Thyroid dysfunction in patients treated with sunitinib or sorafenib

Prevalence and Associated Factors for Thyroid Dysfunction Among Patients On Targeted Therapy for Cancers: A Single-Center Study from Thailand

Objective

This study aimed to explore the prevalence and associated factors of thyroid dysfunction among cancer patients treated with tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs).

Methodology

A cross-sectional study was done in patients who received TKIs at Rajavithi Hospital in 2019. For patients treated with ICI, a retrospective chart review for patients seen in 2018 to 2019 was conducted. If there were abnormal thyroid function tests (TFT), thyroid autoantibodies were tested.

Results

There were 144 patients on TKIs with a mean age of 56.0 years. Thyroid dysfunction was found in 14.6% of patients and most had subclinical hypothyroidism (n = 16, 11.1%). Imatinib (n = 11, 10.8%) and sunitinib (n = 4, 100%) were the 2 most common TKIs given to patients with thyroid dysfunction. Thyroid dysfunction was associated with male sex, chronic kidney disease and hepatitis B virus infection but not with previous thyroid disease and presence of thyroid autoantibodies.There were 18 patients who received ICIs. The mean age was 63.3 years. Twelve patients (66.7%) used programmed cell death protein-1 antibody (anti-PD1), mainly nivolumab. Thyroid dysfunction was found in 50%, which occurred at a median duration of 46 days. Most patients had overt hypothyroidism and 55.6% needed levothyroxine replacement.

Conclusion

Thyroid dysfunctions from TKIs were mostly asymptomatic and mild in severity. Some types of TKIs might be associated with thyroid dysfunction. On the other hand, thyroid dysfunction from ICIs usually occurs within 6 months and requires levothyroxine replacement.

The influence of sunitinib and sorafenib, two tyrosine kinase inhibitors, on development and thyroid system in zebrafish larvae

Recently, the potential toxic effects of various pharmaceuticals on the thyroid endocrine system have raised considerable concerns. In this study, we evaluated the adverse effects of sorafenib and sunitinib, two widely used anti-tumor drugs, on the developmental toxicities and thyroid endocrine disruption by using zebrafish (Danio rerio) model. Zebrafish embryos/larvae were exposed to different contentions (0, 10, 50 and 100 nM) of sorafenib and sunitinib for 96 hpf. The results revealed that waterborne exposure to sorafenib and sunitinib exhibited remarkable toxic effects on the survival and development in zebrafish embryos/larvae, which was accompanied by obvious disturbances of thyroid endocrine system (e.g., decreased T3 and T4 content, increased TSH content) and genes' transcription changes within the hypothalamus-pituitary-thyroid (HPT) axis. In addition, we verified a strikingly abnormal thyroid gland organogenesis in zebrafish larvae in response to sorafenib and sunitinib, by assessing the development of thyroid follicles using the WISH staining of tg, the Tg (tg:GFP) zebrafish transgenic line, and histopathological analysis. Taken together, our results indicated sorafenib and sunitinib exposure could induce obvious developmental toxicities and thyroid function disruption in zebrafish embryos/larvae, which might involve a regulatory mechanism, at least in part, by destroying the thyroid follicle structure, and by disturbing the balance of the HPT axis.

The variants in PTPRB, TRAF3IP3, and DISC1 genes were associated with Graves' disease in the Chinese population

Previously, a case series study was conducted on our part in which 5 patients with Graves' disease (GD) were collected from a 3-generation family to screen for susceptibility genes responsible for GD. The single nucleotide variants of Microtubule-associated protein 7 domain containing 2 c. 452C > T, p. Ala151Val, Solute carrier family 1 member 7 c. 1204C > T, p. Arg402Cys, tumor necrosis factor receptor-associated factor 3 interacting protein 3 (TRAF3IP3) c. 209A > T, p. Asn70Ile, protein tyrosine phosphatase receptor type B (PTPRB) c. 3472A > G, p. Ser1158Gly, Phosphoinositide-3-kinase regulatory subunit 3 c. 121C > T, p. Pro41Ser, disrupted in schizophrenia 1 (DISC1), c. 1591G > C p. Gly531Arg were associated with the familial GD. We then further confirmed these variants and investigated whether other mutations render susceptibility to GD. The case-control study collected patients with sporadic GD or no GD family history. A snapshot program was used for genotyping the selected SNPs in 235 GD patients (GD group 1) and 284 healthy patients (control group). Furthermore, another 184 GD patients were recruited (GD group 2) to sequence the specified exons of these genes. The sequenced data was compared with Chinese Millionome Database (CMDB). Several variants of PTPRB, phosphoinositide-3-kinase regulatory subunit 3, TRAF3IP3, and DISC1 were found in GD group 2 but not in CMDB. Moreover, the allele frequency of SNP rs2076150 (TRAF3IP3) and rs2492367 DISC1 in GD group 2 was significantly higher than that of in CMDB (all P < .05). When the control group or CMDB was set as a reference group, a significantly higher frequency in alter allele C of SNP rs186466118 PTPRB was observed in GD group 1 and GD group (constituted by GD group 1 and GD group 2). Equally importantly, there was a correlation between the allele C of SNP rs186466118 and the increased risk of GD susceptibility (all P < .05). PTPRB, TRAF3IP3, and DISC1 may be susceptibility genes for GD, and more variants of PTPRB, TRAF3IP3, and DISC1 were found in GD patients.

Genetic association and Mendelian randomization for hypothyroidism highlight immune molecular mechanisms

We carried out a genome-wide association analysis including 51,194 cases of hypothyroidism and 443,383 controls. In total, 139 risk loci were associated to hypothyroidism with genes involved in lymphocyte function. Candidate genes associated with hypothyroidism were identified by using molecular quantitative trait loci, colocalization, and enhancer-promoter chromatin looping. Mendelian randomization (MR) identified 42 blood expressed genes and circulating proteins as candidate causal molecules in hypothyroidism. Drug-gene interaction analysis provided evidence that immune checkpoint and tyrosine kinase inhibitors used in cancer therapy increase the risk of hypothyroidism. Hence, integrative mapping and MR support that expression of genes and proteins enriched in lymphocyte function are associated with the risk of hypothyroidism and provide genetic evidence for drug-induced hypothyroidism and identify actionable potential drug targets.

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GWAS for hypothyroidism identified 139 risk loci including 76 novel associations

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GWAS was enriched in pathways related to lymphocyte function

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In total, 28 potentially deleterious missense variants were identified

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Mendelian randomization and colocalization identified 61 blood causal candidate genes

CRISPR-mediated knockout of VEGFR2/KDR inhibits cell growth in a squamous thyroid cancer cell line

Squamous and anaplastic thyroid cancers are the most aggressive and life‐threatening cancer types in humans, with the involvement of lymph nodes in 59% of cases and distant metastases in 26% of cases of all thyroid cancers. The median survival of squamous thyroid cancer patients is < 8 months and therefore is of high clinical concern. Here, we show that both VEGFC and VEGFR2/KDR are overexpressed in thyroid cancers, indicating that VEGF/VEGFR signaling plays a carcinogenic role in thyroid cancer development. Using CRISPR/Cas9, we established a KDR knockout (KO) SW579 squamous thyroid cancer cell line that exhibited dramatically decreased colony formation and invasion abilities (30% and 60% reduction, respectively) when compared to scrambled control cells. To validate the potential of KDR as a therapeutic target for thyroid cancers, we used the KDR RTK inhibitor sunitinib. Protein analysis and live/dead assay were performed to demonstrate that sunitinib significantly inhibited cell growth signal transduction and induced cell apoptosis of SW579 cells. These results suggest that selective targeting of KDR may have potential for development into novel anti‐cancer therapies to suppress VEGF/VEGFR‐mediated cancer development in patients with clinical advanced thyroid cancer.

Anti-VEGF agents: As appealing targets in the setting of COVID-19 treatment in critically ill patients

Recently, the medications used for the severe form of the coronavirus disease-19 (COVID-19) therapy are of particular interest. In this sense, it has been supposed that anti-VEGF compounds would be good candidates in the face of "cytokine storm" and intussuscepted angiogenesis due to having an appreciable anti-inflammatory effect. Therefore, they can be subjected to therapeutic protocols to manage acute respiratory distress syndrome (ARDS). Since the compelling evidence emphasized that VEGFs contribute to the inflammatory process and play a mainstay role in disease pathogenesis, in this review, we aimed to highlight the VEGF's plausible participation in the cytokine storm exacerbation in COVID-19. Next, the recent clinical advances regarding the anti-VEGF medications, including humanized monoclonal antibody, immunosuppressant, a tyrosine kinase inhibitor, and a cytokine inhibitor, have been addressed in the setting of COVID-19 treatment in critically ill patients. Together, retrieving the increased level of VEGF subsets, as well as antagonizing VEGF related receptors, could be helpful for the treatment of COVID-19, especially in those suffering from ARDS.

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.

Acquired Hypothyroidism in Patients with Metastatic Renal Cell Carcinoma Treated with Tyrosine Kinase Inhibitors

PURPOSE

We analyze a number of studies that describe the relationship between the onset of hypothyroidism and the prognosis of patients with metastatic renal cell carcinoma (mRCC) treated with TKIs.

PATIENTS AND METHODS

Targeted therapies are currently considered as the first-line treatment for patients with mRCC. The occurrence of hypothyroidism in the treatment of mRCC with TKIs is a major side effect. A comprehensive search was performed in Pubmed, Cochrane Library, Institute for Scientific Information, and CKNI. The following keywords and descriptors were used during the search and were combined in a number of sequences in English and Chinese languages: protein kinase inhibitors (including sunitinib, pazopanib, tivozanib, cabozantinib, axitinib, sorafenib), hypothyroidism and renal cell carcinoma.

RESULTS

Scholars have studied the clinical relationship between hypothyroidism and TKI treatment and its molecular biology mechanism. Most studies hold that hypothyroidism occurring during TKI therapy may serve as potential biomarkers of response and efficacy of treatment, but there is no consensus on this point.

CONCLUSION

The mechanism of hypothyroidism occurring is still unclear. Therefore, more studies are needed to clarify whether better outcomes are associated with TKI-induced hypothyroidism in mRCC patients, helping to maximize the treatment outcome of mRCC patients.

Clinical observation of apatinib-related hypothyroidism in patients with advanced malignancies

Thyroid dysfunction has been previously reported during treatment with certain small-molecule multi-tyrosine kinase inhibitors, including sunitinib and sorafenib. Apatinib, which has a similar mechanism of action to these inhibitors, has reportedly induced hypothyroidism during treatment. Fully elucidating drug-associated adverse events could aid in patient monitoring and recommendations of suitable management strategies. The current 2-year observational study monitored patients with solid tumors who were prescribed apatinib. A total of 149 patients treated with apatinib from February 2015 to January 2016 were included. Their thyroid function and thyroid ultrastructure was evaluated for at least 24 months or until death. The primary objective of the current study was evaluating accepted thyroid replacement treatment. Secondary objective was ultrastructural changes in the thyroid gland. The current study was approved by the Medical Ethics Committee of Qianfoshan Hospital, affiliated with Shandong University and written informed consent was obtained from all patients prior to commencing the clinical trial. A total of 53 (35.57%) patients developed hypothyroidism, which varied from subclinical (12 cases; 8.05%) to clinical (41 cases; 27.52%). Thyroid nodules were noted in 15 cases (10.07%). Furthermore, 3 cases (2.01%) had thyroid imaging reporting and data system scores of 4a/4b/4c and 12 cases (8.05%) had scores of 1, 2 and 3. A total of 25 patients (16.78%) experienced 1-2 grade fatigue and 2 patients (1.34%) reported 3-4 grade fatigue. There was no reported association between disease control rate and hypothyroidism. Apatinib significantly increased the risk of clinically relevant hypothyroidism and altered thyroid gland structure.

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.

On-target Toxicities Predictive of Survival in Metastatic Renal Cell Carcinoma (mRCC) Treated With Sunitinib: A Multicenter Retrospective Study

BACKGROUND

Preliminary studies suggested that selected drug-related toxicities of sunitinib may correlate with a better prognosis.

PATIENTS AND METHODS

From January 2006 through December 2015, we retrospectively analyzed data of 145 patients with metastatic renal cell carcinoma treated with sunitinib as a first-line therapy in 7 different Italian oncology departments. Hypertension, hypothyroidism, thrombocytopenia, neutropenia, and anemia were evaluated. Overall survival (OS) and progression-free survival (PFS) were calculated. OS and PFS were compared in patients who developed and who did not develop a drug-related toxicity. A multivariate analysis using the Cox regression model was performed.

RESULTS

We evaluated 145 patients (92 males; median age, 70 years); 105 (62.4%) patients experienced at least 1 toxicity: 66 (45.5%) patients developed hypothyroidism, 41 (28.3%) thrombocytopenia, 39 (26.9%) hypertension that required medical therapy, 22 (15.2%) anemia, and 11 (7.6%) neutropenia. The median PFS of patients who developed hypertension was 12 months (95% confidence interval [CI], 9-21 months) versus 9 months (95% CI, 7-12 months) in patients who did not develop toxicity; the median OS was 36 months (95% CI, 22 months to not reached) versus 26 months (95% CI, 18-34 months). For neutropenia, the median PFS was 17.5 months (95% CI, 9-65 months) versus 10 months (95% CI, 8-12 months); the median OS was 23 months (95% CI, 13 months to not reached) versus 28 months (95% CI, 22-35 months). At univariate and multivariate analysis, we observed a protective effect of hypertension and neutropenia on tumor progression (hazard ratio, 0.47; 95% CI, 0.28-0.78 and hazard ratio, 0.26; 95% CI, 0.09-0.76, respectively).

CONCLUSIONS

Many patients developed toxicities during treatment with sunitinib; hypertension and neutropenia were related to longer PFS in our cohort.

Current evidence on thyroid related adverse events in patients treated with protein tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKI) are gaining more ground in oncology, they are widely used in the treatment of multiple types of cancers; still important side effects limit their efficacy. The aim of this study is to evaluate the existing medical literature on TKI induced thyroid dysfunction, to assess the adverse effects of targeted therapy on thyroid function in oncological patients and to evaluate the effects of thyroid dysfunction on disease prognosis. We included in this review 22 original studies published between 2010 and 2019. We used the PubMed database to search for articles upon the development of hypothyroidism and hyperthyroidism in TKI treated patients. After a careful review of the existing literature, we selected the relevant studies and cross-referenced the bibliography of each paper. A number of 1641 patients were included in our review. We found that thyroid dysfunction is not a rare side effect of TKI treatment, approximately 33% of the total number of patients presented clinical hypothyroidism. We also studied the necessity of thyroid hormone substitution treatment, a quarter of evaluated patients needed substitution therapy. Multiple studies showed that there is a link between a patient developing hypothyroidism and progression free survival. Hypothyroidism is a frequent side effect of TKI treatment, which affects the quality of life, sometimes even determines physicians to stop TKI treatment altogether. Our study underlines the necessity of TSH baseline testing and monitoring in patients treated with TKI agents.

Investigation of thyroid function in dogs treated with the tyrosine kinase inhibitor toceranib

Tyrosine kinase inhibitors are widely utilized in veterinary oncology for the treatment of mast cell and solid tumours. In man, these drugs are associated with thyroid dysfunction: however, to date only one study has investigated this in dogs. The aim of this study was to prospectively assess thyroid function in a group of dogs with cancer receiving toceranib. Thirty-four dogs were prospectively enrolled at two referral hospitals into two groups; those receiving toceranib with prednisolone and those receiving toceranib alone. Total thyroxine (TT4) and thyroid stimulating hormone (TSH) was monitored at regular time points during treatment. Follow-up data was available for 19 dogs. Overall, 12 incidences of elevated TSH occurred but none of these dogs had concurrent low TT4 concentrations. There was a significant difference in median TSH at week six compared with baseline. Hypothyroidism was not diagnosed in any patient during the study period. Patient drop-out was higher than anticipated which prevented the assessment of longer term toceranib administration on thyroid function. Toceranib therapy was not associated with hypothyroidism in this study but did result in elevations in TSH which confirms what has been previously reported. Toceranib should be considered to cause thyroid dysfunction in dogs and monitoring is advised.

Chinese consensus on management of tyrosine kinase inhibitor-associated side effects in gastrointestinal stromal tumors

Tyrosine kinase inhibitors (TKIs) have improved the overall survival of patients with gastrointestinal stromal tumors (GISTs), but their side effects can impact dose intensity and, consequently, the clinical benefit. To date, no guideline or consensus has been published on the TKI-associated adverse reactions. Therefore, the Chinese Society of Surgeons for Gastrointestinal Stromal Tumor of the Chinese Medical Doctor Association organized an expert panel discussion involving representatives from gastrointestinal surgery, medical oncology, cardiology, dermatology, nephrology, endocrinology, and ophthalmology to consider the systemic clinical symptoms, molecular and cellular mechanisms, and treatment recommendations of GISTs. Here, we present the resultant evidence- and experience-based consensus to guide the management of TKI-associated side events in clinical practice.

Targeting FGFR pathway in breast cancer

Developments in breast cancer biology over the last years have permitted deconstructing the molecular profile of the most relevant breast cancer subtypes. This has led to an increase in therapeutic options, including more effective personalized therapy for breast cancer and substantial improvements in patient outcomes. Although currently there are only a few targeted therapies approved for metastatic breast cancer, the discovery of druggable kinase gene alterations has radically changed cancer treatment by providing novel and successfully actionable drug targets. Fibroblast growth factors and their receptors (FGFRs) participate in different physiologic processes and also play an essential role in cancer cell proliferation, survival, differentiation, migration, and apoptosis. This article summarizes the main molecular alterations of FGFRs, as well as the available preclinical and clinical data with FGFR inhibitors in breast cancer, and discusses new opportunities for the clinical development of these agents in patients with breast cancer.

Molecular and Clinical Approach to Intra-abdominal Adverse Effects of Targeted Cancer Therapies

Targeted cancer therapies encompass an exponentially growing number of agents that involve a myriad of molecular pathways. To excel within this rapidly changing field of clinical oncology, radiologists must eschew traditional organ system-based approaches of cataloging adverse effects in favor of a conceptual framework that incorporates molecular mechanisms and associated clinical outcomes. Understanding molecular mechanisms that underlie imaging manifestations of adverse effects and known associations with treatment response allows radiologists to more effectively recognize adverse effects and differentiate them from tumor progression. Radiologists can therefore more effectively guide oncologists in the management of adverse effects and treatment decisions regarding continuation or cessation of drug therapy. Adverse effects from targeted cancer therapies can be classified into four categories: (a) category 1, on-target adverse effects associated with treatment response; (b) category 2, on-target adverse effects without associated treatment response; (c) category 3, off-target adverse effects; and (d) category 4, tumor necrosis-related adverse effects. This review focuses on adverse effects primarily within the abdomen and pelvis classified according to established or hypothesized molecular mechanisms and illustrated with images of classic examples and several potential emerging toxic effects. ^©RSNA, 2017.

Pharmacoepidemiology of Clinically Relevant Hypothyroidism and Hypertension from Sunitinib and Sorafenib

BACKGROUND

Thyroid dysfunction and hypertension (HTN) have been sporadically reported with sunitinib (SUN) and sorafenib (SOR). Determination of the side effect incidence will enhance monitoring and management recommendations.

METHODS

An observational cohort study was performed using deidentified pharmacy claims data from a 3-year period to evaluate patients prescribed SUN, SOR, or capecitabine (CAP; comparison group). The primary outcome was time to first prescription for thyroid replacement or HTN treatment. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated by Cox proportional hazards models.

RESULTS

A total of 20,061 patients were eligible for evaluation of thyroid replacement therapy, which was initiated in 11.6% of those receiving SUN (HR, 16.77; 95% CI, 13.54-20.76), 2.6% of those receiving SOR (HR, 3.47; 95% CI, 2.46-4.98), and 1% of those receiving CAP, with median time to initiation of 4 months (range, 1-35 months). A total of 14,468 patients were eligible for evaluation of HTN therapy, which was initiated in 21% of SUN recipients (HR, 4.91; 95% CI, 4.19-5.74), 14% of SOR recipients (HR, 3.25; 95% CI, 2.69-3.91), and 5% of CAP recipients, with median time to initiation of 1 month (range, 1-18 months) for SOR and 2 months (range, 1-25 months) for SUN.

CONCLUSION

SUN and SOR significantly increased the risk for clinically relevant hypothyroidism; the risk was at least 4 times greater with SUN than with SOR. Patients receiving SUN and SOR had a similar elevated risk for clinically relevant HTN. These data provide robust measures of the incidence and time to onset of these clinically actionable adverse events. The Oncologist 2017;22:208-212Implications for Practice: The side effect profiles for novel therapies are typically used to create monitoring and management recommendations using clinical trial data from patient populations that may not represent those seen in standard clinical practice. This analysis using a large pharmacy claims database better reflects typical patients treated with sorafenib or sunitinib outside of a clinical trial. The findings of increased need for thyroid replacement in patients receiving sunitinib compared with sorafenib and a similar increase in need for hypertension therapy with both agents can be used to form clinically relevant monitoring recommendations for these agents.

Clinical significance of sunitinib-associated macrocytosis in metastatic renal cell carcinoma

Increases in the mean corpuscular volume (MCV) have been observed in patients with metastatic renal cell carcinoma (mRCC) on tyrosine kinase inhibitor (TKI) treatment; however, its association with progression‐free‐survival (PFS) is unknown. We aimed to characterize TKI‐associated macrocytosis in mRCC and its relationship with PFS. Retrospective review of data on macrocytosis and thyroid dysfunction on mRCC patients treated with sunitinib and/or sorafenib. These results are evaluated in the context of our previous report on the association of hypothyroidism in this setting. We assessed PFS as clinically defined by the treating physician. Seventy‐four patients, 29 of whom received both drugs, were included. A treatment period was defined as time from initiation to discontinuation of either sunitinib or sorafenib; 103 treatment periods [sorafenib (47), sunitinib (56)] were analyzed. Macrocytosis was found in 55 and 8% of sunitinib‐ and sorafenib‐treated patients, respectively, P < 0.001. The median time to developing macrocytosis was 3 months (m, range 1–7). Median PFS in sunitinib‐treated patients was 11 m (95% CI: 6–19). Median PFS was higher among those with macrocytosis compared to normocytosis (21 m [95% CI: 11–25] vs. 4 m [95% CI: 3–8] P = 0.0001). Macrocytosis and hypothyroidism were two significant predictors of PFS. The greatest difference in PFS among all patients was observed in patients with both macrocytosis and hypothyroidism (25 m), compared to the normocytic and euthyroid patients (5 m) (P < 0.0001). Sunitinib‐related macrocytosis was associated with prolonged PFS, and concurrent development of hypothyroidism and macrocytosis further prolonged PFS. Increased MCV may have a role as a predictive biomarker for sunitinib. Prospective studies accounting for other known prognostic factors are needed to confirm this finding.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT ON THYROID DYSFUNCTION CASE FINDING

Hypothyroidism and hyperthyroidism can be readily diagnosed and can be treated in a safe, cost-effective manner. Professional organizations have given guidance on how and when to employ thyroid-stimulating hormone testing for the detection of thyroid dysfunction. Most recently, the United States Preventive Services Task Force did not endorse screening for thyroid dysfunction based on a lack of proven benefit and potential harm of treating those with thyroid dysfunction, which is mostly subclinical disease. The American Association of Clinical Endocrinologists (AACE) is concerned that this may discourage physicians from testing for thyroid dysfunction when clinically appropriate. Given the lack of specificity of thyroid-associated symptoms, the appropriate diagnosis of thyroid disease requires biochemical confirmation. The Thyroid Scientific Committee of the AACE has produced this White Paper to highlight the important difference between screening and case-based testing in the practice of clinical medicine. We recommend that thyroid dysfunction should be frequently considered as a potential etiology for many of the nonspecific complaints that physicians face daily. The application and success of safe and effective interventions are dependent on an accurate diagnosis. We, therefore, advocate for an aggressive case-finding approach, based on identifying those persons most likely to have thyroid disease that will benefit from its treatment.

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.

Endocrine side-effects of anti-cancer drugs: thyroid effects of tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKIs) are currently used by most oncologists. Among their side effects, thyroid dysfunctions are nowadays clearly observed. Whereas changes in thyroid function tests have been originally described with sunitinib, we now know that many TKIs can induce hypothyroidism and hyperthyroidism. In this study, the various molecules implicated in thyroid dysfunctions are analysed and the latest data on physiopathological mechanisms are approached in order to propose a strategy of thyroid monitoring of patients on TKI therapy.

Granulocyte macrophage colony-stimulating factor as a predictor of the response of metastatic renal cell carcinoma to tyrosine kinase inhibitor therapy

This prospective study was conducted to identify predictive markers for the response of metastatic renal cell carcinoma (RCC) to tyrosine kinase inhibitors (TKIs). Patients with histologically proven RCC with at least one measurable metastatic lesion were enrolled in this study. Blood samples were collected prior to treatment and the plasma levels of 27 cytokines were measured. Tumor response was assessed 8-12 weeks after the initiation of TKI treatment. A total of 13 patients (11 men and 2 women) with a median age of 63 years received sunitinib (8 cases), sorafenib (1 case), or axitinib (4 cases). Partial response (PR) was achieved in 5 patients (38%), stable disease (SD) in 4 (30%) and progressive disease (PD) was noted in 4 (30%). The plasma granulocyte macrophage colony-stimulating factor (GM-CSF) level in PR cases was significantly higher compared to that in SD or PD cases (P=0.012). Therefore, GM-CSF may be a predictive biomarker of the response of RCC to TKI treatment, suggesting that TKIs may exert clinical effects not only through suppression of the vascular endothelial growth factor, but also through immune system modulation.

Clinical practice guidelines for the management of hypothyroidism

INTRODUCTION

Hypothyroidism has long been known for its effects on different organ systems, leading to hypometabolism. However, subclinical hypothyroidism, its most prevalent form, has been recently related to cardiovascular risk and also to maternal-fetal complications in pregnant women.

OBJECTIVES

In these clinical practice guidelines, several aspects of this field have been discussed with the clear objectives of helping physicians treat patients with hypothyroidism, and of sharing some of our Latin American-based clinical experience.

MATERIALS AND METHODS

The Latin American Thyroid Society commissioned a Task Force on Hypothyroidism to develop evidence-based clinical guidelines on hypothyroidism. A systematic review of the available literature, focused on the primary databases of MedLine/PubMed and Lilacs/SciELO was performed. Filters to assess methodological quality were applied to select the best quality studies. The strength of recommendation on a scale from A-D was based on the Oxford Centre for Evidence--based Medicine, Levels of Evidence 2009, allowing an unbiased opinion devoid of subjective viewpoints. The areas of interest for the studies comprised diagnosis, screening, treatment and a special section for hypothyroidism in pregnancy.

RESULTS

Several questions based on diagnosis, screening, treatment of hypothyroidism in adult population and specifically in pregnant women were posed. Twenty six recommendations were created based on the answers to these questions. Despite the fact that evidence in some areas of hypothyroidism, such as therapy, is lacking, out of 279 references, 73% were Grade A and B, 8% Grade C and 19% Grade D.

CONCLUSIONS

These evidence-based clinical guidelines on hypothyroidism will provide unified criteria for management of hypothyroidism throughout Latin America. Although most of the studies referred to are from all over the world, the point of view of thyroidologists from Latin America is also given.

Toxicity of targeted therapy: Implications for response and impact of genetic polymorphisms

Targeted therapies have unique toxicity profiles. Common adverse events include rash, diarrhea, hypertension, hypothyroidism, proteinuria, depigmentation, and hepatotoxicity. Some of these toxicities are caused by on-target, mechanism-associated effects, which can be stratified as to whether or not the targets are relevant to response. Other toxicities are off-target and may be caused by the class of agent, e.g. antibody vs small molecule tyrosine kinase inhibitor, or by immune reactions or toxic metabolites. Both on- and off-target toxicities may be due to higher drug concentrations or altered end-organ sensitivity, which in turn can be a consequence of genetic polymorphisms controlling metabolism or tissue responsiveness. On-target toxicities are important to identify as some correlate with response and, hence, amelioration of these side effects is preferable to dose reduction or stopping drug. Toxicities secondary to relevant target impact may be recognized when distinct types of agents, such as antibodies and small molecule kinase inhibitors, with the same target have a similar side effect. For example, both bevacizumab and vascular endothelial growth factor receptor (VEGFR) kinase inhibitors cause hypertension; both epidermal growth factor receptor (EGFR) antibodies and kinase inhibitors cause rash; and these toxicities correlate with response. Herein we review common targeted agent-related toxicities, relevant genetic polymorphisms, and implications for response and patient management.

Thyroid dysfunction as an unintended side effect of anticancer drugs

BACKGROUND

Several of the currently used anticancer drugs may variably affect thyroid function, with impairment ranging from modified total but not free concentration of thyroid hormones to overt thyroid disease.

SUMMARY

Cytotoxic agents seem to alter thyroid function in a relatively small proportion of adult patients. Anticancer hormone drugs may mainly alter serum levels of thyroid hormone-binding proteins without clinically relevant thyroid dysfunction. Old immunomodulating drugs, such as interferon-α and interleukin-2, are known to induce variably high incidence of autoimmune thyroid dysfunction. Newer immune checkpoint inhibitors, such as anti-CTLA4 monoclonal antibodies, are responsible for a relatively low incidence of thyroiditis and may induce secondary hypothyroidism resulting from hypophysitis. Central hypothyroidism is a well-recognized side effect of bexarotene. Despite their inherent selectivity, tyrosine kinase inhibitors may cause high rates of thyroid dysfunction. Notably, thyroid toxicity seems to be restricted to tyrosine kinase inhibitors targeting key kinase-receptors in angiogenic pathways, but not other kinase-receptors (e.g., epidermal growth factor receptors family or c-KIT). In addition, a number of these agents may also increase the levothyroxine requirement in thyroidectomized patients.

CONCLUSIONS

The pathophysiology of thyroid toxicity induced by many anticancer agents is not fully clarified and for others it remains speculative. Thyroid dysfunction induced by anticancer agents is generally manageable and dose reduction or discontinuation of these agents is not required. The prognostic relevance of thyroid autoimmunity, overt and subclinical hypothyroidism induced by anticancer drugs, the value of thyroid hormone replacement in individuals with abnormal thyrotropin following anticancer systemic therapy, and the correct timing of replacement therapy in cancer patients need to be defined more accurately in well-powered prospective clinical trials.

Tyrosine kinase inhibitors: their on-target toxicities as potential indicators of efficacy

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of certain forms of cancers, raising hopes for many patients with otherwise unresponsive tumours. While these agents are generally well tolerated, clinical experience with them has highlighted their unexpected association with serious toxic effects on various organs such as the heart, lungs, liver, kidneys, thyroid, skin, blood coagulation, gastrointestinal tract and nervous system. Many of these toxic effects result from downstream inhibition of vascular endothelial growth factor or epidermal growth factor signalling in cells of normal organs. Many of these undesirable effects such as hypertension, hypothyroidism, skin reactions and possibly proteinuria are on-target effects. Since tyrosine kinases are widely distributed with specific functional roles in different organs, this association is not too surprising. Various studies suggest that the development of these on-target effects indicates clinically desirable and effective inhibition of the corresponding ligand-mediated receptor linked with oncogenesis. This is reflected as improved efficacy in the subgroup of patients who develop these on-target adverse effects compared with those who do not. Inevitably, issues arise with respect to the regulatory assessment of efficacy and risk/benefit of the TKIs as well as the clinical approach to managing patients who develop these effects. Routine subgroup analysis of efficacy data from clinical trials (patients with and without on-target toxicity) may enable more effective clinical use of TKIs since (i) discontinuing or reducing the dose of the TKI has a negative impact if the tumour is TKI-responsive; and (ii) it is usually possible to manage these undesirable on-target effects with conventional clinical approaches. Prospective studies are needed to investigate this proposition further.

Thyroid dysfunction and tyrosine kinase inhibitors in renal cell carcinoma

The most recent World Health Organization classification of renal neoplasms encompassed nearly 50 distinctive renal neoplasms. Different histological subtypes have different clinical outcomes and show different responses to therapy. Overall, the incidence of kidney cancer has increased worldwide in the last years. Although the most common type of kidney cancer is localized renal cell carcinoma (RCC), with a 5-year survival rate of 85%, about one third of patients present advanced or metastatic disease at diagnosis, with a 5-year survival rate of only 10%. Multi-targeted receptor tyrosine kinase inhibitors (TKIs, sunitinib and sorafenib), the anti-VEGF MAB bevacizumab in association with interferon-α, and the mTOR inhibitors are now approved for the treatment of mRCC. Recently, the novel agents pazopanib and axitinib have also demonstrated efficacy in mRCC patients. Several recent retrospective and prospective trials have suggested that some of their adverse events, such as hypertension, hypothyroidism, and hand foot syndrome (HFS) may act as potential biomarkers of response and efficacy of treatment. In this review, we analyzed the studies that have suggested a relationship between hypothyroidism onset and a better outcome of mRCC patients treated with TKIs. The biological mechanisms suggesting and explaining this correlation are not well known and different speculative theories have been considered in order to investigate the clinical link between hypothyroidism occurrence and the prolonged therapy with TKIs in solid tumors. Furthermore, the management of this unexplained side effect is very important to maximize the efficacy of therapy in mRCC patients because there is a clear and consistent relationship between drug dose and efficacy of treatment. Certainly, other studies are needed to clarify whether a better outcome is associated with hypothyroidism induced to TKIs in patients with mRCC.