Early Structural, Biochemical, and Metabolic Responses to Anlotinib in Patients With Progressive Radioactive Iodine Refractory Differentiated Thyroid Cancer.

OBJECTIVE: We aimed to assess the early efficacy of anlotinib in patients with progressive radioactive iodine refractory differentiated thyroid cancer at the structural, biochemical, and metabolic levels. METHODS: Ten eligible patients were prospectively enrolled to receive anlotinib. Their responses were assessed at 6 weeks. Apart from the structural response according to Response Evaluation Criteria in Solid Tumors version 1.1, the biochemical response was assessed by serum thyroglobulin (Tg), and the metabolic response was assessed by 2-deoxy-2-[18F] fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) according to the European Organization for Research and Treatment of Cancer criteria. A safety profile was recorded. RESULTS: Structurally controlled disease (20% partial response + 80% stable disease) was observed in all patients. The median longest diameter of target lesions shrank from 20.8 mm (IQR, 14.9-27.5) to 17.0 mm (IQR, 14.1-23.7) (P < .001), and the average shrinkage rate was -15.1 ± 14.1%. Sharp serum Tg reduction by 72.8 ± 16.4% was observed in 8 measurable patients. The 18F-FDG PET/CT-mapped glucose metabolic response was not quite comparable to the structural response, with 90% of the patients having controlled disease (30% partial metabolic response + 60% stable metabolic disease), whereas 10% presented progressive metabolic disease. The most common treatment-emergent adverse events (AEs) were hypertension (100%) and proteinuria (70%). Most AEs were grade 1 or 2, whereas grade 3 AEs occurred only in hypertension. CONCLUSION: Anlotinib is generally well tolerated and can bring early disease control within the initial 6 weeks of treatment. The sharp biochemical response suggests Tg to be an early sensitive biomarker to anlotinib, whereas the heterogeneous metabolic response might play a complementary role.

State of the Art in the Current Management and Future Directions of Targeted Therapy for Differentiated Thyroid Cancer.

Two-thirds of differentiated thyroid cancer (DTC) patients with distant metastases would be classified as radioactive iodine-refractory (RAIR-DTC), evolving into a poor outcome. Recent advances underlying DTC molecular mechanisms have shifted the therapy focus from the standard approach to targeting specific genetic dysregulations. Lenvatinib and sorafenib are first-line, multitargeted tyrosine kinase inhibitors (TKIs) approved to treat advanced, progressive RAIR-DTC. However, other anti-angiogenic drugs, including single targeted TKIs, are currently being evaluated as alternative or salvage therapy after the failure of first-line TKIs. Combinatorial therapy of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signalling cascade inhibitors has become a highly advocated strategy to improve the low efficiency of the single agent treatment. Recent studies pointed out targetable alternative pathways to overcome the resistance to MAPK and PI3K pathways' inhibitors. Because radioiodine resistance originates in DTC loss of differentiation, redifferentiation therapies are currently being explored for efficacy. The present review will summarize the conventional management of DTC, the first-line and alternative TKIs in RAIR-DTC, and the approaches that seek to overcome the resistance to MAPK and PI3K pathways' inhibitors. We also aim to emphasize the latest achievements in the research of redifferentiation therapy, immunotherapy, and agents targeting gene rearrangements in advanced DTC.

Emerging Therapies for Radioactive Iodine Refractory Thyroid Cancer.

OPINION STATEMENT: The landscape of treatment options for radioactive iodine refractory thyroid cancer is rapidly changing. While there are no curative options in this setting, tyrosine kinase inhibitors (TKIs) have revolutionized the management of radioiodine refractory disease to help delay progression of metastatic and life-threatening disease. Ongoing development of more selective targeted inhibitors will certainly improve medication tolerability and tumor specificity. In this review, we discuss the epidemiology of radioactive iodine refractory thyroid cancer and examine the definition of radioactive iodine refractory disease and the current systemic therapy options. We then discuss molecularly targeted strategies both approved by the FDA and currently under study in clinical trials. In particular, we examine the data relevant to specific targeted mutations in thyroid cancer. We also discuss novel approaches in development, such as immunotherapy, to the management of radioactive iodine refractory disease.

TERT promoter mutation in primary papillary thyroid carcinoma lesions predicts absent or lower 131 i uptake in metastases.

Genetic mutations play important roles in not only development of papillary thyroid carcinoma (PTC) but also determination of its properties. The radioactive iodine refractory (RAIR) state is a harbinger of poor outcomes for PTC. We used various statistical models to investigate the significance of TERT promoter, BRAF, and RAS mutations in distinguishing the RAIR state and their associations with 131 I uptake. Mutations were examined in primary lesions of 33 RAIR cases and 34 age- and sex-matched 131 I-treated cases with disease-free status. Thyrotropin-stimulated thyroglobulin (sTg) change, 131 I uptake ability, and RAIR categories were evaluated in the RAIR cases. The prevalence of TERT mutation in the RAIR group was 24.24% (8/33), which was significantly higher than that in the disease-free group (0/34). BRAF mutation showed a similar high prevalence in both the RAIR group (69.70%) and disease-free group (64.71%). Among the eight TERT mutation-positive cases, six carried both TERT and BRAF mutations. RAS mutation was detected in only one disease-free case and in two RAIR cases. Despite a significantly higher prevalence of TERT mutations in the RAIR group, only tumor size and N1b lymph node involvement were independently associated with RAIR status. In the RAIR group, all patients carrying a TERT mutation showed maximum or increased sTg. Multivariate analyses demonstrated that the TERT mutation was associated with decreased 131 I uptake and the RAIR categories of absent or weaker 131 I uptake. TERT mutation constitutes a novel genetic biomarker indicating absent or weaker 131 I-avid lesions in RAIR PTC patients. It is worth evaluating the TERT status in all DTC patients undergoing 131 I therapy. © 2019 IUBMB Life, 2019.

Radioactive Iodine-Refractory Differentiated Thyroid Cancer in the Elderly.

Most common thyroid cancers are differentiated thyroid cancers (DTCs) and have papillary, follicular, or Hürthle cell morphology. Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland. The incidence of DTC increases with age. While most of the patients with DTC have an excellent prognosis, the outcome can be poor when diagnosed in elderly patients. PURPOSE OF REVIEW: Current treatment approach for DTC includes surgery, thyroid-stimulating hormone (TSH) suppression, radioactive iodine, external beam radiotherapy, or systemic treatments such as kinase inhibitors. Radioactive iodine therapy (RAI) is the primary first-line systemic treatment for advanced DTC. However, during the course of treatment, the tumor may become refractory to RAI. Elderly patients are more likely to be diagnosed with advanced disease that can be refractory to RAI. RECENT FINDINGS: The advent of TKIs (tyrosine kinase inhibitors) and their usage in RAI refractory disease has shown improved progression-free survival. These agents are, however, associated with increased toxicity. The variable nature of disease and toxicity associated with the systemic therapy makes it important to have an individualized approach to management, especially in the elderly population who can be more susceptible to toxicities.

Cohort study exploring the effect of lenvatinib on differentiated thyroid cancer.

Lenvatinib is a molecular-targeting agent that was recently approved in Japan for treatment of curatively unresectable, radioactive iodine-refractory, progressive differentiated thyroid cancer (DTC). Because only a few Japanese patients have received lenvatinib in clinical trials, there are limited domestic data on its safety and efficacy or prognostic factors. Therefore, a prospective observational study has been designed to collect safety and efficacy data in at least 300 patients with curatively unresectable DTC receiving lenvatinib therapy (24 mg/day), in order to find predictors of antitumor activity and survival. Patients with progressive curatively unresectable DTC refractory to radioiodine therapy will be enrolled and the primary endpoint will be overall survival. This study is designed to estimate the 95% confidence intervals of the 1-year and 2-year survival rates with a two-sided width of less than 10%. Secondary endpoints will be the time to treatment failure, time to strategy failure, progression-free survival time with clinical progressive disease, response rate, quality of life, safety, and patient reports. The ultimate goal is to obtain information for developing evidence-based guidelines for treatment of DTC, including recommendations on patient selection, dosages, and duration of treatment. This study has been registered with the UMIN Clinical Trials Registry (UMIN000022243).

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: What is new and what has changed?

Thyroid nodules are very common, and thyroid cancer is currently the fifth leading cancer diagnosis in women. The American Thyroid Association has led the development and revision of guidelines for the management of patients with thyroid nodules and differentiated thyroid cancer (DTC). The most current revision was published in the January 2016 issue of the journal Thyroid. The current guidelines have 101 recommendations, with 8 figures and 17 tables that are hopefully helpful to those treating patients with thyroid nodules and cancer. The primary goals of the American Thyroid Association Guidelines Task Force were to use the current evidence to guide recommendations and yet be as helpful and practical as possible within the scope and strength of the evidence. The current review focuses on new and significantly revised recommendations that may very well change clinical practice. The author notes 3 new basic principles that have emerged in this guidelines revision: 1) the management of thyroid nodules, including the decision to perform a fine-needle aspiration biopsy as well as follow-up decision making, will be heavily influenced by the newly developed sonographic risk pattern; 2) the long-term management of DTC along with thyroid-stimulating hormone target goals will be heavily influenced by the 4 categories of "response to therapy"; and 3) the management of patients with radioactive iodine-refractory DTC will be divided into 4 basic decision-making groups: patients who should undergo monitoring, patients who should undergo directed therapies, patients who should undergo systemic therapies, and patients who should be offered entry into clinical trials. Cancer 2017;123:372-381. © 2016 American Cancer Society.

Tumor volume doubling time of pulmonary metastases predicts overall survival and can guide the initiation of multikinase inhibitor therapy in patients with metastatic, follicular cell-derived thyroid carcinoma.

BACKGROUND: The current study was conducted to better characterize the association between overall survival (OS) from metastatic thyroid cancer and the rate of structural disease progression. METHODS: In this retrospective study, the average tumor volume doubling time (midDT) of 2 dominant lung metastases was used to group patients into 6 clinically relevant cohorts. OS was calculated from the time of metastasis diagnosis and from the time the pulmonary lesions crossed over the 1-cm diameter threshold. RESULTS: The tumor growth rate was remarkably constant in lung metastases from thyroid cancer over a median follow-up of 8.5 years (median correlation coefficient, 0.92; coefficient of determination, 0.85). Patients with a midDT ≤1 year were found to have worse OS compared with those with a higher midDT (log-rank P = .01). The 5-year OS rate from the 1-cm diameter time point was 20% for patients with a midDT ≤1 year (15 patients), 50% for patients with a midDT of 1 to 2 years (19 patients), 53% for patients with a midDT of 2 to 3 years (9 patients), 80% for patients with a midDT of 3 to 4 years (6 patients), and 80% for patients with a midDT of ≥4 years or who were negative (12 patients). Within the group of patients with a midDT ≤1 year, the 2-year OS rate from the 1-cm diameter point was 88% in the patients treated with multikinase inhibitors (8 patients) versus 43% in the nontreated group (7 patients) (P = .13). CONCLUSIONS: The midDT of lung metastases appears to be a good prognostic indicator of OS in patients with metastatic thyroid cancer. Unlike the thyroglobulin DT, the midDT alone can be used to predict eligibility for multikinase inhibitor therapy. Cancer 2017;123:2955-64. © 2017 American Cancer Society.

Differentiated thyroid cancer: focus on emerging treatments for radioactive iodine-refractory patients.

BACKGROUND: The treatment of differentiated thyroid cancer refractory to radioactive iodine (RAI) had been hampered by few effective therapies. Recently, tyrosine kinase inhibitors (TKIs) have shown activity in this disease. Clinical guidance on the use of these agents in RAI-refractory thyroid cancer is warranted. MATERIALS AND METHODS: Molecular mutations found in RAI-refractory thyroid cancer are summarized. Recent phase II and III clinical trial data for TKIs axitinib, lenvatinib, motesanib, pazopanib, sorafenib, sunitinib, and vandetinib are reviewed including efficacy and side effect profiles. Molecular targets and potencies of these agents are compared. Inhibitors of BRAF, mammalian target of rapamycin, and MEK are considered. RESULTS: Routine testing for molecular alterations prior to therapy is not yet recommended. TKIs produce progression-free survival of approximately 1 year (range: 7.7-19.6 months) and partial response rates of up to 50% by Response Evaluation Criteria in Solid Tumors. Pazopanib and lenvatinib are the most active agents. The majority of patients experienced tumor shrinkage with TKIs. Common adverse toxicities affect dermatologic, gastrointestinal, and cardiovascular systems. CONCLUSION: Multiple TKIs have activity in RAI-refractory differentiated thyroid cancer. Selection of a targeted agent should depend on disease trajectory, side effect profile, and goals of therapy.

Treatment of advanced thyroid cancer with axitinib: Phase 2 study with pharmacokinetic/pharmacodynamic and quality-of-life assessments.

BACKGROUND: In a previous phase 2 trial, axitinib was active and well tolerated in patients with advanced thyroid cancer. In this second phase 2 trial, the efficacy and safety of axitinib were evaluated further in this population, and pharmacokinetic/pharmacodynamic relationships and patient-reported outcomes were assessed. METHODS: Patients (N = 52) with metastatic or unresectable, locally advanced medullary or differentiated thyroid cancer that was refractory or not amenable to iodine-131 received a starting dose of axitinib 5 mg twice daily. The primary endpoint was the objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety, pharmacokinetic parameters, and patient-reported outcomes assessed with the MD Anderson Symptom Inventory questionnaire. RESULTS: The overall ORR was 35% (18 partial responses), and 18 patients had stable disease for ≥16 weeks. The median PFS was 16.1 months, and the median OS was 27.2 months. All-causality, grade ≥3 adverse events (>5%) were fatigue, dyspnea, diarrhea, decreased weight, pain in extremity, hypertension, decreased appetite, palmar-plantar erythrodysesthesia, hypocalcemia, and myalgia. Patients who had greater axitinib exposure had a longer median PFS. Quality of life was maintained during treatment with axitinib, and no significant deterioration in symptoms or interference in daily life caused by symptoms, assessed on MD Anderson Symptom Inventory subscales, were observed. CONCLUSIONS: Axitinib has activity and a manageable safety profile while maintaining quality of life, and it represents an additional treatment option for patients with advanced thyroid cancer.

Digoxin treatment does not reinduce radioiodine uptake in radioiodine refractory non-medullary thyroid carcinoma.

Objective: Patients with non-medullary thyroid carcinoma (NMTC) that are refractory to radioactive iodine (RAI) have a poor prognosis. Strategies for restoring the ability to take up iodine, so-called redifferentiation, are promising but not suitable for all patients. Preclinical studies, in human cell lines just as in a murine model, have shown that the cardiac glycoside digoxin restored RAI uptake. This prospective single-center open-label study aimed to investigate whether treatment with digoxin could reinduce clinically relevant RAI uptake in patients with metastasized RAI-refractory NMTC. Methods: Eight patients with metastasized RAI-refractory NMTC were included between November 2022 and June 2023. Before treatment, a baseline [123I]NaI scintigraphy was performed. Thereafter, patients were treated with digoxin for 3 weeks. Starting doses depended on age and weight. For safety reasons, the usual therapeutic range was aimed for. After 1 week, the digoxin plasma concentration was measured, and the digoxin dose was adjusted if necessary. After 3 weeks of digoxin treatment, a second [123I]NaI scintigraphy was performed. RAI uptake was compared between the two scintigraphies. Results: Seven patients completed the digoxin treatment and were evaluable. None of the seven patients showed clinically relevant RAI uptake after digoxin treatment. No digoxin-related serious adverse events occurred during this trial. Conclusion: Contrary to results from preclinical trials, in this trial, 3 weeks of digoxin treatment did not reinduce RAI uptake in patients with NMTC. This highlights essential challenges regarding the approach toward optimization of studies aimed to restore the RAI uptake and its therapeutic efficacy through drug repurposing.

Pemetrexed-carboplatin salvage therapy in advanced thyroid cancers.

BACKGROUND: The overall survival of patients with advanced thyroid cancers that have progressed following targeted therapies is limited, indicating a strong need for salvage treatments. METHODS: We retrospectively analyzed patients with refractory advanced thyroid cancer treated with pemetrexed-carboplatin (PC) at Mayo Clinic since 2019. RESULTS: Eleven patients, three with anaplastic thyroid cancer (ATC), seven with differentiated or poorly differentiated thyroid cancer (DTC), and one with oncocytic carcinoma of the thyroid, were treated with novel salvage PC. Patients with DTC (n = 7) had durable responses with a median progression-free survival of 29 months. One responder included a patient with ATC whose disease progressed following pembrolizumab/axitinib, lenvatinib, and dabrafenib/trametinib. On this fourth line treatment, the patient remains on therapy to date, over 12 months after initial response. CONCLUSIONS: This case series reinforces prior published phase I clinical trial data and shows that pemetrexed can have potent efficacy in the treatment of the most advanced thyroid cancers.

A Prospective Cohort Study Exploring the Effect of Lenvatinib Planned Drug Holidays in Treatment of Differentiated Thyroid Cancer.

Background: Although lenvatinib is the preferred treatment for unresectable radioactive iodine-refractory differentiated thyroid cancer (RR-DTC), this agent exerts considerable toxicities, which can lead to frequent dose interruptions and modifications. The adoption of planned drug holidays has been recently suggested as one means of minimizing or avoiding these severe adverse events. Our retrospective study demonstrated that planned drug holidays appear to be a promising strategy for continuing of lenvatinib. However, the benefits of planned drug holidays in a prospective study have yet to be clarified. Here, we investigated the impact of planned drug holidays on clinical outcomes in patients treated with lenvatinib in the COLLECT study. Methods: In COLLECT, a prospective observational study, patients with RR-DTC were treated with lenvatinib in a real-world clinical setting. Lenvatinib was administered orally at a dose of 24 mg daily. Dose modification for toxicities was permitted. Furthermore, planned drug holidays were allowed to avoid severe or intolerable toxicities. The present post hoc analysis focused on evaluating the impact of planned drug holidays on clinical outcomes, including overall survival (OS), time to treatment failure (TTF), time to failure strategy (TFS), and progression-free survival (PFS), in patients in the COLLECT study who were treated with lenvatinib. Results: In total, 262 patients were included. Of the 253 patients evaluable for efficacy, 73 undertook a planned drug holiday at the discretion of the attending physician. OS, TTF, TFS, and PFS were significantly longer in patients who used a planned drug holiday than in those who did not. The planned drug holiday group demonstrated notable clinical outcomes, with a 1-year OS of 95.8% and a 1-year PFS of 94.5%. Moreover, planned drug holidays demonstrated a clinically meaningful advantage in clinical outcomes. The planned drug holiday group had a significantly longer duration of administration at a dose of ≥10 mg. Conclusions: Planned drug holidays for lenvatinib were associated with significantly improved clinical outcomes compared to daily oral administration. Further investigation of the optimal treatment schedule for lenvatinib is warranted. Clinical Trial Registration: UMIN000022243.

Clinical and Histopathological Risk Factors for Radioactive Iodine Refractory Follicular and Oncocytic Thyroid Carcinoma.

INTRODUCTION: Risk factors for radioactive iodine (RAI)-refractory disease in follicular (FTC) and oncocytic thyroid carcinoma (OTC) are unknown. Therefore, the aim of this study is to identify clinical and histopathological risk factors for RAI-refractory disease in FTC and OTC patients, facilitated by an extensive histopathological revision. METHODS: All adult FTC and OTC patients treated at Erasmus MC (the Netherlands) between 2000 and 2016 were retrospectively included. 2015 ATA Guidelines were used to define RAI-refractory disease. An extensive histopathological revision was performed applying the 2022 WHO Classification using Palga: Dutch Pathology Databank. Logistic regression was used to identify risk factors for RAI-refractory disease, stratified for histological subtype. RESULTS: Ninety FTC and 52 OTC patients were included, of which 14 FTC (15.6%) and 22 OTC (42.3%) developed RAI-refractory disease over a follow-up time of 8.5 years. RAI-refractory disease occurred in OTC after fewer cycles than in FTC (2.0 [IQR: 1.0-2.0] vs 2.5 [IQR: 2.0-3.75]), and it substantially decreased the 10-year disease specific survival, especially in OTC (46.4%; FTC 85.7%). In FTC, risk factors were higher age at diagnosis, pT3/pT4-stage, N1-stage, widely invasive tumors and extra-thyroidal extension. N1-stage and M1-stage were the strongest risk factors in OTC, rather than histopathological characteristics of the primary tumor. CONCLUSION: To our knowledge, this is the first study that correlates clinical and histopathological risk factors with RAI-refractory disease in FTC and OTC, facilitated by a histopathological revision. In FTC, risk factors for RAI-refractory disease were foremost histopathological characteristics of the primary tumor, whereas in OTC presentation with lymph node and distant metastasis was associated with RAI-refractory disease. Our data can help clinical decision making, particularly in patients at risk for RAI-refractory disease.

Radioactive Iodine in Differentiated Thyroid Carcinoma: A Systematic AGREE II Clinical Practice Guideline Appraisal.

OBJECTIVE: Identify and appraise clinical practice guidelines (CPGs) for radioactive iodine (RAI) indications in differentiated thyroid carcinoma (DTC), and the treatment for radioactive iodine refractory (RAI-R) DTC using the Appraisal of Guidelines for Research and Evaluation II tool. DATA SOURCES: MEDLINE (Pubmed), Ovid (EMBASE), and Scopus. REVIEW METHODS: A systematic literature search was conducted to identify CPGs addressing RAI in DTC. CPGs were appraised by 4 independent reviewers in 6 distinct areas of quality. Scaled domain scores were subsequently calculated for each domain. Intraclass correlation coefficients were calculated for each domain to assess interrater reliability. RESULTS: Sixteen guidelines were found addressing RAI indications for DTC. Of these 16, 9 also addressed the treatment of RAI-R DTC. A further 6 unique guidelines were identified that exclusively address RAI-R DTC, bringing the total number of guidelines to 22. The American Thyroid Association (ATA) guidelines for adult thyroid cancer were the highest scoring with a mean score of 83.5%. Two guidelines scored >60% in 5 or more domains, qualifying as "high" quality: ATA and British Thyroid Association. The highest scoring domain was domain 4: clarity of presentation (80.4%) while the lowest scoring domain was domain 5: applicability (38.6%). CONCLUSION: Of the 22 guidelines identified, only two were "high quality." CPGs exclusively addressing the treatment of RAI-R DTC were weak with most guidelines scoring in the "low" quality range. This report reveals an unmet need for rigorously developed guidelines addressing indications for RAI in DTC, as well as the treatment for RAI-R DTC.

Radioactive iodine refractoriness in Middle Eastern differentiated thyroid cancer: clinical outcome and risk factor analysis.

Background: Radioactive iodine refractory differentiated thyroid cancer (RAIR-DTC) has received increasing attention due to its poor prognosis. However, outcomes may vary among patients with RAIR-DTC. The role of clinico-pathological and molecular prognostic factors in survival remains controversial, resulting in difficulty in selecting patients for new targeted therapies. We assessed mortality rate and DTC-specific survival in Middle Eastern RAIR-DTC to identify prognostic factors associated with survival. Methods: This single center, retrospective study enrolled 268 patients with RAIR-DTC. Mortality rate and DTC-specific survival were analyzed to identify prognostic factors related to survival. Univariate and multivariate analysis were performed using Cox proportional hazards model. Results: Of the 268 cases of RAIR-DTC, 40.3% (108/268) had absent 131I uptake (either on diagnostic or post-therapy whole body scan), 15.3% (41/268) had progressive disease (PD) despite 131I, 7.5% (20/268) had persistent disease despite cumulative activity of I131 of >600 mCi and 36.9% (n=99/268) developed distant metastasis. On multivariate analysis, age (more than 45 years), presence of metastatic disease and tumors harboring telomerase reverse transcriptase (TERT) promoter mutations were independent prognostic factors for poor DTC-specific survival. Subjects were divided into 3 groups according to the number of risk factors; low risk (no risk factors); intermediate (≤ 2 risk factors); and high risk (all the 3 risk factors). Ten-year DTC-specific survival rates in low, intermediate and high-risk groups were 100.0%, 92.9% and 53.6%, respectively. Conclusions: The contribution of age greater than 45 years to RAIR-DTC mortality is impactful. Older age, presence of distant metastasis and TERT mutations could be used as early predictors of RAIR-DTC cases. The identification of prognostic factors for poor survival in RAIR-DTC may improve the selection of patients for more personalized surveillance and therapeutic modalities.

An update on redifferentiation strategies for radioactive iodine-refractory differentiated thyroid carcinoma.

PURPOSE: Although most patients with differentiated thyroid carcinoma (DTC) have an excellent prognosis, a subset will experience radioactive iodine refractory (RAI-R) disease, associated with recurrence, distant metastases and worse prognosis. In recent years, redifferentiation has emerged as an attractive approach for patients with RAI-R DTC, a strategy to induce iodine uptake in RAI-R DTC tumor cells and ultimately prolong time to initiation of systemic therapy. METHODS: An overview and critical appraisal of the existing literature on redifferentiation will be presented in this review under the lens of the genotype-specific targeted therapy administered with redifferentiation intent. RESULTS/CONCLUSIONS: Due to the significant heterogeneity across studies, it will be key to harmonize research methodology and support future larger, multicenter prospective trials in order to identify the most suitable candidates for this therapeutic strategy.

Molecular Perspectives in Radioactive Iodine Theranostics: Current Redifferentiation Protocols for Mis-Differentiated Thyroid Cancer.

Thyroid cancer molecular oncogenesis involves functional dedifferentiation. The initiating genomic alterations primarily affect the MAPK pathway signal transduction and generate an enhanced ERK output, which in turn results in suppression of the expression of transcription of the molecules of iodine metabolomics. The clinical end result of these molecular alterations is an attenuation in theranostic power of radioactive iodine (RAI). The utilization of RAI in systemic therapy of metastatic disease requires restoration of the functional differentiation. This concept has been accomplished by modulation of MAPK signaling. Objective responses have been demonstrated in metastatic disease settings. RAI-refractoriness in "differentiated thyroid cancers" remains a clinical problem despite optimized RAI administration protocols. Functional mis-differentiation and associated RAI-indifference are the underlying primary obstacles. MAPK pathway modulation offers a potential for reversal of RAI-indifference and combat refractoriness. This review presents the latest clinical experience and protocols for the redifferentiation of radioiodine-refractory mis-differentiated thyroid cancer, providing a comprehensive overview of the current protocols and intervention strategies used by leading institutions. Timing and techniques of imaging, thyrotropin (TSH) stimulation methods, and redifferentiation agents are presented. The efficacy and limitations of various approaches are discussed, providing an overview of the advantages and disadvantages associated with each of the protocols.

Theranostic Risk Stratification for Thyroid Cancer in the Genomic Paradigm.

Theranostics define diagnostic evaluations directing patient-specific therapeutic decisions. Molecular theranostics involves genomic, transcriptomic, proteomic, metabolomic and finally phenonic definitions thyroid cancer differentiation. It is the functional differentiation that determines the sensitivity and accuracy of RAI imaging as well as the effectiveness of RAI treatment. Total thyroidectomy is performed to empower an anticipated RAI treatment. A preoperative determination of the genomic and transcriptomic profile of the tumor is a strong predictor of response to therapeutic interventions. This article discusses the oncopathophysiologic basis of the theranostic risk stratification approach.

Neutrophil-to-lymphocyte ratio as an independent factor for worse prognosis in radioiodine refractory thyroid cancer patients.

PURPOSE: This study aimed to evaluate neutrophil to lymphocyte ratio (NLR) as a laboratory biomarker in radioactive iodine-refractory (RAIR) locally advanced and/or metastatic differentiated thyroid cancer (DTC) and determine its correlation with overall survival (OS). METHODS: We retrospectively included 172 patients with locally advanced and/or metastatic RAIR DTC admitted between 1993 and 2021 at INCA. Age at diagnosis, histology, presence of distant metastasis (DM), DM site, neutrophil-to- lymphocyte ratio (NLR), imaging studies such as PET/CT results, progression free survival (PFS) and overall survival (OS) data were analyzed. NLR was calculated at the time of locally advanced and/or metastatic disease diagnosis and the cutoff value was 3. Survival curves were established using the Kaplan-Meier method. The confidence interval is 95%, and a p-value of less than 0.05 was considered statistically significant RESULTS: Out of 172 patients, 106 were locally advanced, and 150 presented DM at some point during follow-up. Regarding NLR data, 35 had NLR over 3 and 137 had NLR under 3. Higher NLR at was associated with shorter OS (6 vs. 10; p = 0.05) and with highest SUV on FDG PET-CT (15.9 vs. 7.7, p = 0.013). We found no association between higher NLR and age at diagnosis, DM or final status. CONCLUSION: NLR higher than 3 at the time of locally advanced and/or metastatic disease diagnosis is an independent fator for shorter OS in RAIR DTC patients. Noteworthy higher NLR was also associated with highest SUV on FDG PET-CT in this population.