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

Evaluation of the Malignancy Risk in Nodules Expanding the Thyroid Gland Capsule

There has been an increase in the diagnosis of thyroid nodules in recent years. In addition to the well-known criteria, features that are likely to increase the risk of malignancy are in the research process. In this study, we aimed to evaluate the malignant potential of nodules that expand the thyroid capsule ultrasonographically. A total of 109 patients with thyroid capsule-expanding nodules and 288 patients with non-expanding nodules were included in the study. Demographical data, ultrasonography features, and cytology results were noted, and histopathological findings were determined in operated patients. While malignant cytology was detected in 5.5% of capsule-expanding nodules in FNAB results, this rate was 0.7% in the non-capsule expanding group (p<0.001). According to the histopathological results, the incidence of malignancy was 15.6% in the capsule-expanding nodule group, while it was 3.1% in the other group (p=0.001). As a result of logistic regression analysis, it was determined that the risk of malignancy increased by 4.44-fold (95% CI 1.4-13.8, p=0.01) in patients with capsule-expanding nodules. Other features that increased the risk of malignancy were hypoechogenicity, microcalcification, and irregular margin presence. In this study, we found that the risk of malignancy increased in nodules expanding the thyroid capsule. Based on the increasing study data on this subject, monitoring thyroid capsule expansion in nodules may take its place among the criteria for malignancy in future evaluations.

Antineoplastic Effect of ALK Inhibitor Crizotinib in Primary Human Anaplastic Thyroid Cancer Cells with STRN-ALK Fusion In Vitro

Anaplastic thyroid cancer (ATC) is one of the deadliest human cancers and represents <2% of thyroid carcinomas. A therapeutic target for ATC is represented by anaplastic lymphoma kinase (ALK) rearrangements, involved in tumor growth. Crizotinib is an oral small-molecule tyrosine kinase inhibitor of the ALK, MET, and ROS1 kinases, approved in ALK-positive non-small cell lung cancer. Until now, the effect of crizotinib in "primary human ATC cells" (pATCs) with transforming striatin (STRN)-ALK fusion has not been reported in the literature. In this study, we aimed to obtain pATCs with STRN-ALK in vitro and evaluate the in vitro antineoplastic action of crizotinib. Thyroid surgical samples were obtained from 12 ATC patients and 6 controls (who had undergone parathyroidectomy). A total of 10/12 pATC cultures were obtained, 2 of which with transforming STRN-ALK fusion (17%). Crizotinib inhibited proliferation, migration, and invasion and increased apoptosis in 3/10 pATC cultures (2 of which with/1 without STRN-ALK), particularly in those with STRN-ALK. Moreover, crizotinib significantly inhibited the proliferation of AF cells (a continuous cell line obtained from primary ATC cells). In conclusion, the antineoplastic activity of crizotinib has been shown in human pATCs (with STRN-ALK) in preclinical studies in vitro, opening the way to future clinical evaluation in these patients.

Molecular Aspects and Therapeutic Implications of Herbal Compounds Targeting Different Types of Cancer

Due to genetic changes in DNA (deoxyribonucleic acid) sequences, cancer continues to be the second most prevalent cause of death. The traditional target-directed approach, which is confronted with the importance of target function in healthy cells, is one of the most significant challenges in anticancer research. Another problem with cancer cells is that they experience various mutations, changes in gene duplication, and chromosomal abnormalities, all of which have a direct influence on the potency of anticancer drugs at different developmental stages. All of these factors combine to make cancer medication development difficult, with low clinical licensure success rates when compared to other therapy categories. The current review focuses on the pathophysiology and molecular aspects of common cancer types. Currently, the available chemotherapeutic drugs, also known as combination chemotherapy, are associated with numerous adverse effects, resulting in the search for herbal-based alternatives that attenuate resistance due to cancer therapy and exert chemo-protective actions. To provide new insights, this review updated the list of key compounds that may enhance the efficacy of cancer treatment.

A new paradigm for epidermal growth factor receptor expression exists in PTC and NIFTP regulated by microRNAs

Intoduction

Identification of molecular alterations associated with tumor behavior is necessary to guide clinical management. The 2022 WHO classification has organized the thyroid follicular cell-derived neoplasms into benign, low-risk and high-risk neoplasms, and emphasized the value of biomarkers that may provide differential diagnostic and prognostic information to avoid overtreatment of low risk neoplasms. This work aims to study the epidermal growth factor receptor (EGFR) expression, functional and spatial dynamics in relation to specific miRNAs alterations in papillary thyroid cancer (PTC) and in non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) considered as models of high-risk and low-risk thyroid tumors respectively.

Methods

Primary thyroid cultured cells were used for miRNA gain/loss of function and luciferase reporter assays. Paraffin embedded tissues were used for real time PCR, immuno-fluorescence stain and confocal microscopy experiments.

Results

Our results showed that in PTC, EGFR mRNA is reduced as an effect of miR-146b-5p upregulation. The EGF expression is low and the ERK pathway is inhibited. The EGFR protein high cytoplasmic expression and colocalization with the endosomal/exosomal markers, ALIX and CD63, suggest the occurrence of stress-induced EGFR internalization, accumulation in endosomal vesicles and secretion via exosomes. In NIFTP EGFR transcription is increased in association with downregulation of miR-7-5p and the EGFR/ERK pathway is active indicating dependence on the canonical EGFR pathway for growth.

Conclusion

Downregulation of transcript level along with cytoplasmic accumulation of undegraded protein is a new pattern of EGFR regulation associated with malignancy in thyroid. Further research is needed to elucidate the intracellular trafficking defects responsible for this specific EGFR dynamic in PTC.

Design of new drugs for medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is one of the common malignant endocrine tumors, which seriously affects human health. Although surgical resection offers a potentially curative therapeutic option to some MTC patients, most patients do not benefit from it due to the difficulty to access the tumors and tumor metastasis. The survival rate of MTC patients has improved with the recent advances in the research, which has improved our understanding of the molecular mechanism underlying MTC and enabled the development and approval of novel targeted drugs. In this article, we reviewed the molecular mechanisms related to MTC progression and the principle for the design of molecular targeted drugs, and proposed some future directions for prospective studies exploring targeted drugs for MTC.

Thyroid Carcinoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Differentiated thyroid carcinomas is associated with an excellent prognosis. The treatment of choice for differentiated thyroid carcinoma is surgery, followed by radioactive iodine ablation (iodine-131) in select patients and thyroxine therapy in most patients. Surgery is also the main treatment for medullary thyroid carcinoma, and kinase inhibitors may be appropriate for select patients with recurrent or persistent disease that is not resectable. Anaplastic thyroid carcinoma is almost uniformly lethal, and iodine-131 imaging and radioactive iodine cannot be used. When systemic therapy is indicated, targeted therapy options are preferred. This article describes NCCN recommendations regarding management of medullary thyroid carcinoma and anaplastic thyroid carcinoma, and surgical management of differentiated thyroid carcinoma (papillary, follicular, Hürthle cell carcinoma).

Novel Therapeutics for Advanced Differentiated Thyroid Cancer

The current treatments for radioactive iodine (RAI) -refractory differentiated thyroid cancer (DTC) are evolving as cancer genomics are further understood. Multitargeted tyrosine kinase inhibitors are the first-line therapy for symptomatic or progressive disease; however, considerable adverse effects have spurred the development of targeted therapies for redifferentiation of iodine avidity and the treatment of RAI-refractory DTC. Next-generation sequencing allows for the use of tumor-targeted therapeutics, such as MEK1/2, BRAF, RET, and NTRK inhibitors. Immunotherapy is also under investigation as a therapeutic option for this disease.

Combination Strategies Involving Immune Checkpoint Inhibitors and Tyrosine Kinase or BRAF Inhibitors in Aggressive Thyroid Cancer

Thyroid cancer is the most common (~90%) type of endocrine-system tumor, accounting for 70% of the deaths from endocrine cancers. In the last years, the high-throughput genomics has been able to identify pathways/molecular targets involved in survival and tumor progression. Targeted therapy and immunotherapy individually have many limitations. Regarding the first one, although it greatly reduces the size of the cancer, clinical responses are generally transient and often lead to cancer relapse after initial treatment. For the second one, although it induces longer-lasting responses in cancer patients than targeted therapy, its response rate is lower. The individual limitations of these two different types of therapies can be overcome by combining them. Here, we discuss MAPK pathway inhibitors, i.e., BRAF and MEK inhibitors, combined with checkpoint inhibitors targeting PD-1, PD-L1, and CTLA-4. Several mutations make tumors resistant to treatments. Therefore, more studies are needed to investigate the patient's individual tumor mutation burden in order to overcome the problem of resistance to therapy and to develop new combination therapies.

Advances in pharmacotherapy for advanced thyroid cancer of follicular origin (PTC, FTC). New approved drugs and future therapies

INTRODUCTION

The most common altered signaling found in aggressive iodine-refractory Thyroid cancer derived from follicular cells (RAI-TC) are RTK, MAPK, PI3K, WNT, BRAF, RAS, RET, and TP53. Tyrosine Kinase Inhibitors (TKI) are multi-kinase inhibitors able to act against different pathways, that elicit an anti-neoplastic activity.

AREAS COVERED

The aim of this paper is to review recent novel molecular therapies of RAI-TC. Recently, sorafenib and lenvatinib, have been approved for the treatment of aggressive RAI-TC. Other studies are evaluating vandetanib and selumetinib in RAI-TC. Furthermore, preliminary studies have evaluated dabrafenib, and vemurafenib in BRAF mutated RAI-TC patients to re-induce 131-iodine uptake. The interplay between cells of the immune system and cancer cells can be altered by immune checkpoints inhibitors. The expression of PDL1 in RAI-TC was related to tumor recurrence and poor survival. Several clinical trials are investigating a combination of different therapies, such as lenvatinib and pembrolizumab.

EXPERT OPINION

Mechanisms of resistance to TKIs inhibitors can be of intrinsic or acquired origin. An acquired resistance to lenvatinib, or sorafenib can be due to upregulation of FGFR; therefore anti-FGFR agents are evaluated. A new strategy is to combine TKIs with immunotherapy. Several studies are evaluating lenvatinib and pembrolizumab in RAI-TC patients.

Noncoding RNAs in Papillary Thyroid Cancer: Interaction with Cancer-Associated Fibroblasts (CAFs) in the Tumor Microenvironment (TME) and Regulators of Differentiation and Lymph Node Metastasis

A large majority of all thyroid cancers are papillary thyroid carcinomas (PTC), named for the specific papillary architecture observed histologically. Despite the high rate of success with modern diagnostic and therapeutic algorithms, there are significant areas where the management of PTC can be improved. Aggressive PTC subtypes that are refractory to radioactive iodine (RAI) therapy carry a more severe prognosis and account for most of PTC-related deaths. As lymph node metastasis is present in roughly 40% of all adult PTC cases, higher specificity in these tests is a clinical need, especially since lymph node metastases are associated with reduced survival and higher recurrence rates. Additionally, this cancer can progress to more dedifferentiated and aggressive variants, such as poorly differentiated papillary thyroid cancer (PDPTC) and anaplastic thyroid cancer (ATC). Therefore, development of more sensitive and specific detection methods that allow unnecessary surgeries to be avoided is of the utmost importance. The body of large-scale, unbiased gene expression analysis in PTC has focused on the coding transcriptome, specifically mRNAs and microRNAs. However, there have been implications for the potential use of long noncoding RNAs (lncRNAs) in PTC diagnosis, prognosis, and treatment via the utilization of genome-wide studies of patient samples. lncRNAs have diverse regulatory potential in gene expression, alternative splicing, posttranscriptional mRNA modification, and epigenomic alterations. Many lncRNAs have tissue-specific expression and are demonstrated to play key roles in cancer progression and prognosis. However, lncRNAs are not being exploited as biomarkers or therapeutic targets currently, despite their elucidated effects on oncogenesis. These potent biomarkers would be revolutionary in detection at early stages, as this significantly increases the chances of survival. Their aberrant expression in cancer and correlation with steps in tumorigenesis as well as their role in differentiation would allow for a promising role as a prognostic and diagnostic biomarker in thyroid cancer. This would help prevent the more aggressive ATC that derives from dedifferentiation of the less aggressive PTC and FTC. The targeting of the specific lncRNAs could also pose a valuable treatment option via preventing or reversing this dedifferentiation process and making this usually refractory form of thyroid cancer more responsive to standard treatment options.

Combined Treatment with Laser Ablation and Tyrosine-Kinase Inhibitor as a Novel Multimodality Approach to Locally Advanced Thyroid Cancer: a Case Report

BACKGROUND

Direct locoregional treatments were recently proposed for the local control of cervical and distant metastasis of thyroid cancer, but data on their use as part of a multimodality approach for primary thyroid tumors are poor. In this feasibility study, laser ablation (LTA) was successfully used for the initial debulking of unresectable radioiodine-refractory thyroid cancer in sequential therapy with tyrosine-kinase inhibitors (TKI).

CLINICAL CASE

A 69-year-old woman underwent partial resection of papillary thyroid cancer with extensive tracheal infiltration. Post-treatment whole-body scan (131I, 8140 MBq) showed the absence of cervical thyroid uptake. The patient experienced a rapid increase in her cervical mass associated with dysphonia, dyspnea, and dysphagia. Due to a concomitant severe hypertensive state and cardiac failure, the patient was treated with LTA after a multidisciplinary consultation. After local anesthesia, two 300 nm optic fibers were inserted into the lesion through 21G spinal needles. Two illuminations with 4-watt output power and 3600 Joules energy delivery were performed with a diode-laser source. LTA resulted in rapid cancer debulking, and mass volume decreased from 23.9 to 7.5 mL resulting in significant improvement of pressure symptoms. Three months later, the patient was started on lenvatinib due to the initial regrowth of the tumor mass. The cervical tumor burden was controlled by TKI for 20 months when a rapid disease progression occurred, and the patient died.

DISCUSSION

Locally advanced, unresectable, and radioiodine-refractory thyroid tumors can be managed with a novel multimodality approach. The initial debulking with LTA of the locally aggressive disease results in rapid control of the tumor burden threatening patients' life and is effectively followed by long-term control with TKI treatment.

CONCLUSION

Based on this experience, sequential multimodality treatment with an initial locally directed laser ablation procedure followed by TKI therapy may be considered as a salvage option in patients with unresectable and rapidly progressive RR thyroid tumors.

Lenvatinib: an investigational agent for the treatment of differentiated thyroid cancer

INTRODUCTION

Differentiated thyroid cancer (DTC; >90% of all TCs) derives from follicular cells. Surgery is the main therapeutic strategy, and radioiodine (RAI) is administered after thyroidectomy. When DTC progresses, it does not respond to RAI and thyroid-stimulating hormone (TSH)-suppressive thyroid hormone treatment, and other therapies (i.e. surgery, external beam radiation therapy and chemotherapy) do not lead to a better survival. Thanks to the understanding of the molecular pathways involved in TC progression, important advances have been done. Lenvatinib is a multitargeted tyrosine kinase inhibitor of VEGFR1-3, FGFR1-4, PDGFRα, RET, and KIT signaling networks implicated in tumor angiogenesis, approved in locally recurrent or metastatic, progressive, RAI-refractory DTC. Unmet needs regarding the patient clinical therapy responsiveness in aggressive RAI-refractory DTC still remain.

AREAS COVERED

We provide an overview from the literature of in vitro, in vivo and real-life studies regarding lenvatinib as an investigational agent for the treatment of aggressive TC.

EXPERT OPINION

According to the SELECT trial, the treatment should be initiated with a dosage of 24 mg/day, subsequently decreasing it in relation to the side effects. The decision making process in patients with aggressive RAI-refractory DTC should be personalized and the potential toxicity should be properly managed.

Ultrasound-guided implantation of radioactive 125I seed in radioiodine refractory differentiated thyroid carcinoma

BACKGROUND

Treatment for radioiodine refractory differentiated thyroid carcinoma (RR-DTC) is challenging. The purpose of this study was to assess the efficacy and safety of ultrasound-guided implantation of radioactive ¹²⁵I-seed in radioiodine refractory differentiated thyroid carcinoma.

METHODS

Thirty-six cervical metastatic lymph nodes (CMLNs) diagnosed with RR-DTC from 18 patients were enrolled in this retrospective study. US and contrast-enhanced ultrasound (CEUS) examinations were performed before implantation. Follow-up comprised US, CEUS, thyroglobulin (Tg) level and routine hematology at 1-3, 6, 9 and 12 months and every 6 months thereafter. The volumes of the nodules were compared before implantation and at each follow-up point. The volume reduction rate (VRR) of nodules was also recorded.

RESULTS

The median volume of the nodules was 523 mm³ (148, 2010mm³) initially, which decreased significantly to 53mm³ (0, 286mm³) (P < 0.01) at the follow-up point of 24 months with a median VRR as 95% (86,100%). During the follow-up period (the range was 24-50 months), 25 (69%) nodules had VRR greater than 90%, of which 12 (33%) nodules had VVR ≈ 100% with unclear structures and only ¹²⁵I seed images were visible in the US. At the last follow-up visit, the serum Tg level decreased from 57.0 (8.6, 114.8) ng/ml to 4.9 (0.7, 50.3) ng/ml, (P < 0.01).

CONCLUSION

US-guided ¹²⁵I seed implantation is safety and efficacy in treating RR- DTC. It could be an effective supplement for the comprehensive treatment of thyroid cancer.

Clinical Indications for Treatment with Multi-Kinase Inhibitors in Patients with Radioiodine-Refractory Differentiated Thyroid Cancer

Differentiated thyroid cancer is usually a slow-growing disease, even if the patients develop distant metastasis. For recurrent or metastatic disease, radioactive iodine therapy is a standard treatment. However, the disease gradually progresses in some of the patients and can ultimately develop into life-threatening conditions. For patients with progressive radioactive iodine-refractory differentiated thyroid cancer (RR-DTC), multi-kinase inhibitors (MKIs) including sorafenib and lenvatinib prolonged progression-free survival compared with placebo in pivotal randomized phase 3 trials, although the benefit in overall survival has not been clearly confirmed, possibly because the patients who received placebo were permitted to cross-over to lenvatinib upon disease progression. Moreover, the adverse events related to MKIs were not negligible. Therefore, the optimal timing of MKI initiation has long been controversial, and physicians should consider various patient and disease factors. Herein, we comprehensively review the clinical factors that can be helpful in determining the initiation of MKIs for patients with RR-DTC.

Recurrent follicular thyroid carcinoma metastatic to axillary lymph nodes mimicking pulmonary adenocarcinoma

Differentiated thyroid cancers generally have favorable prognoses, though follicular thyroid cancer is overall associated with a worse prognosis due in part to increased incidence of distant metastasis. We report a case of a 51-year-old woman with a history of widely invasive follicular thyroid carcinoma treated with a total thyroidectomy, radioactive iodine and external beam radiation. Five and a half years following her surgery, she was found to have an axillary lymph node mass, multiple lung masses, and a hilar mass in the setting of declining thyroglobulin (Tg) antibodies. Her metastases were initially thought to be due to a primary lung adenocarcinoma given a neoplastic cell immunophenotype that included an absence of Tg expression and co-expression of TTF-1 and Napsin A. However, PAX8 expression demonstrated that the axillary and hilar metastases were actually thyroid in origin rather than lung. Axillary metastases in differentiated thyroid carcinoma are exceedingly rare and previous reports have typically involved widely disseminated disease with extensive neck lymphadenopathy. With a decline in Tg antibodies levels in high-risk patients, one should consider progression and loss of differentiation of thyroid carcinoma rather than a response to treatment.

Learning points:

Axillary metastases in differentiated thyroid carcinoma are uncommon.

In patients with high-risk thyroid carcinomas, a decline in thyroglobulin antibody may not signal disease improvement, but rather a progression to a poorly differentiated form of cancer.

PAX8 staining can be used to differentiate thyroid carcinomas from lung adenocarcinomas.

The Antitumour Effect of Prunella vulgaris Extract on Thyroid Cancer Cells In Vitro and In Vivo

Prunella vulgaris, a traditional Chinese medicine, has been used to treat various benign and malignant tumours for centuries in China. In our previous studies, Prunella vulgaris extract (PVE) was shown to promote apoptosis in differentiated thyroid cancer (DTC) cells. However, whether other mechanisms are involved in the antitumour effect of PVE in thyroid cancer (TC) cells remains unclear. The present study aimed to investigate the antiproliferative and antimigratory effects of PVE on TC cell lines both in vitro and in vivo. First, the TPC-1 and SW579 human TC cell lines were screened by MTT assay for their high level of sensitivity to PVE. Then, the results of cell growth curve and colony formation assay and cell cycle analyses, wound healing, and migration assays demonstrated that PVE inhibited the proliferation and migration of TPC-1 and SW579 cells. Moreover, the antitumour effect of PVE was verified in a subcutaneous xenotransplanted tumour model. Next, MKI67, PCNA, CTNNB1, and CDH1 were screened by qRT-PCR for their significantly differential expression levels in xenograft tissue with and without PVE treatment, and expression of MKI67, PCNA, and CDH1 was verified by Western blot. Finally, an integrated bioinformatics analysis containing protein-protein interaction network, KEGG pathway, and GO analysis was conducted to explore more potential antitumour mechanisms of PVE. In summary, PVE could inhibit the proliferation and migration of TC cells both in vitro and in vivo, which may have been achieved by modulation of the expression of MKI67, PCNA, and CDH1. These data suggest that PVE has the potential to be developed into a new anticancer drug for the treatment of TC.

Molecular targets of tyrosine kinase inhibitors in thyroid cancer

Thyroid cancer (TC) is the eighth most frequently diagnosed cancer worldwide with a rising incidence in the past 20 years. Surgery is the primary strategy of therapy for patients with medullary TC (MTC) and differentiated TC (DTC). In DTC patients, radioactive iodine (RAI) is administered after thyroidectomy. Neck ultrasound, basal and thyroid-stimulating hormone-stimulated thyroglobulin are generally performed every three to six months for the first year, with subsequent intervals depending on initial risk assessment, for the detection of possible persistent/recurrent disease during the follow up. Distant metastases are present at the diagnosis in ∼5 % of DTC patients; up to 15 % of patients have recurrences during the follow up, with a survival reduction (70 %-50 %) at 10-year. During tumor progression, the iodide uptake capability of DTC cancer cells can be lost, making them refractory to RAI, with a negative impact on the prognosis. Significant advances have been done recently in our understanding of the molecular pathways implicated in the progression of TCs. Several drugs have been developed, which inhibit signaling kinases or oncogenic kinases (BRAF^V600E, RET/PTC), such as those associated with Platelet-Derived Growth Factor Receptor and Vascular Endothelial Growth Factor Receptor. Tyrosine kinase receptors are involved in cancer cell proliferation, angiogenesis, and lymphangiogenesis. Several tyrosine kinase inhibitors (TKIs) are emerging as new treatments for DTC, MTC and anaplastic TC (ATC), and can induce a clinical response and stabilize the disease. Lenvatinib and sorafenib reached the approval for RAI-refractory DTC, whereas cabozantinib and vandetanib for MTC. These TKIs extend median progression-free survival, but do not increase the overall survival. Severe side effects and drug resistance can develop in TC patients treated with TKIs. Additional studies are needed to identify a potential effective targeted therapy for aggressive TCs, according to their molecular characterization.

Ultrasound validation of predictive model for central cervical lymph node metastasis in papillary thyroid cancer on BRAF

Aim: To compare the value of predictive power of the models for central cervical lymph node metastasis (CLNM) in papillary thyroid carcinomas (PTCs). Patients & methods: 220 PTCs were prospectively enrolled into the study with pathological examination. We established a new risk model with univariate and multivariate analyses and receiver-operating characteristic curves were plotted. Z-test was performed to compare the area under two curves and validated the predictive model for central CLNM in PTCs. The comparison of previous and new predictive model was analyzed. Results: Microcalcification, capsule contact or involvement, internal flow and BRAF^V600E mutation were four independent risk factors for PTCs with central CLNMs. The area under the curves for the new and the previous model were 0.948 and 0.934 (p = 0.572), respectively. Conclusion: Two predictive models showed strong consistency in predicting central CLNM in PTCs. The predictive model may be helpful in selecting appropriate treatment method in PTCs.

Kinase Inhibitors in the Treatment of Thyroid Cancer: Institutional Experience

Although most patients with thyroid cancer have a favorable clinical course, some patients develop a more aggressive type of cancer and exhibit more rapid disease progression with worse prognosis. Those patients usually exhibit mutations of proteins such as tyrosine kinase enzymes that play a significant role in regulation of tumor proliferation and spreading. Development of targeted therapies is based on the inhibition of mutated kinases which are involved in the MAPK signaling pathway. The aim of this study was to present the initial results of clinical experience with kinase inhibitors in patients with metastatic differentiated thyroid cancer (DTC), poorly differentiated thyroid cancer (PDTC), and medullary thyroid cancer (MTC) who exhibited rapid disease progression. A total of 17 adult patients (11 women, mean age 53.3 years) managed for progressive, metastatic disease were included in the study. Twelve patients with DTC and PDTC were previously tested for BRAF mutations, of whom nine that had tumor tissue negative for the BRAF V600E mutation received sorafenib, while three patients with tumors harboring the BRAF V600E mutation were treated with vemurafenib. Patients with MTC were treated with sunitinib, vandetanib, and sorafenib. Two patients with tumors harboring the BRAF mutation treated with vemurafenib showed restoration of radioiodine uptake. Most of patients showed significant improvement in disease status but of limited duration until disease progression. Although there was an improvement in progression-free survival, future research has to achieve a greater and longer-lasting response, probably by utilizing combined targeted therapy.

Preparation and SPECT/CT Imaging of 177Lu-Labeled Peptide Nucleic Acid (PNA) Targeting CITED1: Therapeutic Evaluation in Tumor-Bearing Nude Mice

Purpose

The expression of Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 1 (CITED1) is upregulated in papillary thyroid carcinoma (PTC) and mediates cell proliferation and migration. To facilitate early diagnosis and monitoring of recurrent or metastatic PTC, we designed ¹⁷⁷Lu-labeled antisense peptide nucleic acid (PNA) targeting CITED1 mRNA to evaluate the therapeutic potential, while analyzing its distribution in nude mice and the characteristics withsingle-photon emission-computed tomography/computed tomography (SPECT/CT) imaging.

Materials and Methods

¹⁷⁷Lu-DOTA-anti-CITED1-PNA (¹⁷⁷Lu-asPNA) was obtained by indirect labeling. High-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) were used to determine the labeling rate and radiochemical purity. The stability of ¹⁷⁷Lu-asPNA was evaluated by TLC, and the radioactivity count was measured by a γ counter to calculate its uptake capacity in K1 cells. To analyze the distribution of ¹⁷⁷Lu-asPNA in body tissues and organs of nude mice, static single-photon emission-computed tomography (SPECT) imaging and SPECT/CT image fusion were performed. Then, the therapeutic effects of probes were explored by tumor growth curves and survival analysis.

Results

Our probe showed a radiochemical purity of 96.5±0.15% at 1 hr and specific activity of 8.7±0.53 MBq/μg. The uptake rate in the ¹⁷⁷Lu-asPNA group was much higher than that in the ¹⁷⁷Lu-DOTA-nonsense-PNA (¹⁷⁷Lu-nonsense-PNA) and ¹⁷⁷Lu-DOTA groups (P<0.05). The biological distribution showed that the tumor/muscle ratio was at its highest at 24 h (4.98±0.34) post-inoculation, with SPECT/CT imaging showing clear tumor development. By measuring tumor volume of tumor-bearing nude mice, the ¹⁷⁷Lu-asPNA group showed a significant difference in tumor size 9 days after injection (P < 0.05). Kaplan-Meier survival curves showed that the overall survival rate in the ¹⁷⁷Lu-asPNA group was significantly different from those in the DOTA-anti-CITED1-PNA (asPNA) and saline groups (P = 0.002, log-rank test).

Conclusion

¹⁷⁷Lu-asPNA was developed successfully, showing a high labeling rate and good stability. SPECT/CT imaging demonstrated tumor growth in nude mice, which was effectively inhibited by our probe, thus prolonging survival.

Lenvatinib and sorafenib for differentiated thyroid cancer after radioactive iodine: a systematic review and economic evaluation

BACKGROUND

Thyroid cancer is a rare cancer, accounting for only 1% of all malignancies in England and Wales. Differentiated thyroid cancer (DTC) accounts for ≈94% of all thyroid cancers. Patients with DTC often require treatment with radioactive iodine. Treatment for DTC that is refractory to radioactive iodine [radioactive iodine-refractory DTC (RR-DTC)] is often limited to best supportive care (BSC).

OBJECTIVES

We aimed to assess the clinical effectiveness and cost-effectiveness of lenvatinib (Lenvima®; Eisai Ltd, Hertfordshire, UK) and sorafenib (Nexar®; Bayer HealthCare, Leverkusen, Germany) for the treatment of patients with RR-DTC.

DATA SOURCES

EMBASE, MEDLINE, PubMed, The Cochrane Library and EconLit were searched (date range 1999 to 10 January 2017; searched on 10 January 2017). The bibliographies of retrieved citations were also examined.

REVIEW METHODS

We searched for randomised controlled trials (RCTs), systematic reviews, prospective observational studies and economic evaluations of lenvatinib or sorafenib. In the absence of relevant economic evaluations, we constructed a de novo economic model to compare the cost-effectiveness of lenvatinib and sorafenib with that of BSC.

RESULTS

Two RCTs were identified: SELECT (Study of [E7080] LEnvatinib in 131I-refractory differentiated Cancer of the Thyroid) and DECISION (StuDy of sorafEnib in loCally advanced or metastatIc patientS with radioactive Iodine-refractory thyrOid caNcer). Lenvatinib and sorafenib were both reported to improve median progression-free survival (PFS) compared with placebo: 18.3 months (lenvatinib) vs. 3.6 months (placebo) and 10.8 months (sorafenib) vs. 5.8 months (placebo). Patient crossover was high (≥ 75%) in both trials, confounding estimates of overall survival (OS). Using OS data adjusted for crossover, trial authors reported a statistically significant improvement in OS for patients treated with lenvatinib compared with those given placebo (SELECT) but not for patients treated with sorafenib compared with those given placebo (DECISION). Both lenvatinib and sorafenib increased the incidence of adverse events (AEs), and dose reductions were required (for > 60% of patients). The results from nine prospective observational studies and 13 systematic reviews of lenvatinib or sorafenib were broadly comparable to those from the RCTs. Health-related quality-of-life (HRQoL) data were collected only in DECISION. We considered the feasibility of comparing lenvatinib with sorafenib via an indirect comparison but concluded that this would not be appropriate because of differences in trial and participant characteristics, risk profiles of the participants in the placebo arms and because the proportional hazard assumption was violated for five of the six survival outcomes available from the trials. In the base-case economic analysis, using list prices only, the cost-effectiveness comparison of lenvatinib versus BSC yields an incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained of £65,872, and the comparison of sorafenib versus BSC yields an ICER of £85,644 per QALY gained. The deterministic sensitivity analyses show that none of the variations lowered the base-case ICERs to < £50,000 per QALY gained.

LIMITATIONS

We consider that it is not possible to compare the clinical effectiveness or cost-effectiveness of lenvatinib and sorafenib.

CONCLUSIONS

Compared with placebo/BSC, treatment with lenvatinib or sorafenib results in an improvement in PFS, objective tumour response rate and possibly OS, but dose modifications were required to treat AEs. Both treatments exhibit estimated ICERs of > £50,000 per QALY gained. Further research should include examination of the effects of lenvatinib, sorafenib and BSC (including HRQoL) for both symptomatic and asymptomatic patients, and the positioning of treatments in the treatment pathway.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017055516.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

A systematic review of lenvatinib and sorafenib for treating progressive, locally advanced or metastatic, differentiated thyroid cancer after treatment with radioactive iodine

BACKGROUND

Treatment with radioactive iodine is effective for many patients with progressive, locally advanced or metastatic, differentiated thyroid cancer. However, some patients become refractory to treatment. These types of patients are considered to have radioactive iodine refractory differentiated thyroid cancer (RR-DTC).

METHODS

We searched Embase, MEDLINE, PubMed and the Cochrane Library from January 1999 through January 2017. Reference lists of included studies and ongoing trial registries were also searched. Reports of randomized controlled trials (RCTs), prospective observational studies, and systematic reviews/indirect comparisons were eligible for inclusion. In the absence of direct clinical trial evidence comparing lenvatinib versus sorafenib, we assessed the feasibility of conducting an indirect comparison to obtain estimates of the relative efficacy and safety of these two treatments.

RESULTS

Of 2364 citations, in total, 93 papers reporting on 2 RCTs (primary evidence), 9 observational studies and 13 evidence reviews (supporting evidence) were identified. Compared to placebo, RCT evidence demonstrated improvements with lenvatinib or sorafenib in median progression-free survival (PFS) and objective tumour response rate (ORR). Overall survival (OS) was confounded by high treatment crossover (≥75%) in both trials. Adverse events (AEs) were more common with lenvatinib or sorafenib than with placebo but the most common AEs associated with each drug differed. Primarily due to differences in the survival risk profiles of patients in the placebo arms of the RCTs, we considered it inappropriate to indirectly compare the effectiveness of lenvatinib versus sorafenib. ORR and AE findings for lenvatinib and sorafenib from the supporting evidence were broadly in line with RCT evidence. Health-related quality of life (HRQoL) data were limited.

CONCLUSIONS

Lenvatinib and sorafenib are more efficacious than placebo (a proxy for best supportive care) for treating RR-DTC. Uncertainty surrounds the extent of the impact on OS and HRQoL. Lenvatinib could not reliably be compared with sorafenib. Choice of treatment is therefore likely to depend on an individual patient's circumstances.

Lesion-Based Evaluation Predicts Treatment Response to Lenvatinib for Radioactive Iodine-Refractory Differentiated Thyroid Cancer: A Korean Multicenter Retrospective Study

Background: Lenvatinib, a tyrosine kinase inhibitor (TKI) recently approved for treating radioactive iodine-refractory differentiated thyroid cancer, has been shown to delay disease progression and provide meaningful benefit for overall survival (OS). However, there is no predictive marker for response to lenvatinib before initiating treatment. We comprehensively analyzed clinical and radiological parameters to predict response to lenvatinib using lesion-based assessments. Methods: Medical records were collected from 67 patients treated with lenvatinib in 11 referral hospitals across Korea from June 2015 to December 2017. Up to 96 measurable lesions, defined as per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, were evaluated serially until progressive disease (PD) occurred, and tumor doubling time (TDT) was calculated based on changes between historical computed tomography (CT) scans and baseline CT scans performed at treatment initiation. Results: Excluding patients with anaplastic thyroid cancer, no thyroidectomy, nontarget lesions only, or treatment periods of <1 month, 57 patients were analyzed, of whom 7 (12.2%) were TKI-naive. The median progression-free survival was 5.1 months (95% confidence interval [CI], 4.4-9.5), the median OS was 19.3 months (95% CI 12.4-not reached), the mean duration of response was 6.0 ± 4.4 months, and the objective response rate was 38%. In lesion-based assessments, 31 lesions (32.2%) with significant tumor shrinkage (complete remission or partial response) were significantly associated with shorter TDT (<12 months; p = 0.02). Patients with rapidly PD with a shorter initial TDT (<6 months) were more likely to respond to lenvatinib (p = 0.03). Patients exposed to lenvatinib at an average of ≥16 mg per day, or who were TKI-naive before treatment with lenvatinib, had a lower risk of progression; however, the risk reduction did not reach statistical significance (daily dosage p = 0.07, TKI exposure p = 0.09). Conclusions: TDT calculations at the beginning of treatment and lesion-based tumor assessment may help identify potential responders to lenvatinib therapy and predict therapeutic responses.

Efficacy and safety of lenvatinib in an elderly patient with metastatic papillary thyroid carcinoma and cardiological comorbidity: a case report

Lenvatinib significantly prolonged progression-free survival versus placebo in patients with radio-iodine refractory differentiated thyroid carcinoma. However, the primary adverse effects of any grade that occurred in >40% of patients in the lenvatinib group of the Phase III SELECT trial was hypertension (67.8%). Therefore, this drug should be used with caution in patients with cardiological morbidity. Here, we describe the case of a 73-year-old man with hypertension, obesity and chronic atrial fibrillation, who received lenvatinib for 6 months in the absence of cardiological symptoms.

Embolization of iliac metastasis during lenvatinib treatment in patient with advanced Hürthle cell thyroid carcinoma

Lenvatinib is a tyrosine kinase inhibitor (TKI) with antiproliferative and antiangiogenic effects indicated for the treatment of progressive, locally advanced or metastatic progressive thyroid carcinoma, refractory to radioactive iodine therapy. Antiangiogenic therapies induce ischemic necrosis of tumor tissue, with increased risk of hemorrhagic complications. The management of hemorrhagic risk is based on precautionary measures and for any surgical procedure, it is advised to interrupt the treatment in order to avoid complications. 'Flare-up' of tumor activity may follow TKI interruption. However, it is not known if continuing TKIs during minimally invasive interventions is safe. We report here the first case in which an embolization of metastasis is performed without interrupting lenvatinib treatment. The procedure was successful and free of complications.

Treatment-related adverse effects with TKIs in patients with advanced or radioiodine refractory differentiated thyroid carcinoma: a systematic review and meta-analysis

Background

Tyrosine kinase inhibitors (TKIs) have been administered to advanced or radio-iodine refractory differentiated thyroid carcinoma (RR-DTC) patients for years. We performed a pooled analysis to explore the frequency of severe adverse effects in advanced or RR-DTC patients treated with sorafenib and lenvatinib.

Methods

We performed a comprehensive search of computerized databases, including PubMed, Web of Science, Ovid, EMASE, and the Cochrane Library, from the drugs' inception to July 2018 to identify clinical trials. All grade and severe adverse events (AEs; grade ≥3) were analyzed. This meta-analysis was conducted in accordance with PRISMA guidelines.

Results

In total, seve studies published from 2012-2018 with 657 patients were eligible for this study. We included two studies (238 patients) that received 200 mg sorafenib twice and five studies (419 patients) that received 24 mg lenvatinib daily. The frequency of AEs was different among the two drugs. Patients in the sorafenib group had a significantly higher frequency of all grade hand-foot syndrome, hypocalcemia, rash, elevated alanine aminotransferase (ALT), and elevated aspartate aminotransferase (AST). Conversely, the lenvatinib group experienced more frequent all grade voice change, hypertension, nausea, and vomiting compared with those with sorafenib. For grade ≥3 adverse effects, hand-foot syndrome, hypocalcemia, and elevated ALT were more frequent in sorafenib-treated patients. Moreover, lenvatinib-treated patients had a significantly higher incidence of severe weight loss, hypertension, and nausea.

Conclusion

Significant differences in common adverse effects, such as all-grade and severe AEs, were detected between sorafenib and lenvatinib in the current study. Early intervention and management of treatment-related AEs (TRAEs) can minimize the impact on patients' quality-of-life, and avoid unnecessary dose reductions and treatment-related discontinuations.

DDR1 regulates thyroid cancer cell differentiation via IGF-2/IR-A autocrine signaling loop

Patients with thyroid cancers refractory to radioiodine (RAI) treatment show a limited response to various therapeutic options and a low survival rate. The recent use of multikinase inhibitors has also met limited success. An alternative approach relies on drugs that induce cell differentiation, as the ensuing increased expression of the cotransporter for sodium and iodine (NIS) may partially restore sensitivity to radioiodine. The inhibition of the ERK1/2 pathway has shown some efficacy in this context. Aggressive thyroid tumors overexpress the isoform-A of the insulin receptor (IR-A) and its ligand IGF-2; this IGF-2/IR-A loop is associated with de-differentiation and stem-like phenotype, resembling RAI-refractory tumors. Importantly, IR-A has been shown to be positively modulated by the non-integrin collagen receptor DDR1 in human breast cancer. Using undifferentiated human thyroid cancer cells, we now evaluated the effects of DDR1 on IGF-2/IR-A loop and on markers of cell differentiation and stemness. DDR1 silencing or downregulation caused significant reduction of IR-A and IGF-2 expression, and concomitant increased levels of differentiation markers (NIS, Tg, TSH, TPO). Conversely, markers of epithelial-to-mesenchymal transition (Vimentin, Snail-2, Zeb1, Zeb2 and N-Cadherin) and stemness (OCT-4, SOX-2, ABCG2 and Nanog) decreased. These effects were collagen independent. In contrast, overexpression of either DDR1 or its kinase-inactive variant K618A DDR1-induced changes suggestive of less differentiated and stem-like phenotype. Collagen stimulation was uneffective. In conclusion, in poorly differentiated thyroid cancer, DDR1 silencing or downregulation blocks the IGF-2/IR-A autocrine loop and induces cellular differentiation. These results may open novel therapeutic approaches for thyroid cancer.

Therapeutic options for advanced thyroid cancer

Thyroid cancer can be largely classified as well-differentiated, poorly differentiated, medullary and anaplastic. Differentiated thyroid cancer (DTC) includes follicular and papillary subtypes, with the incidence of papillary thyroid cancer (PTC) on the rise. The mainstay of treatment for DTC includes a combination of surgery, radioactive iodine (RAI) and levothyroxine suppression. DTC portends a favorable prognosis, even in the presence of distant metastases, with a 50% rate of 5-year survival largely due to tumor cell's sensitivity to RAI therapy influencing disease outcome. In radioactive iodine refractory differentiated thyroid cancer (RAI-refractory DTC) there is a lower survival rate prompting the use of other therapeutic options available. RAI refractoriness is more common in older patients (age >40), large metastases and lesions that are fluorodeoxyglucose (FDG) avid on position emission tomography (PET). Over the past decade, Identification of genetic mutations in the signaling pathway involved in thyroid tumorigenesis has led to the approval of tyrosine kinase inhibitors (TKIs); Sorafenib and Lenvatinib in RAI-refractory DTC. Similarly, metastatic medullary thyroid cancer (MTC) implies an unfavorable 10-year survival rate of only 20% as the principal treatment options focuses on loco regional control via surgical and/or non-surgical options. The approval of TKIs such as Cabozantinib and Vandetanib has introduced an encouraging, novel, systemic therapeutic option for metastatic MTC. Lastly, anaplastic thyroid cancer (ATC) carries the worst prognosis with high recurrence rates. Treatment includes surgery, chemotherapy and external beam radiation. The FDA recently approved Dabrafenib plus trametinib for BRAF V600E mutated ATC. Considering the modality of chemotherapy and the expanding field of targeted therapies, the role of the oncologist and interaction with endocrinologist in the management of thyroid cancer needs further clarification aiming at collaborative management plans more than ever. This review summarizes the key phase III trials that led to the approval of TKIs in the treatment of DTC and metastatic MTC. Additionally, the review aims to clarify the patient selection criteria for initiation of TKIs and examine the implications, considerations and adverse effects prior to utilizing targeted therapy. Clinical trials are ongoing with promising results and may contribute to the addition of several targeted molecules and immune check point inhibitors to the therapeutic armamentarium for RAI-refractory DTC, medullary and anaplastic thyroid cancer.

Managing the adverse events associated with lenvatinib therapy in radioiodine-refractory differentiated thyroid cancer

Lenvatinib is a multikinase inhibitor of vascular endothelial growth factor (VEGF) receptors 1-3, fibroblast growth factor receptors 1-4, RET, KIT, and platelet-derived growth factor receptor-α. Lenvatinib is approved as a monotherapy for the treatment of radioiodine-refractory differentiated thyroid cancer and in combination with everolimus for the second-line treatment of advanced renal cell carcinoma. Lenvatinib is also under investigation for the treatment of several malignancies including unresectable hepatocellular carcinoma. Although lenvatinib is associated with favorable efficacy, it is associated with adverse events (AEs) that the clinician will have to closely monitor for and proactively manage. Most of these AEs are known class effects of VEGF-targeted therapies, including hypertension, diarrhea, fatigue or asthenia, decreased appetite, and weight loss. This review summarizes the safety profile of lenvatinib and offers guidance for the management of both frequent and rare AEs. We discuss the potential mechanisms underlying these AEs and present practical recommendations for managing toxicities. The development of treatment plans that include prophylactic and therapeutic strategies for the management of lenvatinib-associated AEs has the potential to improve patient quality of life, optimize adherence, minimize the need for dose reductions, treatment interruptions, or discontinuations, and maximize patient outcomes.

Long-term efficacy of lenvatinib for recurrent papillary thyroid carcinoma after multimodal treatment and management of complications: a case report

Background

The advent of tyrosine kinase inhibitors (TKIs) has changed the treatment of RAI refractory, unresectable recurrent differentiated thyroid cancer (DTC), which was formerly treated with multidisciplinary remedies.

Case presentation

Here we describe the case of a 64-year-old woman who underwent total thyroidectomy with tracheal resection and suffered from a recurrent tumor in the neck and multiple lung and bone metastases 3 and 11 months, respectively, after the operation. Multimodal therapies, RI (I-131), EBRT, and taxane-based chemotherapy were ineffective, and sorafenib was started as a TKI. However, because of disease progression, sorafenib was replaced by lenvatinib after 9 months. The effect of lenvatinib has continued for more than 1 year and 9 months, and the patient has well survived. During the treatment period, a tracheal pin-hole fistula suddenly emerged, which was naturally cured by the temporary cessation of lenvatinib. Adverse events such as hypertension, proteinuria, and diabetes as innate complications have been successfully managed until the present according to our institute regulations.

Conclusions

Even where multimodal treatment was ineffective, lenvatinib was suggested to be an alternative treatment option for RAI refractory recurrent DTC and patient could have a chance to be controlled successfully.

Punicalagin induces senescent growth arrest in human papillary thyroid carcinoma BCPAP cells via NF-κB signaling pathway

Papillary thyroid carcinoma (PTC) is the most common endocrine carcinoma. Our previous study revealed that punicalagin (PUN), an active component from pomegranate, triggered autophagic cell death and DNA damage response (DDR) in papillary thyroid carcinoma BCPAP cells. But the detailed anti-cancer mechanisms of punicalagin against PTC still remained to be further explored. DDR activation is a proven cause of cellular senescence, which mediates anti-tumor processes under certain circumstances. In this study, we reported that punicalagin treatment generated a senescent phenotype of BCPAP cells characterized as altered morphology, increased cell granularity and senescence-associated β-galactosidase (SA-β-Gal) staining. Senescence induced by punicalagin treatment was further confirmed by cell cycle arrest and upregulation of cyclin-dependent kinase inhibitor p21. Meanwhile, the senescence-associated secretory phenotype (SASP) included high levels of inflammatory cytokines, principally IL-6 and IL-1β. Furthermore, punicalagin exposure caused the phosphorylation and subsequent degradation of IκBα as well as the nuclear translocation of p65, suggesting the activation of NF-κB signaling pathway. Inhibition of NF-κB by pyrrolidine dithiocarbamate (PDTC), a selective inhibitor of NF-κB, partially reversed the cellular senescent phenotype induced by punicalagin in BCPAP cells as evidenced by the decreased fraction of SA-β-Gal staining positive cells and blockage of SASP generation. These results collectively showed that punicalagin treatment induced senescent growth arrest and SASP via triggering NF-κB activation. These observations elucidated novel anti-cancer mechanisms of punicalagin and might provide new potential prospects for PTC therapy.

IAPs cause resistance to TRAIL-dependent apoptosis in follicular thyroid cancer

Follicular thyroid cancer's (FTC) excellent long-term prognosis is mainly dependent on postoperative radioactive iodine (RAI) treatment. However, once the tumour becomes refractory, the 10-year disease-specific survival rate drops below 10%. The aim of our study was to evaluate the prognostic and biological role of the TRAIL system in FTC and to elucidate the influence of small-molecule-mediated antagonisation of inhibitor of apoptosis proteins (IAPs) on TRAIL sensitivity in vitro Tissue microarrays were constructed from forty-four patients with histologically confirmed FTC. Expression levels of TRAIL and its receptors were correlated with clinicopathological data and overall as well as recurrence-free survival. Non-iodine-retaining FTC cell lines TT2609-bib2 and FTC133 were treated with recombinant human TRAIL alone and in combination with Smac mimetics GDC-0152 or Birinapant. TRAIL-R2/DR5 as well as TRAIL-R3/DcR1 and TRAIL-R4/DcR2 were significantly higher expressed in advanced tumour stages. Both decoy receptors were negatively associated with recurrence-free and overall survival. TRAIL-R4/DcR2 additionally proved to be an independent negative prognostic marker in FTC (HR = 1.446, 95% CI: 1.144-1.826; P < 0.001). In vitro, the co-incubation of Birinapant or GDC-0152 with rh-TRAIL-sensitised FTC cell lines for TRAIL-induced apoptosis, through degradation of cIAP1/2. The TRAIL system plays an important role in FTC tumour biology. Its decoy receptors are associated with poor prognosis as well as earlier recurrence. The specific degradation of cIAP1/2 sensitises FTC cells to TRAIL-induced apoptosis and might highlight a new point of attack in patients with RAI refractory disease.

CXCR4/CXCR7/CXCL12-Axis in Follicular Thyroid Carcinoma

Background: Follicular thyroid carcinoma's (FTC) often benign course is partially due to adjuvant radioactive iodine (RAI) treatment. However, once the tumour has spread and fails to retain RAI, the therapeutic options are limited and the outcome is poor. In this subset of patients, the identification of novel druggable biomarkers appears invaluable. Here, we investigated the stage dependent expression and functional role of the C-X-C chemokine receptors type 4 and 7 (CXCR4/7) in FTC.

Methods: CXCR4/7 expression was examined in 44 FTC and corresponding non-neoplastic thyroid specimens as well as 10 FTC distant metastases and 18 follicular adenomas using tissue microarray technology. Expression levels were correlated with clinicopathological variables as well as overall and recurrence free survival. Changes regarding cell cycle activation, tumour cell invasiveness and mRNA expression of genes related to epithelial-mesenchymal transition (EMT) were investigated after treatment with recombinant human SDF1α/CXCL12 (rh-SDF1α) and CXCR4 antagonists AMD3100 and WZ811.

Results: CXCR4/7 expression was associated with large tumour size, advanced UICC stage as well as shorter overall and recurrence free survival. CXCR4 was significantly higher expressed in distant metastases than in primary tumour cores. In addition, rh-SDF1α induced invasive growth, cell cycle activation and EMT, while CXCR4 antagonists significantly reduced FTC invasiveness in vitro.

Conclusion: Here we provide first evidence of the biological importance of the CXCR4/CXCR7/CXCL12 axis in FTC. Our findings underscore the therapeutic potential of this chemokine receptor family in advanced FTC and offer new valuable insight into the oncogenesis of metastatic FTC.

High-throughput drug library screening identifies colchicine as a thyroid cancer inhibitor

We employed a high-throughput drug library screening platform to identify novel agents affecting thyroid cancer cells. We used human thyroid cancer cell lines to screen a collection of approximately 5200 small molecules with biological and/or pharmacologial properties. Parallel primary screens yielded a number of hits differentially active between thyroid and melanoma cells. Amongst compounds specifically targeting thyroid cancer cells, colchicine emerged as an effective candidate. Colchicine inhibited cell growth which correlated with G2 cell cycle arrest and apoptosis. These effects were hampered through inhibition of MEK1/2 and JNK. In contrast, inhibition of p38-MAPK had little effect, and AKT had no impact on colchicine action. Systemic colchicine inhibited thyroid cancer progression in xenografted mice. These findings demonstrate that our screening platform is an effective vehicle for drug reposition and show that colchicine warrants further attention in well-defined clinical niches such as thyroid cancer.

Axitinib treatment in advanced RAI-resistant differentiated thyroid cancer (DTC) and refractory medullary thyroid cancer (MTC)

BACKGROUND

Axitinib, an antiangiogenic multikinase inhibitor (MKI), was evaluated in the compassionate use programme (CUP) in Spain (October 2012-November 2014).

SUBJECTS AND METHODS

47 patients with advanced radioactive iodine (RAI)-refractory differentiated thyroid cancer (DTC, n = 34) or medullary thyroid cancer (MTC, n = 13) with documented disease progression were treated with axitinib 5 mg b.i.d. The primary efficacy endpoint was objective response rate (ORR) by Response Evaluation Criteria In Solid Tumors (RECIST) v1.1. Progression-free survival (PFS) and adverse events (AEs) were secondary objectives. Regulatory authorities validated the CUP, and all patients signed informed consent form.

RESULTS

Axitinib was administered as first-line therapy in 17 patients (36.2%), as second-line in 18 patients (38.3%) and as third/fourth-line in 12 patients (25.5%). With a median follow-up of 11.5 months (0-24.3), ORR was 27.7% (DTC: 29.4% and MTC: 23.1%) and median PFS was 8.1 months (95% CI: 4.1-12.2) (DTC: 7.4 months (95% CI: 3.1-11.8) and MTC: 9.4 months (95% CI: 4.8-13.9)). Better outcomes were reported with first-line axitinib, with an ORR of 53% and a median PFS of 13.6 months compared with 16.7% and 10.6 months as second-line treatment. Twelve (25.5%) patients required dose reduction to 3 mg b.i.d. All-grade AEs included asthenia (53.2%), diarrhoea (36.2%), hypertension (31.9%) and mucositis (29.8%); grade 3/4 AEs included anorexia (6.4%), diarrhoea (4.3%) and cardiac toxicity (4.3%).

CONCLUSION

Axitinib had a tolerable safety profile and clinically meaningful activity in refractory and progressive thyroid cancer regardless of histology as first-line therapy. To our knowledge, this is the first time that cross-resistance between MKIs is suggested in thyroid cancer, highlighting the importance of prospective sequential clinical studies.

Survivin and XIAP - two potential biological targets in follicular thyroid carcinoma

Follicular thyroid carcinoma's (FTC) overall good prognosis deteriorates if the tumour fails to retain radioactive iodine. Therefore, new druggable targets are in high demand for this subset of patients. Here, we investigated the prognostic and biological role of survivin and XIAP in FTC. Survivin and XIAP expression was investigated in 44 FTC and corresponding non-neoplastic thyroid specimens using tissue microarrays. Inhibition of both inhibitor of apoptosis proteins (IAP) was induced by shRNAs or specific small molecule antagonists and functional changes were investigated in vitro and in vivo. Survivin and XIAP were solely expressed in FTC tissue. Survivin expression correlated with an advanced tumour stage and recurrent disease. In addition, survivin proved to be an independent negative prognostic marker. Survivin or XIAP knockdown caused a significant reduction in cell viability and proliferation, activated caspase3/7 and was associated with a reduced tumour growth in vivo. IAP-targeting compounds induced a decrease of cell viability, proliferation and cell cycle activity accompanied by an increase in apoptosis. Additionally, YM155 a small molecule inhibitor of survivin expression significantly inhibited tumour growth in vivo. Both IAPs demonstrate significant functional implications in the oncogenesis of FTCs and thus prove to be viable targets in patients with advanced FTC.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Current Standards in Treatment of Radioiodine Refractory Thyroid Cancer

OPINION STATEMENT

Radioiodine refractory differentiated thyroid cancer (RAI-R DTC) is a challenging malignancy with limited prognosis and treatment options. Recently, clinical trials with targeted therapies have advanced the outlook of these patients, and inhibition of the vascular endothelial growth factor (VEGF) axis has led to the approval of small-molecule tyrosine kinase inhibitors (TKIs) for first-line treatment of radioiodine refractory disease. In addition to approved therapies (sorafenib and lenvatinib), other multi-targeted tyrosine kinase inhibitors that are commercially available have been recognized as viable treatment options for RAI-R DTC. Our preference is to initially use lenvatinib, given the dramatic progression-free survival (PFS) improvement versus placebo, with the caveat that 24 mg daily is not often tolerated and lower doses often used. In patients with BRAF V600E mutation, BRAF inhibitors are now considered for treatment, especially if patients are at high risk from antiangiogenic therapy. Research is continuing to evolve in identifying mechanisms related to radioiodine refractoriness, and trials are evaluating therapeutic molecules to overcome this resistance. Clinical care of patients with RAI-R DTC requires careful consideration of both patient and disease characteristics. Many patients with asymptomatic and indolent disease can be followed for years without treatment while others with high volume or rapidly progressive disease merit early intervention.

The Chinese herb Prunella vulgaris promotes apoptosis in human well-differentiated thyroid carcinoma cells via the B-cell lymphoma-2/Bcl-2-associated X protein/caspase-3 signaling pathway

Prunella vulgaris (PV), a traditional Chinese herb, has been shown to be rich in bioactive chemicals and possess anti-proliferative and pro-apoptotic effects on tumor cells. The effect of PV on human well-differentiated thyroid carcinoma (WDTC), which accounts for the majority of common endocrine malignancies, remains to be elucidated. The present study aimed to investigate the function of PV on WDTC cell lines and apoptosis-associated signaling pathway activity. Additional studies demonstrated that PV may induce apoptosis in WDTC TPC-1 and FTC-133 cell lines, using the Cell Counting Kit-8 assay. Morphological changes of apoptotic cells were observed by Hoechst 33342 and acridine orange/ethidium bromide staining. In addition, ladder pattern of fragmented DNA was observed by DNA gel electrophoresis. It was also observed that PV significantly increased Bcl-2-associated X protein and caspase-3 expression, and downregulated B-cell lymphoma-2 expression in TPC-1 and FTC-133 by reverse transcription-quantitative polymerase chain reaction (P<0.05). Thus, the present results indicated that PV has the potential to be a future WDTC therapeutic agent.

Radiolabeling of VEGF165 with 99mTc to evaluate VEGFR expression in tumor angiogenesis

Angiogenesis is the main process responsible for tumor growth and metastatization. The principal effector of such mechanism is the vascular endothelial growth factor (VEGF) secreted by cancer cells and other components of tumor microenvironment. Radiolabeled VEGF analogues may provide a useful tool to noninvasively image tumor lesions and evaluate the efficacy of anti-angiogenic drugs that block the VEGFR pathway. Aim of the present study was to radiolabel the human VEGF165 analogue with 99mTechnetium (99mTc) and to evaluate the expression of VEGFR in both cancer and endothelial cells in the tumor microenvironment. 99mTc-VEGF showed in vitro binding to HUVEC cells and in vivo to xenograft tumors in mice (ARO, K1 and HT29). By comparing in vivo data with immunohistochemical analysis of excised tumors we found an inverse correlation between 99mTc-VEGF165 uptake and VEGF histologically detected, but a positive correlation with VEGF receptor expression (VEGFR1). Results of our studies indicate that endogenous VEGF production by cancer cells and other cells of tumor microenvironment should be taken in consideration when performing scintigraphy with radiolabeled VEGF, because of possible false negative results due to saturation of VEGFRs.

Platelet derived growth factor receptor alpha mediates nodal metastases in papillary thyroid cancer by driving the epithelial-mesenchymal transition

Recently platelet derived growth factor receptor-alpha (PDGFRα) was recognized as a potential target to treat aggressive papillary thyroid cancer given its strong association with lymph node metastases. However, it is unclear how PDGFRα potentiates metastases and if it works through the canonical MAPK pathway traditionally linked to PTC oncogenesis. We explored the phenotypic changes driven by PDGFRα activation in human papillary thyroid cancer (PTC) cells and the downstream signalling cascades through which they are effected. We demonstrate that PDGFRα drives an impressive phenotypic change in PTC cell lines as documented by significant cytoskeletal rearrangement, increased migratory potential, and the formation of invadopodia. Cells lacking PDGFRα formed compact and dense spheroids, whereas cells expressing active PDGFRα exhibited invadopodia in three-dimensional culture. To achieve this, active PDGFRα provoked downstream activation of the MAPK/Erk, PI3K/Akt and STAT3 pathways. We further confirmed the role of PDGFRα as a transformative agent promoting the epithelial to mesenchymal transition of PTC cells, through the augmentation of Snail and Slug expression. Crenolanib, a small molecule inhibitor of PDGFRα, suppressed the levels of Snail and Slug and almost completely reversed all the phenotypic changes. We demonstrate that PDGFRα activation is an essential component that drives aggressiveness in PTC cells, and that the signaling pathways are complex, involving not only the MAPK/Erk but also the PI3K/Akt and STAT3 pathways. This argues for upstream targeting of the PDGFRα given the redundancy of oncogenic pathways in PTC, especially in patients whose tumors over-express this tyrosine kinase receptor.

Lenvatinib: A Review in Refractory Thyroid Cancer

Lenvatinib (Lenvima®) is an oral, multi-targeted tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor (VEGF) receptors 1, 2 and 3, fibroblast growth factor receptors 1, 2, 3 and 4, platelet-derived growth factor receptor alpha, and RET and KIT signalling networks, which are implicated in tumour growth and maintenance. In the EU and USA, lenvatinib is indicated for the treatment of locally recurrent or metastatic progressive, radioiodine-refractory differentiated thyroid cancer (RR-DTC). This approval was based on the results of the randomized, double-blind, multinational, phase 3 SELECT study, in which lenvatinib significantly improved median progression-free survival (PFS) and overall response rate compared with placebo in patients with RR-DTC. The PFS benefit with lenvatinib was seen in all pre-specified subgroups, including patients who had received either one or no prior VEGF-targeted therapy. Moreover, the PFS benefit with lenvatinib was maintained regardless of BRAF or RAS mutation status. The safety and tolerability profile of lenvatinib in SELECT was consistent with that of other VEGF/VEGF receptor-targeted therapies and was mostly manageable. Hypertension was the most common treatment-related adverse event in lenvatinib-treated patients, but only infrequently led to discontinuation of the drug. Although not collected in SELECT, information on quality of life would be useful in assessing the overall impact of therapy on the patient. This notwithstanding, the data which are available indicate that lenvatinib is an effective and generally well-tolerated treatment option for patients with RR-DTC. Lenvatinib, therefore, offers an acceptable alternative to sorafenib--currently, the only other TKI approved for this indication.

Lenvatinib for the treatment of radioiodine-refractory differentiated thyroid carcinoma: a systematic review and indirect comparison with sorafenib

INTRODUCTION

Thyroid carcinoma is the most prevalent endocrine malignancy, with an increasing incidence over the past decades. Treatment of differentiated thyroid cancer consists of surgery followed by radioactive iodine (RAI) ablation of the thyroid remnant, and TSH suppression. Among new therapeutic solutions for patients with advanced RR-DTC stage, the most promising seem to be sorafenib and lenvatinib, up to now considered to be orphan drugs. Areas covered: We performed a systematic review of medical databases to collect all eligible clinical trials referring to the topic of our analysis. Due to the lack of direct clinical trials comparing the drugs we used an adjusted indirect comparison of efficacy and safety of tyrosine kinase inhibitors (TKIs) by Bucher method. Expert commentary: Lenvatinib and sorafenib are drugs with strong evidence on efficacy in treatment of RR-DTC. Based on the currently available clinical data lenvatinib occurred more efficacious then sorafenib in RR-DTC therapy. Safety profile of the drugs was acceptable and comparative. Kinase inhibitors constitute a substantial progress in treatment of advanced thyroid cancer, have achieved long-lasting response and have improved survival without progress of the disease. In the near future we will deal with a range of therapeutic options for patients.

Common carotid artery rupture during treatment with lenvatinib for anaplastic thyroid cancer

Anaplastic thyroid cancer is a fatal disease for which no effective therapeutic strategies exist. Lenvatinib, a tyrosine-kinase inhibitor that targets vascular endothelial growth factor receptor, has recently been approved in Japan for the treatment of patients with unresectable thyroid cancer including anaplastic thyroid cancer. Although lenvatinib, like the other tyrosine-kinase inhibitors, sunitinib and sorafenib, might also confer a risk of bleeding, fatal bleeding as a result of lenvatinib treatment for anaplastic thyroid cancer has not been described. A 61-year-old woman presented with a 7-cm mass in the right lobe of the thyroid, lymph node metastases to the neck and multiple lung metastases. Fine needle aspiration revealed that the tumor was anaplastic thyroid cancer. The TNM classification was T4aN1bM1, stage IVC. Shortly after local curative surgery, a tumor recurred in her neck that was treated with lenvatinib (24 mg/day). Nineteen days later, the common carotid artery ruptured and the lenvatinib was stopped. She received the best possible supportive care but died 40 days after stopping the lenvatinib. Autopsy findings showed that the tumor had invaded the adventitia of the common carotid artery at the region of the neck surgery, and an aneurysm had developed. However, the adventitia of the common carotid artery was preserved at the non-dissected area. Lenvatinib might confer risk for fatal bleeding in patients with recurrent anaplastic thyroid cancer after neck surgery, particularly with dissection around the common carotid artery.

Targeted therapies in thyroid cancer: an extensive review of the literature

INTRODUCTION

Patients with progressive, metastatic, RAI-refractory differentiated thyroid cancer (DTC), as well as patients with advanced medullary (MTC) and anaplastic thyroid cancer represent a cohort for which therapeutic options are limited. The recent discoveries in the molecular mechanisms implicated in TC have provided insight of the pathogenesis and progression of disease. In that respect, targeted therapies have emerged as a promising alternative for the treatment of those patients. Areas covered: Tyrosine Kinase Inhibitors (TKIs) have been studied extensively in TC: sorafenib and lenvatinib have been approved by the FDA for the treatment of metastatic, RAI-refractory DTC, while vandetanib and cabozantinib are FDA approved for use in advanced MTC. Moreover, several additional TKIs, multi-targeted or specific, are currently under investigation in TC. The current manuscript provides an extensive review of the literature regarding targeted therapies in TC including the rationale behind their use, the clinical trials and an expert opinion on their use. Literature in English appearing at PubMed was thoroughly reviewed, especially manuscripts of the last 5 years. Expert commentary: Patients with advanced, progressive, metastatic TC should be evaluated for enrollment in a clinical trial or should be placed on treatment with one of the FDA- and EMA- approved agents.

Calvarium and dura mater as delayed sites of distant metastasis from papillary thyroid carcinoma

Background

Skull calvarium and dura mater are rare sites of distant metastasis, and mostly have been reported in lung, breast, and prostate malignancies. However, the calvarial and dural metastases from papillary thyroid cancer (PTC) are rare entities and pose diagnostic and therapeutic challenges. To date, only seven cases of calvarial metastasis with intracranial extension from PTC have been reported in literature. However, true dural metastasis from PTC has not yet been reported.

Case presentation

A 65-year-old Saudi woman presented with 6 months history of painful posterior scalp lump, 7 years after initial diagnosis of PTC. Computed tomography and magnetic resonance imaging showed occipitoparietal calvarial lesion with massive intracranial extension. Another para-sagittal lesion was found at the top of corpus callosum mimicking a meningioma. Histopathology of para-sagittal lesion and the biopsy of calvarial mass confirmed the diagnosis of metastatic PTC. After surgical resection, residual tumors were treated with postoperative intensity-modulated radiation therapy. At 13 months of follow-up, patient was alive and without any signs of recurrence.

Conclusion

Calvarial and dural metastases from PTC are extremely rare clinical entities. Surgical resection followed by postoperative radiotherapy is the treatment of choice. However, for such cases, multidisciplinary approach can prolong the treatment outcome and survival.

Tumor-Associated Mast Cells in Thyroid Cancer

There is compelling evidence that the tumor microenvironment plays a major role in mediating aggressive features of cancer cells, including invasive capacity and resistance to conventional and novel therapies. Among the different cell populations that infiltrate cancer stroma, mast cells (MCs) can influence several aspects of tumor biology, including tumor development and progression, angiogenesis, lymphangiogenesis, and tissue remodelling. Thyroid cancer (TC), the most frequent neoplasia of the endocrine system, is characterized by a MC infiltrate, whose density correlates with extrathyroidal extension and invasiveness. Recent evidence suggests the occurrence of epithelial-to-mesenchymal transition (EMT) and stemness in human TC. The precise role of immune cells and their mediators responsible for these features in TC remains unknown. Here, we review the relevance of MC-derived mediators (e.g., the chemokines CXCL1/GRO-α, CXCL10/IP-10, and CXCL8/IL-8) in the context of TC. CXCL1/GRO-α and CXCL10/IP-10 appear to be involved in the stimulation of cell proliferation, while CXCL8/IL-8 participates in the acquisition of TC malignant traits through its ability to induce/enhance the EMT and stem-like features of TC cells. The inhibition of chemokine signaling may offer novel therapeutic approaches for the treatment of refractory forms of TC.

Sorafenib in the treatment of thyroid cancer

Sorafenib has been evaluated in several Phase II and III studies in patients with locally advanced/metastatic radioactive iodine-refractory differentiated thyroid carcinomas (DTCs), reporting partial responses, stabilization of the disease and improvement of progression-free survival. Best responses were observed in lung metastases and minimal responses in bone lesions. On the basis of these studies, sorafenib was approved for the treatment of metastatic DTC in November 2013. Few studies suggested that reduction of thyroglobulin levels, or of average standardized uptake value at the fluorodeoxyglucose-PET, could be helpful for the identification of responding patients; but further studies are needed to confirm these results. Tumor genetic marker levels did not have any prognostic or predictive role in DTC patients.The most common adverse events observed included skin toxicity and gastrointestinal and constitutional symptoms. Encouraging results have also been observed in patients with medullary thyroid cancer. Many studies are ongoing to evaluate the long-term efficacy and tolerability of sorafenib in DTC patients.

Selective use of vandetanib in the treatment of thyroid cancer

Vandetanib is a once-daily orally available tyrosine kinase inhibitor that works by blocking RET (REarranged during Transfection), vascular endothelial growth factor receptor (VEGFR-2, VEGFR-3), and epidermal growth factor receptor and to a lesser extent VEGFR-1, which are important targets in thyroid cancer (TC). It is emerging as a potentially effective option in the treatment of advanced medullary thyroid cancer (MTC) and in dedifferentiated papillary thyroid cancer not responsive to radioiodine. The most important effect of vandetanib in aggressive MTC is a prolongation of progression-free survival and a stabilization of the disease. Significant side effects have been observed with the vandetanib therapy (as fatigue, hypertension, QTc prolongation, cutaneous rash, hand-and-foot syndrome, diarrhea, etc), and severe side effects can require the suspension of the drug. Several studies are currently under way to evaluate the long-term efficacy and tolerability of vandetanib in MTC and in dedifferentiated papillary TC. The efficacy of vandetanib in patients with MTC in long-term treatments could be overcome by the resistance to the drug. However, the effectiveness of the treatment could be ameliorated by the molecular characterization of the tumor and by the possibility to test the sensitivity of primary TC cells from each subject to different tyrosine kinase inhibitor. Association studies are evaluating the effect of the association of vandetanib with other antineoplastic agents (such as irinotecan, bortezomib, etc). Further research is needed to determine the ideal therapy to obtain the best response in terms of survival and quality of life.

Molecular Targeted Therapies of Aggressive Thyroid Cancer

Differentiated thyroid carcinomas (DTCs) that arise from follicular cells account >90% of thyroid cancer (TC) [papillary thyroid cancer (PTC) 90%, follicular thyroid cancer (FTC) 10%], while medullary thyroid cancer (MTC) accounts <5%. Complete total thyroidectomy is the treatment of choice for PTC, FTC, and MTC. Radioiodine is routinely recommended in high-risk patients and considered in intermediate risk DTC patients. DTC cancer cells, during tumor progression, may lose the iodide uptake ability, becoming resistant to radioiodine, with a significant worsening of the prognosis. The lack of specific and effective drugs for aggressive and metastatic DTC and MTC leads to additional efforts toward the development of new drugs. Several genetic alterations in different molecular pathways in TC have been shown in the past few decades, associated with TC development and progression. Rearranged during transfection (RET)/PTC gene rearrangements, RET mutations, BRAF mutations, RAS mutations, and vascular endothelial growth factor receptor 2 angiogenesis pathways are some of the known pathways determinant in the development of TC. Tyrosine kinase inhibitors (TKIs) are small organic compounds inhibiting tyrosine kinases auto-phosphorylation and activation, most of them are multikinase inhibitors. TKIs act on the aforementioned molecular pathways involved in growth, angiogenesis, local, and distant spread of TC. TKIs are emerging as new therapies of aggressive TC, including DTC, MTC, and anaplastic thyroid cancer, being capable of inducing clinical responses and stabilization of disease. Vandetanib and cabozantinib have been approved for the treatment of MTC, while sorafenib and lenvatinib for DTC refractory to radioiodine. These drugs prolong median progression-free survival, but until now no significant increase has been observed on overall survival; side effects are common. New efforts are made to find new more effective and safe compounds and to personalize the therapy in each TC patient.