitoring thyrophyma-related biomarkers. In this study, a homogeneous electrochemiluminescence immunoassay (HO-ECLIA) coupled with magnetic beads (MBs)-based enrichment tactic was established for the determination of thyrophyma-related thyroglobulin (Tg). Importantly, owing to the abundant surface groups and good biocompatibility of carbon quantum dots (CQDs), the incorporation of CQDs onto the Tg antigen surface was achieved, resulting in the formation of Tg-encapsulated CQDs (CQDs-Tg), which served not only as an ECL probe but as a biorecognition element. Under optimal experimental conditions, the proposed platform demonstrated a wide linear range from 0.01 to 100 ng·mL-1 with a detection limit of 6.9 pg·mL-1 (S/N = 3), and performed well in real serum sample analysis against interference. Collectively, the proposed platform exhibited the rapid response, satisfactory sensitivity and specificity toward Tg in complex serum milieu, and held a considerable potential for clinical prognosis monitoring of thyrophyma.

PET Imaging of Differentiated Thyroid Cancer with TSHR-Targeted [89Zr]Zr-TR1402

Thyroid cancer is the most common endocrine cancer, with differentiated thyroid cancers (DTCs) accounting for 95% of diagnoses. While most DTC patients are diagnosed and treated with radioiodine (RAI), up to 20% of DTC patients become RAI refractory (RAI-R). RAI-R patients have significantly reduced survival rates compared to patients who remain RAI-avid. This study explores [89Zr]Zr-TR1402 as a thyroid-stimulating hormone receptor (TSHR)-targeted PET radiopharmaceutical for DTC. [89Zr]Zr-TR1402 was synthesized with a molar activity of 25.9 MBq/nmol by conjugating recombinant human TSH (rhTSH) analogue TR1402 to chelator p-SCN-Bn-deferoxamine (DFO) in a molar ratio of 3:1 (DFO/TR1402) and radiolabeling with 89Zr (t1/2 = 78.4 h, β+ = 22.7%). As TSHR is absent in commonly available DTC-derived cell lines, TSHR was reintroduced via stable transduction by delivering a lentivirus containing the full-length coding region of the human TSHR gene. Receptor-mediated uptake of [89Zr]Zr-TR1402 was evaluated in vitro in stably transduced TSHR+ and wild-type TSHR- DTC cell lines. In vivo PET imaging was performed on Days 1-3 postinjection in male and female athymic nude mice bearing TSHR+ and TSHR- xenografts, along with ex vivo biodistribution on Day 3 postinjection. In vitro uptake of 1 nM [89Zr]Zr-TR1402 was significantly higher in TSHR+ THJ529T (P < 0.0001) and FTC133 (P < 0.01) cells than in TSHR- THJ529T and FTC133 cells. This uptake was shown to be specific in both TSHR+ THJ529T (P < 0.0001) and TSHR+ FTC133 (P < 0.0001) cells by blocking uptake with 250 nm DFO-TR1402. In vivo PET imaging showed accumulation of [89Zr]Zr-TR1402 in TSHR+ tumors, which was the highest on Day 1. In the male FTC133 xenograft model, ex vivo biodistribution confirmed a significant difference (P < 0.001) in uptake between FTC133+ (1.3 ± 0.1%ID/g) and FTC133- (0.8 ± 0.1%ID/g) tumors. A significant difference (P < 0.05) in uptake was also seen in the male THJ529T xenograft model between THJ529T+ (1.8 ± 0.6%ID/g) and THJ529T- (0.8 ± 0.4%ID/g) tumors. The in vitro and in vivo accumulation of [89Zr]Zr-TR1402 in TSHR-expressing DTC cell lines support the continued preclinical optimization of this approach.

Radioiodine Uptake at Suture Site Granuloma Mimicking Neck Node Metastasis on 131 I Whole-Body Iodine Scintigraphy

ABSTRACT

Differentiated thyroid carcinoma constitutes over 90% of all thyroid cancers. The standard treatment approach involves total or near-total thyroidectomy with or without neck dissection followed by 131 I whole-body scintigraphy (WBS) to detect local or distant metastases. Radioiodine offers high sensitivity and specificity for detection of metastatic disease in well differentiated thyroid carcinoma. However, despite its high accuracy, 131 I WBS demonstrates false-positive results, mostly at inflammatory or infective site. These false-positive radioiodine accumulation can lead to misdiagnosis and unwarranted radioiodine treatment. This case presents localization of 131 I to the suture site granuloma leading to false-positive results on 131 I WBS.

The Effect of Radioiodine Therapy on the Prognosis of Differentiated Thyroid Cancer with Lung Metastases

Lung metastasis substantially influences the survival of thyroid cancer (TC) patients. This study sought to investigate factors impacting the survival of differentiated thyroid cancer patients with lung metastases (DTC-LM) undergoing radioiodine therapy (RAI) after thyroid surgery. The retrospective study encompassed 609 TC patients with lung metastases. Survival outcomes-specifically, overall survival (OS) and thyroid cancer-specific survival (TCSS)-were examined through both univariate and multivariate Cox regression analyses. Radioiodine therapy (RAI)'s impact on DTC-LM patient survival was further assessed with the Kaplan-Meier survival curve. Of the 609 TC patients with lung metastases, 434 (71.3%) were found to have undergone thyroid surgery after a median follow-up of 59 months. Anaplastic thyroid cancer (ATC), stage IV, and lung metastases associated with other metastases were identified as risk factors for OS and TCSS in TCLM patients. RAI therapy significantly enhances survival in DTC-LM patients followed by primary site surgery under the age of 55, PTC patients, and those with single organ metastases at lung.

Effect of Thyroid-Stimulating Hormone Suppression Therapy on Cardiac Structure and Function in Patients With Differentiated Thyroid Cancer After Thyroidectomy: A Systematic Review and Meta-Analysis

OBJECTIVE

We aimed to evaluate the effects of thyroid-stimulating hormone (TSH) suppression therapy on cardiac structure and function in patients with differentiated thyroid cancer (DTC) following thyroidectomy.

METHODS

Two investigators independently searched the PubMed, Embase, Cochrane Library, and Web of Science databases for relevant studies published from inception to January 6, 2023, without any restrictions on language. Standard mean differences and 95% confidence intervals were calculated using fixed or random effects models. Thirteen clinical outcomes were analyzed, mainly evaluating cardiac morphology, systolic function, and diastolic function.

RESULTS

Thirteen studies were included in the quantitative analysis. Compared to healthy controls, left ventricular mass index, left ventricular posterior wall thickness, interventricular septal thickness, and isovolumic relaxation time values increased; the ratio of E-wave velocity to A-wave velocity and E-wave velocity values decreased. The left ventricular ejection fraction and cardiac output did not change in patients with DTC who underwent long-term TSH suppression therapy. Interventricular septal thickness values were significantly correlated with the duration of TSH suppression therapy.

CONCLUSION

Long-term TSH suppression therapy leads to cardiac hypertrophy and impaired cardiac diastolic function in patients with DTC. These changes may be related to the duration of TSH suppression therapy. Large prospective studies with long follow-up periods are needed to validate these findings.

Clinical perspectives on dosimetry in molecular radiotherapy

Molecular radiotherapy is the use of systemically administered unsealed radioactive sources to treat cancer. Theragnostics is the term used to describe paired radiopharmaceuticals localising to a specific target, one optimised for imaging, the other for therapy. For many decades, molecular radiotherapy has developed empirically. Standard administered activity schedules have been used without the prior estimation of the resulting tumour radiation absorbed dose by theragnostic imaging, or its subsequent measurement by serial scanning. This pragmatic approach has benefited many patients, however others who should have benefited have failed to do so as the radiation absorbed dose in the tumour was suboptimal. The accurate prediction and measurement of tumour and organ at risk radiation absorbed doses allows treatment to be personalised, and offers the prospect of improved clinical outcomes. To deliver this for all molecular radiotherapy patients would require not only a significant financial investment in equipment and skilled personnel, but also a change in attitude of those who believe that simple - or simplistic - schedules are easier to deliver, and that accurate dosimetry is too much trouble. Further clinical studies are required to demonstrate beyond doubt that the advantages of individualised treatment planning outweigh the inconvenience, and that the expense is justified by enhanced results.

Add-on radioiodine during long-term BRAF/MEK inhibition in patients with RAI-refractory thyroid cancers: a reasonable option?

Dual modulation of the MAPK pathway with BRAF (e.g., dabrafenib) and MEK (e.g., trametinib) inhibitors has the potential to re-establish radioiodine (RAI) sensitivity in BRAF-mutated RAI-refractory (RAI-R)-differentiated thyroid carcinoma (DTC) cells. Here we showed that (1) double BRAF/MEK inhibition may still reach a significant redifferentiation in patients with a long-history RAI-R DTC and multiple previous treatments; (2) the addition of high RAI activities may obtain a significant structural response in such patients; and (3) a divergence between increasing thyroglobulin and structural response may be a reliable biomarker or redifferentiation. Accordingly, the add-on prescription of high activities of 131I should be considered in RAI-R patients under multikinase inhibitors with stable or responding structural disease and divergent increase of Tg levels.

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.

Comparison of the different imaging modalities used to image pediatric oncology patients: A COG diagnostic imaging committee/SPR oncology committee white paper

Diagnostic imaging is essential in the diagnosis and management, including surveillance, of known or suspected cancer in children. The independent and combined roles of the various modalities, consisting of radiography, fluoroscopy, ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine (NM), are both prescribed through protocols but also function in caring for complications that may occur during or subsequent to treatment such as infection, bleeding, or organ compromise. Use of a specific imaging modality may be based on situational circumstances such as a brain CT or MR for a new onset seizure, chest CT for respiratory signs or symptoms, or US for gross hematuria. However, in many situations, there are competing choices that do not easily lend themselves to a formulaic approach as options; these situations depend on the contributions of a variety of factors based on a combination of the clinical scenario and the strengths and limitations of the imaging modalities. Therefore, an improved understanding of the potential influence of the imaging decision pathways in pediatric cancer care can come from comparison among the individual diagnostic imaging modalities. The purpose of the following material to is to provide such a comparison. To do this, pediatric imaging content experts for the individual modalities of radiography and fluoroscopy, US, CT, MRI, and NM will discuss the individual modality strengths and limitations.

Prognostic value of adjuvant external beam radiotherapy for papillary thyroid cancer based on competitive risk model and propensity score matching

This study aimed to assess the impact of adjuvant external beam radiotherapy (EBRT) on the survival of patients with locally invasive papillary thyroid carcinoma. This retrospective study used data from the Surveillance, Epidemiology, and End Results database for the diagnosis of papillary thyroid carcinoma, using Cox models to screen for adverse prognostic factors. The prognostic value of using adjuvant external beam radiotherapy in papillary thyroid carcinoma was further evaluated, based on the competing risk model and propensity score matching. Based on the competitive risk model, the sub-distribution hazard ratio (SHR) of the multivariate analysis of patients receiving EBRT alone versus those receiving radioiodine-131 alone was 9.301 (95% CI 5.99-14.44) (P < 0.001), and the SHR of the univariate analysis was 1.97 (95% CI 1.03-3.78) (P = 0.042). In the propensity score-matched Kaplan-Meier analysis, patients who received EBRT still had worse OS (6-year OS, 59.62% vs 74.6%; P < 0.001) and DSS (6-year DSS, 66.6% vs 78.2%; P < 0.001) than patients who did not receive EBRT. Patients who received EBRT had a higher cumulative risk of death due to thyroid cancer after PSM (P < 0.001). Adjuvant EBRT was not associated with survival benefit in the initial management of locally invasive papillary thyroid cancer.

Clinical characteristics of nasolacrimal duct obstruction after iodine therapy in differentiated thyroid cancer patients

OBJECTIVE

To analyze the clinical characteristics of differentiated thyroid cancer (DTC) patients with nasolacrimal duct obstruction (NLDO) after Iodine-131 (131I) therapy and provide guidance for clinical decision-making.

METHODS

Thirty-one DTC patients with NLDO were retrospectively enrolled from the Nuclear Medicine Department of Shanxi Bethune Hospital during follow-up of 131I therapy between June 2018 and March 2021. Eight hundred and seventy-one thyroid cancer patients during this period without NLDO after 131I therapy were enrolled as the control group. Clinical characteristics, including sex, age, dose, anti-thyroglobulin antibodies (TGAb), and metastatic lesions, were analyzed by χ2 test and logistic multifactor regression.

RESULTS

In the NLDO group and without NLDO group, there were statistically significant differences in gender, age, dose, and whether there was metastasis. Among the NLDO group, the proportion of women, age >55 years old, dose >5.55 GBq, and the presence of metastasis was higher, and the difference was statistically significant; There was no significant difference in the proportion of TGAb positive and negative patients based on 131I therapy (χ2 = 0.27, P = .782).Multivariate logistic regression analysis showed that sex (2.59), age (1.45), dose (2.36), and metastatic lesions (1.93) were all statistically significant influential factors of NLDO after iodine therapy. Significant differences were found in the incidence of NLDO between the number of treatment courses (χ2 = 23.541, P < .001). Prevalence rate of repeat radioiodine therapy (2 times or 3 times and more) is higher than 1 time.

CONCLUSION

Women patients over 55 who had metastatic lesions, and received a dose >5.55 GBq, were more likely to have NLDO. When determining therapeutic doses of 131I, doctors should weigh multiple factors and then give appropriate dosage and suggest that high risk populations be referred for appropriate ophthalmic surgical consultation, for timely diagnosis and therapy.

Vascularity depicted by contrast-enhanced ultrasound predicts recurrence of papillary thyroid cancer

PURPOSE

Although angiogenesis is crucial for the occurrence and development of solid tumors, the prognostic value of vascularity remains unclear in papillary thyroid cancer (PTC), due to the lack of effective techniques to evaluate vascularity. Contrast-enhanced ultrasound (CEUS) is an effective technique to evaluate vascularity. This study aimed to investigate whether vascularity depicted by CEUS was associated with structural recurrence in classic PTC.

METHODS

512 consecutive patients who underwent total thyroidectomy and central lymph node dissection for classic PTC larger than 1 cm between January 2015 and December 2018 and who were followed up for 12 months or longer were retrospectively enrolled. For this study, iso- and hyperenhancement were considered hypervascularity, whereas hypovascularity referred to hypoenhancement. Kaplan-Meier cumulative event curves for structural recurrence were compared using the log-rank test. The multivariate Cox proportional hazard regression analysis was used to estimate hazard ratios (HRs) of hypervascularity depicted by CEUS for structural recurrence.

RESULTS

61 (11.9 %) of 512 patients had structural recurrence. Hypervascular PTCs had a shorter recurrence-free survival rate than hypovascular PTCs (P < 0.001). In the multivariate analysis, hypervascularity (HR, 2.069; 95 % confidence interval [CI]: 1.087, 3.937), larger size (HR, 1.279; 95 % CI: 1.011, 1.618), multifocality (HR, 1.976; 95 % CI: 1.150, 3.396), extrathyroidal extension (HR, 2.276; 95 % CI: 1.026, 5.046), and lymph node metastasis (HR, 3.631; 95 % CI: 1.515, 8.701) were independently associated with structural recurrence.

CONCLUSION

Hypervascularity depicted by CEUS was independently associated with structural recurrence in patients with classic PTC.

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.

Differential distribution and prognostic value of CD4+ T cell subsets before and after radioactive iodine therapy in differentiated thyroid cancer with varied curative outcomes

Differentiated thyroid cancer is the most frequently diagnosed endocrine tumor. While differentiated thyroid cancers often respond to initial treatment, little is known about the differences in circulating immune cells amongst patients who respond differently. A prospective study of 39 patients with differentiated thyroid cancer was conducted. Serum thyroglobulin levels and thyroid and immunological functions were tested before and after radioactive iodine treatment (RAIT). Efficacy assessments were performed 6 to 12 months after radioactive iodine treatment. Most patients showed an excellent response to radioactive iodine treatment. Before radioactive iodine treatment, the excellent response group had considerably fewer circulating CD4⁺ T cell subsets than the non-excellent response group. Both the excellent response and non-excellent response groups had considerably lower circulating CD4⁺ T lymphocyte subsets 30 days after radioactive iodine treatment, but those of the excellent response group were still lower than those of the non-excellent response group. All circulating CD4⁺ T cell subsets in the excellent response group rose by varying degrees by the 90th day, but only Treg cell amounts increased in the non-excellent response group. Interestingly, in the non-excellent response group, we noticed a steady drop in Th1 cells. However, the bulk of circulating CD4⁺ T cell subsets between the two groups did not differ appreciably by the 90th day. Finally, we discovered that CD4⁺ T cell subsets had strong predictive potential, and we thus developed high-predictive-performance models that deliver more dependable prognostic information. In conclusion, in individuals with differentiated thyroid cancer, there is great variation in circulating immune cells, resulting in distinct treatment outcomes. Low absolute CD4⁺ T cell counts is linked to improved clinical outcomes as well as stronger adaptive and resilience capacities.

Bone metastases in newly diagnosed patients with thyroid cancer: A large population-based cohort study

Background

Population-based estimates of the incidence and prognosis of bone metastases (BM) stratified by histologic subtype at diagnosis of thyroid cancer are limited.

Methods

Using multivariable logistic and Cox regression analyses, we identified risk factors for BM and investigated the prognostic survival of BM patients between 2010 and 2015 via the Surveillance, Epidemiology, and End Results (SEER) database.

Results

Among 64,083 eligible patients, a total of 347 patients with BM at the time of diagnosis were identified, representing 0.5% of the entire cohort but 32.4% of the subset with metastases. BM incidence was highest (11.6%) in anaplastic thyroid cancer (ATC), which, nevertheless, was highest (61.5%) in follicular thyroid cancer (FTC) among the subset with metastases. The median overall survival among BM patients was 40.0 months, and 1-, 3-, and 5-year survival rates were 65.2%, 51.3%, and 38.7%, respectively. Compared with papillary thyroid cancer (PTC), FTC (aOR, 6.33; 95% CI, 4.72–8.48), medullary thyroid cancer (MTC) (aOR, 6.04, 95% CI, 4.09–8.92), and ATC (aOR, 6.21; 95% CI, 4.20–9.18) significantly increased the risk of developing BM. However, only ATC (aHR, 6.07; 95% CI, 3.83–9.60) was independently associated with worse survival in multivariable analysis. Additionally, patients with BM alone (56.5%) displayed the longest median survival (66.0 months), compared with those complicated with one extraskeletal metastatic site (lung, brain, or liver) (35.2%; 14.0 months) and two or three sites (8.3%; 6.0 months). The former 5-year overall survival rate was 52.6%, which, however, drastically declined to 23.0% in patients with one extraskeletal metastatic site and 9.1% with two or three sites.

Conclusion

Closer bone surveillance should be required for patients with FTC, MTC, and ATC, and extraskeletal metastases at initial diagnosis frequently predict a poorer prognosis.

The role of thyroglobulin doubling time in differentiated thyroid cancer: a meta-analysis

OBJECTIVE

In patients with differentiated thyroid cancer (DTC), recurrences may occur in up to 20% and may have a fatal outcome in 10% of cases. Thyroglobulin doubling time (Tg-DT) values may contribute to predict response to treatment and disease recurrence in DTC patients. This study aimed to address the following questions: (1) Are Tg-DT values indicative of response to treatments in patients with DTC (i.e. 'treatment monitoring')?; (2) Is Tg-DT predictive of 2-[18F]fluoro-2-deoxy-d-glucose (2-[18F]FDG) PET/CT in patients with DTC?; (3) Are Tg-DT values predictive of DTC prognosis (i.e. 'prediction')?

DESIGN

Systematic review and meta-analysis.

METHODS

Methodology was registered in the PROSPERO database (CRD42021257947). A systematic search was carried out in PubMed, Web Of Science, and Scopus from June to August 2021 without time and language restrictions.

RESULTS

Eleven studies were included for a total of 1421 patients. Positive association between Tg-DT < 1 year and recurrence or disease progression was observed. Tg-DT was found to be related with (2-[18F]FDG) PET/CT results in patients with DTC. The area under the curve was 0.86 (95% CI: 0.83-0.89), sensitivity was 0.84 (0.64;0.94), specificity was 0.71 (0.35; 0.92), DOR was 13.1 (3.1; 55.0), LR+ was 2.9 (1.0; 8.1), LR- was 0.22 (0.1; 0.5). For patients with Tg-DT < 1 year (n = 247), the survival risk ratio was 2.09 (95% CI: 1.49; 2.94).

CONCLUSIONS

Tg-DT values are valuable in predicting response to treatment and disease recurrence in patients with DTC, as well as their overall survival. In addition, Tg-DT significantly increases the detection rate of 2-[18F]-FDG PET/CT.

Individualized treatment of differentiated thyroid cancer: The value of surgery in combination with radioiodine imaging and therapy - A German position paper from Surgery and Nuclear Medicine

A consensus statement about indications for post-surgical radioiodine therapy (RIT) in differentiated thyroid cancer patients (DTC) was recently published by the European Thyroid Association (ETA) 1. This publication discusses indications for RIT on the basis of an individual risk assessment. Many of the conclusions of this consensus statement are well founded and accepted across the disciplines involved. However, especially from the perspective of nuclear medicine, as the discipline responsible for indicating and executing RIT, some of the recommendations may require further clarification with regard to their compatibility with established best practice and national standards of care. Assessment of the indications for RIT is strongly dependent on the weighing up of benefits and risks. On the basis of longstanding clinical experience in nuclear medicine, RIT represents a highly specific precision medicine procedure of proven efficacy with a favorable side-effect profile. This distinguishes RIT significantly from other adjuvant oncological therapies and has resulted in the establishment of this procedure as a usually well-tolerated, standard safety measure. With regard to its favorable risk/benefit ratio, this procedure should not be unnecessarily restricted, in the interest of offering reassurance to the patients. Both patients' interests and regional/national differences need to be taken into account. We would therefore like to comment on the recent consensus from the perspective of authors and to provide recommendations based on the respective published data.

Molecular Imaging and Theragnostics of Thyroid Cancers

Molecular imaging plays an important role in the evaluation and management of different thyroid cancer histotypes. The existing risk stratification models can be refined, by incorporation of tumor-specific molecular markers that have theranostic power, to optimize patient-specific (individualized) treatment decisions. Molecular imaging with varying radioisotopes of iodine (i.e., 131I, 123I, 124I) is an indispensable component of dynamic and theragnostic risk stratification of differentiated carcinoma (DTC) while [18F]F-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) helps in addressing disease aggressiveness, detects distant metastases, and risk-stratifies patients with radioiodine-refractory DTC, poorly differentiated and anaplastic thyroid cancers. For medullary thyroid cancer (MTC), a neuroendocrine tumor derived from thyroid C-cells, [18F]F-dihydroxyphenylalanine (6-[18F]FDOPA) PET/CT and/or [18F]FDG PET/CT can be used dependent on serum markers levels and kinetics. In addition to radioiodine therapy for DTC, some theragnostic approaches are promising for metastatic MTC as well. Moreover, new redifferentiation strategies are now available to restore uptake in radioiodine-refractory DTC while new theragnostic approaches showed promising preliminary results for advanced and aggressive forms of follicular-cell derived thyroid cancers (i.e., peptide receptor radiotherapy). In order to help clinicians put the role of molecular imaging into perspective, the appropriate role and emerging opportunities for molecular imaging and theragnostics in thyroid cancer are discussed in our present review.

Advances in Functional Imaging of Differentiated Thyroid Cancer

Simple Summary

Since the 1940s, radioactive iodine has been used for functional imaging and for treating patients with differentiated thyroid cancer (DTC). During this long-lasting experience, the use of iodine isotopes evolved, especially during the last years due to improved knowledge of thyroid cancer biology and improved performances of imaging tools. The present review summarizes recent advances in the field of functional imaging and theragnostic approach of DTC.

Abstract

The present review provides a description of recent advances in the field of functional imaging that takes advantage of the functional characteristics of thyroid neoplastic cells (such as radioiodine uptake and FDG uptake) and theragnostic approach of differentiated thyroid cancer (DTC). Physical and biological characteristics of available radiopharmaceuticals and their use with state-of-the-art technologies for diagnosis, treatment, and follow-up of DTC patients are depicted. Radioactive iodine is used mostly with a therapeutic intent, while PET/CT with ¹⁸F-FDG emerges as a useful tool in the diagnostic management and complements the use of radioactive iodine. Beyond ¹⁸F-FDG PET/CT, other tracers including ¹²⁴I, ¹⁸F-TFB and ⁶⁸Ga-PSMA, and new methods such as PET/MR, might offer new opportunities in selecting patients with DTC for specific imaging modalities or treatments.