Five-year survival is similar in thyroid cancer patients with distant metastases prepared for radioactive iodine therapy with either thyroid hormone withdrawal or recombinant human TSH

Theranostics of Thyroid Cancer

Molecular imaging is pivotal in evaluating and managing patients with different thyroid cancer histotypes. The existing, pathology-based, risk stratification systems can be usefully refined, by incorporating tumor-specific molecular and molecular imaging biomarkers with theranostic value, allowing patient-specific treatment decisions. Molecular imaging with different radioactive iodine isotopes (ie, I131, I123, I124) is a central component of differentiated carcinoma (DTC)'s risk stratification while [18F]F-fluorodeoxyglucose ([18F]FDG) PET/CT is interrogated about disease aggressiveness and presence of distant metastases. Moreover, it is particularly useful to assess and risk-stratify patients with radioiodine-refractory DTC, poorly differentiated, and anaplastic thyroid cancers. [18F]F-dihydroxyphenylalanine (6-[18F]FDOPA) PET/CT is the most specific and accurate molecular imaging procedure for patients with medullary thyroid cancer (MTC), a neuroendocrine tumor derived from thyroid C-cells. In addition, [18F]FDG PET/CT can be used in patients with more aggressive clinical or biochemical (ie, serum markers levels and kinetics) MTC phenotypes. In addition to conventional radioiodine therapy for DTC, new redifferentiation strategies are now available to restore uptake in radioiodine-refractory DTC. Moreover, peptide receptor theranostics showed promising results in patients with advanced and metastatic radioiodine-refractory DTC and MTC, respectively. The current appropriate role and future perspectives of molecular imaging and theranostics in thyroid cancer are discussed in our present review.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Thyroid Hormone Withdrawal versus Recombinant Human TSH as Preparation for I-131 Therapy in Patients with Metastatic Thyroid Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Differentiated thyroid carcinoma (DTC) is characterized by an excellent prognosis with a 10-year survival rate > 90%. However, when DTC develops in a metastatic form, it has been shown to significantly impact patient survival and quality of life. Although I-131 has been shown to be an effective therapy in patients with metastatic DTC, whether its efficacy after recombinant human TSH (rhTSH) is comparable to endogenous TSH stimulation by thyroid hormone deprivation (THW) is still debated. Our present study was prompted to compare clinical results obtained in metastatic DTC by I-131 administered after rhTSH and THW stimulation protocols, respectively.

METHODS

A systematic search on PubMed, Web of Science, and Scopus was performed from January to February 2023. Pooled risk ratios with 95% CI were determined for evaluating the initial response after to I-131 therapy after preparation with rhTSH or THW and the disease progression. To track the accumulation of evidence and reduce type I errors because of small data, a cumulative meta-analysis was performed. A sensitivity analysis was also performed to examine the impact of individual studies on overall prevalence results.

RESULTS

Ten studies were included with a total of 1929 patients pre-treated with rhTSH (n = 953) and THW (n = 976), respectively. The cumulative data of our systematic review and meta-analysis showed an increase in the risk ratio over the years without any change in favour of a pre-treatment or the other on the effectiveness of I-131 therapy of metastatic DTC.

CONCLUSIONS

Our data suggest that pretreatment with rhTSH or THW has no significant impact on the effectiveness of I-131 therapy for metastatic DTC. This implies that concerns about the use of one or the other pretreatment should be deferred to clinical evaluations made considering patient characteristics and reduction in side effects.

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

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

Strategies for Radioiodine Treatment: What’s New

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

Metastatic Differentiated Thyroid Cancer Survival Is Unaffected by Mode of Preparation for 131I Administration

Context

Recombinant human thyrotropin (rhTSH) is currently not Food and Drug Administration approved for the treatment of high-risk patients with differentiated thyroid cancer (DTC).

Objective

The goal of our study was to compare the outcomes in higher-risk patients with metastatic DTC prepared for radioiodine (RAI) therapy with rhTSH vs thyroid hormone withdrawal (THW).

Methods

A retrospective chart review was performed of patients with metastatic DTC in follow-up at MedStar Washington Hospital Center and MedStar Georgetown University Hospital from 2009 to 2017. Patients were divided according to their preparation for RAI therapy, with assessment of progression-free survival (PFS) and overall survival (OS).

Results

Fifty-five patients with distant metastases (16 men, 39 women) were prepared for RAI therapy exclusively either with rhTSH (n = 27) or with THW (n = 28). There were no statistically significant differences between the groups regarding clinicopathological features and history of RAI therapies. The median follow-up time for patients with rhTSH-aided therapies was 4.2 years (range, 3.3-5.5 years) and for patients with THW-aided therapies was 6.8 years (range, 4.2-11.6 years) (P = .002). Multivariate analysis showed that the method of thyrotropin stimulation was not associated with a difference in PFS or OS.

Conclusion

As has been shown previously for low-risk DTC, this study indicates that the mode of preparation for RAI therapy does not appear to influence the outcomes of patients with metastatic DTC. PFS and OS were similar for patients with THW-aided or rhTSH-aided RAI therapies.

Feasibility of Recombinant Human TSH as a Preparation for Radioiodine Therapy in Patients with Distant Metastases from Papillary Thyroid Cancer: Comparison of Long-Term Survival Outcomes with Thyroid Hormone Withdrawal

Background: this study was designed to compare the long-term survival outcomes of patients prepared for radioiodine (RAI) therapy using either thyroid hormone withdrawal (THW) or recombinant human thyrotropin (rhTSH) stimulation, by specifically focusing on cases with distant metastases from papillary thyroid cancer (PTC). Methods: A retrospective analysis was performed on 88 patients with distant metastases from PTC. Fifty-one and thirty-seven patients were prepared for RAI treatment by either THW or rhTSH stimulation, respectively. The primary endpoints were progression-free survival (PFS) and disease-specific survival (DSS). Results: The 10-year DSS rates of patients prepared for RAI therapy using either THW or rhTSH stimulation were 62.2% and 73.3%, respectively. Using multivariate analysis, RAI-avid metastases (p = 0.025) and preparation with rhTSH (p = 0.041) were identified as independent prognostic factors for PFS. Notably, PFS in the group of patients with RAI-avid metastases and preparation with rhTSH was significantly better than that in the other groups (p = 0.025). Conclusions: Preparation for RAI therapy using rhTSH stimulation is not inferior to THW preparation in terms of long-term survival outcomes experienced by patients with PTC and distant metastasis. Patients with RAI-avid metastases and preparation with rhTSH had the most favorable PFS.

Outcomes of Thyrotropin Alfa Versus Levothyroxine Withdrawal-Aided Radioiodine Therapy for Distant Metastasis of Papillary Thyroid Cancer

Background: Thyrotropin alfa (rhTSH) is not currently approved by the Food and Drug Administration or European Medicines Agency for the preparation of radioactive iodine therapy (RAIT) in patients with distant metastatic papillary thyroid cancer (PTC). There are only a few studies comparing rhTSH with levothyroxine withdrawal (LTW) in this context. Our main aim was to compare the two methods of RAIT preparation in terms of avidity and structural/biochemical response in distant metastatic PTC. We also intended to evaluate whether the two methods of RAIT preparation represented independent prognostic factors for progression-free survival (PFS) and disease-specific survival (DSS) in this subset of patients. Methods: We performed a retrospective analysis of all patients with PTC treated with RAIT for distant metastatic disease between 2006 and 2018. We included 95 PTC patients-27 (28.4%) had LTW and 68 (71.6%) had rhTSH for RAIT. Results: The two groups presented similar clinicopathological characteristics, except for median age at PTC diagnosis, which was higher in the rhTSH group (p = 0.001), but the median age at first RAIT for distant metastatic disease was not different between the two methods of preparation, 63 years old (interquartile range [IQR] 23) in the LTW group versus 70 (IQR 26.75), p = 0.06. Avidity was similar between the two groups (p = 0.973). Median estimate PFS (p = 0.076) and DSS (p = 0.084) were also similar between LTW and rhTSH. Regarding RAIT-related side effects, only 1 (3.7%) patient and 5 (7.4%) patients in the LTW and rhTSH groups, respectively, reported sialadenitis (p = 0.670). Conclusions: There were no differences between the two methods of RAIT preparation regarding avidity and clinical response. rhTSH may be used as an alternative method of preparation for RAIT in patients with known distant lesions, as it presents similar clinical outcomes to LTW and a good safety profile.

Recombinant human thyroid-stimulating hormone versus thyroid hormone withdrawal preparation for radioiodine ablation in differentiated thyroid cancer in children, adolescents and young adults

OBJECTIVE

Recombinant human TSH (rhTSH) is commonly used to prepare patients for postoperative radioiodine (I-131) ablation after surgery for differentiated thyroid cancer (DTC). In adults, rhTSH is associated with equivalent oncologic efficacy in comparison to thyroid hormone withdrawal (THW), but its use has not been well studied in children. We aimed to measure time to disease progression after rhTSH stimulation vs. THW in paediatric patients under the age of 21 with DTC following total thyroidectomy.

DESIGN

Retrospective cohort study (March 2001-July 2018).

PATIENTS

Sixteen children and adolescents (75% female, median age, 17.4 years) who received rhTSH were compared to 29 historical controls (72% female, median age, 18.5 years) prepared with THW, followed for a median of 2.4 years (range, 0.5-14).

MEASUREMENTS

Stimulated serum TSH concentrations prior to I-131 ablation and time to disease progression, as determined by a component outcome variable encompassing both structural and biochemical disease persistence/recurrence.

RESULTS

No differences were observed in tumour characteristics and I-131 dose (median 2.3 [1.8-2.90] mCi/kg rhTSH) between groups. Patients who received rhTSH achieved a similar median stimulated TSH level (163 [127-184] mU/L), compared to those who underwent THW (136 [94.5-197] mU/L; p = .20). Both groups exhibited similar time to progression (p = .13) and disease persistence/recurrence rates (rhTSH 31% vs. THW 59%, p = .14).

CONCLUSION

In this cohort of children and adolescents with DTC, we observed similar time to disease progression among those who received rhTSH or underwent THW prior to postoperative I-131 ablation.

Influence of Levothyroxine With Recombinant Human Thyroid-Stimulating Hormone on Urinary Iodine Excretion Before Radioactive Iodine Administration

OBJECTIVE

Stimulation with recombinant human thyroid-stimulating hormone (rhTSH) before radioactive iodine administration for patients with thyroid cancer may increase the body iodine pool in the presence of continued levothyroxine; however, the precise significance of its influence remains unclear.

METHODS

This was a prospective observational study conducted between March 2017 and August 2020. We measured the 24-hour urinary iodine excretion and urinary iodine-to-creatinine ratio in patients with thyroid cancer stimulated by rhTSH or thyroid hormone withdrawal (THW) before radioactive iodine administration. Oral iodine intake was controlled by a 7-day self-managed low iodine diet, followed by a strict 3-day low iodine diet while in the hospital.

RESULTS

Overall, 343 subjects were included (rhTSH: n = 181; THW: n = 162). The mean levothyroxine dose in the rhTSH group was 115.2 μg daily. The median 24-hour urinary iodine and urinary iodine-to-creatinine ratio in the rhTSH group (71.0 [interquartile range, 57.5-88.0] μg/day and 80.0 [59.0-97.5] μg/gCr, respectively) were significantly higher than those in the THW group (42.0 [30.0-59.0] μg/day and 39.0 [28.0-61.3] μg/gCr, respectively; both P < .001). After propensity score matching by age, sex, body weight, and renal function (rhTSH: n = 106; THW: n = 106), consistent results for both values were observed for both methods. The increase in urinary iodine with the rhTSH method was smaller than the expected value calculated from the amount of levothyroxine.

CONCLUSION

Urinary iodine excretion was significantly higher among patients with rhTSH stimulation than those with THW, indicating that the rhTSH method slightly increases the body iodine pool.

Radio-Iodide Treatment: From Molecular Aspects to the Clinical View

Simple Summary

This year marks the 80th commemoration of the first time that radio-iodide treatment (RAI) was used. RAI is one of the most effective targeted internal radiation anticancer therapies ever devised and it has been used for many decades, however, a thorough understanding of the underlying molecular mechanisms involved could greatly improve the success of this therapy. This is an in-depth innovative review focusing on the molecular mechanisms underlying radio-iodide therapy in thyroid cancer and how the alteration of these mechanisms affects the results in the clinic.

Abstract

Thyroid radio-iodide therapy (RAI) is one of the oldest known and used targeted therapies. In thyroid cancer, it has been used for more than eight decades and is still being used to improve thyroid tumor treatment to eliminate remnants after thyroid surgery, and tumor metastases. Knowledge at the molecular level of the genes/proteins involved in the process has led to improvements in therapy, both from the point of view of when, how much, and how to use the therapy according to tumor type. The effectiveness of this therapy has spread into other types of targeted therapies, and this has made sodium/iodide symporter (NIS) one of the favorite theragnostic tools. Here we focus on describing the molecular mechanisms involved in radio-iodide therapy and how the alteration of these mechanisms in thyroid tumor progression affects the diagnosis and results of therapy in the clinic. We analyze basic questions when facing treatment, such as: (1) how the incorporation of radioiodine in normal, tumor, and metastatic thyroid cells occurs and how it is regulated; (2) the pros and cons of thyroid hormonal deprivation vs. recombinant human Thyroid Stimulating Hormone (rhTSH) in radioiodine residence time, treatment efficacy, thyroglobulin levels and organification, and its influence on diagnostic imaging tests and metastasis treatment; and (3) the effect of stunning and the possible causes. We discuss the possible incorporation of massive sequencing data into clinical practice, and we conclude with a socioeconomical and clinical vision of the above aspects.

Personalized management of differentiated thyroid cancer in real life - practical guidance from a multidisciplinary panel of experts

PURPOSE

The standard of care for differentiated thyroid carcinoma (DTC) includes surgery, risk-adapted postoperative radioiodine therapy (RaIT), individualized thyroid hormone therapy, and follow-up for detection of patients with persistent or recurrent disease. In 2019, the nine Martinique Principles for managing thyroid cancer were developed by the American Thyroid Association, European Association of Nuclear Medicine, Society of Nuclear Medicine and Molecular Imaging, and European Thyroid Association. In this review, we present our clinical practice recommendations with regard to implementing these principles in the diagnosis, treatment, and long-term follow-up of patients with DTC.

METHODS

A multidisciplinary panel of five thyroid cancer experts addressed the implementation of the Martinique Principles in routine clinical practice based on clinical experience and evidence from the literature.

RESULTS

We provide a suggested approach for the assessment and diagnosis of DTC in routine clinical practice, including the use of neck ultrasound, measurement of serum thyroid-stimulating hormone and calcitonin, fine-needle aspiration, cytology, and molecular imaging. Recommendations for the use of surgery (lobectomy vs. total thyroidectomy) and postoperative RaIT are also provided. Long-term follow-up with neck ultrasound and measurement of serum anti-thyroglobulin antibody and basal/stimulated thyroglobulin is standard, with ¹²³/¹³¹I radioiodine diagnostic whole-body scans and ¹⁸F-fluoro-2-deoxyglucose positron emission tomography/computed tomography suggested in selected patients. Management of metastatic DTC should involve a multidisciplinary team.

CONCLUSIONS

In routine clinical practice, the Martinique Principles should be implemented in order to optimize clinical management/outcomes of patients with DTC.

Major limits of dosimetrically determined activities in advanced differentiated thyroid carcinoma

The 2013/59 EURATOM directive defines all nuclear medicine applications for therapeutic purpose as a form of radiotherapy and underlines the need of both justification and optimization of these procedures, including radioactive iodine therapy (RAIT) with [131I] for metastatic differentiated thyroid cancer (DTC). In metastatic DTC, optimal activity to be administered to achieve the best response rate with limited toxicity is still a matter of debate and international guidelines do not provide univocal recommendations on the preferable use of empiric versus a dosimetry-based approach in these patients. The purpose of this literature review is to describe the possible limits of dosimetry in RAIT planning according to methodological aspects, tumoral heterogeneity and to report clinical data on the impact on patients' outcome of different approaches. Due to the lack of standardized dosimetry protocols and clinical data assessing the superiority of a dosimetry-based vs an empiric approach in these patients, there is a need of standardisation and prospective, properly conducted studies to validate and to assess the best approach.

Vemurafenib Redifferentiation of BRAF Mutant, RAI-Refractory Thyroid Cancers

CONTEXT

BRAFV600E mutant thyroid cancers are often refractory to radioiodine (RAI).

OBJECTIVES

To investigate the utility and molecular underpinnings of enhancing lesional iodide uptake with the BRAF inhibitor vemurafenib in patients with RAI-refractory (RAIR).

DESIGN

This was a pilot trial that enrolled from June 2014 to January 2016.

SETTING

Academic cancer center.

PATIENTS

Patients with RAIR, BRAF mutant thyroid cancer.

INTERVENTION

Patients underwent thyrotropin-stimulated iodine-124 (124I) positron emission tomography scans before and after ~4 weeks of vemurafenib. Those with increased RAI concentration exceeding a predefined lesional dosimetry threshold (124I responders) were treated with iodine-131 (131I). Response was evaluated with imaging and serum thyroglobulin. Three patients underwent research biopsies to evaluate the impact of vemurafenib on mitogen-activated protein kinase (MAPK) signaling and thyroid differentiation.

MAIN OUTCOME MEASURE

The proportion of patients in whom vemurafenib increased RAI incorporation to warrant 131I.

RESULTS

Twelve BRAF mutant patients were enrolled; 10 were evaluable. Four patients were 124I responders on vemurafenib and treated with 131I, resulting in tumor regressions at 6 months. Analysis of research tumor biopsies demonstrated that vemurafenib inhibition of the MAPK pathway was associated with increased thyroid gene expression and RAI uptake. The mean pretreatment serum thyroglobulin value was higher among 124I responders than among nonresponders (30.6 vs 1.0 ng/mL; P = 0.0048).

CONCLUSIONS

Vemurafenib restores RAI uptake and efficacy in a subset of BRAF mutant RAIR patients, probably by upregulating thyroid-specific gene expression via MAPK pathway inhibition. Higher baseline thyroglobulin values among responders suggest that tumor differentiation status may be a predictor of vemurafenib benefit.

Radioiodine treatment of differentiated thyroid cancer related to guidelines and scientific literature

In differentiated thyroid cancer (DTC), radioiodine is administered to eliminate residual normal thyroid tissue after thyroidectomy (ablative treatment), to treat residual microscopic disease (adjuvant treatment), and to treat macroscopic or metastatic disease. Currently, treatment of DTC with ¹³¹I is still a matter of controversy due to the absence of prospective clinical trials assessing its benefit in terms of overall survival and recurrence-free interval. The current recommendations of the experts are based on observational retrospective data and on their interpretation of the literature. Pending the results of the prospective trials that are currently underway, the use of ¹³¹I seems to be justified not only in high-risk patients, but also in intermediate-risk and low-risk patients. The guidelines of The American and British Thyroid Association, European and American Societies of Nuclear Medicine, The European Consensus Group and the latest edition of National Comprehensive Cancer Network (NCCN) were considered in drawing up this continuing education document, we also undertook a review of the related scientific literature.

An H-TERT Mutated Skin Metastasis as First Occurrence in a Case of Follicular Thyroid Carcinoma

Differentiated thyroid cancer arising from thyroid follicular epithelial cells is the most frequent endocrine malignancy, and skin metastases are very rare. We describe a case of a 70-year-old women with a history of an indeterminate thyroid nodule on cytology. A painless, erythematous skin nodule of about 7 mm diameter was removed from the scalp and diagnosed as a metastasis from thyroid cancer. After total thyroidectomy, a histological diagnosis of follicular thyroid cancer was made. Two cycles of radioactive iodine were performed. Both the follicular thyroid carcinoma (FTC) and the metastasis were investigated for the presence of BRAF/RAS and TERT promoter mutations. The results showed that the cutaneous metastasis was BRAF wild-type and TERT promoter-mutated (position g.1,295,228 C>T); in contrast, the primary thyroid lesion was negative for both molecular markers.

The effect of lithium on the progression-free and overall survival in patients with metastatic differentiated thyroid cancer undergoing radioactive iodine therapy

OBJECTIVE

Pretreatment with lithium (Li) is associated with an increased residence time of radioactive iodine (RAI) in differentiated thyroid cancer (DTC) metastases. There are no data translating this observation into long-term outcomes. The study goal was to compare the efficacy of three methods of preparation for RAI therapy in metastatic DTC-thyroid hormone withdrawal (THW), THW with pretreatment with Li (THW+Li), and recombinant human TSH (rhTSH).

DESIGN/PATIENTS/MEASUREMENTS

We performed a cohort study comparing overall survival (OS) and progression-free survival (PFS) between the three groups: THW (n = 52), THW+Li (n = 41) and rhTSH (n = 42). Kaplan-Meier analyses were performed to compare OS and PFS between the groups. Cox proportional hazards regression model with a stepwise variable selection was performed to study the contribution of age, gender, histology, TNM status, a location of distant metastases and RAI dose.

RESULTS

During the follow-up of median 5.1 (IQR = 3.0-8.1) years, 52% of patients had disease progression and 12.6% died. Although THW+Li group was characterized by the longest OS (P = 0.007), only age (HR 1.05, CI 1.01-1.09, P = 0.01) and widespread disease (HR 3.8, CI 1.2-11.8, P = 0.02) were found to affect OS in a multivariate model. There was no difference in PFS between the groups (P = 0.47). Presence of distant metastases limited to the lungs only was associated with longer PFS (PFS HR 0.35, CI 0.20-0.60, P = 0.0002).

CONCLUSION

The older age is associated with shorter OS, while disease burden affects OS and PFS in patients with metastatic thyroid cancer. The method of preparation for RAI therapy does not affect the outcome.

Italian consensus on diagnosis and treatment of differentiated thyroid cancer: joint statements of six Italian societies

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent.

METHODS

Six scientific Italian societies entitled to cure thyroid cancer patients (the Italian Thyroid Association, the Medical Endocrinology Association, the Italian Society of Endocrinology, the Italian Association of Nuclear Medicine and Molecular Imaging, the Italian Society of Unified Endocrine Surgery and the Italian Society of Anatomic Pathology and Diagnostic Cytology) felt the need to develop a consensus report based on significant scientific advances occurred in the field.

OBJECTIVE

The document includes recommendations regarding initial evaluation of thyroid nodules, clinical and ultrasound criteria for fine-needle aspiration biopsy, initial management of thyroid cancer including staging and risk assessment, surgical management, radioiodine remnant ablation, and levothyroxine therapy, short-term and long-term follow-up strategies, and management of recurrent and metastatic disease. The objective of this consensus is to inform clinicians, patients, researchers, and health policy makers about the best strategies (and their limitations) relating to the diagnosis and treatment of differentiated thyroid cancer.

Treatment of refractory thyroid cancer

Distant metastases from thyroid cancer of follicular origin are uncommon. Treatment includes levothyroxine administration, focal treatment modalities with surgery, external radiation therapy and thermal ablation, and radioiodine in patients with uptake of ¹³¹I in their metastases. Two-thirds of distant metastases become refractory to radioiodine at some point, and when there is a significant tumor burden and documented progression on imaging, a treatment with a kinase inhibitor may provide benefits.

Importance of recombinant human thyrotropin as an adjuvant in the radioiodine treatment of thyroid cancer

Radioiodine (RAI) therapy for treatment of differentiated thyroid cancer (DTC) requires high serum thyroid-stimulating hormone (TSH) levels to induce a sufficient iodine uptake within thyroid cells. Recombinant Human TSH (rhTSH) induces an exogenous TSH level increase without LT4 withdrawal. It is a valid alternative to LT4-withdrawal (LT4-W) to achieve the TSH levels required for RAI therapy. According to the recent American Thyroid Association (ATA) guidelines, candidates for RAI therapy should be selected based on their DTC risk of recurrence. Areas covered: In this review, we report the studies assessing the effects of rhTSH on RAI ablation compared to thyroid hormone withdrawal in patients with thyroid cancer at different ATA risk of recurrence. We focus our attention on high risk patients and metastatic disease in which RAI treatment is routinely recommended although there are few controversial data about the best possible way of preparing for it. Expert commentary: rhTSH-aided therapy is associated to a better quality of life and to a lower body radiation exposure. Several studies have reported an equivalent efficacy of RAI ablation after TSH stimulation with rhTSH or LT4-W in patients with DTC at low and intermediate risk of recurrence. Although more studies are required, the results are promising even in patients with high risk DTC and metastatic disease.

Comparison of Empiric Versus Whole-Body/-Blood Clearance Dosimetry-Based Approach to Radioactive Iodine Treatment in Patients with Metastases from Differentiated Thyroid Cancer

The optimal management of radioactive iodine (RAI) treatment in patients with metastatic thyroid cancer (TC) is still a matter of debate. Methods: We retrospectively analyzed 352 patients with RAI-avid metastatic well-differentiated TC treated with ¹³¹I by an empiric fixed activity of 3.7 GBq at Gustave Roussy (GR, n = 231) or by personalized activity (2.7-18.6 GBq) based on whole-body/-blood clearance (WB/BC) dosimetry at Memorial Sloan Kettering Cancer Center (MSKCC, n = 121). The primary endpoint was to compare overall survival (OS) in the 2 groups of patients by log-rank test. Results: Patients received a median cumulative activity of 14.8 GBq at GR and 24.2 GBq at MSKCC (P < 0.0001). The median follow-up after the diagnosis of metastases was 7.2 y (0.4-31 y). Five-year OS was 86.8% and 78.8% for patients treated at GR and at MSKCC, respectively (P < 0.01). However, there was no statistical difference in OS after correction for sex, age at the diagnosis of distant metastases, metastases site, and metastases extension between the 2 centers (P = 0.16). OS at 5 y was 96% and 96% for patients younger than 40 y with micrometastases, 70% and 65% for patients older than 40 y with macrometastases or multiple metastases, and 92% and 87% for younger patients with macrometastases or older patients with micrometastases treated at GR and MSKCC, respectively (P = not significant). Conclusion: Routine use of WB/BC dosimetry without lesional dosimetry provided no OS advantage when compared with empiric fixed RAI activity in the management of thyroid cancer patients with RAI-avid distant metastases.

Complete blood counts are frequently abnormal 1 year after dosimetry-guided radioactive iodine therapy for metastatic thyroid cancer

OBJECTIVE

Radioactive iodine (RAI) has been associated with hematologic abnormalities. Previous research has shown that even a single dose of RAI can cause changes in the peripheral complete blood count (CBC). It is unclear if the use of dosimetry guidance would prevent the effects of high doses of RAI on bone marrow suppression.

METHODS

CBC at baseline was compared to a CBC obtained 1 year after the last RAI treatment in 50 thyroid cancer patients that received ≥250 mCi RAI during the course of their disease. Cumulative dose, number of treatments, patients' age, and the use of external beam radiation therapy (EBRT) were considered in the analysis.

RESULTS

We observed a small but statistically significant decrease in hemoglobin (Hb), hematocrit (Hct), and platelet (Plt) counts at 1 year in 50 patients who had received ≥250 mCi RAI. We did not find a significant change in white blood cell count (WBC). Approximately 60% of patients who developed anemia had concomitant WBC and Plt abnormalities. RAI dose, number of treatments, and age at diagnosis did not confer a higher risk of bone marrow suppression.

CONCLUSION

High cumulative activities of RAI administered under dosimetric guidance are associated with a small but statistically significant decreases in Hb, Hct, and Plt counts. The clinical implications of these changes, if any, are unclear. The benefits obtained with high doses of RAI, when indicated, are likely to outweigh the minimal hematologic risks observed in the present study.

Evaluation of patients with disseminated or locoregionally advanced thyroid cancer: a primer for medical oncologists

Historically, patients with thyroid cancers are managed by endocrinologists, surgeons and radiation oncologists. Due to recent progress in this field with advances in treatment of thyroid cancer, medical oncologists are now commonly involved in care of patients with advanced thyroid cancers. In this manuscript, we describe general principles in management of patients with various types of thyroid cancers including differentiated, medullary and anaplastic thyroid cancers.

Novel Approaches to Thyroid Cancer Treatment and Response Assessment

The incidence of thyroid cancer has been increasing. After total thyroidectomy of well-differentiated thyroid tumors with intermediate- or high-risk features on pathology, radioiodine remains one of the mainstays of therapy for both thyroid remnant ablation as well as for treatment of metastatic disease. SPECT/CT, a relatively new modality, has been shown to play a pivotal role predominantly in the post-therapy setting by changing the risk stratification of patients with thyroid cancer. In the case of radioiodine treatment failure, FDG-PET/CT may provide prognostic information based on extent and intensity of metabolically active metastatic sites as well as serve as an important imaging test for response assessment in patients treated with chemotherapy, targeted therapies, or radiotherapy, thereby affecting patient management in multiple ways. The role of newer redifferentiation drugs has been evaluated with the use of I-124 PET/CT.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Sensitivity of preparation with rhTSH or thyroid hormone withdrawal using ¹³¹I-whole body scans to identify metastases of differentiated thyroid cancer

It has been reported that there is a higher sensitivity for Thyroid Hormone Withdrawal (THW) in detection of metastases of Differentiated Thyroid Cancer (DTC) when compared to Recombinant Human Thyroid-Stimulating Hormone (rhTSH). This study aims to confirm this reported difference in the sensitivity using radioiodine whole body scans (WBS).

MATERIALS AND METHODS

In a retrospective study forty three patients with evidence or suspicion of metastatic differentiated thyroid cancer DTC (evaluated by thyroglobulin or abnormal findings in previous WBS) underwent WBS using of 24 h after oral administration of 370 MBq (131)I. The WBS was interpreted by two independent experienced observers categorizing their findings into a positive or negative for metastatic disease. The findings were controlled by stimulated thyroglobulin (TG) measurement and a two years follow-up.

RESULTS

Of the evaluated patients, 14 patients were prepared with rhTSH and 29 with THW. No statistical differences in patient characteristics were documented between the two groups (age, sex, thyroglobulin level, TSH level, type of cancer). In this study, no differences in the sensitivity of WBS of patients prepared with rhTSH or THW were found. There were 11 of 14 patients (78%) that were positive after rhTSH and 19 of 29 patients (65%) after THW. Metastatic disease was confirmed by stimulated thyroglobulin value and follow-up.

CONCLUSION

In contrast to previously published data, this study couldn't found any differences in the sensitivity of rhTSH or THW for the preparation of DTC patients undergoing (131)I imaging.

Treatment of distant metastases from follicular cell-derived thyroid cancer

Distant metastases from thyroid cancer of follicular origin are uncommon. Treatment includes levothyroxine administration at suppressive doses, focal treatment modalities with surgery, external radiation therapy and thermal ablation, and radioiodine in patients with uptake of ¹³¹I in their metastases. Two thirds of distant metastases will become refractory to radioiodine at some point, and when there is a significant tumor burden and documented progression on imaging, a treatment with a kinase inhibitor may provide benefits.

Diagnosis and treatment of patients with thyroid cancer

BACKGROUND

Thyroid cancer is the most common malignancy of the endocrine system, representing 3.8% of all new cancer cases in the United States and is the ninth most common cancer overall. The American Cancer Society estimates that 62,450 people in the United States will be diagnosed with thyroid cancer in 2015, and 1950 deaths will result from the disease.

OBJECTIVE

To review the current approach to the diagnosis and treatment of patients with thyroid cancer.

DISCUSSION

Over the past 3 decades, there has been a dramatic increase in the number of people diagnosed with thyroid cancer, which may be attributable to the wide use of imaging studies, including ultrasounds, computed tomography, magnetic resonance imaging, and positron emission tomography scans that incidentally detect thyroid nodules. Thyroid cancer is divided into several main types, with papillary thyroid cancer being the most common. The treatment options for patients with thyroid cancer include the surgical removal of the entire thyroid gland (total thyroidectomy), radioactive iodine therapy, and molecular-targeted therapies with tyrosine kinase inhibitors. This article summarizes the diagnosis and treatment of thyroid cancer, with recommendations from the American Thyroid Association regarding thyroid nodules and differentiated thyroid cancer. Recently approved drugs and treatment trends are also explored.

CONCLUSION

The prognosis and treatment of thyroid cancer depend on the tumor type and its stage at the time of diagnosis. Many thyroid cancers remain stable, microscopic, and indolent. The increasing treatment options for patients with thyroid cancer, including therapies that were recently approved by the US Food and Drug Administration, have kept the mortality rate from this malignancy low, despite the increase in its incidence. Early diagnosis and appropriate treatment can improve prognosis and reduce mortality.

The evolving use of radioiodine therapy in differentiated thyroid cancer

The incidence of differentiated thyroid cancer has increased worldwide over the last three decades, but thyroid cancer-related mortality remains stable. Until recently, the standard treatment for most thyroid cancers has been near-total thyroidectomy followed by radioiodine remnant ablation. Observational data support lower recurrence rates and improved survival after radioiodine ablation in patients with high-risk cancers; however, a similar benefit has not been established for all patients with thyroid cancer. Risk stratification should be used to identify patients who are likely to benefit from radioiodine ablation and guide therapeutic decisions. For most patients who need radioiodine remnant ablation, preparation for therapy with recombinant human thyroid-stimulating hormone stimulation is as effective as thyroid hormone withdrawal. Lower therapeutic doses of radioiodine are recommended for the majority of thyroid remnant ablations. Higher doses are reserved for advanced disease at initial diagnosis, local recurrences that cannot be treated with surgery alone, and distant metastatic disease.

Postoperative radioactive iodine administration for differentiated thyroid cancer patients

PURPOSE OF REVIEW

Radioactive iodine (RAI) is administered postoperatively to the majority of thyroid cancer patients. No available study has demonstrated any benefit in low-risk patients.

RECENT FINDINGS

RAI should be used selectively in low and intermediate-risk patients, based on the surgical and pathological reports and on postoperative serum thyroglobulin level and neck ultrasonography. When used, a low activity (30 mCi) is administered following recombinant human thyrotropin stimulation. High-risk patients are treated with a high activity of RAI (100 mCi or more).

SUMMARY

RAI is not administered in many low-risk patients who can be reliably followed up with serum thyroglobulin determination on L-thyroxine treatment and neck ultrasonography. RAI may be administered in case of abnormality, and this delay will not reduce the chance of cure.

Initial radioiodine administration: when to use it and how to select the dose

All published guidelines on the use of radioactive iodine for the treatment of well-differentiated thyroid cancer agree that an individualized assessment of the risk of cancer-related mortality and of disease recurrence should direct the decision of whether radioiodine treatment is needed and how much to administer. At the author's institution, they mostly follow the American Thyroid Association's risk stratification system, with the addition of a category of very-low-risk patients that do not receive radioactive iodine.

Thyrotropin in the development and management of differentiated thyroid cancer

Thyrotropin (TSH) is the major regulator and growth factor of the thyroid. TSH may be important in the development of human thyroid cancer, with both suggestive animal models and clinical evidence, although definitive proof is still required. Applications for TSH in thyroid cancer management include TSH stimulation of radioiodine uptake, enhancement of biochemical monitoring through thyroglobulin measurement, and long-term suppression of TSH with supraphysiologic levothyroxine. This review synthesizes current knowledge of TSH in both the development and management of differentiated thyroid cancer.

Examining recombinant human TSH primed ¹³¹I therapy protocol in patients with metastatic differentiated thyroid carcinoma: comparison with the traditional thyroid hormone withdrawal protocol

PURPOSE

Recombinant human thyroid-stimulating hormone (rhTSH)-based protocol is a promising recent development in the management of differentiated thyroid carcinoma (DTC). The objectives of this prospective study were: (1) to assess the feasibility and efficacy of the rhTSH primed (131)I therapy protocol in patients with DTC with distant metastatic disease, (2) to perform lesional dosimetry in this group of patients compared to the traditional protocol, (3) to document the practical advantages (patient symptoms and hospital stay) of the rhTSH protocol compared to the traditional thyroid hormone withdrawal protocol, (4) to document and record any adverse effect of this strategy, (5) to compare the renal function parameters, and (6) to compare the serum TSH values achieved in either of the protocols in this group of patients.

METHODS

The study included 37 patients with metastatic DTC having lung or skeletal metastases or both. A comparison of lesional radiation absorbed dose, hospital stay, renal function tests, and symptom profile was undertaken between the traditional thyroid hormone withdrawal protocol and rhTSH-based therapy protocol. Dosimetric calculations of metastatic lesions were performed using lesion uptake and survey meter readings for calculation of effective half-life. Non-contrast-enhanced CT was used for assessment of tumor volume. Quality of life was assessed using the European Organization for Research and Treatment of Cancer (EORTC) QOL forms. A comparison of pretreatment withdrawal thyroglobulin (TG) was done with the withdrawal TG level 3 months after treatment.

RESULTS

The mean effective half-life of (131)I in metastatic lesions was less during the rhTSH protocol (29.49 h) compared to the thyroid hormone withdrawal protocol (35.48 h), but the difference was not statistically significant (p = 0.056). The mean 24-h % uptake of the lesions during the traditional protocol (4.84 %) was slightly higher than the 24-h % uptake during the rhTSH protocol (3.56 %), but the difference was not found to be statistically significant (p = 0.301). The mean tumor radiation absorbed dose per mCi was less during the rhTSH protocol (6.04 rad/mCi) than during the thyroid hormone withdrawal protocol (8.68 rad/mCi), and the difference was statistically significant (p = 0.049), though visual analysis of the rhTSH posttherapy scans showed avid concentration of (131)I in the metastatic sites and revealed more lesions in 30 % of the patients compared to the traditional large dose scan and equal number of lesions in 65 % of the patients. Visual analysis of the traditional large dose scan, rhTSH pretreatment scan, and rhTSH posttherapy scans showed that the traditional large dose scan is better compared to the rhTSH 1 mCi scan as it showed more lesions in 19 of 37 patients (51.35 %). rhTSH posttherapy scans were better compared to the traditional large dose scans and rhTSH pretreatment scans. More lesions were seen on rhTSH posttherapy scans in 11 of 37 patients (29.7 %) compared to the traditional large dose scans and in 24 of 37 (64.86 %) patients compared to the rhTSH 1 mCi scans. Our findings demonstrate that the rhTSH primed pretreatment scan undertaken at 24 h after diagnostic dose is suboptimal to evaluate whether a metastatic lesion concentrates (131)I. The majority of these lesions demonstrated radioiodine accumulation in the posttreatment scan. Quality of life as assessed using EORTC QOL-3 forms clearly showed that rhTSH improved the quality of life of patients compared to the thyroid hormone withdrawal protocol. Functional scale and global health status were significantly better in the rhTSH protocol compared to the thyroid hormone withdrawal protocol (p < 0.001). The mean symptom scale score was significantly higher in the thyroid hormone withdrawal protocol (45.25) compared to the rhTSH protocol (13.59) (p < 0.001). Of the 20 patients, 4 (20 %) had more than 25 % increase in the TG value on follow-up. The median hospital stay of patients receiving (131)I therapy with the rhTSH protocol was shorter (2 days, range 2-8 days) compared to the thyroid hormone withdrawal protocol (3 days, range 1-8 days) and the difference was found to be statistically significant (p = 0.007). The mean serum creatinine level was significantly lower in the rhTSH protocol (0.826 mg/dl) than the thyroid hormone withdrawal protocol (0.95 mg/dl) (p = 0.013), though the mean blood urea level of patients during the rhTSH therapy protocol was slightly higher (22.81 mg/dl) than during the thyroid hormone withdrawal protocol (21.91 mg/dl) without statistical significance (p = 0.55). The mean serum TSH on day 2 of the rhTSH protocol was 140.99 μIU/ml (range 71-176 μIU/ml) compared to 72.62 μIU/ml (range 2.05-154 μIU/ml) in the traditional protocol after around 4-6 weeks of thyroid hormone withdrawal (p < 0.05).

CONCLUSION

Overall, the rhTSH primed (131)I therapy protocol was found to be feasible and a good alternative to the thyroid hormone withdrawal protocol in patients with metastatic DTC. The lesional dosimetry findings need to be further examined in subsequent studies. The rhTSH primed pretreatment scan at 24 h after diagnostic dose is suboptimal to determine whether a metastatic lesion concentrates (131)I and the posttreatment scan is important for the correct impression.

Stimulated thyroglobulin at recombinant human TSH-aided ablation predicts disease-free status one year later

CONTEXT

Thyroglobulin (Tg) levels measured at the time of remnant ablation after thyroid hormone withdrawal (THW) were shown to have prognostic value in predicting disease-free status.

OBJECTIVES

Our objectives were to determine whether stimulated Tg levels, measured at the time of remnant ablation performed under recombinant human TSH (rhTSH) stimulation, has value in predicting absence of detectable disease 1 year after radioiodine therapy and to compare the results obtained with this approach with a cohort of patients submitted to ablation after THW.

DESIGN

This was a prospective observational study.

SETTING AND PATIENTS

The study included 293 consecutive patients treated for a differentiated thyroid carcinoma with no initial evidence of distant metastasis. All patients were submitted to a total or near-total thyroidectomy, followed by ablation either under rhTSH (n = 151) or endogenous TSH stimulation (n = 142). Patients with positive Tg antibodies were excluded.

MAIN OUTCOME MEASURES

The predictive value of Tg at ablation was assessed by receiver operating characteristic curve analysis.

RESULTS

In the rhTSH group, 96 patients (73.3%) were considered disease-free at 1 year. Stimulated Tg at ablation after rhTSH was found to be an independent prognostic indicator of disease persistence 12 months later. The highest-accuracy cutoff value for absence of detectable disease was defined as 7.2 ng/mL, with a negative predictive value of 90%. In the THW group, Tg at ablation also proved to have independent predictive value. Using the same threshold (7.2 ng/mL), the negative predictive value of Tg was 95% in the THW group.

CONCLUSIONS

When rhTSH was used, stimulated Tg at ablation had independent predictive value for disease-free status 1 year later. A low stimulated Tg at rhTSH-aided ablation may be considered a favorable prognosis factor.

Potential use of recombinant human thyrotropin in the treatment of distant metastases in patients with differentiated thyroid cancer

OBJECTIVE

In order to effectively treat differentiated thyroid cancer (DTC) with radioiodine (RAI) it is necessary to raise serum TSH levels either endogenously by thyroid hormone withdrawal (THW) or exogenously by administration of recombinant human TSH (rhTSH). The goal of this review is to present current data on the relative efficacy and side effects profile of rhTSH-aided versus THW-aided RAI therapy for the treatment of patients with distant metastases of DTC.

METHODS

We have searched the PubMed database for articles including the keywords "rhTSH", "thyroid cancer", and "distant metastases" published between January 1, 1996 and January 7, 2012. As references, we used clinical case series, case reports, review articles, and practical guidelines.

RESULTS

Exogenous stimulation of TSH is associated with better quality of life because it obviates signs and symptoms of hypothyroidism resulting from endogenous TSH stimulation. The rate of neurological complications after rhTSH and THW-aided RAI therapy for brain and spine metastases is similar. The rate of leukopenia, thrombocytopenia, xerostomia, and pulmonary fibrosis is similar after preparation for RAI treatment with rhTSH and THW. There is currently a controversy regarding RAI uptake in metastatic lesions after preparation with rhTSH versus THW, with some studies suggesting equal and some superior uptake after preparation with THW. Analysis of available retrospective studies comparing survival rates, progression free survival, and biochemical and structural response to a dosimetrically-determined dose of RAI shows similar efficacy after preparation for therapy with rhTSH and THW.

CONCLUSION

The rhTSH stimulation is not presently approved by the FDA as a method of preparation for adjunctive therapy with RAI in patients with metastatic DTC. Data on rhTSH compassionate use suggest that rhTSH stimulation is as equally effective as THW as a method of preparation for dosimetry-based RAI treatment in patients with RAI-avid metastatic DTC.

Thyroid nodules and differentiated thyroid cancer: update on the Brazilian consensus

Thyroid nodules are frequent findings, especially when sensitive imaging methods are used. Although thyroid cancer is relatively rare, its incidence is increasing, particularly in terms of small tumors, which have an uncertain clinical relevance. Most patients with differentiated thyroid cancer exhibit satisfactory clinical outcomes when treatment is appropriate, and their mortality rate is similar to that of the overall population. However, relapse occurs in a considerable fraction of these patients, and some patients stop responding to conventional treatment and eventually die from their disease. Therefore, the challenge is how to identify the individuals who require more aggressive disease management while sparing the majority of patients from unnecessary treatments and procedures. We have updated the Brazilian Consensus that was published in 2007, emphasizing the diagnostic and therapeutic advances that the participants, representing several Brazilian university centers, consider most relevant in clinical practice. The formulation of the present guidelines was based on the participants' experience and a review of the relevant literature.

Selumetinib-enhanced radioiodine uptake in advanced thyroid cancer

BACKGROUND

Metastatic thyroid cancers that are refractory to radioiodine (iodine-131) are associated with a poor prognosis. In mouse models of thyroid cancer, selective mitogen-activated protein kinase (MAPK) pathway antagonists increase the expression of the sodium-iodide symporter and uptake of iodine. Their effects in humans are not known.

METHODS

We conducted a study to determine whether the MAPK kinase (MEK) 1 and MEK2 inhibitor selumetinib (AZD6244, ARRY-142886) could reverse refractoriness to radioiodine in patients with metastatic thyroid cancer. After stimulation with thyrotropin alfa, dosimetry with iodine-124 positron-emission tomography (PET) was performed before and 4 weeks after treatment with selumetinib (75 mg twice daily). If the second iodine-124 PET study indicated that a dose of iodine-131 of 2000 cGy or more could be delivered to the metastatic lesion or lesions, therapeutic radioiodine was administered while the patient was receiving selumetinib.

RESULTS

Of 24 patients screened for the study, 20 could be evaluated. The median age was 61 years (range, 44 to 77), and 11 patients were men. Nine patients had tumors with BRAF mutations, and 5 patients had tumors with mutations of NRAS. Selumetinib increased the uptake of iodine-124 in 12 of the 20 patients (4 of 9 patients with BRAF mutations and 5 of 5 patients with NRAS mutations). Eight of these 12 patients reached the dosimetry threshold for radioiodine therapy, including all 5 patients with NRAS mutations. Of the 8 patients treated with radioiodine, 5 had confirmed partial responses and 3 had stable disease; all patients had decreases in serum thyroglobulin levels (mean reduction, 89%). No toxic effects of grade 3 or higher attributable by the investigators to selumetinib were observed. One patient received a diagnosis of myelodysplastic syndrome more than 51 weeks after radioiodine treatment, with progression to acute leukemia.

CONCLUSIONS

Selumetinib produces clinically meaningful increases in iodine uptake and retention in a subgroup of patients with thyroid cancer that is refractory to radioiodine; the effectiveness may be greater in patients with RAS-mutant disease. (Funded by the American Thyroid Association and others; ClinicalTrials.gov number, NCT00970359.).