Thyroid dysfunction from antineoplastic agents

Thyroid disorders induced by immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) are a revolutionary class of drugs that powerfully contribute to cancer therapy by harnessing the immune system to fight malignancies. However, their successful use as anti-cancer drugs is accompanied by a wide spectrum of immune-related adverse effects (irAEs), including endocrinopathies. Among them, thyroid dysfunction stands out as one of the most common endocrinopathies induced by ICI therapy and surfaces as a prominent concern. Destructive thyroiditis is the pathophysiological basis shared by the most common patterns of thyrotoxicosis followed by hypothyroidism and isolated hypothyroidism. Diagnostic approach is guided by clinical manifestation, laboratory evaluation and imaging modalities. Treatment approaches range from the substitution of levothyroxine to the utilization of beta blockers, depending on the extent of thyroid dysfunction's severity. While the medical community is dealing with the evolution and complexities of immunotherapy, recognizing and effectively managing ICI-induced thyroid dysfunction emerged as crucial for enhancing patient safety and achieving improved outcomes. The aim of this review is to navigate the significance of ICI-induced thyroid dysfunction unraveling the various patterns, underlying mechanisms, diagnostic approaches, and treatment strategies. It, also, highlights the impact of various factors such as cancer subtype, ICI dosage, age, and genetic susceptibility on the risk of experiencing dysfunction.

Long-term health outcomes by cancer diagnosed age among adolescent and young adult: multinational representative database

BACKGROUND

The cancer experienced in adolescent and young adult (AYA) could disturb developmental changes and long-term life. The current AYA guidelines and research for survivorship were developed and reported according to the general age range of 15-39 years; however, expected life events vary by diagnosed age. We aimed to examine the social, psychological, and physical well-being of AYA cancer survivors by age at diagnosis using a multinational representative dataset focusing on age at diagnosis.

METHODS

We conducted a cross-sectional study using the US and Korean National Health and Nutrition Examination Surveys from 2007 to 2018. Participants diagnosed with any cancer aged 15-39 years and were aged > 18 years at the survey year were defined as AYA cancer survivors. AYA were classified into three groups based on their diagnosed age: adolescent survivors (diagnosed between the ages of 15 and 19, n = 45), young adult survivors (diagnosed between the ages of 20 and 29, n = 238), and late young adult survivors (diagnosed between the ages of 30 and 39, n = 539). We also selected an age-, sex-, race-, and survey year-matched general population with 1:5 ratio among participants without cancer (N = 4110).

RESULTS

The average age of the survey was 29.1, 43.7, and 48.7 years for AYA survivors diagnosed during adolescence, young adulthood, and late young adulthood, respectively. Adolescent survivors had more non-couple marital status (adjusted odds ratio (aOR), 1.34; 95% CI, 1.10-1.64) and unemployed (aOR, 1.30; 95% CI, 1.05-1.61) compared to late young adult survivors. Comparing with the matched general, adolescent survivors were more in poor general health (aOR, 4.65; 95% CI, 2.09-10.38) and unemployed (aOR, 2.17; 95% CI, 1.12-4.24) and late young adult survivors were more non-couple (aOR, 1.40; 95% CI, 1.05-1.86).

CONCLUSION

This study provides evidence for future studies on long-term health, which may vary according to age at the time of diagnosis among AYA with cancer.

Incidence and risk factors of hypothyroidism after treatment for early breast cancer: a population-based cohort study

PURPOSE

An increased incidence of hypothyroidism among breast cancer survivors has been observed in earlier studies. The impact of the postoperative treatment modalities and their potential interplay on hypothyroidism development needs to be studied.

METHODS

We conducted a population- and registry-based study using the Breast Cancer Data Base Sweden (BCBaSe) including females diagnosed with breast cancer between 2006 and 2012. In total, 21,268 female patients diagnosed with early breast cancer between 2006 and 2012, with no previous prescription of thyroid hormones and no malignant diagnosis during the last ten years before breast cancer diagnosis, were included in the final analysis.

RESULTS

During the follow-up (median follow-up time 7.9 years), 1212 patients (5.7%) developed hypothyroidism at a median time of 3.45 years from the index date. No association of the systemic oncological treatment in terms of either chemotherapy or endocrine therapy and hypothyroidism development could be identified. A higher risk (HR 1.68;95% CI 1.42-1.99) of hypothyroidism identified among patients treated with radiation treatment of the regional lymph nodes whereas no increased risk in patients treated only with radiation therapy to the breast/chest wall was found (HR 1.01; 95% CI 0.86-1.19). The risk of hypothyroidism in the cohort treated with radiotherapy of the regional lymph nodes was present irrespective of the use of adjuvant chemotherapy treatment.

CONCLUSIONS

Based on the results of our study, the implementation of hypothyroidism surveillance among the breast cancer survivors treated with radiotherapy of the regional lymph nodes can be considered as reasonable in the follow-up program.

Lenalidomide use in multiple myeloma (Review)

Lenalidomide is a second-generation new immunomodulatory medication used to treat multiple myeloma (MM). Its mechanism of action involves affecting the expression of vascular endothelial growth factor, interleukin-6, cytochrome c, caspase-8, as well as other factors including immunological modulation and the direct killing of cells, among others, rendering it a fundamental medication, useful for the treatment of MM. Combining lenalidomide with other medications such dexamethasone, bortezomib, ixazomib, carfilzomib and daratumumab can markedly alleviate MM. When autologous-hematopoietic stem cell transplantation (ASCT) cannot be utilized to treat newly diagnosed individuals with MM (NDMM), monotherapy maintenance following lenalidomide and dexamethasone may be employed. Following ASCT, single-agent maintenance with lenalidomide can be performed as an additional treatment. The combination of bortezomib and lenalidomide has been demonstrated to be associated with favorable response rates, tolerable toxicity, and therapeutic benefits although caution is warranted to prevent the onset of peripheral neuropathy with its use. A new-generation oral drug with an excellent safety profile, ixazomib, is more practical and therapeutically applicable in relapsed refractory MM. However, the frequent occurrence of cardiovascular events, hematocrit, and infections with it require flexible adjustment in its clinical application. Carfilzomib produces a rapid and profound response in patients with NDMM eligible for transplantation, but its cardiovascular side effects need to be closely monitored. The primary aim of the present review was to examine the pharmacological properties and pharmacokinetics of lenalidomide, as well as the efficacy and safety of lenalidomide-based treatments with reference to data from clinical trials and real-world studies.

Relationship between TSH and free thyroxine in outpatient cancer patient population

BACKGROUND

The inverse log-linear relationship between Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) is well established and reliably used for evaluation of hypothalamus-pituitary-thyroid (HPT) axis function. However, there are limited data regarding oncologic states in the TSH-FT4 relationship. The purpose of this study was to evaluate thyroid pituitary hypothalamic feedback regulation by the inverse log TSH and FT4 relationship in the cancer patient population at the Ohio State University Comprehensive Cancer Center (OSUCCC-James).

METHODS

This retrospective study analyzed the correlation between TSH and FT4 results from 18846 outpatient subjects collected in August 2019-November 2021 at the Department of Family Medicine (OSU Wexner Medical Center), Department of Oncology (OSUCCC-James). Patients with diagnoses related to cancers were included in the oncology group. Patients with diagnoses not related to cancers were included in the non-oncology group. Patients of the Department of Endocrinology, Department of Cardiology, Department of Obstetrics & Gynecology and Department of Hematology were excluded from this study. Time of collection for TSH and FT4 was from 7am to 7 pm. Data were analyzed by morning (7am-12pm) and afternoon (12pm-7pm). Spearman correlation and non-linear fit were used for data analysis. Sex differences were analyzed as well in each group.

RESULTS

Overall, an inverse correlation was observed between TSH and FT4 in both groups (non-oncology and oncology) regardless of sample collection time and sex differences. Further analysis by linear model in log TSH and FT4 showed a significant inverse fit in males compared with females in the group of oncology, both in the afternoon (p < 0.05). Data were further analyzed by ranges of FT4, as lower or higher (pathophysiology) or within (physiology) the reference interval of FT4. There was no statistical significance between the non-oncology and oncology groups, but relatively good correlation in non-oncology group in either physiologic or pathophysiologic FT4 levels and sample collection time. Interestingly, the best correlation between TSH and FT4 was found in the non-oncology group at pathophysiologic FT4 concentrations (abnormally high). In addition, at pathophysiologic FT4 concentrations (abnormally low), the oncology group demonstrated a significant TSH response in the morning than in the afternoon (p < 0.05).

CONCLUSIONS

Though overall the TSH-FT4 curves showed an inverse relationship, there are variations of TSH-FT4 relationship for collection times when considering FT4 in physiologic or pathophysiologic states. The results advance understanding of TSH response, which is beneficial for the interpretation of thyroid disease. We recommend re-evaluation for interpretation of pituitary hypothalamic axis by TSH results when FT4 is abnormally high in oncology patients or low in non-oncology patients, due to poor predictability and the potential for misdiagnosis. A better understanding of the complex nature of the TSH-FT4 relationship may need further study with better defining subclinical states of cancer patients.

Changes in thyroid function in prostate cancer patients receiving docetaxel chemotherapy at Haji Adam Malik Hospital, Indonesia

Background

Prostate cancer treatment is determined based on several factors, namely tumor grading, staging, co-morbidity, patient preferences, life expectancy at diagnosis. Today, taxanes are commonly prescribed to treat several types of cancer and have been shown to have antitumor effects in many cancers. This research has never been done in prostate cancer patients but similar studies have been done before in breast cancer patients.

Materials and methods

The research design was observational analytic where this type of research was a prospective cohort where data was collected to record prostate cancer patients who received docetaxel chemotherapy which were then examined for thyroid function in cancer patients at the Adam Malik Hospital, Medan, Indonesia.

Result

In this study, data were collected regarding the thyroid function of the study sample in the form of free thyroxine (fT4) and thyroid-stimulating hormone (TSH) levels before chemotherapy with the docetaxel regimen. The mean of fT4 in all research subjects was 1.05 with a standard deviation of 0.26. The mean TSH in all study subjects was 1.52 with a standard deviation of 1.21. Thyroid function was examined after 3 cycles of docetaxel chemotherapy. The mean of fT4 in all research subjects was 0.91 with a standard deviation of 0.23. The mean TSH in all study subjects was 1.69 with a standard deviation of 1.09.

Conclusion

There are traces of the use of docetaxel chemotherapy in prostate cancer patients on decreased thyroid function at the Adam Malik Hospital in the form of decreased fT4 levels and increased TSH.

Immune checkpoint inhibitor-induced hypophysitis: clinical and biochemical features

Immune checkpoint inhibitors are a very promising novel class of immune response-regulating drugs for cancer treatment. Hypophysitis is one of their most common immune-related adverse events, occurring in a significant proportion of patients. Since this is a potentially severe entity, regular hormone monitoring is recommended during treatment to allow for a timely diagnosis and adequate treatment. Identification of clinical signs and symptoms, such as headaches, fatigue, weakness, nausea and dizziness, can also be key for its recognition. Compressive symptoms, such as visual disturbances, are uncommon, as is diabetes insipidus. Imaging findings are usually mild and transient and can easily go unnoticed. However, the presence of pituitary abnormalities in imaging studies should prompt closer monitoring, as these can precede clinical manifestations. The clinical importance of this entity relates mainly to the risk of hormone deficiency, especially ACTH, which occurs in the majority of patients and is rarely reversible, requiring lifelong glucocorticoid replacement therapy.

Targeting angiogenesis in oncology, ophthalmology and beyond

Angiogenesis is an essential process in normal development and in adult physiology, but can be disrupted in numerous diseases. The concept of targeting angiogenesis for treating diseases was proposed more than 50 years ago, and the first two drugs targeting vascular endothelial growth factor (VEGF), bevacizumab and pegaptanib, were approved in 2004 for the treatment of cancer and neovascular ophthalmic diseases, respectively. Since then, nearly 20 years of clinical experience with anti-angiogenic drugs (AADs) have demonstrated the importance of this therapeutic modality for these disorders. However, there is a need to improve clinical outcomes by enhancing therapeutic efficacy, overcoming drug resistance, defining surrogate markers, combining with other drugs and developing the next generation of therapeutics. In this Review, we examine emerging new targets, the development of new drugs and challenging issues such as the mode of action of AADs and elucidating mechanisms underlying clinical benefits; we also discuss possible future directions of the field.

Refining personalized diagnosis, treatment and exploitation of hypothyroidism related to solid nonthyroid cancer

Hypothyroidism in the setting of cancer is a puzzling entity due to the dual role of the thyroid hormones (TH) in cancer – promoting versus inhibitory – and the complexity of the hypothyroidism itself. The present review provides a comprehensive overview of the personalized approach to hypothyroidism in patients with solid nonthyroid cancer, focusing on current challenges, unmet needs and future perspectives. Major electronic databases were searched from January 2011 until March 2022. The milestones of the refinement of such a personalized approach are prompt diagnosis, proper TH replacement and development of interventions and/or pharmaceutical agents to exploit hypothyroidism or, on the contrary, TH replacement as an anticancer strategy. Further elucidation of the dual role of TH in cancer – especially of the interference of TH signaling with the hallmarks of cancer – is anticipated to inform decision-making and optimize patient selection.

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.

Immune Checkpoint Inhibitors as a Threat to the Hypothalamus-Pituitary Axis: A Completed Puzzle

Immune checkpoint inhibitors (ICI) prolong the survival in an increasing number of patients affected by several malignancies, but at the cost of new toxicities related to their mechanisms of action, autoimmunity. Endocrine toxicity frequently occurs in patients on ICI, but endocrine dysfunctions differ based on the ICI-subclass, as follows: agents targeting the CTLA4-receptor often induce hypophysitis and rarely thyroid dysfunction, which is the opposite for agents targeting the PD-1/PD-L1 axis. Recently, few cases of central diabetes insipidus have been reported as an adverse event induced by both ICI-subclasses, either in the context of anterior hypophysitis or as selective damage to the posterior pituitary or in the context of hypothalamitis. These new occurrences demonstrate, for the first time, that ICI-induced autoimmunity may involve any tract of the hypothalamic-pituitary axis. However, the related pathogenic mechanisms remain to be fully elucidated. Similarly, the data explaining the endocrine system susceptibility to primary and ICI-induced autoimmunity are still scarce. Since ICI clinical indications are expected to expand in the near future, ICI-induced autoimmunity to the hypothalamic-pituitary axis presents as a unique in vivo model that could help to clarify the pathogenic mechanisms underlying both the dysfunction induced by ICI to the hypothalamus-pituitary axis and primary autoimmune diseases affecting the same axis.

An Underestimated Toxicity Radiation-Induced Hypothyroidism in Patients Multimodally Treated for Breast Cancer

Radiation therapy is part of the therapeutic arsenal for breast cancer, whether it is adjuvant treatment after lumpectomy or radical mastectomy, or it is used as a palliative option in the case of metastatic or recurrent disease. Significant advances in diagnostic and therapeutic stratification of breast cancers have significantly prolonged survival, even in the metastatic stage. Exposure of patients during the course of the disease in a multidisciplinary therapeutic approach including chemotherapy, hormone therapy, targeted anti-HER therapies or CDK4/6 inhibitors had led to improved survival but with the price of additional toxicity. Among them, hypothyroidism is a well-known consequence of external radiation therapy, especially in the case of cervical region irradiation, including supraclavicular and infra-clavicular nodal levels. In this situation, the thyroid gland is considered as an organ at risk (OAR) and receives a significant dose of radiation. Subclinical hypothyroidism is a common endocrine disorder characterized by elevated TSH levels with normal levels of FT4 (free T4) and FT3 (free T3), and as a late effect, primary hypothyroidism is one of the late effects that significantly affects the quality of life for patients with breast cancer receiving multimodal treatment. Hypothyroidism has a significant impact on quality of life, most often occurring as late clinical toxicity, secondary to thyroid irradiation at doses between 30 and 70 Gy. Dose-volume parameters of irradiation, gland function at the beginning of the treatment and associated systemic therapies may be factors that alter thyroid radio-sensitivity and affect thyroid gland tolerance. In the case of head and neck tumor pathology, in which doses of >50 Gy are routinely used, the thyroid gland is generally considered as an OAR, the rate of radio-induced hypothyroidism being estimated at rates of between 20% and 52%. For breast cancer, the thyroid is often neglected in terms of dosimetry protection, the rate of late dysfunction being 6–21%.

The Continuum of Thyroid Disorders Related to Immune Checkpoint Inhibitors: Still Many Pending Queries

BACKGROUND

Until more data are available to shed light on the thyroid disorders related to immune checkpoint inhibitors (ICPi) implemented for the treatment of hematological malignancies, the decision-making is guided by pertinent data derived mostly from solid tumors.

METHODS

The present review provides a comprehensive and updated overview of the thyroid disorders related to ICPi, namely to inhibitors of cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death (PD) 1 (PD-1), and the ligand of the latter (PD-L1).

RESULTS

With the increasing recognition of ir thyroid disorders, many outstanding issues have emerged. Ir thyroid disorders are reminiscent of, but not identical to, thyroid autoimmunity. Interclass and intraclass ICPi differences regarding thyroid immunotoxicity await interpretation. The available data concerning the predictive value of thyroid autoantibodies for the development of ir thyroid disorders are inconclusive. Mounting data indicate an association of ir thyroid disorders with ICPi efficacy, but a causative link is still lacking. The path forward is a tailored approach, entailing: (i) the validation of tumor-specific, patient-specific, and ICPi-specific predictive factors; (ii) appropriate patient selection; (iii) the uncoupling of antitumor immunity from immunotoxicity; (iv) a multidisciplinary initiative; and (v) global registry strategies.

CONCLUSIONS

Untangling and harnessing the interrelationship of immuno-oncology with endocrinology underlying the ir thyroid disorders will yield the optimal patient care.

Association between the use of allopurinol and risk of increased thyroid-stimulating hormone level

Allopurinol is the first-line agent for patients with gout, including those with moderate-to-severe chronic kidney disease. However, increased thyroid-stimulating hormone (TSH) levels are observed in patients with long-term allopurinol treatment. This large-scale, nested case-control, retrospective observational study analysed the association between allopurinol use and increased TSH levels. A common data model based on an electronic medical record database of 19,200,973 patients from seven hospitals between January 1997 and September 2020 was used. Individuals aged > 19 years in South Korea with at least one record of a blood TSH test were included. Data of 59,307 cases with TSH levels > 4.5 mIU/L and 236,508 controls matched for sex, age (± 5), and cohort registration date (± 30 days) were analysed. An association between the risk of increased TSH and allopurinol use in participants from five hospitals was observed. A meta-analysis (I² = 0) showed that the OR was 1.51 (95% confidence interval: 1.32-1.72) in both the fixed and random effects models. The allopurinol intake group demonstrated that increased TSH did not significantly affect free thyroxine and thyroxine levels. After the index date, some diseases were likely to occur in patients with subclinical hypothyroidism and hypothyroidism. Allopurinol administration may induce subclinical hypothyroidism.

Immunotherapy-Mediated Thyroid Dysfunction: Genetic Risk and Impact on Outcomes with PD-1 Blockade in Non-Small Cell Lung Cancer

PURPOSE

Genetic differences in immunity may contribute to toxicity and outcomes with immune checkpoint inhibitor (CPI) therapy, but these relationships are poorly understood. We examined the genetics of thyroid immune-related adverse events (irAE).

EXPERIMENTAL DESIGN

In patients with non-small cell lung cancer (NSCLC) treated with CPIs at Memorial Sloan Kettering (MSK) and Vanderbilt University Medical Center (VUMC), we evaluated thyroid irAEs. We typed germline DNA using genome-wide single-nucleotide polymorphism (SNP) arrays and imputed genotypes. Germline SNP imputation was also performed in an independent Dana-Farber Cancer Institute (DFCI) cohort. We developed and validated polygenic risk scores (PRS) for hypothyroidism in noncancer patients using the UK and VUMC BioVU biobanks. These PRSs were applied to thyroid irAEs and CPI response in patients with NSCLC at MSK, VUMC, and DFCI.

RESULTS

Among 744 patients at MSK and VUMC, thyroid irAEs occurred in 13% and were associated with improved outcomes [progression-free survival adjusted HR (PFS aHR) = 0.68; 95% confidence interval (CI), 0.52-0.88]. The PRS for hypothyroidism developed from UK Biobank predicted hypothyroidism in the BioVU dataset in noncancer patients [OR per standard deviation (SD) = 1.33, 95% CI, 1.29-1.37; AUROC = 0.6]. The same PRS also predicted development of thyroid irAEs in both independent cohorts of patients treated with CPIs (HR per SD = 1.34; 95% CI, 1.08-1.66; AUROC = 0.6). The results were similar in the DFCI cohort. However, PRS for hypothyroidism did not predict CPI benefit.

CONCLUSIONS

Thyroid irAEs were associated with response to anti-PD-1 therapy. Genetic risk for hypothyroidism was associated with risk of developing thyroid irAEs. Additional studies are needed to determine whether other irAEs also have shared genetic risk with known autoimmune disorders and the association with treatment response.

L-T4 Therapy in the Presence of Pharmacological Interferents

Pharmacological interference on L-thyroxine (L-T4) therapy can be exerted at several levels, namely from the hypothalamus/pituitary through the intestine, where the absorption of exogenous L-T4 takes place. A number of medications interfere with L-T4 therapy, some of them also being the cause of hypothyroidism. The clinician should be aware that some medications simply affect thyroid function tests with no need of modifying the dose of L-T4 that the patient was taking prior to their prescription. Usually, the topic of pharmacological interference on L-T4 therapy addresses the patient with primary hypothyroidism, in whom periodic measurement of serum thyrotropin (TSH) is the biochemical target. However, this minireview also addresses the patient with central hypothyroidism, in whom the biochemical target is serum free thyroxine (FT4). This minireview also addresses two additional topics. One is the costs associated with frequent monitoring of the biochemical target when L-T4 is taken simultaneously with the interfering drug. The second topic is the issue of metabolic/cardiovascular complications associated with undertreated hypothyroidism.

Incidence of hypothyroidism after treatment for breast cancer-a Danish matched cohort study

Background

Breast cancer survivors (BCS) may have increased risk of hypothyroidism, but risk according to treatment modality is unclear. We estimated the incidence of hypothyroidism in women with breast cancer, and according to cancer treatment.

Methods

Using nationwide registries, we identified all Danish women aged ≥ 35 years diagnosed with non-metastatic breast cancer (1996–2009). We matched up to five cancer-free women (controls) for each BCS. We excluded women with prevalent thyroid disease. Cancer treatment was chemotherapy with or without radiotherapy (RT) targeting the breast/chest wall only, or also the lymph nodes (RTn). We identified hypothyroidism using diagnostic codes, and/or levothyroxine prescriptions. We calculated the cumulative incidence, incidence rates (IR) per 1000 person-years, and used Cox regression to estimate hazard ratios (HR) and associated 95% confidence intervals (CIs) of hypothyroidism, adjusting for comorbidities.

Results

We included 44,574 BCS and 203,306 matched controls with 2,631,488 person-years of follow-up. BCS had a slightly higher incidence of hypothyroidism than controls [5-year cumulative incidence, 1.8% (95%CI = 1.7–1.9) and 1.6% (95%CI = 1.5–1.6), respectively]. The overall IR was 4.45 (95%CI = 4.25–4.67) and 3.81 (95%CI = 3.73–3.90), corresponding to an adjusted HR = 1.17 (95%CI = 1.11–1.24). BCS who received RTn with chemotherapy (HR = 1.74, 95%CI = 1.50–2.02) or without chemotherapy (HR = 1.31, 95%CI = 1.14–1.51) had an elevated risk of hypothyroidism compared with matched controls and compared with BCS who underwent surgery alone [HR = 1.71, 95%CI = 1.45–2.01 and HR = 1.36, 95%CI = 1.17–1.58, respectively].

Conclusions

BCS have an excess risk of hypothyroidism compared with age-matched controls. BCS and those working in cancer survivorship settings ought to be aware that this risk is highest in women treated with radiation therapy to the lymph nodes and chemotherapy.

Effect of chemoradiation on the size of the thyroid gland

We aimed to evaluate changes in thyroid gland size during the treatment of malignancies outside the head and neck with chemotherapy and/or external beam radiation. We performed a retrospective review of records of adult patients treated at our institution with external beam radiation to the chest and/or chemotherapy with taxanes, alkylating agents, and/or a topoisomerase II inhibitor. Neck and chest computed tomography (CT) images were used to calculate thyroid gland volume before and after therapy, using Vitrea^® software or the volumetric ellipsoid method. Thirty-seven patients were included. After treatment, there was a significant reduction in thyroid gland volume of 14.0% (P < 0.01) using Vitrea and 17.1% (P < 0.05) using the volumetric ellipsoid method. Exposure to radiation or chemotherapy was not found to be associated with the degree of thyroid gland reduction, nor was the number of days between CT scans or the stage of the malignancy being treated. Finally, the degree of thyroid gland size reduction did not predict mortality. Our results showed that the treatment of malignancies outside the head and neck with chemotherapy and/or external beam radiation results in a reduction in thyroid gland size. The impact on thyroid gland function remains unknown.

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.

Complications and Toxicities Associated with Cancer Therapies in the Intensive Care Unit

Advances in the management of hematologic malignancies and solid tumors have given rise to diverse modalities to treat cancer other than cytotoxic chemotherapy, including targeted therapies, immunotherapies, and cellular therapies. Currently, there are over 175 FDA-approved antineoplastic agents in the United States, many with a diverse and profound toxicity profile. Complications of antineoplastic therapy may result in the need for intensive care unit (ICU) admission to provide acute symptom management. Accordingly, ICU providers caring for cancer patients should have a working knowledge of the toxicities and complications associated with antineoplastic therapy.

A case of severe hypothyroidism due to lenalidomide

Lenalidomide, an immunomodulatory drug often used to treat multiple myeloma, can cause hypo- or hyperthyroidism. We present a patient being treated with lenalidomide for 2 years who developed severe hypothyroidism that was complicated by rhabdomyolysis and acute kidney injury. Thyroid function tests should be serially monitored in patients taking lenalidomide.

2019 European Thyroid Association Guidelines on the Management of Thyroid Dysfunction following Immune Reconstitution Therapy

Thyroid dysfunction (TD) frequently occurs as an autoimmune complication of immune reconstitution therapy (IRT), especially in individuals with multiple sclerosis treated with alemtuzumab, a pan-lymphocyte depleting drug with subsequent recovery of immune cell numbers. Less frequently, TD is triggered by highly active antiretroviral therapy (HAART) in patients infected with human immunodeficiency virus (HIV), or patients undergoing bone-marrow/hematopoietic-stem-cell transplantation (BMT/HSCT). In both alemtuzumab-induced TD and HIV/HAART patients, the commonest disorder is Graves' disease (GD), followed by hypothyroidism and thyroiditis; Graves' orbitopathy is observed in some GD patients. On the contrary, GD is rare post-BMT/HSCT, where hypothyroidism predominates probably as a consequence of the associated radiation damage. In alemtuzumab-induced TD, the autoantibodies against the thyrotropin receptor (TRAb) play a major role, and 2 main aspects distinguish this condition from the spontaneous form: (1) up to 20% of GD cases exhibit a fluctuating course, with alternating phases of hyper- and hypothyroidism, due to the coexistence of TRAb with stimulating and blocking function; (2) TRAb are also positive in about 70% of hypothyroid patients, with blocking TRAb responsible for nearly half of the cases. The present guidelines will provide up-to-date recommendations and suggestions dedicated to all phases of IRT-induced TD: (1) screening before IRT (recommendations 1-3); (2) monitoring during/after IRT (recommendations 4-7); (3) management of TD post-IRT (recommendations 8-17). The clinical management of IRT-induced TD, and in particular GD, can be challenging. In these guidelines, we propose a summary algorithm which has particular utility for nonspecialist physicians and which is tailored toward management of alemtuzumab-induced TD. However, we recommend prompt referral to specialist endocrinology services following diagnosis of any IRT-induced TD diagnosis, and in particular for pregnant women and those considering pregnancy.

Current perspectives for the treatment of chronic myeloid leukemia

With an annual incidence of 1–2 in a million, Ph*(+) chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disease that makes myeloid neoplastic cells breed out of control. This BCR-ABL(+) myeloproliferative disease makes up about 15%–20% of all leukemia cases in adults. CML is seen more in males than females, with a rate of three to two. However, it does not show differences in prevalence in terms of age. CML consists of three clinical phases. The first one is the chronic phase, defined by rising white blood cell levels and also by myeloid proliferation and bone marrow maturation. While this phase does not exhibit complications, in diagnosis, it comprises most of the patients. The second phase is the accelerated phase, which the disease progresses to if it is not treated or does not respond to treatment. This usually takes about 3 years. The third phase is the blastic phase. The chronic phase can still progress to the next two phases within the first 2 years, with a rate of 10%. In the following years, the possibility increases by 15%–20% each year. Tyrosine kinase inhibitors (TKIs) are revolutionary drugs for the management of disease course in CML. The aim of this review is to assess current approaches to CML patients’ follow-up and treatment with TKIs. A literature search on CML and TKIs was made in PubMed, Web of Science, and Scopus with particular focus on randomized clinical trials, recommendations, guidelines, and expert opinions. In managing CML, various treatment methods have been utilized for many decades. Prior to the development of TKIs, interferon alpha was the primary tool, which was then complemented by allogeneic hematopoietic stem cell transplantation (HSCT). HSCT was successful in slowing the disease down in the long term and curing up to 50% of patients. Then the coming of the imatinib era opened up different treatment perspectives. For the patients resistant or intolerant to imatinib, second- and third-generation TKIs are successfully used in distinct CML disease states. The survival benefits of TKIs including imatinib, nilotinib, dasatinib, bosutinib, and ponatinib for CML patients are outstanding. TKI-related adverse events could impact the clinical course, especially in long-term drug administrations. The current aim for CML disease management in the TKI era is to provide age- and sex-matched normal life duration to CML patients.

Radioresistance of cancer cells, integrin αvβ3 and thyroid hormone

Radioresistance is a substantial barrier to success in cancer management. A number of molecular mechanisms support radioresistance. We have shown experimentally that the thyroid hormone analogue receptor on the extracellular domain of integrin αvβ3 may modulate the state of radiosensitivity of tumor cells. Specifically, tetraiodothyroacetic acid (tetrac), a derivative of L-thyroxine (T₄), can reduce radioresistance in cancer cells. In this review, we list a number of intrinsic signal transduction molecules and other host factors that have been reported to support/induce radioresistance in cancer cells and that are also subject to control by T₄ through actions primarily initiated at integrin αvβ3. Additional preclinical evidence is needed to support these radioresistance-relevant actions of thyroid hormone.

Clostridium difficilecolitis in the setting of subacute thyroiditis: the chicken or the egg

Subacutethyroiditis is a self-limited inflammatory condition commonly of viral aetiology, that manifests through phases of thyroid hormone changes over a 6–8 month period. A 24-year-old active duty military man, undergoing treatment for recurrentClostridiumdifficileinfection, presented for clinical evaluation and was found to have a thyroid stimulating hormone level of 0.003 mg/dL. Further labs revealed a normal T4, elevated T3 at 5.0 pg/mL and elevated C reactive protein at 3.69 mg/L. The patient was followed with monthly labs and the abnormal thyroid stimulating hormone and triiodothyronine levels resolved after the completion of hisC. difficiletreatment. While subacute thyroiditis has historically been due to viral causes, rarely do we see this condition associated with an intestinal bacterial source.

Thyroid disorders induced by checkpoint inhibitors

Immune checkpoint inhibitors are drugs that inhibit the "checkpoint molecules". Different types of cancer immune checkpoint inhibitors have been approved recently: CTLA-4 monoclonal antibodies (as ipilimumab); anti-PD-1 monoclonal antibodies (as pembrolizumab and nivolumab); and anti-PD-L1 monoclonal antibodies (as atezolizumab, avelumab, and durmalumab). The increased immune response induced by these agents leads to immune-related adverse events (irAEs), that can vary from mild to fatal, according to the organ system and severity. Immune-related endocrine toxicities are thyroid dysfunctions, hypophysitis, adrenal insufficiency, and type 1 diabetes mellitus, and are usually irreversible in 50%. In particular, hypophysitis is the most frequent anti-CTLA-4-antibodies-related irAE, while thyroid abnormalities (as hypothyroidism, thyrotoxicosis, painless thyroiditis, or even "thyroid storm") are more frequently associated with anti-PD-1-antibodies. The combination of anti-CTLA-4-antibodies, with anti-PD-1-antibodies, is associated with about 30% of irAEs. Clinical signs and symptoms vary according to the influenced target organ. Endocrinopathies can often be managed by the treating oncologist. However in more severe cases (i.e. in the presence of insulin-dependent diabetes, adrenal insufficiency, or disorders of gonadal hormones, or severe hyperthyroidism, or hypothyroidism, or long-lasting management of hypophysitis) an endocrinological evaluation, and a prompt therapy, are needed.

Expert opinion on thyroid complications in immunotherapy

Thyroid pathologies are the most common forms of endocrinopathy under anticancer immunotherapy. Frequency ranges from 3% to 22% for hypothyroidism and 1% to 11% for thyrotoxicosis. Risk is higher with anti-PD-1 than anti-CTLA-4 treatment and higher again with associated treatment. Pathophysiology mainly consists in silent inflammatory thyroiditis, which accounts for the usual presentation of transient thyrotoxicosis followed by hypothyroidism. Therapeutic strategy usually consists in monitoring with or without symptomatic treatment in case of thyrotoxicosis, and levothyroxine replacement therapy in case of symptomatic hypothyroidism or TSH>10 mIU/L. Screening for dysthyroidism should be systematic ahead of treatment and before each immunotherapy injection for the first 6 months, then at a lower rhythm. It comprises clinical assessment and TSH assay. Onset of thyroid dysfunction should not interrupt immunotherapy, being mainly transient, easy to treat and mild. Teamwork between oncologists and endocrinologists improves screening and management, so as better to accompany the patient during treatment.

The Current Understanding of the Endocrine Effects From Immune Checkpoint Inhibitors and Recommendations for Management

Clinical trials in the past decade have established the antitumor effects of immune checkpoint inhibition as a revolutionary treatment for cancer. Namely, blocking antibodies to cytotoxic T-lymphocyte antigen 4 and programmed death 1 or its ligand have reached routine clinical use. Manipulation of the immune system is not without side effects, and autoimmune toxicities often known as immune-related adverse events (IRAEs) are observed. Endocrine IRAEs, such as hypophysitis, thyroid dysfunction, and insulin-dependent diabetes mellitus, can present with unique profiles that are not seen with the use of traditional chemotherapeutics. In this Review, we discuss the current hypotheses regarding the mechanism of these endocrinopathies and their clinical presentations. Further, we suggest guidelines and algorithms for patient management and future clinical trials to optimize the detection and treatment of immune checkpoint–related endocrinopathies.

Thyroid dysfunction in patients with childhood-onset medulloblastoma or primitive neuroectodermal tumor

PURPOSE

We investigated the clinical characteristics of patients who developed thyroid dysfunction and evaluated the risk factors for hypothyroidism following radiotherapy and chemotherapy in pediatric patients with medulloblastoma or primitive neuroectodermal tumor (PNET).

METHODS

The medical records of 66 patients (42 males) treated for medulloblastoma (n=56) or PNET (n=10) in childhood between January 2000 and December 2014 at Seoul National University Children's Hospital were retrospectively reviewed. A total of 21 patients (18 high-risk medulloblastoma and 3 PNET) underwent high-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR).

RESULTS

During the median 7.6 years of follow-up, 49 patients (74%) developed transient (n=12) or permanent (n=37) hypothyroidism at a median 3.8 years of follow-up (2.9-4.6 years). Younger age (&lt;5 years) at radiation exposure (P=0.014 vs. ≥9 years) and HDCT (P=0.042) were significantly predictive for hypothyroidism based on log-rank test. However, sex, type of tumor, and dose of craniospinal irradiation (less vs. more than 23.4 Gy) were not significant predictors. Cox proportional hazard model showed that both younger age (&lt;5 years) at radiation exposure (hazard ratio [HR], 3.1; vs. ≥9 years; P=0.004) and HDCT (HR, 2.4; P=0.010) were significant predictors of hypothyroidism.

CONCLUSION

Three-quarters of patients with pediatric medulloblastoma or PNET showed thyroid dysfunction, and over half had permanent thyroid dysfunction. Thus, frequent monitoring of thyroid function is mandatory in all patients treated for medulloblastoma or PNET, especially, in very young patients and/or high-risk patients recommended for HDCT/ASCR.

Thyroid function in the etiology of fatigue in breast cancer

Background

Cancer related fatigue (CRF), reported in about 90% of breast cancer patients receiving chemotherapy, and has a profound impact on physical function, psychological distress and quality of life. Although several etiological factors such as anemia, depression, chronic inflammation, neurological pathology and alterations in metabolism have been proposed, the mechanisms of CRF are largely unknown.

Methods

We conducted a pilot, prospective, case-control study to estimate the magnitude of change in thyroid function in breast cancer patients from baseline to 24 months, compared to cancer-free, age-matched controls. Secondary objectives were to correlate changes in thyroid function and obesity over time with fatigue symptoms scores in this patient population.

Results

The proportion of women with breast cancer who developed subclinical or overt hypothyroidism (TSH >4.0 mIU/L) from baseline to year 1 was significantly greater compared to controls (9.6% vs. 5%; p=0.02). Subjects with breast cancer reported significantly worse fatigue symptoms than age-matched controls, as indicated by higher disruption indices (p<0.001 at baseline, p=0.02 at year 1, p=0.09 at year 2). Additionally, a significant interaction effect on disruption index score (p=0.019), general level of activity over time (p=0.006) and normal work activity (p= 0.002) was observed in the subgroup of women with BMI>30.

Conclusion

Screening breast cancer patients for thyroid function status at baseline and serially post-treatment to evaluate the need for thyroid hormone replacement may provide for a novel strategy for treating chemotherapy-induced fatigue.

Long-term and late treatment consequences: endocrine and metabolic effects

PURPOSE OF REVIEW

Cancer therapies often result in the 'late effect of cancer treatment' whereby secondary health complications emerge years after radiotherapy and chemotherapy. This review focuses on endocrine and metabolic consequences in adult cancer survivors as late treatment effects.

RECENT FINDINGS

Endocrine and metabolic disorders are among the most common late effects. Endocrine disorders include hypopituitarism, which leads to growth hormone deficiency, hypogonadism, adrenal insufficiency and hypothyroidism and related clinical manifestations. Hypogonadism in particular is associated with a wide range of health complications requiring input from the like of endocrine and fertility specialists. Immune checkpoint inhibitors are novel anticancer agents, some of which are uniquely associated with hypophysitis which requires early recognition and management, including steroid replacement. Metabolic syndrome, a significant risk for cardiovascular disease, is highly prevalent. Although the effects of cranial irradiation on the hypothalamic-pituitary system are more apparent, the relationship between chemotherapy and endocrine/metabolic disorders remains to be elucidated. There exist published guidelines for monitoring endocrine and cardiometabolic risk in cancer survivors, but the extent of monitoring appears insufficient.

SUMMARY

Regular monitoring and early management of endocrine/metabolic disorders is required to prevent the elevated rates of health complications after cancer treatment, and thereby improve cancer survivorship.

Lymphomas and thyroid: Bridging the gap

The thyroid gland is often involved in the development of neoplastic diseases, including lymphoproliferative disorders. The aim of this paper is to provide a comprehensive overview of the multiple interactions between lymphoma and thyroid. Through an extensive research among the literature, the relationship between lymphomas and thyroid can be established at various levels, and the possible interconnections are here summarized in 5 points: (1) the greater risk of lymphoma development in some thyroid diseases; (2) the primary thyroid lymphoma, with focus on issues related to the diagnosis, differential diagnosis, and treatment; (3) the incidence of thyroid involvement in primitive nodal lymphomas or in extranodal lymphomas of the other sites; (4) thyroid changes after treatment of lymphoma, in relation to the effects of radiation therapy and immuno-chemotherapy; (5) the incidental findings of thyroid changes, on imaging, in patients with lymphoma, without a direct involvement of the gland in malignant disease. In conclusion, issues that until now have been dealt with separately will therefore be analyzed in a unique paper, allowing a global view of the topic and emphasizing the need of a multidisciplinary approach. Future learning areas in this topic mainly relate to rapidly increasing the knowledge of imaging studies together with expanding the armamentarium of novel biological and targeting agents in lymphoma patients.

Pathophysiology of cardiotoxicity from target therapy and angiogenesis inhibitors

The progress in cancer therapy and the increase in number of long-term survivors reveal the issue of cardiovascular side-effects of anticancer drugs. Cardiotoxicity has become a significant problem, and the risks of adverse cardiac events induced by systemic drugs need to be seriously considered. Potential cardiovascular toxicities linked to anticancer agents include arrhythmias, myocardial ischemia and infarction, hypertension, thromboembolism, left ventricular dysfunction, and heart failure. It has been shown that several anticancer drugs seriously affect the cardiovascular system, such as ErbB2 inhibitors, vascular endothelial growth factor (VEGF) inhibitors, multitargeted kinase inhibitors, Abelson murine leukemia viral oncogene homolog inhibitors, and others. Each of these agents has a different mechanism through which it affects the cardiovascular system. ErbB2 inhibitors block the ErbB4/ErbB2 heterodimerization pathway triggered by Neuregulin-1, which is essential for cardiomyocyte survival. VEGF signaling is crucial for vascular growth, but it also has a major impact on myocardial function, and the VEGF pathway is also essential for maintenance of cardiovascular homeostasis. Drugs that inhibit the VEGF signaling pathway lead to a net reduction in capillary density and loss of contractile function. Here, we review the mechanisms and pathophysiology of the most significant cardiotoxic effects of ErbB2 inhibitors and antiangiogenic drugs. Moreover, we highlight the role of cardioncology in recognizing these toxicities, developing strategies to prevent or minimize cardiovascular toxicity, and reducing long-term cardiotoxic effects.

The Pathology of Hyperthyroidism

This article reviews those pathologic lesions which are associated with clinical and/or biochemical hyperthyroidism. Beginning with the descriptive pathology of classical Graves' disease and the less common toxic nodular goiter and hyper-functioning thyroid nodules, this paper describes the effects of non-thyroidal hormones, glandular function (including pituitary and hypothalamic lesions), ectopic production of thyroid stimulating proteins by non-thyroidal neoplasms, exogenous drug reactions causing hyper-function and finally conditions associated with a mechanic- destructive cause of hyperthyroidism.

RAPID EVOLUTION OF THYROID DYSFUNCTION IN PATIENTS TREATED WITH NIVOLUMAB

OBJECTIVE

To describe the evolution of thyroid dysfunction in a series of patients with cancer treated with the immune checkpoint inhibitor anti-programmed cell death protein-1 (PD-1) monoclonal antibody, nivolumab.

METHODS

Cases of thyroid dysfunction after initiation of checkpoint inhibitor treatment were identified from the Division of Endocrinology clinical practice at Mount Sinai Hospital, New York from April 2016 to February 2017. Charts were reviewed to identify patients treated with nivolumab with new onset of thyroid dysfunction.

RESULTS

Nine cases of thyroid function in patients who were treated with nivolumab were identified. There were 4 male and 5 female patients, with a mean age of 66 years (range 50-76 years). Seven patients ultimately developed hypothyroidism. Five of the 7 patients developed abnormal thyroid function tests within the first 90 days of starting therapy (range 21-84 days), 3 of whom had transient hyperthyroidism. Transient hyperthyroidism evolved rapidly to hypothyroidism; elevated thyroid-stimulating hormone (TSH) levels were detected within 16 to 32 days of the last documented low TSH. In the 2 patients without a hyperthyroid phase, TSH levels >50 were found 18 to 28 days after the last normal TSH value.

CONCLUSION

As the use of immune checkpoint inhibitor therapy increases, the need for prompt diagnosis and treatment of drug-induced thyroid disease will become more important. As illustrated in this case series, in contrast to other causes of auto-immune thyroiditis, hypothyroidism can develop rapidly within 3 months of treatment. Close monitoring is necessary to detect the development of thyroid dysfunction and avoid preventable morbidity.

ABBREVIATIONS

Anti-TPO Abs = anti-thyroglobulin antibodies; CT = computed tomography; CTLA-4 = cytotoxic T-lymphocyte-associated protein 4; FDA = U.S. Food & Drug Administration; FDG-PET = fluorodeoxyglucose-positron emission tomography; PD-1 = programmed cell death protein-1; PD-L1 = programmed death-ligand 1; T3 = triiodothyronine; T4 = thyroxine; TG = thyroglobulin; TPO = thyroperoxidase; TSH = thyroid-stimulating hormone.

Pomalidomide-induced hypothyroidism

Hypothyroidism is a recognized side effect of thalidomide drugs. We herein report a case of 83-year-old Irish female with a diagnosis of multiple myeloma and a background history of type 2 diabetes mellitus and hypertension. Our patient received pomalidomide and multiple courses of chemotherapy and achieved very good initial response for her multiple myeloma but subsequently she relapsed. She did not have any past history of thyroid disease or family history of thyroid disorders. Prior to treatment with pomalidomide, her thyroid function test was completely normal. She was commenced on pomalidomide in February 2017. Four weeks post treatment, she presented with worsening fatigue, and as a part of her workup, a thyroid function test was performed. Her free T4 was low at 7.2 pmol/L (reference range: 9.0–20.0) while her TSH was elevated at 44.7 mIU/L (reference range: 0.35–4.94). Pomalidomide treatment was terminated, and she was commenced on thyroid hormonal therapy replacement therapy with thyroxine with good clinical and biochemical response. Practitioners prescribing pomalidomide should be aware of this potential complication and patients who are receiving immunomodulatory drugs like pomalidomide should undergo regular thyroid hormone levels screen.

TNFR2: A Novel Target for Cancer Immunotherapy

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy but exhibit variable efficacy and relapse and can induce autoimmunity. Tumor necrosis factor (TNF) receptor 2 (TNFR2) is a signaling molecule found on the surface of a subset of potent regulatory T cells (T_regs) that can activate the proliferation of these cells through nuclear factor kappa B (NF-κB). TNFR2 is also abundantly expressed on the surface of many human tumors. We propose that blocking TNFR2 might target abundant TNFR2⁺ tumor-infiltrating T_regs and directly kill TNFR2-expressing tumors. We also posit that TNFR2 inhibitors might potentially constitute safer and more targeted alternatives to ICI cancer treatment because the expression of TNFR2 on immune cells, concentrated in the tumor microenvironment of various cancers, appears to be more selective than that of checkpoint molecules.

Case of painless thyroiditis that developed during adjuvant chemotherapy for breast cancer

We report a case of painless thyroiditis that occurred during adjuvant chemotherapy for breast cancer. A 41-year-old woman was diagnosed with right breast cancer and underwent surgery followed by adjuvant chemotherapy, given the tumor size and relatively high ratio of Ki-67-positive cells. Three weeks after the first intravenous administration of fluorouracil (500 mg/m²), epirubicin (100 mg/m²), cyclophosphamide (500 mg/m²), and dexamethasone (6.6 mg/body), followed by 3 days of oral dexamethasone (8 mg/day), she complained of continued palpitations. Although Graves' disease was initially suspected, she was diagnosed with painless thyroiditis because of a low free T3:free T4 ratio and low thyroid uptake of iodine. The mechanism of painless thyroiditis, in this case, remains unclear, although supposed etiologic event was the use of cytotoxic drugs (including fluorouracil) or the withdrawal of short-term steroid administration. Painless thyroiditis very rarely occurs during chemotherapy. However, we should consider painless thyroiditis when a patient undergoing cytotoxic chemotherapy for breast cancer experiences continued palpitations. The appropriate diagnosis and treatment of symptoms might avoid an unnecessary dose reduction or discontinuation of chemotherapy and, moreover, may prevent adverse effects associated with the metabolism of anticancer agents.

Cancer immunotherapy - immune checkpoint blockade and associated endocrinopathies

Advances in cancer therapy in the past few years include the development of medications that modulate immune checkpoint proteins. Cytotoxic T-lymphocyte antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) are two co-inhibitory receptors that are expressed on activated T cells against which therapeutic blocking antibodies have reached routine clinical use. Immune checkpoint blockade can induce inflammatory adverse effects, termed immune-related adverse events (IRAEs), which resemble autoimmune disease. In this Review, we describe the current data regarding immune-related endocrinopathies, including hypophysitis, thyroid dysfunction and diabetes mellitus. We discuss the clinical management of these endocrinopathies within the context of our current understanding of the mechanisms of IRAEs.

Pathogenesis of Hyperthyroidism

Hyperthyroidism is a form of thyrotoxicosis in which there is excess thyroid hormone synthesis and secretion. Multiple etiologies can lead to a common clinical state of "thyrotoxicosis," which is a consequence of the high thyroid hormone levels and their action on different tissues of the body. The most common cause of thyrotoxicosis is Graves' disease, an autoimmune disorder in which stimulating thyrotropin receptor antibodies bind to thyroid stimulating hormone (TSH) receptors on thyroid cells and cause overproduction of thyroid hormones. Other etiologies include: forms of thyroiditis in which inflammation causes release of preformed hormone, following thyroid gland insult that is autoimmune, infectious, mechanical or medication induced; secretion of human chorionic gonadotropin in the setting of transient gestational thyrotoxicosis and trophoblastic tumors; pituitary thyrotropin release, and exposure to extra-thyroidal sources of thyroid hormone that may be endogenous or exogenous. © 2017 American Physiological Society. Compr Physiol 7:67-79, 2017.