Outcomes and Prognostic Factors in Radioiodine Refractory Differentiated Thyroid Carcinomas

Lactate Dehydrogenase A is Associated with Elevated FDG Metabolism, Radioiodine Non-avidity, and Poor Prognosis in Differentiated Thyroid Cancer

RATIONALE AND OBJECTIVES

The role of lactate dehydrogenase A (LDHA) expression in differentiated thyroid cancer (DTC), especially in radioiodine-refractory DTC, remains unclear. The aim of this study was to analyse the relationships and the prognostic value of LDHA, glycolysis, and radioactive iodine (RAI) avidity in DTC.

METHODS

DTC patients who underwent 18F-FDG PET/CT and subsequent total thyroidectomy or metastasectomy were enroled. The expression levels of LDHA, glucose transporters (Glut) and Ki67 proteins in tumour tissue were measured using immunohistochemistry. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) of 18F-FDG PET/CT were measured. A radioiodine whole body scan was used to determine lesion radioiodine avidity.

RESULTS

69 patients with DTC were enroled in this study, including 37 women (53.6%) and 32 men (46.4%), with a median age of 52 years (11 to 77 years). Regarding the pathological category, papillary thyroid cancer was documented in 50 patients (72.5%), while follicular and poorly differentiated thyroid cancer were found in 12 patients (17.4%) and seven patients (10.1%), respectively. Distant metastases were observed in 27 (39.1%) patients; 34 (49.3%) were classified as stage I, 16 (23.2%) as stage II, and 3 (4.3%) and 16 (23.2%) patients in stages III and IV, respectively. LDHA expression levels were correlated with Glut3 expression levels (r = 0.395, P = 0.003) and SUVmax (r = 0.408, P = 0.002). The median LDHA expression and lesion SUVmax of the RAI avidity group were lower than those of the non-RAI avidity group (200 vs. 285, P = 0.036; 3.06 vs. 8.38, P = 0.038, respectively). Elevated SUVmax (P = 0.004), MTV (P = 0.014), TLG (P = 0.001) and LDHA expression (P = 0.048) led to shorter time to progression (TTP); Cox regression analysis revealed that TLG (HR: 4.773, P = 0.047) was an independent prognostic factor of TTP.

CONCLUSION

Elevated LDHA is correlated with increased glucose metabolism, decreased radioiodine avidity, and accelerated disease progression. Moreover, 18F-FDG PET/CT acting as "in vivo pathology" is an excellent predictor of DTC prognosis.

Clinico-pathological factors associated with radioiodine refractory differentiated thyroid carcinoma status

PURPOSE

Risk factors for developing radioiodine refractory thyroid cancer (RAIR-TC) have rarely been analyzed. The purpose of the present study was to find clinical and pathological features associated with the occurrence of RAIR-disease in differentiated thyroid cancers (DTC) and to establish an effective predictive risk score.

METHODS

All cases of RAIR-DTC treated in our center from 1990 to 2020 were retrospectively reviewed. Each case was matched randomly with at least four RAI-avid DTC control patients based on histological and clinical criteria. Conditional logistic regression was used to examine the association between RAIR-disease and variables with univariate and multivariate analyses. A risk score was then developed from the multivariate conditional logistic regression model to predict the risk of refractory disease occurrence. The optimal cut-off value for predicting the occurrence of RAIR-TC was assessed by receiver operating characteristic (ROC) curves and Youden's statistic.

RESULTS

We analyzed 159 RAIR-TC cases for a total of 759 controls and found 7 independent risk factors for predicting RAIR-TC occurrence: age at diagnosis ≥ 55, vascular invasion, synchronous cervical, pulmonary and bone metastases at initial work-up, cervical and pulmonary recurrence during follow-up. The predictive score of RAIR-disease showed a high discrimination power with a cut-off value of 8.9 out of 10 providing 86% sensitivity and 92% specificity with an area under the curve (AUC) of 0.95.

CONCLUSION

Predicting the occurrence of RAIR-disease in DTC patients may allow clinicians to focus on systemic redifferentiating strategies and/or local treatments for metastatic lesions rather than pursuing with ineffective RAI-therapies.

Next-Generation-Sequencing on fine needle aspirates in neck recurrence of thyroid cancers

OBJECTIVES

Tumor molecular genotyping plays a key role in improving the management of advanced thyroid cancers. Molecular tests are classically performed on Formalin-Fixed Paraffin-Embedded (FFPE) carcinoma tissue. However alternative molecular testing strategies are needed when FFPE tumoral tissue is unavailable. The objective of our study was to retrospectively assess the performance of targeted DNA and RNA-based Next Generation Sequencing (NGS) on the fine needle aspirate from thyroid cancer cervical recurrences to determine if this strategy is efficient in clinical practice.

DESIGN/METHODS

A retrospective study of 33 patients who had had DNA and/or RNA-based NGS on ultrasound (US)-guided fine needle aspirates of cervical thyroid cancer recurrences in our Department from July 2019 to September 2022.

RESULTS

In total, 34 DNA and 32 RNA-based NGS analyses were performed. Out of the 34 DNA-based NGS performed, 27 (79%) were conclusive allowing the identification of an oncogenic driver for 18 patients (53%). The most common mutation (n = 13) was BRAF c.1799T>A. Out of the 32 RNA-based NGS performed, 26 were interpretable (81%) and no gene fusion was found. The identification of a BRAFV600E mutation was decisive for one patient in our series, who was prescribed dabrafenib and trametinib.

CONCLUSIONS

NGS performed on fine needle aspirates of neck lymph node metastases enabled the identification of an oncogenic driver alteration in 53% of the cases in our series of advanced thyroid cancer patients and could significantly alter patient management.

CTC, ctDNA, and Exosome in Thyroid Cancers: A Review

Thyroid cancer has become more common in recent years all around the world. Many issues still need to be urgently addressed in the diagnosis, treatment, and prognosis of thyroid cancer. Liquid biopsy (mainly circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and circulating exosomes) may provide a novel and ideal approach to solve these issues, allows us to assess the features of diseases more comprehensively, and has a function in a variety of malignancies. Recently, liquid biopsy has been shown to be critical in thyroid cancer diagnosis, treatment, and prognosis in numerous previous studies. In this review, by testing CTCs, ctDNA, and exosomes, we focus on the possible clinical role of liquid biopsy in thyroid cancer, including diagnostic and prognostic biomarkers and response to therapy. We briefly review how liquid biopsy components have progressed in thyroid cancer by consulting the existing public information. We also discuss the clinical potential of liquid biopsy in thyroid cancer and provide a reference for liquid biopsy research. Liquid biopsy has the potential to be a useful tool in the early detection, monitoring, or prediction of response to therapies and prognosis in thyroid cancer, with promising clinical applications.

Lenvatinib for the treatment of radioiodine-refractory differentiated thyroid cancer: treatment optimization for maximum clinical benefit

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Radioactive Iodine-Refractory Pulmonary Metastases of Papillary Thyroid Cancer in Children, Adolescents, and Young Adults

CONTEXT

Few studies have explored radioactive iodine-refractory (RAIR) disease in children, adolescents, and young adults with papillary thyroid cancer (CAYA-PTC).

OBJECTIVE

This study systematically investigated the clinicopathologic characteristics and prognosis of CAYA-PTC with RAIR disease.

METHODS

Sixty-five patients with PTC aged ≤20 years were enrolled in this study, and all patients were confirmed to have pulmonary metastases. Clinicopathologic profiles were compared between the radioactive iodine-avid (RAIA) and RAIR groups. Univariate and multivariate regression analyses were performed to identify risk factors for RAIR status and progressive disease (PD). Gene alterations were detected in 17 patients.

RESULTS

Overall, 20 patients were included in the RAIR group, accounting for 30.8% (20/65) of all patients. No significant difference in pathologic characteristics was observed between patients aged <15 years and patients aged 15-20 years, but younger patients were more likely to develop RAIR disease (hazard ratio [HR] 3.500, 95% CI 1.134-10.803, P = .023). RET fusions were the most common genetic alterations in CAYA-PTC, but an association with RAIR disease was not detected (P = .210). RAIR disease (HR 10.008, 95% CI 2.427-41.268, P = .001) was identified as an independent predictor of PD. The Kaplan-Meier curve revealed a lower progression-free survival (PFS) and disease-specific survival (DSS) rate in the RAIR group than in the RAIA group (P < .001 and P = .039). Likewise, RAIR disease was a risk factor for unfavorable PFS in patients aged <15 years (P < .001).

CONCLUSION

RAIR disease occurs in one-third of CAYA-PTC with pulmonary metastases. Younger patients (aged < 15 years) are more susceptible to RAIR status, which leads to unfavorable PFS and DSS.

Blood Profiles in the Prediction of Radioiodine Refractory Papillary Thyroid Cancer: A Case-Control Study

Purpose

Although most patients with papillary thyroid cancer can be cured by surgery and I-131 ablation, a small proportion will progress to radioactive iodine refractory (RAIR) thyroid cancer. The prediction of RAIR in its early stages can improve patient prognosis. The aim of this article is to evaluate the blood biomarkers in patients with RAIR and to establish a prediction model.

Patients and Methods

Data collected from patients with thyroid cancer that were enrolled from Jan. 2017 to Dec. 2021 were screened. RAIR was defined based on the criteria in the 2015 American Thyroid Association guidelines. The blood biomarkers from the study participants at three admissions timepoints (surgery and first and secondary I-131 ablations) were compared using both parametric and nonparametric tests to identify predictive factors for RAIR. Binary logistic regression analysis was used to construct a prediction model using parameters associated with surgical procedure decision. The model was then assessed with receiver operating characteristic curves.

Results

Thirty-six patients were included in the data analysis. Sixteen blood variables, including the low density lipoprotein-cholesterol-total cholesterol ratio, neutrophils, thyroglobulins, thyroglobulin antibody, thyroid peroxidase antibody, anion gap, etc., were revealed to be predictors for RAIR. The prediction model, which incorporated two parameters, reached an area under the curve of 0.861 (p<0.001).

Conclusion

Conventional blood biomarkers can be used in the prediction of early-stage RAIR. In addition, a prediction model incorporating multiple biomarkers can improve the predictive accuracy.

Using 18F-FDG-PET/CT Metrics to Predict Survival in Ra-Dio-Iodine Refractory Thyroid Cancers

Radio-iodine refractory (RAI-R) differentiated thyroid cancer (DTC) is a rare disease with a poor prognosis and limited therapeutic resources. Therefore, identifying prognostic factors is essential in order to select patients who could benefit from an early start of treatment. The aim of this study is to identify positron emission tomography with 18F-fluorodeoxyglucose with integrated computed tomography (18F-FDG-PET/CT) parameters to predict overall survival (OS) in patients with RAI-R DTC. In this single-center retrospective study, we analyze the 18F-FDG-PET/CT parameters of 34 patients with RAI-R DTC between April 2007 and December 2019. The parameters collected are MTV, SUVmax and progression for each site of metastasis (neck, mediastinum, lungs, liver, bone) and total sites. ROC curves, Kaplan–Meier survival analysis curves, univariate and multivariate Cox analyses determine prognostic factors for 1-year and 5-year OS. The parameters for mediastinum, liver and total sites are significantly associated with worse 1-year and 5-year OS by both ROC curve analysis and Kaplan–Meier survival analysis. Univariate Cox analysis confirms significance of mediastinum SUVmax (HR 1.08; 95% CI [1.02–1.15]; p = 0.014) and total SUVmax (HR 1.06; 95% CI [1–1.12]; p = 0.042) for worse 1-year OS; of mediastinum SUVmax (HR 1.06; 95% CI [1.02–1.10]; p = 0.003), liver SUVmax (HR 1.04; 95% CI [1.01–1.08]; p = 0.02), liver MTV (HR 2.56; 95% CI [1.13–5.82]; p = 0.025), overall SUVmax (HR 1.05; 95% CI [1.02–1.08]; p = 0.001) and total MTV (HR 1.41; 95% CI [1.07–1.86]; p = 0.016) for worse 5-year OS. Multivariate Cox analysis confirms a significant association between liver MTV (HR 1.02; 95% CI [1–1.04]; p = 0.042) and decrease 1-year OS. In this study, we demonstrate that in RAI-R DTC, 18F-FDG-PET/CT parameters of the mediastinum, liver and overall tumor burden were prognostic factors of poor 1-year and 5-year OS. Identifying these criteria could allow early therapeutic intervention in order to improve patients’ survival.

Efficacy of Combination Therapy with Lenvatinib and Radioactive Iodine in Thyroid Cancer Preclinical Model

Patients with differentiated thyroid cancer (DTC) usually have good prognosis, while those with advanced disease have poor clinical outcomes. This study aimed to investigate the antitumor effects of combination therapy with lenvatinib and ¹³¹I (CTLI) using three different types of DTC cell lines with different profiling of sodium iodide symporter (NIS) status. The radioiodine accumulation study revealed a significantly increased radioiodine uptake in K1-NIS cells after lenvatinib treatment, while there was almost no uptake in K1 and FTC-133 cells. However, lenvatinib administration before radioiodine treatment decreased radioiodine uptake of K1-NIS xenograft tumor in the in vivo imaging study. CTLI synergistically inhibited colony formation and DTC cell migration, especially in K1-NIS cells. Finally, ¹³¹I treatment followed by lenvatinib administration significantly inhibited tumor growth of the NIS-expressing thyroid cancer xenograft model. These results provide important clinical implications for the combined therapy that lenvatinib should be administered after ¹³¹I treatment to maximize the treatment efficacy. Our synergistic treatment effects by CTLI suggested its effectiveness for RAI-avid thyroid cancer, which retains NIS function. This potential combination therapy suggests a powerful and tolerable new therapeutic strategy for advanced thyroid cancer.

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.

2-[18F]FDG PET in the Management of Radioiodine Refractory Differentiated Thyroid Cancer in the Era of Thyrosin-Kinases Inhibitors: A Real-Life Retrospective Study

Purpose To evaluate the role of 2-[¹⁸F]FDGPET/CT in the follow-up of radioiodine refractory thyroid cancer (RR-TC). Methods Forty-six 2-[¹⁸F]FDGPET/CT scans from 14 RR-TC patients were considered. Thyroid function tests: thyroglobulin (Tg), levothyroxine (LT4), and tyrosine-kinases inhibitors (TKIs) assumptions were recorded. Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated from each scan and correlated with clinical parameters and the overall survival (OS). Results Baseline TLG and MTV predicted OS (p = 0.027 and p = 0.035), and negative correlation with OS was also confirmed when the same parameters were measured in follow-up scans (p = 0.015 and p = 0.021). Tg also correlated with the OS; (p = 0.014; p = 0.019 and p = 0.009). However, TLG and MTV were not significantly correlated with Tg levels. MTV and TLG variation in time were reduced during TKI therapy (p = 0.045 and p = 0.013). Conclusions 2-[¹⁸F]FDGPET/CT confirmed its prognostic role at the first assessment and during the follow-up of RR-TC patients. 2-[¹⁸F]FDGPET/CT parameters seem at least partially independent from Tg. TKI therapy resulted in a measurable effect on the variation of 2-[¹⁸F]FDGPET/CT parameters over time.

Initial or salvage treatment with apatinib shows promise against radioiodine-refractory differentiated thyroid carcinoma

OBJECTIVE

Sorafenib and lenvatinib have been recommended as standard tyrosine kinase inhibitors (TKIs) for progressive radioiodine-refractory differentiated thyroid carcinoma (RR-DTC). However, their efficacy remains limited with unresolved drug resistance. Therefore, we conceived this open-label study based on real-world evidence to investigate the efficacy and safety of apatinib in patients with progressive RR-DTC.

METHODS

Off-label use of apatinib as either initial treatment or salvage treatment for sorafenib resistance was investigated. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included objective response rate (ORR), overall survival (OS), and safety.

RESULTS

For all 28 enrolled patients, the median PFS was 15.1 months, with an ORR of 69.6%. The median OS was not reached at the data cut-off. In detail, the median PFS of 17.3 months and the ORR of 75% were determined in patients with TKI-naive RR-DTC (initial treatment group, n = 14). And, in patients with first-line sorafenib-resistant RR-DTC (salvage treatment group, n = 14), a median PFS of 12.0 months was reached, with an ORR of 45.5%. In the salvage treatment group, the median OS from the start of apatinib administration was 20.6 months, reaching 89.1 months from sorafenib treatment initiation. Adverse events at grade 3 or higher occurred in 64.3% of all subjects treated with apatinib.

CONCLUSIONS

This study demonstrated that apatinib shows promise against RR-DTC with tolerable toxicity, representing a novel initial treatment for progressive RR-DTC and effective salvage treatment for RR-DTC resistant to sorafenib.

OUP accepted manuscript

Background

Lenvatinib is a multitargeted tyrosine kinase inhibitor approved for treating patients with locally recurrent or metastatic progressive radioiodine-refractory differentiated thyroid cancer (RR-DTC). In this review, we discuss recent developments in the optimization of RR-DTC treatment with lenvatinib.

Summary

Initiation of lenvatinib treatment before a worsening of Eastern Cooperative Oncology Group performance status and elevated neutrophil-to-lymphocyte ratio could benefit patients with progressive RR-DTC. The median duration of response with lenvatinib was inversely correlated with a smaller tumor burden, and prognosis was significantly worse in patients with a high tumor burden. An 18 mg/day starting dose of lenvatinib was not noninferior to 24 mg/day and had a comparable safety profile. Timely management of adverse events is crucial, as patients with shorter dose interruptions benefitted more from lenvatinib treatment. Caution should be exercised when initiating lenvatinib in patients who have tumor infiltration into the trachea or other organs, or certain histological subtypes of DTC, as these are risk factors for fistula formation or organ perforation. The Study of (E7080) LEnvatinib in Differentiated Cancer of the Thyroid (SELECT) eligibility criteria should be considered prior to initiating lenvatinib treatment.

Conclusions

Current evidence indicates that patients benefit most from lenvatinib treatment that is initiated earlier in advanced disease when the disease burden is low. A starting dose of lenvatinib 24 mg/day, with dose modifications as required, yields better outcomes as compared to 18 mg/day. Appropriate supportive care, including timely identification of adverse events, is essential to manage toxicities associated with lenvatinib, avoid longer dose interruptions, and maximize efficacy.

The role of Tg kinetics in predicting 2-[18F]-FDG PET/CT results and overall survival in patients affected by differentiated thyroid carcinoma with detectable Tg and negative 131I-scan

PURPOSE

The aim of this study was to assess the potential role of thyroglobulin (Tg) kinetics in predicting 2-[¹⁸F]-FDG-PET/CT results and overall survival (OS) in patients affected by differentiated thyroid carcinoma (DTC) and suspected recurrence.

METHODS

On hundred and thirty-nine patients were retrospectively included. All patients underwent 2-[¹⁸F]-FDG-PET/CT due to detectable Tg levels and negative [¹³¹I] whole-body scan. The last two consecutive serum Tg measurements before PET/CT were used for Tg-doubling time (TgDT) and Tg-velocity (Tg-vel) calculation. Receiver operating characteristic (ROC) curves were used to determine the optimal cutoff points for Tg, TgDT and Tg-vel for predicting PET/CT results.

RESULTS

One hundred and fifteen (83%) patients had positive PET/CT for DTC recurrence, while the remaining 24 (17%) negative. Stimulated Tg before PET and Tg-vel were significantly higher in patients with a positive PET/CT scan than negative scan (average Tg 190 vs 14 ng/mL, p = 0.006; average Tg-vel 4.2 vs 1.7 ng/mL/y, p < 0.001). Instead, TgDT was significantly shorter in positive scan (average TgDT 1.4 vs 4.4 years, p < 0.001). ROC curve analysis revealed the best Tg, TgDT and Tg-vel cutoff of 18 ng/mL,1.36 years and 1.95 ng/mL/y. In patients with Tg<18 ng/mL, the PET/CT detection rate was significantly lower in patients with low Tg-vel (p = 0.018) and with long TgDT (p = 0.001). ATA class risk, PET/CT results and Tg before PET were confirmed to be independent prognostic variables for OS.

CONCLUSIONS

Tg kinetics may help to predict 2-[¹⁸F]-FDG-PET/CT results in DTC patients with negative [¹³¹I]WBS and detectable Tg, especially in case of low-moderate Tg.

Predictive Impact of Metastatic Lymph Node Burden on Distant Metastasis Across Papillary Thyroid Cancer Variants

Background: While numerous factors determine prognosis in papillary thyroid carcinoma (PTC), distant metastasis (M1) represents one of the most dire. Escalating nodal burden and aggressive histology may contribute to higher metastatic risk, but this relationship is poorly defined and challenging to anticipate. We evaluate the predictive impact of these histological features on predicting distant metastases at initial presentation. Methods: Univariate and multivariable logistic regression models of conventional and aggressive thyroid cancer variants (well-differentiated papillary thyroid carcinoma [WDPTC], diffuse sclerosing variant [DSV], tall cell variant [TCV], poorly differentiated thyroid cancer [PDTC], and anaplastic thyroid carcinoma [ATC]) identified via U.S. cancer registry data were constructed to determine associations between M1 status and quantitative nodal burden. Associations between metastatic lymph node (LN) number and M1 disease were modeled using univariate and multivariable logistic regression with interaction terms, as well as a linear continuous probability model. Results: Overall, M1 prevalence at disease presentation was 3.6% (n = 1717). When stratified by subtype, M1 prevalence varied significantly by histology (WDPTC [1.0%], DSV [2.3%], TCV [4.1%], PDTC [17.4%], ATC [38.4%] [p < 0.001]). For WDPTC, M1 prevalence escalated with metastatic LN number (0 LN+ [0.5%], 1-5 LN+ [2.0%], 6-10 LN+ [3.4%], >10 LN+ [5.5%] [p < 0.001]) and LN ratio (p < 0.001). A statistically significant interaction was observed between histology and increasing nodal burden for M1 risk. On multivariable analysis, each successive metastatic LN conferred increased M1 risk for WDPTC (odds ratio [OR] 1.06 [1.05-1.08], p < 0.001) and TCVs (OR 1.04 [1.02-1.07], p < 0.001). In contrast, other aggressive variants had a higher baseline M1 risk, but this did not vary based on the number of positive LN (DSV, OR 1.02 [0.95-1.10], p = 0.52; PDTC, OR 1.00 [0.98-1.02], p = 0.66; ATC, 1.00 [0.98-1.02], p = 0.97). Conclusions: Progressive nodal burden independently escalates the risk of distant metastasis in WDPTC and TCVs of PTC. Conversely, aggressive variants such as PDTC and ATC have substantial M1 risk at baseline and appear to be minimally affected by metastatic nodal burden. Consideration of these factors after surgery may help tailor clinical decision-making for treatment and surveillance. Further studies are warranted to calibrate the ideal management approach for these higher risk patient groups.

Risk Stratification Using a Novel Genetic Classifier Including PLEKHS1 Promoter Mutations for Differentiated Thyroid Cancer with Distant Metastasis

Background: Although most differentiated thyroid carcinomas (DTCs) have indolent behavior, DTCs with distant metastasis have a poor prognosis. However, there are no validated markers that predict the risk of distant metastasis and the prognosis of DTC. We aimed to develop a genetic classifier for predicting the outcomes of DTC patients with distant metastases. Methods: Targeted deep sequencing of 157 cancer-related genes was performed for 61 DTCs with distant metastases. A candidate mutation was validated with independent thyroid cancer samples using digital polymerase chain reaction. Results: The most frequently mutated gene in the 61 DTCs was BRAF (n = 31, 51%), followed by TERT promoter (n = 28, 46%), NRAS (n = 13, 11%), PLEKHS1 promoter (n = 6, 10%), and STK11 (n = 6, 10%) mutations. PLEKHS1 promoter mutations were more common in the radioactive iodine (RAI)-refractory cases (p = 0.003). Losses of 9q and 11q were associated with RAI-refractory disease (p = 0.002) and cancer-specific mortality (p = 0.028), respectively. In multivariate analysis, bone metastasis (adjusted odds ratio [aOR] = 15.17, 95% confidence interval [CI 3.38-68.06], p < 0.001) and at least one mutation in the TERT promoter, the PLEKHS1 promoter, or TP53 (aOR = 7.64 [CI 1.78-32.76], p = 0.006) remained significant factors associated with RAI-refractoriness. In independently collected papillary thyroid carcinomas without initial distant metastasis (n = 75), a PLEKHS1 promoter mutation was only found in one case that developed distant metastasis during the follow-up period. We developed a genetic classifier consisting of BRAF, RAS, the TERT promoter, the PLEKHS1 promoter, and TP53 for categorizing the prognosis of patients with DTC with distant metastasis. In the poor-prognosis group, 61% of the patients were RAI-refractory and death occurred in 21% during the follow-up. In the intermediate-prognosis group, 29% were RAI-refractory, but no death occurred. In the good-prognosis group, all patients were RAI-responsive and no death occurred. Conclusions: Mutations in the PLEKHS1 promoter are a novel genetic marker of aggressive DTC. Our genetic classifier can be useful for predicting RAI-refractory disease and poor prognosis in DTC patients with distant metastases.

Late-onset distant metastases confer poor prognosis in patients with well-differentiated thyroid cancer

Background

Distant metastases from well-differentiated thyroid carcinoma (WDTC) occasionally occur over a wide range of time intervals after primary thyroid surgery. The prognostic impact of the timing of distant metastasis onset remains unclear.

Methods

We retrospectively reviewed the clinicopathologic features and clinical outcomes of 57 patients with WDTC and distant metastases, and evaluated the mutational profiles of BRAF, RAS, and TERT promoter genes. All patients underwent thyroidectomy and radioactive iodine (RAI) ablation using the same treatment protocol. Synchronous distant metastases were defined as those detected within 12 months of the primary WDTC diagnosis. Metachronous metastases were considered early- and late-onset diseases if detected 1-5 and ≥5 years after the primary diagnosis, respectively.

Results

In all patients, the 5- and 10-year cancer-specific survival (CSS) rates after the diagnosis of distant metastasis were 86% and 57%, respectively. Late-onset (≥5 years) metachronous distant metastasis was associated with age of ≥55 years (P=0.043) and patients refractory to RAI therapy (P=0.026). TERT promoter mutations were associated with RAI refractivity (P=0.026). BRAF V600E and RAS mutations had no prognostic significance. Bone metastasis (P=0.002) and the onset time of distant metastasis (P=0.004) were associated with poor CSS. There was no significant difference in CSS between patients with synchronous distant metastases and those with early-onset (1-5 years) metachronous distant metastases. In the multivariate analysis, bone metastasis [hazard ratio (HR) =10.24; 95% confidence interval (CI): 1.25-83.74; P=0.030] and late-onset (≥5 years) metachronous distant metastasis (HR =5.20; 95% CI: 1.01-26.63; P=0.048) were independent predictors for worse CSS.

Conclusions

The prognosis of patients with WDTC was poorer for late metachronously detected metastases than for synchronous or early metachronous metastases. Patients with distant metastasis occurring 5 years later after primary thyroid diagnosis should, therefore, be more carefully treated.

Clinical, Pathological, and Molecular Characteristics Correlating to the Occurrence of Radioiodine Refractory Differentiated Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Background: Recently, radioiodine refractory differentiated thyroid cancer (RR-DTC) has received increasing attention due to its poor prognosis. The roles of clinical, pathological, and molecular features in the development of RR-DTC remain controversial and require additional investigation. This study aimed to evaluate the association between these risk factors and the occurrence of RR-DTC.

Methods: We performed a systematic search for relevant literature following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in PubMed, EMBASE, Medline, SCOPUS, and Web of Science up to the July 15, 2020. Observational studies that investigated the risk factors for RR-DTC were included. Fixed- or random-effects models were used to calculate pooled odds ratios (ORs) or mean differences (MD) with corresponding 95% confidence intervals.

Results: We included 13 eligible studies incorporating 1,431 cases, of which 603 were patients with RR-DTC. The pooled analysis indicated that four parameters significantly increased the risk of RR-DTC: extrathyroidal extension (ETE) (OR: 2.28, 95% CI: 1.43–3.64, I² = 14%), BRAF^V600E mutation (OR: 3.60, 95% CI: 1.74–7.46, I² = 69%), TERT promoter mutation (OR: 9.84, 95% CI: 3.60–26.89, I² = 61%) and high-risk histological subtype (OR: 1.94, 95% CI: 1.15–3.27, I² = 15%), including tall cell variant papillary thyroid carcinoma (PTC), sclerosing diffuse PTC, hobnail variant PTC, follicular thyroid carcinoma (FTC) (including Hürthle cell), and poorly differentiated thyroid carcinoma (PDTC). However, there was no statistical significance regarding sex, age, tumor size, multifocality, or lateral lymph node metastasis. Subgroup and sensitivity analyses were conducted to further confirm the robustness of the results.

Conclusions: Histological subtype, ETE, BRAF^V600E mutation, and TERT promoter mutation could be considered clinicopathological factors and biomarkers. They could assist in risk stratification, prognostic prediction, and individual therapy options for RR-DTC.

Outcomes following I-131 treatment with cumulative dose exceeding or equal to 600 mCi in differentiated thyroid carcinoma patients

To evaluate treatment outcomes following radioactive iodine (RAI) treatment with a cumulative dose of ≥≥600 mCi in differentiated thyroid carcinoma (DTC) patients, a retrospective review of medical records was done in 176 DTC patients with a cumulative dose of ≥600 mCi from January 1993 to December 2013. All patients were followed up for at least 2 years after receiving 600 mCi of I-131 treatment. Remission criteria were no clinical and imaging evidence of disease and low serum thyroglobulin levels during thyroid-stimulating hormone suppression of <0.2 ng/ml or of <1 ng/ml after stimulation in the absence of interfering antibodies. A total of 176 patients were included in the study: 137 - papillary thyroid cancer, 29 - follicular thyroid cancer, 9 - mixed papillary and follicular thyroid cancer, and 1 - Hurthle cell carcinoma. Most of the patients (118, 67%) had locoregional metastasis, whereas 48 patients (27%) had distant metastases at presentation. The median cumulative dose was 900 mCi (range: 600-2200 mCi). The mean follow-up period was 82.84 ± 42.41 months. Only 16 patients (9.1%) met remission criteria at the end of treatment. The rest of patients (160, 90.9%) were not remitted: stable disease in 94 (53.4%), at least 1 metastasis without I-131 uptake in 34 (19.3%), progressive disease in 21 (11.9%), and death during the whole follow-up period in 11 (6.3%). Two patients (1.1%) developed second primary malignancy. Eighteen cases were suspected of bone marrow suppression (14 cases [7.9%] had anemia and 5 cases [2.8%] had neutropenia). Seven patients (3.9%) developed permanent salivary gland dysfunction. Although the complications after receiving RAI treatment with a cumulative dose of ≥≥600 mCi were low and not severe, the patients with remission were in <10%. Our study suggests that the decision to administer further treatments should be made on an individual basis because beneficial effects may be controversial.

Thyroglobulin doubling time offers a better threshold than thyroglobulin level for selecting optimal candidates to undergo localizing [18F]FDG PET/CT in non-iodine avid differentiated thyroid carcinoma

PURPOSE

To investigate the potential role of serum thyroglobulin doubling time (TgDT) in predicting 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) PET/CT results in patients affected by differentiated thyroid carcinoma (DTC) who demonstrated a combination of positive Tg but a negative [¹³¹I] whole-body scan ([¹³¹I]-WBS).

MATERIALS AND METHODS

Inclusion criteria were (1) prior [¹³¹I] treatment for DTC, (2) negative subsequent [¹³¹I]-WBS, (3) no interfering anti-Tg antibodies, (4) three consecutive Tg measurements under the thyroid hormone replacement therapy to calculate TgDT before 2-[¹⁸F]FDG PET/CT, and (5) at least 6 months of clinical and/or imaging follow-up to ascertain the diagnosis. Receiver operating characteristic (ROC) curve and the area under the curve (AUC) were used to identify the optimal cutoff point for the last stimulated Tg and TgDT prior to [¹⁸F]FDG PET/CT.

RESULTS

One hundred and thirteen patients were included. Seventy-four (65%) patients had positive [¹⁸F]FDG PET/CT for DTC recurrence, while the remaining 39 (35%) negative. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of [¹⁸F]FDG PET/CT were 92%, 94%, 97%, 87%, and 93%. Patients with positive [¹⁸F]FDG PET/CT had higher Tg and TgDT than those with negative PET/CT. ROC curve analysis revealed an optimal Tg cutoff of 19 ng/mL (sensitivity 78%, specificity 85%, AUC = 0.844) and TgDT of 2.5 years (sensitivity 93%, specificity 87%, AUC = 0.911). TgDT threshold of 2.5 years predicted significantly (p = 0.023) better than Tg level PET/CT results.

CONCLUSIONS

The diagnostic performance of [¹⁸F]FDG PET/CT could be significantly improved when TgDT is less than or equal to 2.5 years, as compared with using the absolute Tg level.

Appraisal of radioiodine refractory thyroid cancer: advances and challenges

The incidence of thyroid cancer ranks top among all endocrine cancers, which has increased worldwide. Some patients suffer from recurrent/residual diseases after primary treatment. The recurrent/residual disease often turns out to be radioiodine refractory and shows poor response to radioiodine therapy. A lot of studies have explored the precise appraisal of radioiodine refractory disease in recent years. The mechanism of iodine uptake and the definition of radioiodine refractory disease have been summarized and discussed. The advances in tumor characteristics, histologies, and mutant conditions have been explored for a more accurate method in the early-stage appraisal. We then offer a review of opinions in the evaluation of refractory disease during follow-up, including Tg doubling time, ¹⁸F PET/CT, ¹³¹I WBS, and others. The sensitivity and specificity have been compared between different diagnostic methods. Some novel methods may be introduced for more precise appraisal, such as a scoring system and RNA expression profiling. This review aims to provide physicians a broad insight into the appraisal of radioiodine refractory disease and to pave way for future study.

Locally unresectable differentiated thyroid cancer: outcomes and perspectives

PURPOSE

Differentiated thyroid cancer (DTC) patients with an unresectable primary tumor cannot benefit from curative surgery, and radioiodine treatment for locoregional and distant disease is not possible with the thyroid gland still in place. Due to local invasion, these patients cannot be included in clinical trials, so that treatment options are limited. The aim of this study was to describe the characteristics and the prognosis of patients with these locally unresectable DTC.

PATIENTS AND METHODS

A retrospective and multicentric analysis of consecutive cases of unresectable DTC diagnosed between 2000 and 2015 was performed.

RESULTS

The study population consisted in 22 patients, 13 females (59%); median age: 77 years (range: 52-91). Thyroid tumors were papillary in six, follicular in seven, Hürthle cell in one and poorly differentiated in eight patients. Patients were treated with external beam radiation therapy (EBRT) (57%), locoregional therapy of distant metastases (41%), cytotoxic chemotherapy (38%) and tyrosine kinase inhibitors (TKIs) (33%). TKI treatment resulted in median disease control duration of 7 months with a grade 3-4 toxicity rate of 44%. Only one patient had a total thyroidectomy after neo-adjuvant EBRT. The 1, 3 and 5-year cumulative survival rate was 81%, 27.7% and 21.5%, respectively. The cause of death was DTC in 11 cases (local progression in 7), and to other causes in 7 cases; no patient died from treatment toxicity.

CONCLUSIONS

Clinical trials and approved treatments are lacking for unresectable DTC. TKI treatment may allow prolonged disease control with acceptable toxicity.

Long-Term Outcomes and Prognoses of Elderly Patients (≥65-Years-Old) With Distant Metastases From Well-Differentiated Thyroid Cancer During Radioiodine Therapy and Follow-Up

OBJECTIVE

The objective of this study was to investigate the clinicopathological characteristics, long-term outcomes, and prognostic factors of elderly patients with distant metastases at initial diagnosis from well-differentiated thyroid cancer (WDTC) during radioactive iodine (¹³¹I) treatment and follow-up.

METHODS

A retrospective review of medical records identified 183 elderly patients with DTC who underwent ¹³¹I treatment at our institution between 2006 and 2019.

RESULTS

In total, 57 elderly WDTC patients with distant metastases were enrolled in this study. After ¹³¹I treatment, 32 (56.14%) patients had ¹³¹I avidity and 25 (43.86%) had non-¹³¹I avidity; 35 (61.40%) cases were classified as radioiodine refractory (RR)-WDTC and 22 (38.60%) as non-RR-WDTC. At the end of follow-up, 25 (43.86%) patients had died and 32 (56.14%) were alive. The 5- and 10-year overall survival (OS) rates were 71.50% and 30.49%, respectively, while the 5- and 10-year disease-specific survival (DSS) rates were 76.89% and 48.71%, respectively. Multivariate analyses showed that gross extrathyroidal extension and RR-DTC were independent prognostic factors for poor OS (P=0.04 and P=0.03, respectively), while gross extrathyroidal extension, extrapulmonary distant metastases, and RR-WDTC were independent prognostic factors for poor DSS at the end of follow-up (P=0.02, P=0.03, and P=0.02, respectively).

CONCLUSIONS

WDTC with distant metastases at initial diagnosis accounted for 31.15% of all elderly patients with DTC. Gross extrathyroidal extension and RR-DTC were the major factors associated with poor OS; gross extrathyroidal extension, extrapulmonary distant metastases, and RR-DTC were independent prognostic factors for poor DSS in elderly DTC patients with distant metastases.

Mouse Model of Thyroid Cancer Progression and Dedifferentiation Driven by STRN-ALK Expression and Loss of p53: Evidence for the Existence of Two Types of Poorly Differentiated Carcinoma

Background: Thyroid tumor progression from well-differentiated cancer to poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma (ATC) involves step-wise dedifferentiation associated with loss of iodine avidity and poor outcomes. ALK fusions, typically STRN-ALK, are found with higher incidence in human PDTC compared with well-differentiated cancer and, as previously shown, can drive the development of murine PDTC. The aim of this study was to evaluate thyroid cancer initiation and progression in mice with concomitant expression of STRN-ALK and inactivation of the tumor suppressor p53 (Trp53) in thyroid follicular cells. Methods: Transgenic mice with thyroid-specific expression of STRN-ALK and biallelic p53 loss were generated and aged on a regular diet or with methimazole and sodium perchlorate goitrogen treatment. Development and progression of thyroid tumors were monitored by using ultrasound imaging, followed by detailed histological and immunohistochemical evaluation. Gene expression analysis was performed on selected tumor samples by using RNA-Seq and quantitative RT-PCR. Results: In mice treated with goitrogen, the first thyroid cancers appeared at 6 months of age, reaching 86% penetrance by the age of 12 months, while a similar rate (71%) of tumor occurrence in mice on regular diet was observed by 18 months of age. Histological examination revealed well-differentiated papillary thyroid carcinomas (PTC) (n = 26), PDTC (n = 21), and ATC (n = 8) that frequently coexisted in the same thyroid gland. The tumors were frequently lethal and associated with the development of lung metastasis in 24% of cases. Histological and immunohistochemical characteristics of these cancers recapitulated tumors seen in humans. Detailed analysis of PDTC revealed two tumor types with distinct cell morphology and immunohistochemical characteristics, designated as PDTC type 1 (PDTC1) and type 2 (PDTC2). Gene expression analysis showed that PDTC1 tumors retained higher expression of thyroid differentiation genes including Tg and Slc5a5 (Nis) as compared with PDTC2 tumors. Conclusions: In this study, we generated a new mouse model of multistep thyroid cancer dedifferentiation with evidence of progression from PTC to PDTC and ATC. Further, PDTC in these mice showed two distinct histologic appearances correlated with levels of expression of thyroid differentiation and iodine metabolism genes, suggesting a possibility of existence of two PDTC types with different functional characteristics and potential implication for therapeutic approaches to these tumors.

Lung Metastases From Papillary Thyroid Cancer With Persistently Negative Thyroglobulin and Elevated Thyroglobulin Antibody Levels During Radioactive Iodine Treatment and Follow-Up: Long-Term Outcomes and Prognostic Indicators

Background: The lung is the most frequent site of distant metastasis from differentiated thyroid cancer (DTC). However, lung metastasis from papillary thyroid cancer (PTC) with persistently negative thyroglobulin (Tg) and elevated Tg antibody (TgAb) levels is an extremely rare entity, and the prognosis is therefore elusive. We investigated the clinical characteristics, long-term outcomes, and prognostic factors of lung metastases in PTC patients with persistently negative thyroglobulin (Tg) and elevated Tg antibody (TgAb) levels during radioactive iodine (¹³¹I) treatment and follow-up. Methods: We retrospectively reviewed 10,482 patients with DTC who underwent postoperative ¹³¹I treatment from 2007 to 2017 at Shanghai Sixth's People's Hospital. The relationships between progression-free survival (PFS) and several variables were assessed by univariate and multivariate analyses using the Kaplan-Meier method and a Cox proportional hazards model, respectively. Results: Forty-seven patients with PTC were enrolled in this study (4.48‰ of all patients with DTC). The median age at the initial diagnosis of lung metastasis was 39.6 ± 15.4 years, and the patients comprised 14 male and 33 female patients (male: female ratio = 1.00:2.36). Twenty-five patients had ¹³¹I avidity and 22 had non-¹³¹I avidity. At the end of the 5-years follow-up, 12 patients exhibited progressive disease (PD), and 2 patients had died. At the end of the 10-years follow-up, 21 patients showed PD and five patients had died. The 5- and 10-year PFS rates were 74.47 and 53.32%, respectively; the 5- and 10-years overall survival (OS) rates were 95.74 and 89.36%, respectively. The timing of diagnosis of lung metastases, maximal size of lung metastases, and ¹³¹I avidity were significantly associated with the 5-years PFS rate (P = 0.035, P = 0.030, and P<0.001, respectively). Only ¹³¹I avidity was associated with the 10-years PFS rate (P < 0.001). The multivariate analyses also showed that non-¹³¹I avidity were the independent poor prognostic factors for 10-years PFS at the end of follow-up (P < 0.001). Conclusions: Lung metastases from PTC in patients with persistently negative Tg and elevated TgAb levels had an excellent prognosis and survival rate during ¹³¹I treatment and follow-up. The loss of ¹³¹I avidity remained the strongest independent predictor of a poor prognosis and survival in these patients.

European Perspective on 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: Proceedings of an Interactive International Symposium

BACKGROUND

The American Thyroid Association (ATA) management guidelines for patients with thyroid nodules and differentiated thyroid cancer (DTC) are highly influential practice recommendations. The latest revision appeared in 2015 ("ATA 2015"). These guidelines were developed predominantly by North American experts. European experts frequently have different perspectives, given epidemiological, technological/methodological, practice organization, and medicolegal differences between the respective regions.

SUMMARY

Divergent viewpoints were the focus of an invited symposium organized by the European Association of Nuclear Medicine involving 17 European thyroidologists, four ATA Guidelines Taskforce members, and an audience of 200 international experts. The group discussed the preoperative assessment of thyroid nodules, surgery and the role of pathology, radioiodine (RAI) therapy (RAIT), the assessment of initial therapy and dynamic risk stratification, and the treatment of persistent disease, recurrences, and advanced thyroid cancer. The dialogue resulted in this position paper contrasting European and ATA 2015 perspectives on key issues. One difference pertains to the permissiveness of ATA 2015 regarding lobectomy for primary tumors ≤4 cm. European panelists cited preclusion of RAIT, potential need for completion thyroidectomy, frequent inability to avoid chronic thyroid hormone replacement, and limitations of supportive evidence as arguments against widely applying lobectomy. Significant divergence involved ATA 2015's guidance regarding RAIT. European panelists favored wider use of postoperative RAIT than does ATA 2015. Rationales included the modality's association with favorable patient outcomes and generally limited toxicity, and lack of high-quality evidence supporting withholding RAIT. Additionally, European panelists favored recombinant human thyrotropin (rhTSH) in more settings than does ATA 2015, citing avoidance of hypothyroid morbidity and quality-of-life impairment, without apparent sacrifice in oncologic outcomes. Based on clinical evidence plus theoretical advantages, European experts advocated dosimetric versus fixed-activity RAIT approaches for advanced DTC. European panelists noted that the ATA 2015 risk-stratification system requires information sometimes unavailable in everyday practice. ATA 2015 recommendations regarding RAI-refractory DTC should consider potential palliative benefits of RAIT in patients who also have RAI-susceptible lesions.

CONCLUSIONS

European panelists suggested modifications to approximately one-third of ATA 2015 recommendations. Varying European and ATA 2015 perspectives can stimulate analysis and discussion of the literature and performance of primary research to resolve discrepant recommendations and potentially improve patient outcomes.

Pulmonary metastases in children and adolescents with papillary thyroid cancer in China: prognostic factors and outcomes from treatment with 131I

PURPOSE

Papillary thyroid carcinoma (PTC) with pulmonary metastases is rare in children and adolescents. Unlike adults, limited data are available on children with this disease. Thus, this study evaluated the therapeutic efficacy and prognostic factors of individuals less than 21 years of age with pulmonary metastases from PTC.

METHODS

Seventy-six children and adolescents with pulmonary metastases from PTC treated with ¹³¹I were retrospectively analyzed. Therapeutic efficacy was evaluated by changes in serum thyroglobulin (Tg) and chest computed tomography (CT). Factors predictive of progression-free survival and overall survival were measured by the Kaplan-Meier method.

RESULTS

Among the 76 patients included in this study, 22.4% (17 of 76) were less than 15 years old and 65.8% (50 of 76) were female. Under the evaluation of stimulated serum Tg levels, RAI treatment were effective in 55.9% (38 of 68), stable in 26.5% (18 of 68) and ineffectvie in 17.6% (12 of 68) of patients. Changes on anatomical imaging suggested complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) in 8.5, 62.0, 15.5, and 14.1% of individuals, respectively. Univariate analysis showed that size and tumor doubling time of pulmonary metastases were independent factors affecting therapeutic efficacy. Extra-thyroidal extension, tumor diameter of pulmonary metastases and tumor doubling time were significant independent factors regarding progression-free survival rates, while only tumor doubling time and tumor diameter were significant risk factors associated with overall survival rate.

CONCLUSIONS

Radioactive iodine therapy is an effective treatment for children and adolescents with pulmonary metastases from PTC. Extra-thyroid extension was associated with disease progression while did not show significant influence on overall survival. Tumor doubling time and tumor diameter were the main factors influencing both progression-free survival and overall survival.

Radioiodine Refractory Differentiated Thyroid Cancer: Time to Update the Classifications

BACKGROUND

The management of aggressive and progressing metastatic differentiated thyroid cancer (DTC) is very difficult, and the determination as to when such patients are refractory to ¹³¹I therapy (e.g., radioiodine refractory) is problematic and controversial.

OBJECTIVE

The objective of this review is to discuss (i) the present major classifications of radioiodine refractory disease in DTC, (ii) factors that should be considered before designating a patient's DTC as radioiodine refractory, (iii) potential approaches and caveats to help manage and minimize a patient's exclusion from an ¹³¹I therapy that may have potential benefit in patients with aggressive and progressing metastatic DTC, (iv) next steps for revision of the classifications of radioiodine refractory DTC, and (v) areas for future research.

SUMMARY

To date, the classifications of radioiodine refractory DTC, although very useful, are not sacrosanct especially in the context of individualized patient management, and merely because a patient meets one or more of the various classifications, one should not consider by definition, fiat, or de facto that that a patient's DTC is radioiodine refractory. Rather, each patient should be individually managed with a good understanding of the limitations of the various classifications and potential approaches to help manage that patient. With awareness of the suggestions and caveats discussed herein and with assessment of the many other factors that affect the patient's specific clinical situation, the managing physician can deliver appropriate individualized patient care. A multi-organizational committee should be established as a standing committee to supervise and assist in the update of the classifications of radioiodine refractory DTC, including discussions of their limitations.

CONCLUSION

Classifications to help determine radioiodine refractory disease will continue to evolve as (i) more studies are published, (ii) managing physicians better understand the limitations and confounding factors of present classifications, and (iii) new agents either increase or reestablish ¹³¹I uptake.

Ectopic Papillary Thyroid Cancer with Distant Metastasis

Ectopic thyroid tissue is a rare clinical entity wherein malignant lesions may arise, the most common one being papillary carcinoma. We present a case of a 68-year-old female who presented with a growing mass in the right clavicle. An MR of the shoulder showed a soft tissue mass arising from the anterior margin of the right distal clavicle. A fine needle aspiration of the mass showed papillary thyroid carcinoma. PET/CT confirmed the clavicular and mediastinal mass. Excision of the clavicular mass and total thyroidectomy with modified right neck dissection were performed. Pathology revealed no evidence of malignancy in the thyroid; lymph nodes were positive for metastatic thyroid carcinoma. Postsurgery CT showed the superior mediastinal mass with surrounding adenopathy; radioiodine (RAI) treatment with dose of 142.1 mCi [5257.7 MBq] was recommended. Posttherapy whole-body scan (WBS) showed RAI avid tissue in the neck and superior mediastinum. Follow-up chest CT revealed pulmonary nodules that increased in number and size; a second RAI therapeutic dose was given. The posttherapy RAI WBS was negative. Repeat PET/CT showed multiple hypermetabolic lesions in the mediastinum, neck, lymph nodes, pulmonary nodes, and right shoulder. The FDG avid lesions with no RAI uptake suggested tumor dedifferentiation.

Teriparatide Replacement Therapy for Hypoparathyroidism During Treatment With Lenvatinib for Advanced Thyroid Cancer: A Case Report

Thyroid cancer metastasizes in 4% of cases. Approximately two-thirds of these patients are refractory to radioactive iodine-131 (RAI) therapy and have a poor 10-year survival prognosis. Treatment with tyrosine kinase inhibitors (TKIs) may be administered in selected RAI-refractory patients. However, these agents are often associated with adverse events, including vomiting. We report the case of a patient affected by RAI-refractory thyroid cancer with lung and intracranial metastases undergoing treatment with the antiangiogenic TKI lenvatinib, and with teriparatide replacement therapy for postsurgical hypoparathyroidism. Due to lenvatinib-related vomiting, which did not respond to therapy, conventional oral calcium supplementation failed to maintain normal serum calcium levels and the patient had repeated episodes of hypocalcemia. Subcutaneous teriparatide injections restored serum calcium levels, and thus lenvatinib therapy could be continued. This experience indicates that hormone replacement with teriparatide is a feasible option for cancer patients affected by hypoparathyroidism not treatable with oral calcium supplementation.

Therapeutic response and long-term outcome of differentiated thyroid cancer with pulmonary metastases treated by radioiodine therapy

Objective

To explore the therapeutic response (TR) and long-term outcomes of iodine-131 (I-131) treatment for patients with differentiated thyroid cancer and pulmonary metastases (DTC+PM), as well as the association between the assessment of TR and long-term outcomes.

Methods

This retrospective study comprised 151 DTC+PM patients. TR was evaluated by changes in serum levels of thyroglobulin, anatomic imaging and iodine uptake in pulmonary nodules; logistic regression was applied to identify predictors. Overall survival (OS) was calculated using the Kaplan–Meier method and predictive factors of outcome by multivariate analyses.

Results

After I-131 treatment, 17 patients achieved a complete response, 71 a partial response, and 63 no response. Age, pulmonary nodule size, iodine-concentration within PM, extra-PM, frequency and cumulative dose of I-131 treatment were significant for TR. OS was 72.2% at 5, 55.2% at 10 and 51.3% at 15 years. After adjustment for other factors, age, pulmonary nodule size, extra-PM, frequency and cumulative dose of I-131 treatment were significant. A significant difference of survival rate in patients with different TR group was observed.

Conclusions

There was a supportive response and prognosis for I-131 treatment upon DTC+PM patients. Older patients and those with non-I-131-avid PM were more likely to have no response to I-131 treatment, and greater benefits could be achieved by patients who complete treatment. Long-term outcome was better in patients with age <45 years, pulmonary nodule size <2 cm, without extra-PM, and the frequency of iodine treatment ≥5 times. The predictive power of the TR on long-term prognosis was favorable.

Chapter 4 Thyroid Malignancy: Staging and Restaging

Determining the extent of disease is necessary for guiding the management of thyroid carcinomas. Diagnostic imaging, including ultrasound, computed tomography, magnetic resonance imaging, and nuclear medicine scans, plays an essential role in staging and restaging of thyroid carcinomas. This article reviews the approaches and imaging findings for evaluating the primary tumor, regional lymph node metastases, and distant metastases. In addition, potential pitfalls are discussed and depicted.

Defining Radioiodine-Refractory Differentiated Thyroid Cancer: Efficacy and Safety of Lenvatinib by Radioiodine-Refractory Criteria in the SELECT Trial

BACKGROUND

While there is a clear consensus for defining radioiodine-refractory differentiated thyroid cancer (RR-DTC), it is unknown whether these criteria are equally valid for determining when radioiodine (RAI) therapy is no longer beneficial and systemic treatment should be considered. Lenvatinib, a multikinase inhibitor, significantly prolonged progression-free survival (PFS) compared to placebo in a Phase 3 trial in RR-DTC (SELECT; hazard ratio [HR]: 0.21 [99% confidence interval (CI) 0.14-0.31]; p < 0.001). This sub-analysis compared clinical outcomes of lenvatinib-treated patients in SELECT stratified by RR-DTC inclusion criteria.

METHODS

In SELECT, patients with measurable RR-DTC and radiologic evidence of disease progression ≤13 months prior to study entry were randomized 2:1 to lenvatinib (24 mg/day; 28-day cycle) or placebo. In this analysis, patients were stratified based on the following RR-DTC inclusion criteria: no RAI uptake, disease progression within 12 months of RAI therapy despite RAI avidity at the time of treatment, and extensive (>600 mCi) cumulative RAI exposure. All had disease progression as an inclusion criterion for SELECT.

RESULTS

Of 392 patients (261 lenvatinib; 131 placebo) enrolled, 275, 235, and 73 patients met the inclusion criteria for no RAI uptake, disease progression despite RAI avidity, and extensive RAI exposure, respectively. There was significant overlap between the patient groups, with 167 (42.6%) patients meeting more than one inclusion criterion. Lenvatinib improved median PFS compared to placebo in all groups ("no RAI uptake": lenvatinib not quantifiable [NQ; CI 14.8-NQ] vs. placebo, 3.7 months [CI 2.5-5.3]; "disease progression despite RAI avidity": lenvatinib 16.5 months [CI 12.8-NQ] vs. placebo, 3.7 months [CI 1.9-5.4]; "extensive RAI exposure": lenvatinib 18.7 months [CI 10.7-NQ] vs. placebo, 3.6 months [CI 1.9-5.5]). Objective response rates were 71.8%, 60.0%, and 56.0% for patients with no RAI uptake, disease progression despite RAI avidity, and extensive RAI exposure, respectively. Lenvatinib-related adverse events were similar across groups.

CONCLUSIONS

Comparable efficacy and safety profiles were observed in lenvatinib-treated patients regardless of RR-DTC criteria, possibly because of a large overlap among patients fulfilling each criterion. However, differing definitions for RR-DTC may be equally valid because both lenvatinib and placebo arms exhibited similar PFS outcomes across groups.

Advances in small molecule therapy for treating metastatic thyroid cancer

INTRODUCTION

Multi kinase inhibitors (MKIs) are new drugs, which show activity against receptors of different growth factors leading to the inhibition of tumor cells growth and proliferation. This review summarizes a 10-year experience with the use of MKIs in thyroid cancer (TC). It focuses not only on sorafenib, lenvatinib, vandetanib and cabozantinib, already approved in TC, but also presents an overview of the results of different trials with distinct MKIs so far carried out in TC. Areas covered: Published results of phase I, II and III studies and other reports evaluated the efficacy of different targeted drugs in TC. Expert opinion: Despite numerous clinical trials with distinct MKIs, only four of them unequivocally demonstrated a beneficial effect on progression free survival in radioiodine refractory differentiated or medullary TC. In contrast to other solid tumors, we are still lacking in convincing evidences of their impact on overall survival. We still do not have any strong proof fulfilling evidence-based medicine criteria, when to start MKIs and which drug to use. The questions whether we really have to wait for disease progression in patients with a large tumor burden and/or aggressive types TC or when to stop MKIs treatment remain open.

The Treatment of Advanced Thyroid Cancer in the Age of Novel Targeted Therapies

Until recently, patients with advanced thyroid cancers had limited options for systemic treatment. With the introduction of tyrosine kinase inhibitors (TKIs) as a promising new class of targeted therapies for thyroid cancer, suddenly patients with advanced disease were given new options to extend survival. Guidelines worldwide have been updated to include general indications for these newer agents, but questions remain regarding which agent(s) to select, when to begin treatment, and how long therapy should continue. Additionally, the true impact of TKIs on overall survival and quality-of-life in thyroid cancer patients needs further clarification. As familiarity with approved agents and longer-term data become available, better strategies for implementation of these targeted drugs will evolve to optimize benefit for patients living with metastatic disease.