Tyrosine kinase inhibitor-induced thyroid disorders: a review and hypothesis

Underlying mechanisms and management strategies for regorafenib-induced toxicity in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) accounts for 85% of liver cancer cases and is the third leading cause of cancer death. Regorafenib is a multi-target inhibitor that dramatically prolongs progression-free survival in HCC patients who have failed sorafenib therapy. However, one of the primary factors limiting regorafenib's clinical utilization is toxicity. Using Clinical Trials.gov and PubMed, we gathered clinical data on regorafenib and conducted a extensive analysis of the medication's adverse reactions and mechanisms. Next, we suggested suitable management techniques to improve regorafenib's effectiveness.

AREAS COVERED

We have reviewed the mechanisms by which regorafenib-induced toxicity occurs and general management strategies through clinical trials of regorafenib. Furthermore, by examining the literature on regorafenib and other tyrosine kinase inhibition, we summarized the mechanics of the onset of regorafenib toxicity and mechanism-based intervention strategies by reviewing the literature related to regorafenib and other tyrosine kinase inhibition.

EXPERT OPINION

One of the primary factors restricting regorafenib's clinical utilization and combination therapy is its toxicity reactions. To optimize regorafenib treatment regimens, it is especially important to further understand the specific toxicity mechanisms of regorafenib as a multi-kinase inhibitor.

Recent advances in the use of tyrosine kinase inhibitors against thyroid cancer

INTRODUCTION

Oncogenic tyrosine kinases (TK) are enzymes that play a key role in cell growth and proliferation and their mutations can lead to uncontrolled cell growth and development of aggressive cancer. This knowledge has led to the development of new classes of drugs, Tyrosine kinase inhibitors (TKI). They target oncogenic kinases who are associated with advanced radioactive iodine (RAI) refractory TC, which is not able to uptake RAI anymore and/or still grows between consecutive treatments with Iodine 131 (I131).

AREAS COVERED

Since Lenvatinib and Sorafenib approval, several other molecular inhibitors have been studied and then introduced for the treatment of aggressive and refractory thyroid cancer (TC), and, although the development of adverse effects or tumor resistance mechanisms, more and more compounds are still under investigation. The literature search was executed in PubMed and ClinicalTrials.gov to identify relevant articles and clinical trials published until December 2023.

EXPERT OPINION

In the context of clinical trials, driven by the presence of specific molecular mutations or even in the absence of both conditions, systemic therapy TKIs are valuable weapons to be used in patients affected by aggressive forms of TC, waiting for further expansion of the treatment landscape with more efficacious and safer drugs.

Adverse Events of Cabozantinib as a Potential Prognostic Factor in Metastatic Renal Cell Carcinoma Patients: Real-World Experience in a Single-Center Retrospective Study

Cabozantinib, an oral inhibitor targeting MET, AXL, and VEGF receptors, has become a key component of a sequential treatment strategy for clear cell renal cell carcinoma (ccRCC). The purpose of this work is to show that effective management of adverse events (AEs) during cabozantinib treatment and achieving a balance between AEs and treatment efficacy is crucial to achieving therapeutic goals. In this retrospective study, involving seventy-one metastatic RCC (mRCC) patients receiving second or subsequent lines of cabozantinib at the Department of Genitourinary Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, we explored the impact of AEs on overall survival (OS) and progression-free survival (PFS). AEs were observed in 92% of patients. Hypothyroidism during treatment was significantly associated with prolonged OS and PFS (HR: 0.31; p < 0.001 and HR: 0.34; p < 0.001, respectively). The occurrence of hand-foot syndrome (HFS) was also linked to improved OS (HR: 0.46; p = 0.021). Patients experiencing multiple AEs demonstrated superior OS and PFS compared to those with one or no AEs (HR: 0.36; p < 0.001 and HR: 0.30; p < 0.001, respectively). Hypothyroidism and HFS serve as valuable predictive factors during cabozantinib treatment in ccRCC patients, indicating a more favorable prognosis.

Histological findings of thyroid cancer after lenvatinib therapy

AIMS

Lenvatinib is a multikinase inhibitor used for treating unresectable or metastatic cancers, including thyroid cancer. As total thyroidectomy followed by radioactive iodine therapy is a commonly recommended initial treatment for thyroid cancer, histological findings of the thyroid after lenvatinib therapy remain unclear. Therefore, the aim of this study was to analyse in-vivo changes in patients who underwent thyroidectomy after lenvatinib therapy.

METHODS AND RESULTS

We screened 167 patients with thyroid cancer [papillary thyroid cancer (PTC), n = 102; follicular thyroid cancer (FTC), n = 26; anaplastic thyroid cancer (ATC), n = 39] who underwent lenvatinib therapy. Among these patients, six underwent thyroidectomy (lenvatinib-treated group: PTC, n = 3; FTC, n = 1; ATC, n = 2), and the specimens were examined. Five patients with PTC who did not receive lenvatinib therapy were included for comparison (untreated group). Microvessel density (MVD) was evaluated in both groups. The PTC and FTC specimens showed relatively more ischaemic changes than ATC specimens. Coagulative necrosis and ischaemic changes in cancer cells were frequently observed. ATC specimens showed fibrosis and mild cell damage. As hypothyroidism is a common side effect of lenvatinib therapy, non-cancerous thyroid tissues were also examined. Histological findings included mild lymphocytic infiltration, lymphoid follicular formation, histiocytic reaction and follicular epithelial destruction. The MVD in lenvatinib-treated tissues was significantly lower than that in untreated tissues.

CONCLUSIONS

Lenvatinib therapy probably induces relatively specific ischaemic changes in thyroid cancer cells. Moreover, inflammatory cell infiltration and decreased MVD occur to varying degrees in non-cancerous thyroid tissue and may be related to hypothyroidism, a side effect of lenvatinib.

Tyrosine kinase inhibitors induced thyroid dysfunction: myth or reality?

Background

Chronic myelogenous leukemia (CML) is a hematopoietic stem cell disorder. It is associated with acquired genetic changes in the hematopoietic stem cells in the form of BCR-ABL fusion gene also known as Philadelphia chromosome.

Materials and methods

We prospectively studied thyroid function at baseline and at 6 months of imatinib treatment in 26 newly diagnosed BCR-ABL positive CML patients.

Result

The thyroid-stimulating hormone (TSH) levels increased significantly from baseline (3.20 ± 0.978 mIU/L vs. 3.724 ± 1.726 mIU/L, p < 0.05) after 6 months of treatment, 88.4% of the patients remained euthyroid. Only 2 patients had subclinical hypothyroidism, 1 had hypothyroidism after 6 months of tyrosine kinase inhibitors (TKI) therapy.

Conclusion

Imatinib did not have any significant effect on thyroid function in CML patients in this study.

Thyroid dysfunction with atezolizumab plus bevacizumab after lenvatinib in hepatocellular carcinoma: A case series

Atezolizumab plus bevacizumab is the recommended first-line treatment for unresectable hepatocellular carcinoma, based on guidelines from the Barcelona Clinic Liver Cancer prognosis and treatment strategy. However, atezolizumab plus bevacizumab may be used after administration of lenvatinib. Here, we present four patients who developed thyroid dysfunction after second-line treatment with atezolizumab plus bevacizumab, but not after lenvatinib alone. The patients were treated with lenvatinib and/or atezolizumab plus bevacizumab for unresectable hepatocellular carcinoma at Showa University Northern Yokohama Hospital. Of patients treated with only lenvatinib or atezolizumab plus bevacizumab, 2/18 (11%) and 4/15 (27%) developed thyroid dysfunction, respectively. All four patients treated with atezolizumab plus bevacizumab after lenvatinib developed hypothyroidism after 2–14 doses of atezolizumab plus bevacizumab. Three patients developed Grade 2 symptoms and were treated with levothyroxine sodium. In patients with hepatocellular carcinoma, the incidence of thyroid dysfunction may be higher among patients treated with atezolizumab plus bevacizumab after lenvatinib than those treated with lenvatinib or atezolizumab plus bevacizumab alone.

Endocrine-related adverse conditions in patients receiving immune checkpoint inhibition: an ESE clinical practice guideline

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment but are associated with significant autoimmune endocrinopathies that pose both diagnostic and treatment challenges. The aim of this guideline is to provide clinicians with the best possible evidence-based recommendations for treatment and follow-up of patients with ICI-induced endocrine side-effects based on the Grading of Recommendations Assessment, Development, and Evaluation system. As these drugs have been used for a relatively short time, large systematic investigations are scarce. A systematic approach to diagnosis, treatment, and follow-up is needed, including baseline tests of endocrine function before each treatment cycle. We conclude that there is no clear evidence for the benefit of high-dose glucocorticoids to treat endocrine toxicities with the possible exceptions of severe thyroid eye disease and hypophysitis affecting the visual apparatus. With the exception of thyroiditis, most endocrine dysfunctions appear to be permanent regardless of ICI discontinuation. Thus, the development of endocrinopathies does not dictate a need to stop ICI treatment.

The continuum of care of anticancer treatment-induced hypothyroidism in patients with solid non thyroid tumors: time for an intimate collaboration between oncologists and endocrinologists

INTRODUCTION

Hypothyroidism is a common adverse event of various anticancer treatment modalities, constituting a notable paradigm of the integration of the endocrine perspective into precision oncology.

AREAS COVERED

The present narrative review provides a comprehensive and updated overview of anticancer treatment-induced hypothyroidism in patients with solid non-thyroid tumors. A study search was conducted on the following electronic databases: PubMed, Google Scholar, Scopus.com, ClinicalTrials.gov, and European Union Clinical Trials Register from 2011 until August 2021.

EXPERT OPINION

In patients with solid non-thyroid tumors, hypothyroidism is a common adverse event of radiotherapy, high dose interleukin 2 (HD IL-2), interferon alpha (IFN-α), bexarotene, immune checkpoint inhibitors (ICPi), and tyrosine kinase inhibitors (TKIs), while chemotherapy may induce hypothyroidism more often than initially considered. The path forward for the management of anticancer treatment-induced hypothyroidism in patients with solid non-thyroid tumors is an integrated approach grounded on 5 pillars: prevention, vigilance, diagnosis, treatment and monitoring. Current challenges concerning anticancer treatment-induced hypothyroidism await counteraction, namely awareness of the growing list of related anticancer treatments, identification of predictive factors, counteraction of diagnostic pitfalls, tuning of thyroid hormone replacement, and elucidation of its prognostic significance. Close collaboration of oncologists with endocrinologists will provide optimal patient care.

The Clinical Relevance of Hypothyroidism in Patients with Solid Non-Thyroid Cancer: A Tantalizing Conundrum

Hypothyroidism in patients with solid non-thyroid cancer is a tantalizing entity, integrating an intriguing thyroid hormones (THs)-cancer association with the complexity of hypothyroidism itself. The present narrative review provides a comprehensive overview of the clinical relevance of hypothyroidism in solid non-thyroid cancer. Hypothyroidism in patients with solid non-thyroid cancer is reminiscent of hypothyroidism in the general population, yet also poses distinct challenges due to the dual role of THs in cancer: promoting versus inhibitory. Close collaboration between oncologists and endocrinologists will enable the prompt and personalized diagnosis and treatment of hypothyroidism in patients with solid non-thyroid cancer. Clinical data indicate that hypothyroidism is a predictor of a decreased or increased risk of solid non-thyroid cancer and is a prognostic factor of favorable or unfavorable prognosis in solid non-thyroid cancer. However, the impact of hypothyroidism with respect to the risk and/or prognosis of solid non-thyroid cancer is not a consistent finding. To harness hypothyroidism, or THs replacement, as a personalized anticancer strategy for solid non-thyroid cancer, four prerequisites need to be fulfilled, namely: (i) deciphering the dual THs actions in cancer; (ii) identifying interventions in THs status and developing agents that block tumor-promoting THs actions and/or mimic anticancer THs actions; (iii) appropriate patient selection; and (iv) counteracting current methodological limitations.

Thyroid Dysfunction from Treatments for Solid Organ Cancers

In recent years, cancer care has been transformed by immune-based and targeted treatments. Although these treatments are effective against various solid organ malignancies, multiple adverse effects can occur, including thyroid dysfunction. In this review, the authors consider treatments for solid organ cancers that affect the thyroid, focusing on immune checkpoint inhibitors, kinase inhibitors, and radioactive iodine-conjugated treatments (I-131-metaiodobenzylguanidine). They discuss the mechanisms causing thyroid dysfunction, provide a framework for their diagnosis and management, and explore the association of thyroid dysfunction from these agents with patient survival.

The Intriguing Thyroid Hormones-Lung Cancer Association as Exemplification of the Thyroid Hormones-Cancer Association: Three Decades of Evolving Research

Exemplifying the long-pursued thyroid hormones (TH)-cancer association, the TH-lung cancer association is a compelling, yet elusive, issue. The present narrative review provides background knowledge on the molecular aspects of TH actions, with focus on the contribution of TH to hallmarks of cancer. Then, it provides a comprehensive overview of data pertinent to the TH-lung cancer association garnered over the last three decades and identifies obstacles that need to be overcome to enable harnessing this association in the clinical setting. TH contribute to all hallmarks of cancer through integration of diverse actions, currently classified according to molecular background. Despite the increasingly recognized implication of TH in lung cancer, three pending queries need to be resolved to empower a tailored approach: (1) How to stratify patients with TH-sensitive lung tumors? (2) How is determined whether TH promote or inhibit lung cancer progression? (3) How to mimic the antitumor and/or abrogate the tumor-promoting TH actions in lung cancer? To address these queries, research should prioritize the elucidation of the crosstalk between TH signaling and oncogenic signaling implicated in lung cancer initiation and progression, and the development of efficient, safe, and feasible strategies leveraging this crosstalk in therapeutics.

The Real-World Practice of Fruquintinib for Chinese Patients with Metastatic Colorectal Cancer

BACKGROUND

In FRESCO trial, a phase III study of fruquintinib demonstrated a significant improvement on the overall survival (OS) of patients with metastatic colorectal cancer (mCRC) who failed to response to available standard treatments. The aim of the current study was to evaluate the safety and effectiveness of fruquintinib in Chinese mCRC patients in the real-world setting.

METHODS

Patients with mCRC treated with fruquintinib at our hospital were retrospectively reviewed. Patient demographics, treatment, adverse events and survival data were collected. OS and progression-free survival (PFS) were estimated using the Kaplan-Meier method.

RESULTS

In total, 76 patients were evaluated from December 2018 to January 2020. The median (range) age was 59.5 (34-86) years, ECOG PS 0-1/2 was 86.8%/13.2%, and 38 (50%)/30 (39.5%) patients had experienced more than two prior therapies for mCRC. The median treatment duration was 3.6 cycles. Treatment-related adverse events (TRAEs) resulted in dose reduction were 17.1% of the patients without any treatment discontinuation. The most common grade 3 or 4 TRAEs were hypertension (9.2%), hand-foot skin reaction (7.9%), thrombocytopenia (3.9%), anaemia (2.6%), increased ALT (1.3%), oral mucositis (1.3%), proteinuria (1.3%) and neutropenia (1.3%). The median PFS was 5.1 months (95% CI 3.8-6.4 months), and the median OS was 12.0 months (95% CI 8.0-16.1 months). In patients with hypertension or hypothyroidism, a survival extension approximate to 6 months was observed, but the difference is not yet statistically significant. CEA decreased after fruquintinib treatment could be considered as a potential predictor for better OS.

CONCLUSION

The outcome of this real-life study was consistent with that of the randomised controlled trial. There were no new safety concerns. Future studies of fruquintinib should be conducted to identify patients who tend to obtain more benefits from fruquintinib alone or in combination with other agents.

Thyroid dysfunction related to vascular endothelial growth factor receptor tyrosine kinase inhibitors: A real-world study based on FAERS

WHAT IS KNOWN AND OBJECTIVE

The adverse events of thyroid dysfunction caused by the use of vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) have not been confirmed in a real-world investigation. The aim of this study was to evaluate the relationship between thyroid dysfunction and treatment using Food and Drug Administration (FDA)-approved VEGFR-TKIs.

METHODS

Four data-mining algorithms were employed to detect thyroid dysfunction signals for VEGFR-TKIs, using data in the FDA Adverse Event Reporting System (FAERS) database from 68 quarters. MySQL Workbench and R were used to conduct statistical analysis.

RESULTS AND DISCUSSION

We identified 32679 reports of thyroid dysfunction, of which 1567 listed VEGFR-TKIs as the primary suspected drugs. All four algorithms showed that the strength of the signals for hypothyroidism were greater than those for hyperthyroidism, for all the VEGFR-TKIs. In most cases, the median appearance time was within 100 days of initiation of VEGFR-TKIs therapy, except in the case of ponatinib. This indicated the need to actively identify and manage thyroid dysfunction during the early stages of VEGFR-TKIs treatment.

WHAT IS NEW AND CONCLUSIONS

This study systematically identified the pharmacovigilance signals of thyroid dysfunction associated with the use of VEGFR-TKIs, using the FAERS database.

Endocrine complications of new anticancer therapies

Studying and analyzing of complex molecular mechanisms and immunological processes of cancer enables oncology to introduce new cancer therapies. In the treatment of cancer, we successively increase the use of targeted therapies with tyrosine kinase inhibitors and mTOR inhibitors and immunotherapy using checkpoint inhibitors CTLA-4 (cytotoxic T-cell antigen-4) and PD-1/PD-L1 (programmed death receptor 1/programmed death ligand 1). New anticancer drugs gradually replace conventional chemotherapy and have already found application in the treatment of many cancers, including thyroid cancer, hepatocellular carcinoma, non-small cell lung cancer, kidney cancer, bladder cancer, melanoma, breast cancer, acute and chronic myelogenous leukemia. The use of these drugs is less toxic than classical chemotherapy, but it can cause gastrointestinal, cardiovascular, respiratory, skin and endocrine complications. Most of the side effects of new cancer therapies are mild and moderate disorders, however some might be severe and life-threatening. Endocrinopathies are one of the more common side effects of these treatments. They can affect many endocrine glands (pituitary, thyroid, parathyroid, adrenal, pancreas) and cause both transient and permanent disorders.

Effects of tyrosine kinase inhibitors on thyroid function and thyroid hormone metabolism

The increasing knowledge of the molecular mechanisms in the cell signaling pathways of malignant cells, has recently led to the discovery of several tyrosine kinases (TKs), mainly TK receptors (TKR), which play a major role in the pathogenesis of many types of cancer. These receptors, physiologically involved in cell growth and angiogenesis, may harbor mutations or be overexpressed in malignant cells, and represent a target for anticancer therapy. Indeed, several therapeutic agents targeting specific altered pathways such as RET, BRAF, RAS, EGFR and VEGFR, have been identified. Tyrosine kinase inhibitors (TKIs) affect TK dependent oncogenic pathways by competing with ATP binding sites of the TK domain, thus blocking the activity of the enzyme, and thereby inhibiting the growth and spread of several cancers. Although the therapeutic action may be very effective, these molecules, due to their mechanism of multitargeted inhibition, may produce adverse events involving several biological systems. Both hypothyroidism and thyrotoxicosis have been reported during treatment with TKI, as well as an effect on the activity of enzymes involved in thyroid hormone metabolism. The pathogenic mechanisms leading to thyroid dysfunction and changes in serum thyroid function tests occurring in patients on TKI are reviewed and discussed in this manuscript.

Understanding the Pathogenesis of Gestational Hypothyroidism

Pregnancy is a complex state with many endocrinological challenges to a woman's physiology. Gestational Hypothyroidism (GHT) is an emerging condition where insufficiency of the thyroid gland has developed during pregnancy in a previously euthyroid woman. It is different to overt hypothyroidism, where marked elevation of thyroid-stimulating hormone with corresponding reduction in free thyroxine levels, is well known to cause detrimental effects to both the mother and the baby. During the past couple of decades, it has been shown that GHT is associated with multiple adverse maternal and fetal outcomes such as miscarriage, pre-eclampsia, placental abruption, fetal loss, premature delivery, neurocognitive and neurobehavioral development. However, three randomized controlled trials and a prospective cohort study performed within the last decade, show that there is no neurodevelopmental improvement in the offspring of mothers who received levothyroxine treatment for GHT. Thus, the benefit of initiating treatment for GHT is highly debated within the clinical community as there may also be risks associated with over-treatment. In addition, regulatory mechanisms that could possibly lead to GHT during pregnancy are not well elucidated. This review aims to unravel pregnancy induced physiological challenges that could provide basis for the development of GHT. During pregnancy, there is increased renal clearance of iodine leading to low iodine state. Also, an elevated estrogen level leading to an increase in circulating thyroglobulin level and a decrease in free thyroxine level. Moreover, placenta secretes compounds such as human chorionic gonadotropin (hCG), placental growth factor (PIGF) and soluble FMS-like tyrosine kinase-1 (s-Flt1) that could affect the thyroid function. In turn, the passage of thyroid hormones and iodine to the fetus is highly regulated within the placental barrier. Together, these mechanisms are hypothesized to contribute to the development of intolerance of thyroid function leading to GHT in a vulnerable individual.

Regorafenib-Induced Hypothyroidism as a Predictive Marker for Improved Survival in Metastatic or Unresectable Colorectal Cancer Refractory to Standard Therapies: A Prospective Single-Center Study

BACKGROUND

Tyrosine kinase inhibitor-induced hypothyroidism is associated with favorable survival in patients with various cancers.

OBJECTIVE

We aimed to investigate the incidence of regorafenib-induced hypothyroidism and assess its prognostic value in patients with metastatic or unresectable colorectal cancer (CRC) receiving regorafenib.

PATIENTS AND METHODS

This study included 68 patients treated at Asan Medical Center (Seoul, Republic of Korea) between 2014 and 2016 with metastatic or unresectable CRC refractory to standard therapies. Regorafenib (160 mg/day on days 1-21 followed by a 7-day break) was administered.

RESULTS

The median patient age was 58 (range 26-72) years; 61.8% of patients were male. Among the 68 patients, 50 (73.5%) showed hypothyroidism; 39 (57.4%) had subclinical and 11 (16.2%) had symptomatic hypothyroidism. Overall, the objective response rate (ORR) and disease control rate (DCR) were 7.4% and 70.6%, respectively; both were significantly higher in patients with symptomatic or subclinical hypothyroidism than in euthyroid patients (ORR 27.3% vs. 5.1% vs. 0.0%, P = 0.001; DCR 100% vs. 76.9% vs. 38.9%, P = 0.001). Median progression-free survival (PFS) and overall survival (OS) were longer in patients with symptomatic hypothyroidism than in those with subclinical hypothyroidism (median PFS 9.1 vs. 3.8 months, P = 0.018; median OS: 19.2 vs. 9.4 months, P = 0.012) or with euthyroid status (median PFS 9.1 vs. 1.8 months, P < 0.001; median OS 19.2 vs. 4.7 months, P = 0.001). Symptomatic hypothyroidism was a significant protective factor for PFS (hazard ratio (HR) = 0.37, P = 0.006) and OS (HR = 0.35, P = 0.007); no other adverse events were associated with survival.

CONCLUSIONS

Regorafenib-induced hypothyroidism frequently occurs in patients with metastatic CRC receiving regorafenib and is associated with improved survival. Thyroid function status should be actively monitored in CRC patients receiving regorafenib.

Kinome multigenic panel identified novel druggable EPHB4-V871I somatic variant in high-risk neuroblastoma

Neuroblastoma (NB) is the most common extracranial neoplasm in children. The overall outcome for high‐risk NB patients is still unacceptable, therefore, it is critical to deeply understand molecular mechanisms associated with NB, which in turn can be utilized for developing drugs towards the treatment of NB. Protein kinases (TKs) play an essential role in the regulation of cell survival and proliferation. Different kinases, such as anaplastic lymphoma kinase (ALK), Aurora kinase, RET receptor tyrosine kinase, are potential therapeutic targets in various cancers, including NB. We analysed a cohort of 45 high‐risk NB patients and 9 NB cell lines by a targeted—(t)NGS custom gene panel (genes codifying for the kinase domains of 90 TKs). We identified somatic variants in four TK genes (ALK, EPHB4, LMTK3 and EPHB6) in NB patients and we functionally characterized an interesting somatic variant, V871I, in EPHB4 gene. EPHB4 plays a crucial role in cardiovascular development and regulates vascularization in cancer‐promoting angiogenesis, tumour growth and metastasis. Several EPHB4 mutations have previously been identified in solid and haematological tumour specimens but EPHB4 mutations were not described until now in NB. Interestingly, a re‐analysis of public CGH‐array showed that the EPHB4 gain is associated with advanced diseases in NB. We further demonstrated that higher EPHB4 expression is correlated to stage 4 of NB and with poor overall survival. Additionally, we also revealed that the EPHB4‐V871I accounts for increased proliferation, migration and invasion properties in two NB cell lines by acting on VEGF, c‐RAF and CDK4 target genes and by increasing the phosphorylation of ERK1‐2 pathway. The use of two EPHB4 inhibitors, JI‐101 and NVP‐BHG712, was able to rescue the phenotype driven by the variant. Our study suggested that EPHB4 is a promising therapeutic target in high‐risk NB.

Anticancer Drug-induced Thyroid Dysfunction

Cancer immunotherapy and targeted therapy, though less toxic than conventional chemotherapy, can increase the risk of thyroid dysfunction. Immune checkpoint inhibitors render the cancer cells susceptible to immune destruction, but also predispose to autoimmune disorders like primary hypothyroidism as well as central hypothyroidism secondary to hypophysitis. Tyrosine kinase inhibitors act by blocking vascular endothelial growth factor receptors and their downstream targets. Disruption of the vascular supply from the inhibition of endothelial proliferation damages not only cancer cells but also organs with high vascularity like the thyroid. Interferon-α, interleukin-2 and thalidomide analogues can cause thyroid dysfunction by immune modulation. Alemtuzumab, a monoclonal antibody directed against the cell surface glycoprotein CD52 causes Graves' disease during immune reconstitution. Metaiodobenzylguanidine, combined with 131-iodine, administered as a radiotherapeutic agent for tumours derived from neural crest cells, can cause primary hypothyroidism. Bexarotene can produce transient central hypothyroidism by altering the feedback effect of thyroid hormone on the pituitary gland. Thyroid dysfunction can be managed in the usual manner without a requirement for dose reduction or discontinuation of the implicated agent. This review aims to highlight the effect of various anticancer agents on thyroid function. Early recognition and appropriate management of thyroid disorders during cancer therapy will help to improve treatment outcomes.

Anorexia, Hypertension, Pneumothorax, and Hypothyroidism: Potential Signs of Improved Clinical Outcome Following Apatinib in Advanced Osteosarcoma

Aim

Apatinib, a specific tyrosine kinase inhibitor (TKI) that targets mainly vascular endothelial growth factor receptor-2 (VEGFR-2) as well as Ret, c-Kit and c-Src, has been assessed in patients with advanced osteosarcoma (phase II), the primary report of which has been published in PMID 30559126. This sub-study explored the potential signs of Adverse Events (AEs) for apatinib-treated osteosarcoma.

Methods

Participants with advanced osteosarcoma progressing upon chemotherapy received apatinib until disease progression or unacceptable toxicity. Toxicities, progression-free survival (PFS), and clinical benefit rate (CBR) following treatment were evaluated.

Results

Of the 41 patients recruited to the study, 37 received treatment and constituted the safety population. At data cut-off (December 30, 2017), median follow-up for safety was 7.37 (IQR, 6.33–11.07) months. The most common grade 3–4 AEs were pneumothorax (16.22%), wound dehiscence (10.81%), proteinuria (8.11%), diarrhea (8.11%), and skin reaction (8.11%). Only hypertension was an independent predictive factor for both PFS (hazard ratio [HR], 0.44; P = 0.07) and CBR (P = 0.07). Anorexia was also significantly related to a longer PFS in a Cox regression model (HR, 0.35; P =0.01). For CBR, pneumothorax and hypothyroidism showed more clinical benefit (P = 0.07 and 0.00, respectively).

Conclusion

The results of this study suggest that anorexia, hypertension, pneumothorax, and hypothyroidism might be markers for a favorable clinical outcome following apatinib-treated refractory osteosarcoma.

Bexarotene-induced hypothyroidism: Characteristics and therapeutic strategies

OBJECTIVE

Central hypothyroidism (CH) is a well-known adverse effect of bexarotene treatment for cutaneous T-cell lymphoma (CTCL). While concomitant levothyroxine therapy is recommended in these cases, associations between ethnic variation or susceptibility and bexarotene-induced CH have not yet been reported. This study aimed to characterize the kinetics and dose dependency of bexarotene-induced CH in Japanese patients.

DESIGN AND PATIENTS

Sixty-six Japanese patients with CTCL were retrospectively investigated by evaluating thyroid function during the early phase of bexarotene therapy.

RESULTS

At one week after bexarotene initiation, TSH and FT4 values significantly declined. However, this effect was not bexarotene dose-dependent at least at the dose of 96-320 mg/m² . Approximately 1 month later, 61 patients exhibited hypothyroidism at a relatively low dose of bexarotene (average 251 mg/m² /day). Forty-five study cases showed this effect at 1 week. Simple regression analyses indicated that higher pretreatment TSH values (at a cut-off value of 1.30:73% sensitivity, 57% specificity) or lower normal (within the lower half of the reference range) pretreatment FT4 values (84% sensitivity, 57% specificity) were predictive of hypothyroidism at 1 week. The remaining 21 cases showed euthyroidism at 1 week, at which TSH values may roughly predict their thyroid function at 1 month (at a cut-off value of 0.05:100% sensitivity, 80% specificity).

CONCLUSIONS

Preventive treatment with levothyroxine is recommended for Japanese CTCL patients prior to bexarotene therapy. Minimally, it should be considered for patients with a pretreatment TSH above 1.30, a lower normal pretreatment FT4, or a TSH below 0.05 at 1 week.

Safety and Tolerability of Anti-Angiogenic Protein Kinase Inhibitors and Vascular-Disrupting Agents in Cancer: Focus on Gastrointestinal Malignancies

Angiogenesis is an essential process for tumor growth and metastasis. Inhibition of angiogenesis as an anticancer strategy has shown significant results in a plethora of tumors. Anti-angiogenic agents are currently part of many standard-of-care options for several metastatic gastrointestinal cancers. Bevacizumab, aflibercept, ramucirumab, and regorafenib have significantly improved both progression-free and overall survival in different lines of treatment in metastatic colorectal cancer. Second-line ramucirumab and third-line apatinib are effective anti-angiogenic treatments for patients with metastatic gastric cancer. Unfortunately, the anti-angiogenic strategy has major practical limitations: resistance inevitably develops through redundancy of signaling pathways and selection for subclonal populations adapted for hypoxic conditions. Anti-angiogenic agents may be more effective in combination therapies, with not only cytotoxics but also other emerging compounds in the anti-angiogenic class or in the separate class of the so-called vascular-disrupting agents. This review aims to provide an overview of the approved and "under development" anti-angiogenic compounds as well as the vascular-disrupting agents in the treatment of gastrointestinal cancers, focusing on the actual body of knowledge available on therapy challenges, pharmacodynamic and pharmacokinetic mechanisms, safety profiles, promising predictive biomarkers, and future perspectives.

Tyrosine kinase inhibitors and immune checkpoint inhibitors-induced thyroid disorders

Recently, tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICPIs) have emerged as new classes of anticancer therapies. Although generally considered less toxic than cytotoxic chemotherapy, these new drugs can cause significant unanticipated side effects including thyroid dysfunction. This review provides a literature assessment of thyroid dysfunctions induced by TKI and ICPIs. We intend to define for these two classes the frequency of thyroid involvement, the potential mechanisms that result in this toxicity, the clinical-biological impact and the therapeutic management. Detection of thyroid dysfunction requires monitoring of TSH, in combination with free T4 if needed and, depending on the clinical impact and the kinetics of biological abnormalities, starting symptomatic treatment of hyperthyroidism and/or correcting hypothyroidism.

Case Series: Minocycline-Associated Thyroiditis

INTRODUCTION

Minocycline, a member of the tetracycline class of antibiotics, has been associated with benign thyroid pigmentation but reports of thyroid dysfunction are sparse.

METHODS

Cases were selected via an inquiry of the electronic medical records for patients with thyroid dysfunction and the use of a tetracycline antibiotic. Non-autoimmune thyroiditis was defined as abnormally low or suppressed thyroid-stimulating hormone (TSH, <0.3 µIU/mL), elevated free thyroxine or total thyroxine, and undetectable antithyroid antibodies.

RESULTS

Nine cases of thyroiditis without autoimmunity were identified out of 423 reviewed patients. Cases of thyroiditis occurred in adolescents ages 14-17 years who had been taking minocycline for 6 months to 4 years. In all cases, minocycline was prescribed for the treatment of acne. Four of the 9 received treatment for thyrotoxicosis with a β-blocker (in 3 cases) and/or antithyroid drug (in 2 cases). Thyroiditis was symptomatic in all but one individual who presented with painless goiter. All thyroiditis was transient and resolved after a median of 4.5 months (range 2-5 months). In one case, thyroiditis was followed by transient hypothyroidism.

DISCUSSION

Minocycline is known to cause thyroid abnormalities, although it has not been definitively linked to thyroid dysfunction. Here, we report 9 cases of non-autoimmune thyroiditis in adolescents receiving minocycline for acne. We recommend that minocycline exposure be considered in the differential diagnosis for thyroiditis and that patients receiving minocycline be counseled regarding the risk of thyroid dysfunction.

MELK is a novel therapeutic target in high-risk neuroblastoma

Maternal embryonic leucine zipper kinase (MELK) is known to modulate intracellular signaling and control cellular processes. However, the role of MELK in oncogenesis is not well defined. In this study, using two microarray datasets of neuroblastoma (NB) patients, we identified that MELK expression is significantly correlated to poor overall survival, unfavorable prognosis, and high-risk status. We found that MELK is a direct transcription target of MYCN and MYC in NB, and MYCN increases MELK expression via direct promoter binding. Interestingly, knockdown of MELK expression significantly reduced the phosphorylation of target protein Retinoblastoma (pRb) and inhibited NB cell growth. Furthermore, pharmacological inhibition of MELK activity by small-molecule inhibitor OTSSP167 significantly inhibited cell proliferation, anchorage-independent colony formation, blocked cell cycle progression, and induced apoptosis in different NB cell lines including a drug-resistant cell line. Additionally, OTSSP167 suppressed NB tumor growth in an orthotopic xenograft mouse model. Overall, our data suggest that MELK is a novel therapeutic target for NB and its inhibitor OTSSP167 is a promising drug for further clinical development.

Sorafenib-Induced Changes in Thyroid Hormone Levels in Patients Treated for Hepatocellular Carcinoma

CONTEXT

The pathogenesis of tyrosine kinase inhibitor-induced thyroid hormone (TH) alterations are still a matter of debate.

OBJECTIVE

The objective of this study was to determine the effects of sorafenib on TH levels in patients with hepatocellular carcinoma (HCC) and to evaluate possible mechanisms.

DESIGN

We performed a prospective cohort study between 2009 and 2016.

SETTING

This study was conducted at a tertiary referral center.

PATIENTS

This study included 57 consecutive patients with HCC who were treated with sorafenib.

MAIN OUTCOME MEASURE

Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels were measured every 6 weeks, and extensive thyroid function tests (TFTs) were measured before treatment (t0), after 6 weeks (t6), and at the end of therapy. The effect of sorafenib on TH transport by monocarboxylate transporter (MCT)8 or MCT10 was tested in transfected COS1 cells.

RESULTS

Four patients (7%) developed thyroiditis. Among the other patients, 30% had elevation of TSH or FT4 above the normal range. Overall, between t0 and t6, mean TSH increased from 1.28 to 1.57 mU/L (P < 0.001) and mean FT4 from 18.4 to 21.2 pmol/L (P < 0.001). Simultaneously, the serum triiodothyronine (T3)/reverse triiodothyronine ratio and the (T3/thyroxine) ×100 ratio decreased. Sorafenib decreased cellular T3 uptake by MCT8 and to a lesser extent by MCT10.

CONCLUSIONS

These in vivo data suggest that sorafenib affects TFTs on multiple levels. Our in vitro experiments suggest a possible role of sorafenib-induced inhibition of T3 transport into the cell by MCT8 and MCT10.

Regorafenib-induced hypothyroidism and cancer-related fatigue: is there a potential link?

OBJECTIVE

Thyroid dysfunction has been reported during Regorafenib (Reg) administration, but no detailed study is presently available.

DESIGN

Prospective, observational cohort study. Patients with documented metastatic colorectal cancer and progression of disease during or within 3 months after the last standard therapy, with no evidence and history of previous thyroid disease were enrolled.

METHODS

Twenty-five consecutive patients were evaluated before and 8-50 weeks after initiating Reg therapy by monthly clinical, ultrasound and laboratory (thyrotropin (TSH), free thyroxine (fT4), antithyroglobulin (TgAb) and antithyroid peroxidase (TPOAb)) evaluation.

RESULTS

Thirteen/25 patients (52%) became hypothyroid (TSH: 12.5 ± 4.01 IU/L, range: 4.6-22.0) within 5 months of therapy. TPOAb became detectable (99-155 IU/mL) in 2/25 (8%) patients. Thyroid volume progressively decreased (from 8.6 ± 2.2 mL to 4.9 ± 2.4 mL after 5 months of Reg therapy, P < 0.0001). The progression-free survival (PFS) was longer in patients developing hypothyroidism (43 weeks) than in those remaining euthyroid (17 weeks, P < 0.01). Fatigue (the most common general serious Reg adverse event) was associated with hypothyroidism severity and reversed after levothyroxine therapy (L-T4).

CONCLUSIONS

Reg rapidly causes hypothyroidism in about 50% of patients and in a minority of them also triggers thyroid autoimmunity. Reg-induced hypothyroidism was strictly related to fatigue, easily reversed by L-T4 administration and associated to longer survival. These results suggest that prompt recognition of hypothyroidism in patients with severe fatigue may prevent unnecessary Reg dose reduction or withdrawal.

Sunitinib-induced hypothyroidism predicts progression-free survival in metastatic renal cell carcinoma patients

Sunitinib is a tyrosine kinase inhibitor (TKI) used in treatment of metastatic renal cell carcinoma (mRCC), gastrointestinal stromal tumors and pancreatic neuroendocrine tumors. One of the most common side effects related to sunitinib is hypothyroidism. Recent trials suggest correlation between the incidence of hypothyroidism and treatment outcome in patients treated with TKI. This study evaluates whether development of hypothyroidism is a predictive marker of progression-free survival (PFS) in patients with mRCC treated with sunitinib. Twenty-seven patients diagnosed with clear cell mRCC, after nephrectomy and in ‘good’ or ‘intermediate’ MSKCC risk prognostic group, were included in the study. All patients received sunitinib as a first-line treatment on a standard schedule (initial dose 50 mg/day, 4 weeks on, 2 weeks off). The thyroid-stimulating hormone serum levels were obtained at the baseline and every 12 weeks of treatment. In statistic analyses, we used Kaplan–Meier method for assessment of progression-free survival; for comparison of survival, we used log-rank test. In our study, the incidence of hypothyroidism was 44%. The patients who had developed hypothyroidism had better median PFS to patients with normal thyroid function 28,3 months [95% (CI) 20.4–36.2 months] versus 9.8 months (6.4–13.1 months). In survival analysis, we perceive that thyroid dysfunction is a predictive factor of a progression-free survival (PFS). In the unified group of patients, the development of hypothyroidism during treatment with sunitinib is a positive marker for PFS. During that treatment, thyroid function should be evaluated regularly.

Cabozantinib for the treatment of progressive metastatic medullary thyroid cancer

Cabozantinib (XL-184) is a potent inhibitor of MET, VEGFR 2/KDR, RET and other receptor tyrosine kinases, such as KIT, AXL and FLT3. Its efficacy against MTC has been demonstrated in a prospective, randomized, placebo-controlled study (EXAM). Cabozantinib comparing to placebo significantly prolonged progression free survival both in hereditary and sporadic MTC, 11.2 vs 4.0 months, respectively. Final analysis showed no global differences in overall survival (OS) between cabozantinib and placebo. However, in a subgroup with RET M918T mutation the difference in OS was significant: 44.3 vs 18.9 months, respectively. Among the most frequent cabozantinib-related adverse events (AEs), observed in >30% of patients were diarrhea, palmar-plantar erythrodysesthesia, decreased weight, decreased appetite, nausea, fatigue, dysgeusia, hair color changes and hypertension. Expert Commentary: Cabozantinib constitutes an effective treatment option with acceptable toxicity in MTC patients showing either germinal or sporadic tumor RET M918T mutation as the drug prolonged OS in these subjects.

Thyroid Dysfunction in Patients with Metastatic Carcinoma Treated with Sunitinib: Is Thyroid Autoimmunity Involved?

BACKGROUND

Sunitinib is a tyrosine kinase inhibitor (TKI) inducing thyroid dysfunction, but the precise mechanism(s) involved remains to be explained, including the role of thyroid autoimmunity. The objective of this study was to evaluate thyroid function, parameters of autoimmunity, and thyroid ultrasound findings in patients with metastatic cancer and normal thyroid function/autoimmunity before the initiation of sunitinib therapy. This was a prospective, observational cohort study.

METHODS

Twenty-seven patients with metastatic carcinomas at comparable tumor stages were evaluated over 12-18 months after initiating therapy with sunitinib given at a daily oral dose of 50 mg for four weeks (ON), followed by one to two weeks off therapy (OFF). Serum thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and antithyroglobulin (TgAb), and antithyroid peroxidase (TPOAb) autoantibodies were measured in all cases. Thyroid morphology and volume were evaluated by echo-color Doppler ultrasound.

RESULTS

A total of 16/27 patients (60%) became hypothyroid (TSH range 7-114 mIU/L) within 30-120 days of therapy. The thyroid volume decreased in 24/27 (89%) patients (from M = 14.6 mL, SD = 6.4 mL to M = 3.8 mL, SD = 2.6 mL after 12 months; p < 0.001), together with the appearance of mild to severe hypoechogenicity. TPOAb (40-3000 IU/mL) became detectable in 7/27 (25%) patients, and TPOAb-positive patients displayed a higher degree of hypothyroidism and volume reduction. The progression-free survival (PFS) was significantly longer in patients developing TPOAb (10.8 months) than in the other group of patients (5.8 months).

CONCLUSIONS

These data confirm the thyroid inhibitory effect of sunitinib, in keeping with the key role of kinases in controlling thyroid function and growth. However, the novel appearance of TPOAb in a subgroup of patients with more severe hypothyroidism and longer survival indicates that sunitinib may also trigger/exacerbate thyroid autoimmunity contributing to thyroid failure. The development of TPOAb was associated with a longer PFS.

Nilotinib-Associated Destructive Thyroiditis

Protein tyrosine kinase inhibitors are currently an important drug class in the treatment of leukemia. They represent targeted cancer therapy and have become the treatment of choice in chronic myeloid leukemia. Tyrosine kinases are enzymes expressed in multiple tissues and are involved in several signaling pathways influencing cellular growth. Below we describe a patient who developed an unusual complication of tyrosine kinase inhibitor therapy: thyrotoxicosis due to destructive thyroiditis. We review the pathophysiology of tyrosine kinase inhibitor-induced thyroid dysfunction particularly with regard to new second-generation tyrosine kinase inhibitors.

Patterns of thyroid hormone levels in pediatric medullary thyroid carcinoma patients on vandetanib therapy

BACKGROUND

Tyrosine kinase inhibitors (TKIs) have been associated with elevated TSH as a drug class effect. Prior studies of vandetanib in adults with medullary thyroid carcinoma (MTC) described an increase in levothyroxine (LT) requirement. We studied TSH, free T4, and LT dosing in children and adolescents enrolled in the phase I/II trial of vandetanib for medullary thyroid cancer (MTC).

METHODS

Data from 13 patients with multiple endocrine neoplasia type 2B (MEN 2B) and MTC were analyzed [6 M, 7 F, median age 13.0 y (9.1-17.3)] Eleven patients (85%) had undergone prior thyroidectomy and all received single-drug therapy with vandetanib for > 6 months. Confirmed compliance with vandetanib (67-150 mg/m(2)/day) and LT was a necessary inclusion criterion.

RESULTS

While on vandetanib treatment, all 11 athyerotic patients exhibited significantly increased TSH levels. The baseline TSH level was 4.37 mclU/ml (0.08 - 23.30); in comparison, the first peak TSH concentration on vandetanib was 15.70 mclU/ml (12.50 - 137.00, p = 0.0010). The median time to reach the initial peak of elevated TSH was 1.8 months (0.3 - 9.3). Free T4 levels remained within the normal reference range. An increase from a baseline LT dose of 91 mcg/m(2)/day (±24) to 116 mcg/m(2)/day (±24) was required in order to resume normative TSH levels (p = 0.00005), equal to an increase of 36.6% (±16.56) in the dosage of LT in mcg/day. For the 2 patients with intact thyroid glands, free T4 and TSH remained normal over a combined 6 patient years of follow up.

CONCLUSIONS

In our cohort of pediatric MTC patients, athyreotic patients with preexisting hypothyroidism developed increased TSH and reduced free T4 during the first few months of treatment with vandetanib, necessitating an increase in LT dosage. Additional patients with normal thyroid function before treatment and intact glands (n = 2) maintained normal thyroid function tests during treatment. Elevated TSH in athyreotic patients may be due to an indirect effect of vandetanib on the metabolism of thyroid hormone, or to altered TSH sensitivity at the pituitary. Proper recognition and management of abnormal thyroid hormone levels is critical in growing children on TKIs.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00514046.

Sorafenib for the treatment of thyroid cancer: an updated review

INTRODUCTION

Sorafenib (Nexavar) is an oral multi-kinase inhibitor targeting B-type Raf kinase (BRAF) (both wild type and BRAF(V600E)), VEGFR1, VEGFR2, VEGFR3, PDGFRβ and RET (also RET/PTC) influencing both differentiated thyroid cancer (DTC) cell proliferation and angiogenesis.

AREAS COVERED

Encouraging results achieved in numerous Phase II trials were confirmed in a Phase III study conducted in radioiodine-refractory DTC. Sorafenib compared to placebo significantly prolongs progression-free survival, 10.8 versus 5.8 months, respectively. However, its administration resulted mainly in disease stabilization. No complete remission was obtained in any study. Beneficial effects were also demonstrated for medullary and anaplastic thyroid cancer; however further studies fulfilling evidence based medicine criteria are necessary. Its toxicity profile is convergent with other VEGFR inhibitors. The most common treatment-related side-effects involve skin toxicity (predominantly hand-foot skin reaction, different rashes and alopecia), gastrointestinal disturbances (diarrhea, abdominal pain), constitutional adverse reactions (anorexia, weight loss, fatigue) and hypertension. Although most adverse reactions are manageable, > 50% of patients required dose reduction.

EXPERT OPINION

Sorafenib constitutes the first line treatment option in advanced, radioiodine-refractory DTC. However, there are still no data on its efficacy in patients progressed after another tyrosine kinase inhibitor. Other applications of the drug, such as use as adjuvant therapy to 131-I treatment, requires further studies.

Acquired Hypothyroidism as a Predictive Marker of Outcome in Patients With Metastatic Renal Cell Carcinoma Treated With Tyrosine Kinase Inhibitors: A Literature-Based Meta-Analysis

Hypothyroidism in patients with metastatic renal cell carcinoma (mRCC) during treatment with the tyrosine kinase inhibitors (TKIs) sunitinib and sorafenib is a well-established side effect. Furthermore, the potential role of hypothyroidism as predictive marker of outcome has been studied but with conflicting results. The aim of the present meta-analysis was to assess the predictive value of hypothyroidism for progression-free (PFS) and overall survival (OS) in patients with mRCC during TKI therapy. We searched PubMed and the electronic abstract databases of the major international congresses' proceedings to identify all eligible studies that reported a correlation between the development of hypothyroidism during TKI treatment and outcome in patients with mRCC. Hazard ratios (HRs) with 95% confidence intervals (CIs) for PFS and OS were obtained from these publications and pooled in a meta-analysis. Eleven studies with a total of 500 patients fulfilled the inclusion criteria. We found no statistical significant difference in PFS between patients who developed hypothyroidism during sunitinib therapy and unaffected patients (HR, 0.82; 95% CI, 0.59-1.13; P = .22; 6 studies; 250 patients). The HR for OS was 0.52 (95% CI, 0.31-0.87; P = .01) for patients who developed hypothyroidism during sunitinib therapy compared with patients who did not (4 studies; 147 patients). The development of hypothyroidism during TKI therapy is not clearly shown to be predictive of efficacy in patients with mRCC. The observed advantage in OS for the patients with acquired hypothyroidism should be interpreted with caution.

Soluble Flt1 and placental growth factor are novel determinants of newborn thyroid (dys)function: the generation R study

CONTEXT

Adequate thyroid hormone availability during fetal and early life is crucial for normal child growth and development. Fetal growth heavily depends on angiogenesis. Placental growth factor (PlGF) is a proangiogenic factor sharing high homology with vascular endothelial growth factor, whereas soluble FMS-like tyrosine kinase-1 (sFlt1) is a potent antagonist of vascular endothelial growth factor and PlGF signaling. Because the thyroid is a highly vascularized organ, we hypothesized that fetal angiogenic factors influence in utero thyrogenesis and impair newborn thyroid function. Therefore, we investigated the association between sFlt1 and PlGF on newborn thyroid function.

DESIGN, SETTING, AND PARTICIPANTS

sFlt1, PlGF, TSH, and free T4 (FT4) were determined in cord serum of 3525 newborns from a large prospective cohort study. Analyses were adjusted for relevant maternal and child covariates.

RESULTS

sFlt1 levels were positively associated with TSH (β 0.07 ± 0.02 mU/L; P < .001) and inversely with FT4 (β -0.58 ± 0.11; P < .001). PlGF showed a positive association with FT4 (β 0.19 ± 0.02; P < .001). Elevated levels of sFlt1 were associated with a 2.8-fold increased risk of hypothyroxinemia (P = .04). Decreased levels of PlGF were associated with a 6.7-fold increased risk of hypothyroxinemia (P < .001). Within the normal range, a dose-dependent effect of sFlt1 on thyroid dysfunction was observed: high-normal sFlt1 levels were associated with a 17.7-fold increased risk of hypothyroxinemia (P < .001) and a 2.7-fold increased risk of hyperthyrotropinemia (P = .01).

CONCLUSION

Fetal angiogenic factors sFlt1 and PlGF are associated with newborn thyroid function. Possible effects are most likely mediated through effects on in utero thyrogenesis. Abnormal as well as normal-range fetal sFlt1 and PlGF levels influence the risk of impaired newborn thyroid function, which has been associated with adverse neurodevelopmental effects. These data provide important novel insights into the physiology of thyrogenesis and into the etiology of newborn thyroid (dys)function.

Recurrent thyroid cancers have more peritumoural lymphatic vasculature than nonrecurrent thyroid cancers

BACKGROUND

The goal of the study was to evaluate angiogenesis and lymphangiogenesis in differentiated thyroid cancer and recurrences.

METHODS

Twenty-seven patients with recurrent differentiated thyroid cancer (20 papillary and seven follicular thyroid carcinomas) and 24 nonrecurrent thyroid cancers were included in this study. Additionally, 24 thyroid adenomas were included as benign controls. All thyroid cancer recurrences were operatively managed, and local recurrences in cervical lymph nodes or cervical soft tissue were histologically confirmed. Altogether, a total of 108 samples were evaluated using CD31 and D2-40 immunohistochemical staining and microscopy.

RESULTS

As measured in primary tumours, the median density of CD31-positive vascular structures was 327 vessels (v)/mm(2) for recurrent cancers, 362 v/mm(2) for nonrecurrent cancers and 484 v/mm(2) for thyroid adenomas (P = 0·017). Among the subgroups, the lowest median vascular density of 316 v/mm(2) was found in recurrent papillary cancers and the highest vascular density of 604 v/mm(2) was observed in nonrecurrent follicular cancers (P = 0·018). The median density of D2-40-positive peritumoural lymphatic vessels was 101/mm(2) in recurrent cancers, 56·1/mm(2) in nonrecurrent cancers and 53·9/mm(2) for adenomas (P = 0·015). In the subgroups, peritumoural lymphatic vascular density was 102 v/mm(2) in recurrent papillary cancers and 56·0 v/mm(2) in nonrecurrent papillary cancers (P = 0·044).

CONCLUSIONS

Recurrent thyroid cancers expressed less intratumoural microvessels than thyroid adenomas. A high density of peritumoural lymphatic vessels was found in recurrent papillary cancers. High blood vessel density may be a marker for less aggressive tumours, while high peritumoural lymphatic vasculature is a marker for more aggressive and recurrence-prone tumours.

Cabozantinib-induced thyroid dysfunction: a review of two ongoing trials for metastatic bladder cancer and sarcoma

BACKGROUND

Thyroid dysfunction is a common adverse event associated with tyrosine kinase inhibitors (TKI), but its underlying pathophysiology is unclear. Cabozantinib is a novel TKI currently Food and Drug Administration approved for advanced medullary thyroid cancer and tested in clinical trials on solid tumors including prostate, liver, bladder, breast, and ovarian cancer.

METHODS

We analyzed the thyroid function of patients enrolled in two phase 2 clinical trials using cabozantinib at the National Institutes of Health Clinical Center. Two cases of thyroiditis associated with cabozantinib therapy are presented in detail, and a systematic review of the literature on TKI-associated thyroid dysfunction is also discussed.

RESULTS

Between September 2012 and September 2013, 33 patients were treated with cabozantinib, and follow-up thyroid function tests were available for 31 (20 males, 11 females; age 59±1 years). Thyroid dysfunction was recorded in the majority of patients (93.1%), with a predominance of subclinical hypothyroidism. Two cases showed a biphasic pattern of thyroid dysfunction characterized by a transient thyrotoxicosis followed by hypothyroidism. Color Doppler demonstrated an increase in vascularization during the thyrotoxic phase, but no uptake was visualized on nuclear medicine imaging. A systematic review of the literature resulted in the identification of 40 original manuscripts, of which 13 were case series and 6 were case reports describing TKI-associated thyroid dysfunction.

CONCLUSION

TKI therapy often results in clinically significant thyroid dysfunction. Cabozantinib treatment commonly results in thyroid dysfunction varying from subclinical hypothyroidism to symptomatic thyrotoxicosis. Early detection and characterization of cabozantinib-associated thyroid dysfunction and close follow-up are essential to provide adequate management of this common adverse event.

Complete resolution of hypercortisolism with sorafenib in a patient with advanced medullary thyroid carcinoma and ectopic ACTH (adrenocorticotropic hormone) syndrome

BACKGROUND

The treatment of advanced medullary thyroid carcinoma (MTC) has evolved significantly over the past decade. The discovery of genetic abnormalities in MTC has led to the development of targeted therapies such as vandetanib and cabozantinib. Other kinase inhibitors (KI), such as sorafenib, have been investigated in this setting and are an alternative therapeutic option. The lack of specificity of these KIs to a single target may result in additional, unexpected effects. In this report, we describe a patient with metastatic MTC and Ectopic ACTH (adrenocorticotropic hormone) Syndrome in whom treatment with sorafenib resulted in complete resolution of hypercortisolism.

SUMMARY

A 45-year-old male with progressive metastatic MTC presented with clinical manifestations suspicious for Cushing's syndrome. Investigation revealed ACTH-dependent hypercortisolism suggestive of Ectopic ACTH Syndrome. Treatment with sorafenib 400 mg twice a day was initiated resulting in a rapid and significant reduction of cortisol and ACTH levels associated with dramatic clinical improvement. The rapid and effective control of hypercortisolism in the absence of a significant tumor reduction raises the question of whether sorafenib may have a direct effect on ACTH or cortisol hypersecretion.

CONCLUSIONS

This report suggests a previously unknown potential effect of sorafenib on the pituitary-adrenal axis. Further studies will be necessary to investigate the role of sorafenib in other cases of ACTH excess and to understand the mechanisms by which it alters steroid synthesis, action, or secretion.