Incidence of thyroid hormone therapy in patients treated with sunitinib or sorafenib: A cohort study

Normal tissue complication probability models of hypothyroidism after radiotherapy for breast cancer

Purpose

We aimed to develop Lyman-Kutcher-Burman (LKB) and multivariable normal tissue complication probability (NTCP) models to predict the risk of radiation-induced hypothyroidism (RIHT) in breast cancer patients.

Materials and methods

A total of 1,063 breast cancer patients who underwent whole breast irradiation between 2009 and 2016 were analyzed. Individual dose-volume histograms were used to generate LKB and multivariable logistic regression models. LKB model was fit using the thyroid radiation dose-volume parameters. A multivariable model was constructed to identify potential dosimetric and clinical parameters associated with RIHT. Internal validation was conducted using bootstrapping techniques, and model performance was evaluated using the area under the curve (AUC) and Hosmer-Lemeshow (HL) goodness-of-fit test.

Results

RIHT developed in 4 % of patients with a median follow-up of 77.7 months. LKB and multivariable NTCP models exhibited significant agreement between the predicted and observed results (HL P values > 0.05). The multivariable NTCP model outperformed the LKB model in predicting RIHT (AUC 0.62 vs. 0.54). In the multivariable model, systemic therapy, age, and percentage of thyroid volume receiving ≥ 10 Gy (V10) were significant prognostic factors for RIHT. The cumulative incidence of RIHT was significantly higher in patients who exceeded the cut-off values for all three risk predictors (systemic therapy, age ≥ 40 years, and thyroid V10 ≥ 26 %, P < 0.005).

Conclusions

Systemic therapy, age, and V10 of the thyroid were identified as strong risk factors for the development of RIHT. Our NTCP models provide valuable insights to clinicians for predicting and preventing hypothyroidism by identifying high-risk patients.

Risk of Hypothyroidism in Women After Radiation Therapy for Breast Cancer

PURPOSE

To study the hypothyroidism risk after adjuvant radiation therapy (RT) and the association of different RT targets with hypothyroidism risk.

METHODS

We studied 4073 women treated with adjuvant RT for breast cancer from 2007 to 2016. The primary endpoint was hypothyroidism development after RT. Patients were divided and analyzed into 3 groups: whole breast (WB)-alone (n = 2468), regional node irradiation (RNI)-Lv.4 (n = 215; cranial border at the subclavian artery, according to the European Society for Radiotherapy and Oncology consensus guideline), and RNI-supraclavicular lymph node (SCL) (n = 1390; cranial border at the cricoid cartilage). In general, RNI-Lv.4 was used in the patients with high-risk pN0 and pN1 breast cancer. In auxiliary analysis, the mean thyroid dose was estimated in each group (total n = 600, 200 from each group). All the doses were converted to the equivalent dose in 2 Gy fractions (EQD2) with α/β ratios of 3.

RESULTS

The median follow-up duration was 84 months (WB-alone, 84 months; RNI-Lv.4, 44 months; RNI-SCL, 91 months). The 3-year hypothyroidism incidence rate differed significantly between the RNI-SCL and WB-alone groups (2.2% vs 0.8%; Bonferroni corrected P [Pc] < .001) but not between the RNI-Lv.4 and WB-alone groups (0.9% vs 0.8%; Pc > .05). The Cox model revealed an adjusted hazard ratio of 2.25 (95% CI, 1.49-3.38) for RNI-SCL vs WB-alone, 1.69 (95% CI, 1.12-2.56) for adjuvant systemic therapies, and 2.07 (95% CI, 1.07-3.99) for age <60 years. In the subgroup analysis, the hypothyroidism risk became more prominent in patients aged <60 years. The mean exposure doses to the thyroid were 0.23 versus 1.93 versus 7.89 Gy (EQD2) for the WB-alone versus RNI-Lv.4 versus RNI-SCL groups (P < .001). No statistically different locoregional recurrence rates were seen between groups (5-year rate: <3%).

CONCLUSIONS

The risk of hypothyroidism increases after RNI-SCL for breast cancer but not after RNI-Lv 4. These data support routine contouring of the thyroid in the RNI setting, and future studies are required to develop optimal dose-volume constraints.

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.

Targeting cancer stem cells for reversing therapy resistance: mechanism, signaling, and prospective agents

Cancer stem cells (CSCs) show a self-renewal capacity and differentiation potential that contribute to tumor progression and therapy resistance. However, the underlying processes are still unclear. Elucidation of the key hallmarks and resistance mechanisms of CSCs may help improve patient outcomes and reduce relapse by altering therapeutic regimens. Here, we reviewed the identification of CSCs, the intrinsic and extrinsic mechanisms of therapy resistance in CSCs, the signaling pathways of CSCs that mediate treatment failure, and potential CSC-targeting agents in various tumors from the clinical perspective. Targeting the mechanisms and pathways described here might contribute to further drug discovery and therapy.

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.

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.

A phase II evaluation of brivanib in the treatment of persistent or recurrent carcinoma of the cervix: An NRG Oncology/Gynecologic Oncology Group study

BACKGROUND

Brivanib is an oral, tyrosine kinase inhibitor against vascular endothelial growth factor (VEGF) and fibroblast growth factor receptor (FGFR). We studied its efficacy and tolerability in persistent or recurrent cervical cancer patients.

METHODS

Eligible patients had at least one prior cytotoxic regimen for recurrence and with measurable disease. Brivanib 800mg was administered orally every day (1cycle=28days) until disease progression or prohibitive toxicity. Primary endpoints were progression-free survival (PFS) >6months and objective tumor response.

RESULTS

Of 28 eligible and evaluable women enrolled, 11 (39%) had primary surgery and 25 (89%) had prior radiation. Eighteen (64%) received one prior cytotoxic treatment and 10 (36%) had 2 prior regimens. Twelve (43%) had >2cycles of brivanib with 4 (14%) receiving >10cycles (range: 1-20). Seven (25%) patients had PFS >6months (90% CI: 7.3%-33.9%). Two (7%) (90% CI: 1.3%-20.8%) patients had partial tumor response with duration of 8 and 22months and 12 (43%) had stable disease. The median PFS was 3.2months (90% CI: 2.1-4.4). The median overall survival was 7.9months (90% CI: 6.1-11.7). More common grade 3 adverse events were hypertension, anemia, hyponatremia, hyperglycemia, elevated liver enzymes, nausea, headache, and colon hemorrhage. Grade 4 adverse events included sepsis and hypertension.

CONCLUSIONS

Based on early results of this phase II trial, brivanib was well tolerated and demonstrated sufficient activity after first stage but trial was stopped due to lack of drug availability.

Tumor angiogenesis revisited: Regulators and clinical implications

Since Judah Folkman hypothesized in 1971 that angiogenesis is required for solid tumor growth, numerous studies have been conducted to unravel the angiogenesis process, analyze its role in primary tumor growth, metastasis and angiogenic diseases, and to develop inhibitors of proangiogenic factors. These studies have led in 2004 to the approval of the first antiangiogenic agent (bevacizumab, a humanized antibody targeting vascular endothelial growth factor) for the treatment of patients with metastatic colorectal cancer. This approval launched great expectations for the use of antiangiogenic therapy for malignant diseases. However, these expectations have not been met and, as knowledge of blood vessel formation accumulates, many of the original paradigms no longer hold. Therefore, the regulators and clinical implications of angiogenesis need to be revisited. In this review, we discuss recently identified angiogenesis mediators and pathways, new concepts that have emerged over the past 10 years, tumor resistance and toxicity associated with the use of currently available antiangiogenic treatment and potentially new targets and/or approaches for malignant and nonmalignant neovascular diseases.

Managing tyrosine kinase inhibitors side effects in thyroid cancer

BACKGROUND

Tyrosine kinase inhibitors (TKIs) are a new group of drugs that show the activity against receptors of different growth factors leading to the inhibition of tumor cells growth and proliferation. To date, four different TKIs have been approved for RAI-refractory DTC or MTC: sorafenib, lenvatinib, vandetanib and cabozantinib.

METHODS

This review focuses on treatment toxicity related to above-mentioned TKIs administration in thyroid carcinoma.

RESULTS

TKIs cause a variety of side effects in nearly all treated patients, among them: hypertension, gastrointestinal disturbances (diarrhea, abdominal pain, nausea, vomiting), skin reactions (rashes, acne, hand-foot syndrome), fatigue and weight loss. Most of side effects are mild and moderate and manageable by dose adjustment (dose interruptions and dose reductions) and concomitant therapy. However, some complications although rare may be life-threatening or even fatal. Conclusion​: TKIs shows an acceptable toxicity profile in patients with advanced and progressive RAI refractory DTC and MTC but only in experienced hands familiar with TKIs, particularly with diagnostics and management of treatment-related complications and also with thyroid carcinoma, what is essential to safely care for the patients and keep them on kinase inhibitor therapy as long as the treatment is beneficial without an unfavorable impact on their quality of life.

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.

Targeting Angiogenesis in Colorectal Cancer: Tyrosine Kinase Inhibitors

Colorectal cancer is commonly diagnosed throughout the world, and treatment options have greatly expanded over the last 2 decades. Targeting angiogenesis has been a major focus of study in a variety of malignancy types. Targeting angiogenesis has been achieved by several mechanisms in colorectal cancer, including use of antiangiogenic small molecule tyrosine kinase inhibitors (TKIs). There have been many attempts and failures to prove efficacy of TKIs in the treatment of colorectal cancer including sorafenib, sunitinib, vatalanib, and tivozanib. Regorafenib was the first TKI to demonstrate efficacy and is an orally active inhibitor of angiogenic (including the vascular endothelial growth factor receptors 1, 2, and 3), stromal, and oncogenic receptor tyrosine kinases. There are ongoing investigations of both regorafenib and ninetanib; however, there remains a critical need to better understand novel combinations with TKIs that could prove more efficacious than available options.

Optimizing patient adherence to targeted therapies in renal cell carcinoma

The current standard of care for treating metastatic renal cell carcinoma is sequential therapy with vascular endothelial growth factor-targeted agents (i.e., axitinib, bevacizumab, pazopanib, sorafenib, and sunitinib) and mammalian target of rapamycin inhibitors (i.e., everolimus and temsirolimus). To maximize adherence to and persistence with targeted therapy, which should help improve clinical benefit, a clear understanding of the tolerability profiles of these agents and implementation of early, appropriately aggressive adverse event (AE) prevention and management strategies are key. Active and aggressive AE management should improve the quality of life of patients during the course of their treatment. Nurses are in a unique position to educate patients on the potential AEs they may experience and their prevention and management. This article reviews the safety and tolerability of currently available targeted therapies recommended for use in the second-line treatment setting, as well as their management in the context of maximizing clinical outcomes and patient quality of life.

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.

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.

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.

Thyroid dysfunctions induced by tyrosine kinase inhibitors

INTRODUCTION

Recently, tyrosine kinase inhibitors (TKIs) have emerged as a new class of anticancer therapy. Although generally considered less toxic than cytotoxic chemotherapy, TKIs do cause significant side effects including fatigue and hypertension. In addition, thyroid dysfunction is a well-known adverse effect of TKI.

AREAS COVERED

This review provides a comprehensive assessment of TKI-induced thyroid dysfunctions by sunitinib, sorafenib, pazopanib, imatinib, dasatinib, nilotinib, vandetanib, axitinib, motesanib and tivozanib. Furthermore, the potential mechanisms that result in this toxicity, the clinical impact of thyroid dysfunction in these patients and the controversies regarding treatment with thyroid hormone (TH) therapy are evaluated.

EXPERT OPINION

Detection of TKI-induced thyroid dysfunction requires routine monitoring of thyroid function and may necessitate treatment. Potential benefits in developing thyroid dysfunction and potential harm in treating it necessitate controlled studies. Finally, if treatment is pursued, appropriate dosing and timing of TH replacement will require prospective clinical evaluation.

Hypothyroidism after a cancer diagnosis: etiology, diagnosis, complications, and management

Hypothyroidism is a common disease that is easily treated in the majority of cases, when readily diagnosed; however, presentation of an aggregate of its symptoms is often clinically overlooked or attributed to another disease and can potentially be lethal. Already prevalent in older women, its occurrence in younger patients is rising as a result of radiation therapy, radioactive iodine therapy, and newer antineoplastic agents used to manage various malignancies. The presence of nonspecific constitutional symptoms and neuropsychiatric complaints in cancer patients can be attributed to a myriad of other diagnoses and therapies. Thyroid dysfunction can be easily overlooked in cancer patients because of the complexity of cancer's clinical picture, particularly in the pediatric population. Underdiagnosis can have important consequences for the management of both hypothyroidism and the malignancy. At minimum, quality of life is adversely affected. Untreated hypothyroidism can lead to heart failure, psychosis, and coma and can reduce the effectiveness of potentially life-saving cancer therapies, whereas iatrogenic causes can provoke atrial fibrillation and osteoporosis. Consequently, the diagnosis and treatment of hypothyroidism in cancer patients are pertinent. We summarize the history, epidemiology, pathophysiology, clinical diagnosis, and management of hypothyroidism in cancer patients.

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.

Brivanib in Patients With Advanced Hepatocellular Carcinoma Who Were Intolerant to Sorafenib or for Whom Sorafenib Failed: Results From the Randomized Phase III BRISK-PS Study

Purpose

Brivanib is a selective dual inhibitor of vascular endothelial growth factor and fibroblast growth factor receptors implicated in tumorigenesis and angiogenesis in hepatocellular carcinoma (HCC). An unmet medical need persists for patients with HCC whose tumors do not respond to sorafenib or who cannot tolerate it. This multicenter, double-blind, randomized, placebo-controlled trial assessed brivanib in patients with HCC who had been treated with sorafenib.

Patients and Methods

In all, 395 patients with advanced HCC who progressed on/after or were intolerant to sorafenib were randomly assigned (2:1) to receive brivanib 800 mg orally once per day plus best supportive care (BSC) or placebo plus BSC. The primary end point was overall survival (OS). Secondary end points included time to progression (TTP), objective response rate (ORR), and disease control rate based on modified Response Evaluation Criteria in Solid Tumors (mRECIST) and safety.

Results

Median OS was 9.4 months for brivanib and 8.2 months for placebo (hazard ratio [HR], 0.89; 95.8% CI, 0.69 to 1.15; P = .3307). Adjusting treatment effect for baseline prognostic factors yielded an OS HR of 0.81 (95% CI, 0.63 to 1.04; P = .1044). Exploratory analyses showed a median time to progression of 4.2 months for brivanib and 2.7 months for placebo (HR, 0.56; 95% CI, 0.42 to 0.76; P < .001), and an mRECIST ORR of 10% for brivanib and 2% for placebo (odds ratio, 5.72). Study discontinuation due to treatment-related adverse events (AEs) occurred in 61 brivanib patients (23%) and nine placebo patients (7%). The most frequent treatment-related grade 3 to 4 AEs for brivanib included hypertension (17%), fatigue (13%), hyponatremia (11%), and decreased appetite (10%).

Conclusion

In patients with HCC who had been treated with sorafenib, brivanib did not significantly improve OS. The observed benefit in the secondary outcomes of TTP and ORR warrants further investigation.

Thyroid hormone, thyroid hormone receptors, and cancer: a clinical perspective

Thyroid hormones (THs) may play a role in diseases other than hyper- and hypothyroidism. Several lines of evidence suggest tumor-promoting effects of TH and TH receptors. They are possibly mediated by phosphatidylinositol-3-kinase and MAPK and involve among others stimulation of angiogenesis via αvβ3. Thus, an increased risk for colon, lung, prostate, and breast cancer with lower TSH has been demonstrated in epidemiological studies, even suggesting a TH dose effect on cancer occurrence. Furthermore, higher TH levels were associated with an advanced clinical stage of breast and prostate cancer. In rodent models, TH stimulated growth and metastasis of tumor transplants, whereas hypothyroidism had opposite effects. In clinical studies of glioblastoma and head and neck cancer, hypothyroid patients showed longer survival than euthyroid patients. Also, patients with renal cell cancer that were treated with the tyrosine kinase inhibitor sunitinib and developed hypothyroidism in due course showed significantly longer survival than patients that remained euthyroid. Development of hypothyroidism was an independent predictor for survival in two studies. Yet, it is still possible that hypothyroidism is only a surrogate marker for treatment efficacy and does not positively influence treatment outcome by itself. Future cancer treatment studies, especially with substances that can induce hypothyroidism, should therefore be designed in a way that allows for an analysis of thyroid function status and its contribution on treatment outcome.

Sorafenib therapy decreases the clearance of thyrotropin

OBJECTIVE

Thyroid function abnormalities are common during treatment with tyrosine kinase inhibitors such as sorafenib. Suggested causes are direct effects on thyroid tissue and increased extrathyroidal metabolism of serum thyroxine and 3,5,3-triiodothyronine. We postulated that tyrosine kinase inhibitors may affect the peripheral metabolism of TSH as well. The effect of sorafenib on TSH clearance was studied.

DESIGN

In a study of athyreotic patients on TSH suppression therapy, TSH concentrations were measured after recombinant human TSH (rhTSH) injections before and after 26 weeks of sorafenib therapy.

METHODS

Before and after the last week of sorafenib therapy, 20 patients with progressive differentiated thyroid carcinoma received a standard dose regimen of two injections 0.9 mg rhTSH on two consecutive days. TSH concentrations were measured 48 h (TSH(48 h)) and 96 h (TSH(96 h)) after the first rhTSH injection. The area under the curve (TSH-AUC), reflecting TSH content between 48 and 96 h following rhTSH administration, was calculated.

RESULTS

TSH(48 h) levels (120.5 mU/l before vs 146.3 mU/l after; P=0.029), TSH(96 h) levels (22.0 mU/l before vs 35.5 mU/l after; P=0.001), and TSH-AUC (142.7 vs 186.8 mU/l; P=0.001) were significantly higher after sorafenib treatment. Higher sorafenib doses were associated with increased changes in TSH(96 h) and TSH-AUC. In two patients, TSH levels after sorafenib therapy exceeded 200 mU/l.

CONCLUSIONS

Sorafenib therapy is accompanied by higher rhTSH levels, probably due to a decreased TSH clearance. Further studies are recommended to clarify whether a decreased clearance of TSH is sorafenib specific.