Cardioprotective interventions for cancer patients receiving anthracyclines

An update of the molecular mechanisms underlying anthracycline induced cardiotoxicity

Anthracycline drugs mainly include doxorubicin, epirubicin, pirarubicin, and aclamycin, which are widely used to treat a variety of malignant tumors, such as breast cancer, gastrointestinal tumors, lymphoma, etc. With the accumulation of anthracycline drugs in the body, they can induce serious heart damage, limiting their clinical application. The mechanism by which anthracycline drugs cause cardiotoxicity is not yet clear. This review provides an overview of the different types of cardiac damage induced by anthracycline-class drugs and delves into the molecular mechanisms behind these injuries. Cardiac damage primarily involves alterations in myocardial cell function and pathological cell death, encompassing mitochondrial dysfunction, topoisomerase inhibition, disruptions in iron ion metabolism, myofibril degradation, and oxidative stress. Mechanisms of uptake and transport in anthracycline-induced cardiotoxicity are emphasized, as well as the role and breakthroughs of iPSC in cardiotoxicity studies. Selected novel cardioprotective therapies and mechanisms are updated. Mechanisms and protective strategies associated with anthracycline cardiotoxicity in animal experiments are examined, and the definition of drug damage in humans and animal models is discussed. Understanding these molecular mechanisms is of paramount importance in mitigating anthracycline-induced cardiac toxicity and guiding the development of safer approaches in cancer treatment.

Novel PLGA-based nanoformulation decreases doxorubicin-induced cardiotoxicity

Nanotechnology has the potential to provide formulations of antitumor agents with increased selectivity towards cancer tissue thereby decreasing systemic toxicity. This in vivo study evaluated the potential of novel nanoformulation based on poly(lactic-co-glycolic acid) (PLGA) to reduce the cardiotoxic potential of doxorubicin (DOX). In vivo toxicity of PLGADOX was compared with clinically approved non-PEGylated, liposomal nanoformulation of DOX (LipoDOX) and conventional DOX form (ConvDOX). The study was performed using Wistar Han rats of both sexes that were treated intravenously for 28 days with 5 doses of tested substances at intervals of 5 days. Histopathological analyses of heart tissues showed the presence of myofiber necrosis, degeneration processes, myocytolysis, and hemorrhage after treatment with ConvDOX, whereas only myofiber degeneration and hemorrhage were present after the treatment with nanoformulations. All DOX formulations caused an increase in the troponin T with the greatest increase caused by convDOX. qPCR analyses revealed an increase in the expression of inflammatory markers IL-6 and IL-8 after ConvDOX and an increase in IL-8 expression after lipoDOX treatments. The mass spectra imaging (MSI) of heart tissue indicates numerous metabolic and lipidomic changes caused by ConvDOX, while less severe cardiac damages were found after treatment with nanoformulations. In the case of LipoDOX, autophagy and apoptosis were still detectable, whereas PLGADOX induced only detectable mitochondrial toxicity. Cardiotoxic effects were frequently sex-related with the greater risk of cardiotoxicity observed mostly in male rats.

Renin-angiotensin System Antagonists and Beta-blockers in Prevention of Anthracycline Cardiotoxicity: a Systematic Review and Meta-analysis

BACKGROUND

The evidence supporting the use of renin-angiotensin-aldosterone system (RAAS) inhibitors and beta-blockers for the prevention of anthracycline-induced cardiomyopathy is controversial.

OBJECTIVE

We performed a meta-analysis to assess the effectiveness of these drugs in preventing cardiotoxicity.

METHODS

The meta-analysis included prospective, randomized studies in adults receiving anthracycline chemotherapy and compared the use of RAAS inhibitors or beta-blockers versus placebo with a follow-up of 6 to 18 months. The primary outcome was change in left ventricular ejection fraction (LVEF) during chemotherapy. Secondary outcomes were the incidence of heart failure, all-cause mortality, and changes in end-diastolic measurement. Heterogeneity was assessed by stratification and meta-regression. A significance level of p < 0.05 was adopted.

RESULTS

The search resulted in 17 studies, totaling 1,530 patients. The variation (delta) in LVEF was evaluated in 14 studies. Neurohormonal therapy was associated with a lower delta in pre- versus post-therapy LVEF (weighted mean difference 4.42 [95% confidence interval 2.3 to 6.6]) and higher final LVEF (p < 0.001). Treatment resulted in a lower incidence of heart failure (risk ratio 0.45 [95% confidence interval 0.3 to 0.7]). There was no effect on mortality (p = 0.3). For analysis of LVEF, substantial heterogeneity was documented, which was not explained by the variables explored in the study.

CONCLUSION

The use of RAAS inhibitors and beta-blockers to prevent anthracycline-induced cardiotoxicity was associated with less pronounced reduction in LVEF, higher final LVEF, and lower incidence of heart failure. No changes in mortality were observed. (CRD PROSPERO 42019133615).

Cardiac and noncardiac biomarkers in patients undergoing anthracycline chemotherapy - a prospective analysis

BACKGROUND

Biomarkers represent a potential tool to identify individuals at risk for anthracycline-induced cardiotoxicity (AICT) prior to symptom onset or left ventricular dysfunction.

METHODS

This study examined the levels of cardiac and noncardiac biomarkers before, after the last dose of, and 3-6 months after completion of doxorubicin chemotherapy. Cardiac biomarkers included 5th generation high-sensitivity cardiac troponin T (cTnT), N-terminal pro-brain natriuretic peptide, growth/differentiation factor-15 (GDF-15), and soluble suppression of tumorigenesis-2 (sST2). Noncardiac biomarkers included activated caspase-1 (CASP-1), activated caspase-3, C-reactive protein, tumor necrosis factor-α, myeloperoxidase (MPO), galectin-3, and 8-hydroxy-2'-deoxyguanosine. Echocardiographic data (LVEF and LVGLS) were obtained at pre- and post-chemotherapy. Subanalysis examined interval changes in biomarkers among high (cumulative doxorubicin dose ≥ 250 mg/m²) and low exposure groups.

RESULTS

The cardiac biomarkers cTnT, GDF-15, and sST2 and the noncardiac biomarkers CASP-1 and MPO demonstrated significant changes over time. cTnT and GDF-15 levels increased after anthracycline exposure, while CASP-1 and MPO decreased significantly. Subanalysis by cumulative dose did not demonstrate a larger increase in any biomarker in the high-dose group.

CONCLUSIONS

The results identify biomarkers with significant interval changes in response to anthracycline therapy. Further research is needed to understand the clinical utility of these novel biomarkers.

Cardiotoxicities of Novel Therapies in Hematological Malignancies: Monoclonal Antibodies and Enzyme Inhibitors

Monoclonal antibodies (mAB) selectively target leukemia surface antigens and work by either blocking cell surface receptors or triggering the target cell's destruction. Similarly, enzyme inhibitors bind to complex molecular platforms and induce downstream mechanisms that trigger cell death. These are used in a variety of hematologic malignancies. Yet, they also elicit severe immune-mediated reactions as biological agents that require careful monitoring. Cardiovascular effects include cardiomyopathy, ventricular dysfunction, cardiac arrest, and acute coronary syndrome. While there have been scattered reviews of mAB and enzyme inhibitors, a consolidated resource regarding their cardiovascular risk profile is lacking. We provide general recommendations for initial screening and serial monitoring based on the literature.

Therapeutic approaches targeting CD95L/CD95 signaling in cancer and autoimmune diseases

Cell death plays a pivotal role in the maintenance of tissue homeostasis. Key players in the controlled induction of cell death are the Death Receptors (DR). CD95 is a prototypic DR activated by its cognate ligand CD95L triggering programmed cell death. As a consequence, alterations in the CD95/CD95L pathway have been involved in several disease conditions ranging from autoimmune diseases to inflammation and cancer. CD95L-induced cell death has multiple roles in the immune response since it constitutes one of the mechanisms by which cytotoxic lymphocytes kill their targets, but it is also involved in the process of turning off the immune response. Furthermore, beyond the canonical pro-death signals, CD95L, which can be membrane-bound or soluble, also induces non-apoptotic signaling that contributes to its tumor-promoting and pro-inflammatory roles. The intent of this review is to describe the role of CD95/CD95L in the pathophysiology of cancers, autoimmune diseases and chronic inflammation and to discuss recently patented and emerging therapeutic strategies that exploit/block the CD95/CD95L system in these diseases.

Effect of Dexrazoxane on Left Ventricular Systolic Function and Treatment Outcomes in Patients With Acute Myeloid Leukemia: A Report From the Children's Oncology Group

PURPOSE

To determine whether dexrazoxane provides effective cardioprotection during frontline treatment of pediatric acute myeloid leukemia (AML) without increasing relapse risk or noncardiac toxicities of the chemotherapy regimens.

PATIENTS AND METHODS

This was a multicenter study of all pediatric patients with AML without high allelic ratio FLT3/ITD treated in the Children's Oncology Group trial AAML1031 between 2011 and 2016. Median follow-up was 3.5 years. Dexrazoxane was administered at the discretion of treating physicians and documented at each course. Ejection fraction (EF) and shortening fraction (SF) were recorded after each course and at regular intervals in follow-up. Per protocol, anthracyclines were to be withheld if there was evidence of left ventricular systolic dysfunction (LVSD) defined as SF < 28% or EF < 55%. Occurrence of LVSD, trends in EF and SF, 5-year event-free survival (EFS) and overall survival (OS), and treatment-related mortality (TRM) were compared by dexrazoxane exposure.

RESULTS

A total of 1,014 patients were included in the analyses; 96 were exposed to dexrazoxane at every anthracycline course, and 918 were never exposed. Distributions of sex, age, race, presenting WBC count, risk group, treatment arm, and compliance with cardiac monitoring were similar for dexrazoxane-exposed and -unexposed patients. Dexrazoxane-exposed patients had significantly smaller EF and SF declines than unexposed patients across courses and a lower risk for LVSD (26.5% v 42.2%; hazard ratio, 0.55; 95% CI, 0.36 to 0.86; P = .009). Dexrazoxane-exposed patients had similar 5-year EFS (49.0% v 45.1%; P = .534) and OS (65.0% v 61.9%; P = .613) to those unexposed; however, there was a suggestion of lower TRM with dexrazoxane (5.7% v 12.7%; P = .068).

CONCLUSION

Dexrazoxane preserved cardiac function without compromising EFS and OS or increasing noncardiac toxicities. Dexrazoxane should be considered for cardioprotection during frontline treatment of pediatric AML.

Effects of doxorubicin-induced cardiotoxicity on cardiac mitochondrial dynamics and mitochondrial function: Insights for future interventions

Anthracyclines is an effective chemotherapeutic treatment used for many types of cancer. However, high cumulative dosage of anthracyclines leads to cardiac toxicity and heart failure. Dysregulation of mitochondrial dynamics and function are major pathways driving this toxicity. Several pharmacological and non‐pharmacological interventions aiming to attenuate cardiac toxicity by targeting mitochondrial dynamics and function have shown beneficial effects in cell and animal models. However, in clinical practice, there is currently no standard therapy for the prevention of anthracycline‐induced cardiotoxicity. This review summarizes current reports on the impact of anthracyclines on cardiac mitochondrial dynamics and mitochondrial function and potential interventions targeting these pathways. The roles of mitochondrial dynamics and mitochondrial function in the development of anthracycline‐induced cardiotoxicity should provide insights in devising novel strategies to attenuate the cardiac toxicity induced by anthracyclines.

Efficacy of Dexrazoxane in Preventing Anthracycline Cardiotoxicity in Breast Cancer

Objectives

The authors performed a systematic review and meta-analysis of randomized and nonrandomized trials on the efficacy of dexrazoxane in patients with breast cancer who were treated with anthracyclines with or without trastuzumab.

Background

Breast cancer treatment with anthracyclines and trastuzumab is associated with an increased risk of cardiotoxicity. Among the various strategies to reduce the risk of cardiotoxicity, dexrazoxane is an option for primary prevention, but it is seldom used in clinical practice.

Methods

Online databases were searched from January 1990 up to March 1, 2019, for clinical trials on the use of dexrazoxane for the prevention of cardiotoxicity in patients with breast cancer receiving anthracyclines with or without trastuzumab. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model meta-analysis.

Results

Seven randomized trials and 2 retrospective trials with a total of 2,177 patients were included. Dexrazoxane reduced the risk of clinical heart failure (RR: 0.19; 95% CI: 0.09 to 0.40; p < 0.001) and cardiac events (RR: 0.36; 95% CI: 0.27 to 0.49; p < 0.001) irrespective of previous exposure to anthracyclines. The rate of a partial or complete oncological response, overall survival, and progression-free survival were not affected by dexrazoxane.

Conclusions

Dexrazoxane reduced the risk of clinical heart failure and cardiac events in patients with breast cancer undergoing anthracycline chemotherapy with or without trastuzumab and did not significantly impact cancer outcomes. However, the quality of available evidence is low, and further randomized trials are warranted before the systematic implementation of this therapy in clinical practice.

Anthracycline-induced cardiotoxicity in the chemotherapy treatment of breast cancer: Preventive strategies and treatment

Anthracyclines are highly effective chemotherapeutic agents, used for a wide variety of malignancies. Cardiotoxicity is a well-recognized side effect of anthracycline therapy that limits the total amount of drug administered and can cause heart failure in some patients. Most experimental data support oxidative stress as the etiology of anthracycline-induced cardiotoxicity. The objective of this paper was to provide a review of the clinical classification, risk factors, monitoring and prevention of anthracycline-induced cardiotoxicity in patients with breast cancer.

Personalized medicine in cardio-oncology: the role of induced pluripotent stem cell

Treatment of cancer has evolved in the last decade with the introduction of new therapies. Despite these successes, the lingering cardiotoxic side-effects from chemotherapy remain a major cause of morbidity and mortality in cancer survivors. These effects can develop acutely during treatment, or even years later. Although many risk factors can be identified prior to beginning therapy, unexpected toxicity still occurs, often with lasting consequences. Specifically, cardiotoxicity results in cardiac cell death, eventually leading to cardiomyopathy and heart failure. Certain risk factors may predispose an individual to experiencing adverse cardiovascular effects, and when unexpected cardiotoxicity occurs, it is generally managed with supportive care. Animal models of chemotherapy-induced cardiotoxicity have provided some mechanistic insights, but the precise mechanisms by which these drugs affect the heart remains unknown. Moreover, the genetic rationale as to why some patients are more susceptible to developing cardiotoxicity has yet to be determined. Many genome-wide association studies have identified genomic variants that could be associated with chemotherapy-induced cardiotoxicity, but the lack of validation has made these studies more speculative rather than definitive. With the advent of human induced pluripotent stem cell (iPSC) technology, researchers not only have the opportunity to model human diseases, but also to screen drugs for their efficacy and toxicity using human cell models. Furthermore, it allows us to conduct validation studies to confirm the role of genomic variants in human diseases. In this review, we discuss the role of iPSCs in modelling chemotherapy-induced cardiotoxicity.

Cardiac Complications in the Adult Bone Marrow Transplant Patient

PURPOSE OF REVIEW

Due to advancements in oncologic treatment strategies and techniques, the number of survivors who have undergone hematopoetic stem cell transplant (HCT) continues to increase in the United States; this number is projected to reach 502,000 by the year 2030. There is significant interest within the field of cardio-oncology to identify cardiotoxicity and cardiovascular disease in the HCT population. Epidemiologic studies analyzing both short- and long-term cardiovascular effects, risk stratification modeling, cardioprotective strategies, and expert consensus documents for cardiotoxicity surveillance recommendations are reviewed.

RECENT FINDINGS

Patients who have undergone HCT are at increased risk of cardiovascular events and mortality compared to matched controls. The type of cardiotoxicity and the incidence rates vary based on specific therapeutic regimens and pre-existing cardiovascular risk factors. Life-threatening cardiotoxicity can present during HCT as acute heart failure, arrhythmias, pericardial tamponade, or cardiac arrest; or it can present late after treatment as cardiomyopathy, ischemic heart disease, vascular disease, stroke, or comorbid conditions, such as hypertension and diabetes mellitus that are associated with cardiac events. HCT is associated with excess cardiovascular risk partially due to exposure to cardiotoxic chemotherapy and radiation, as well as indirect and direct detrimental effects on cardiovascular reserve. This review discusses the epidemiology and the known cardiotoxic effects of historical chemoradiation agents in addition to newer targeted therapies. Recent expert consensus statements from cardiology and hematology/oncology societies are reviewed in regard to risk stratification of the cancer patient based on the type of treatments. Finally, gaps in knowledge are identified with proposed avenues of research that will allow for more accurate risk assessment, prediction, and potential treatment of the HCT patient in attenuating the risk of developing both short- and long-term cardiovascular comorbidities.

Cardio-oncology: management of cardiovascular toxicity

Traditional chemotherapeutic agents and newer targeted therapies for cancer have the potential to cause cardiovascular toxicities. These toxicities can result in arrhythmias, heart failure, vascular toxicity, and even death. It is important for oncologists and cardiologists to understand the basic diagnostic and management strategies to employ when these toxicities occur. While anti-neoplastic therapy occasionally must be discontinued in this setting, it can often be maintained with caution and careful monitoring. In the second of this two-part review series, we focus on the management of cardiovascular toxicity from anthracyclines, HER2/ErbB2 inhibitors, immune checkpoint inhibitors, and vascular endothelial growth factor inhibitors.

Modern-day cardio-oncology: a report from the 'Heart Failure and World Congress on Acute Heart Failure 2018'

During the ‘Heart Failure and World Congress on Acute Heart Failure 2018’, many sessions and lectures focused on cardio‐oncology. This important field of research is constantly growing, and therefore, a great amount of time during the congress focused on it. Prevention and early recognition of side effects is very important in cancer patients. One of the most common and potentially severe problems during antineoplastic therapy is cardiotoxicity. Hence, cardio‐oncology is vital in managing cancer patients. This paper will summarize the topics discussed in three main sessions and many additional lectures throughout the ‘Heart Failure and World Congress on Acute Heart Failure 2018’. The covered topics included pathophysiological mechanisms in the development of heart failure, risk factors, and early signs of cardiotoxicity detectable with different circulating and imaging biomarkers, as well as cardioprotective treatments recommended by different guidelines and position papers.

The cardioprotective effect of dexrazoxane (Cardioxane) is consistent with sequestration of poly(ADP-ribose) by self-assembly and not depletion of topoisomerase 2B

Following systematic scrutiny of the evidence in support of the hypothesis that the cardioprotective mechanism of action of dexrazoxane is mediated by a 'depletion' or 'downregulation' of Top2β protein levels in heart tissue, the author concludes that this hypothesis is untenable. In seeking to understand how dexrazoxane protects the heart, the outcomes of a customised association rule learning algorithm incorporating the use of antecedent surrogate variables (CEME, 2017 McCormack Pharma) reveal a previously unknown relationship between dexrazoxane and poly(ADP-ribose) (PAR) polymer. The author shows how this previously unknown relationship explains both acute and long-term cardioprotection in patients receiving anthracyclines. In addition, as a direct inhibitor of PAR dexrazoxane has access to the epigenome and this offers a new insight into protection by dexrazoxane against doxorubicin-induced late-onset damage [McCormack K, manuscript in preparation]. Notably, through this review article, the author illustrates the practical application of probing natural language text using an association rule learning algorithm for the discovery of new and interesting associations that, otherwise, would remain lost. Historically, the use of CEME enabled the first report of the capacity of a small molecule to catalyse the hybrid self-assembly of a nucleic acid biopolymer via canonical and non-canonical, non-covalent interactions analogous to Watson Crick and Hoogsteen base pairing, respectively.

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Patients with cancer have high risk of cardiovascular complications. They may be caused by tumor and cancer therapy. The possible approaches to the prevention of cardiotoxicity are discussed in this article: risk factors assessment, laboratory and instrumental diagnostics, non-pharmacological and pharmacological interventions.

A recommended practical approach to the management of anthracycline-based chemotherapy cardiotoxicity: an opinion paper of the working group on drug cardiotoxicity and cardioprotection, Italian Society of Cardiology

Anthracyclines are the mainstay of treatment of a variety of haematological malignancies and solid tumours. Unfortunately, the clinical use of these drugs is limited by cumulative, dose-related cardiotoxicity which may ultimately lead to a severe and irreversible form of cardiomyopathy. Thus, there is an increasing need for close cooperation among cardiologists, oncologists and haemato-oncologists. As anthracyclines save lives, the logical goal of this cooperation, besides preventing or mitigating cardiotoxicity, is to promote an acceptable balance between the potential cardiac side effects and the vital benefit of anticancer treatment. This manuscript, which is specifically addressed to the cardiologist who has not accumulated much experience in the field of cancer therapy, focuses on several topics, that is old and new mechanisms of cardiac toxicity, late cardiac toxicity, the importance of overall risk assessment, the key role of a cardiology consult before starting cancer therapy, and the pros and cons of primary and secondary prevention programmes.

Cardiovascular Complications of Cancer Therapy: Best Practices in Diagnosis, Prevention, and Management: Part 1

Modern cancer therapy has successfully cured many cancers and converted a terminal illness into a chronic disease. Because cancer patients often have coexisting heart diseases, expert advice from cardiologists will improve clinical outcome. In addition, cancer therapy can also cause myocardial damage, induce endothelial dysfunction, and alter cardiac conduction. Thus, it is important for practicing cardiologists to be knowledgeable about the diagnosis, prevention, and management of the cardiovascular complications of cancer therapy. In this first part of a 2-part review, we will review cancer therapy-induced cardiomyopathy and ischemia. This review is based on a MEDLINE search of published data, published clinical guidelines, and best practices in major cancer centers. With the number of cancer survivors expanding quickly, the time has come for cardiologists to work closely with cancer specialists to prevent and treat cancer therapy-induced cardiovascular complications.

Cardiac telomere length in heart development, function, and disease

Telomeres are repetitive nucleoprotein structures at chromosome ends, and a decrease in the number of these repeats, known as a reduction in telomere length (TL), triggers cellular senescence and apoptosis. Heart disease, the worldwide leading cause of death, often results from the loss of cardiac cells, which could be explained by decreases in TL. Due to the cell-specific regulation of TL, this review focuses on studies that have measured telomeres in heart cells and critically assesses the relationship between cardiac TL and heart function. There are several lines of evidence that have identified rapid changes in cardiac TL during the onset and progression of heart disease as well as at critical stages of development. There are also many factors, such as the loss of telomeric proteins, oxidative stress, and hypoxia, that decrease cardiac TL and heart function. In contrast, antioxidants, calorie restriction, and exercise can prevent both cardiac telomere attrition and the progression of heart disease. TL in the heart is also indicative of proliferative potential and could facilitate the identification of cells suitable for cardiac rejuvenation. Although these findings highlight the involvement of TL in heart function, there are important questions regarding the validity of animal models, as well as several confounding factors, that need to be considered when interpreting results and planning future research. With these in mind, elucidating the telomeric mechanisms involved in heart development and the transition to disease holds promise to prevent cardiac dysfunction and potentiate regeneration after injury.

Heart failure in chemotherapy-related cardiomyopathy: Can exercise make a difference?

Medical therapies in oncology have resulted in better survival resulting in a large population who are at risk of early and late cardiac complications of chemotherapy. Cardiotoxicity related to chemotherapy can manifest decades after treatment with a threefold higher mortality rate as compared to idiopathic dilated cardiomyopathy. The leading cause of death in cancer survivors seems to be cardiac. Early detection and intervention could prevent progression of heart failure to end stage disease requiring advanced therapies such as implantation of ventricular assist devices or cardiac transplantation. This review focuses on the role of exercise in cardioprotection in this population. The current practice of depending on ejection fraction for diagnosis of heart failure is suboptimal to detect subclinical disease. It is also important to diagnose and treat early diastolic dysfunction as this tends to lead to heart failure with preserved ejection fraction. Hence we suggest an algorithm here that is based on using strain rate and tissue Doppler imaging modalities to detect subclinical systolic and diastolic dysfunction. Further research is warranted in terms of defining exercise prescriptions in this population. Human studies with multicenter participation in randomized controlled trials should be done to elucidate the intricacies of aerobic exercise intervention in cardiotoxicity dependent heart failure. It is also necessary to assess the utility of exercise interventions in the different chemotherapeutic regimens as they impact the outcomes.

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The need for exercise prescription to prevent cardiotoxicity in chemotherapy patients

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The molecular basis of exercise as an intervention

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Summary of existing evidence

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Need for further studies on the role of exercise in different chemotherapeutic regimens

Improving the preclinical models for the study of chemotherapy-induced cardiotoxicity: a Position Paper of the Italian Working Group on Drug Cardiotoxicity and Cardioprotection

Although treatment for heart failure induced by cancer therapy has improved in recent years, the prevalence of cardiomyopathy due to antineoplastic therapy remains significant worldwide. In addition to traditional mediators of myocardial damage, such as reactive oxygen species, new pathways and target cells should be considered responsible for the impairment of cardiac function during anticancer treatment. Accordingly, there is a need to develop novel therapeutic strategies to protect the heart from pharmacologic injury, and improve clinical outcomes in cancer patients. The development of novel protective therapies requires testing putative therapeutic strategies in appropriate animal models of chemotherapy-induced cardiomyopathy. This Position Paper of the Working Group on Drug Cardiotoxicity and Cardioprotection of the Italian Society of Cardiology aims to: (1) define the distinctive etiopatogenetic features of cardiac toxicity induced by cancer therapy in humans, which include new aspects of mitochondrial function and oxidative stress, neuregulin-1 modulation through the ErbB receptor family, angiogenesis inhibition, and cardiac stem cell depletion and/or dysfunction; (2) review the new, more promising therapeutic strategies for cardioprotection, aimed to increase the survival of patients with severe antineoplastic-induced cardiotoxicity; (3) recommend the distinctive pathological features of cardiotoxicity induced by cancer therapy in humans that should be present in animal models used to identify or to test new cardioprotective therapies.

Recent Advances on Pathophysiology, Diagnostic and Therapeutic Insights in Cardiac Dysfunction Induced by Antineoplastic Drugs

Along with the improvement of survival after cancer, cardiotoxicity due to antineoplastic treatments has emerged as a clinically relevant problem. Potential cardiovascular toxicities due to anticancer agents include QT prolongation and arrhythmias, myocardial ischemia and infarction, hypertension and/or thromboembolism, left ventricular (LV) dysfunction, and heart failure (HF). The latter is variable in severity, may be reversible or irreversible, and can occur soon after or as a delayed consequence of anticancer treatments. In the last decade recent advances have emerged in clinical and pathophysiological aspects of LV dysfunction induced by the most widely used anticancer drugs. In particular, early, sensitive markers of cardiac dysfunction that can predict this form of cardiomyopathy before ejection fraction (EF) is reduced are becoming increasingly important, along with novel therapeutic and cardioprotective strategies, in the attempt of protecting cardiooncologic patients from the development of congestive heart failure.

Evaluation of lecithinized human recombinant super oxide dismutase as cardioprotectant in anthracycline-treated breast cancer patients

AIM

Anthracycline-induced cardiotoxicity is (partly) mediated by free radical overload. A randomized study was performed in breast cancer patients to investigate whether free radical scavenger super oxide dismutase (SOD) protects against anthracycline-induced cardiotoxicity as measured by changes in echo, electrocardiography and an array of biomarkers.

METHOD AND RESULTS

Eighty female, chemotherapy-naïve breast cancer patients (median age 49, range 24-67 years) scheduled for four or five courses of adjuvant 3 weekly doxorubicin plus cyclophosphamide (AC) chemotherapy, were randomly assigned to receive 80 mg PC-SOD (human recombinant SOD bound to lecithin) or placebo, administered intravenously (i.v.) immediately prior to each AC course. The primary end point was protection against cardiac damage evaluated using echocardiography, QT assessments and a set of biochemical markers for myocardial function, oxidative stress and inflammation. Assessments were performed before and during each course of chemotherapy, and at 1, 4 and 9 months after completion of the chemotherapy regimen. In all patients cardiac effects such as increases in NT-proBNP concentration and prolongation of the QTc interval were noticed. There were no differences between the PC-SOD and placebo-treated patients in systolic or diastolic cardiac function or for any other of the biomarkers used to assess the cardiac effects of anthracyclines.

CONCLUSION

PC-SOD at a dose of 80 mg i.v. is not cardioprotective in patients with breast carcinoma treated with anthracyclines.

Recommendations for cardiomyopathy surveillance for survivors of childhood cancer: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Survivors of childhood cancer treated with anthracycline chemotherapy or chest radiation are at an increased risk of developing congestive heart failure. In this population, congestive heart failure is well recognised as a progressive disorder, with a variable period of asymptomatic cardiomyopathy that precedes signs and symptoms. As a result, several clinical practice guidelines have been developed independently to help with detection and treatment of asymptomatic cardiomyopathy. These guidelines differ with regards to definitions of at-risk populations, surveillance modality and frequency, and recommendations for interventions. Differences between these guidelines could hinder the effective implementation of these recommendations. We report on the results of an international collaboration to harmonise existing cardiomyopathy surveillance recommendations using an evidence-based approach that relied on standardised definitions for outcomes of interest and transparent presentation of the quality of the evidence. The resultant recommendations were graded according to the quality of the evidence and the potential benefit gained from early detection and intervention.

Late effects of childhood cancer and its treatment

Treatment for childhood cancer with chemotherapy, radiation and/or hematopoietic cell transplant can result in adverse sequelae that may not become evident for many years. A clear understanding of the association between therapeutic exposures and specific long-term complications, and an understanding of the magnitude of the burden of morbidity borne by childhood cancer survivors, has led to the development of guidelines to support lifelong risk-based follow up for this population. It is important to develop interventions to reduce the impact of treatment-related late effects on morbidity and mortality and to continue research regarding the etiopathogenesis of therapy-related cancers and other late effects.

Dexrazoxane may prevent doxorubicin-induced DNA damage via depleting both topoisomerase II isoforms

BACKGROUND

The bisdioxopiperazine dexrazoxane (DRZ) prevents anthracycline-induced heart failure, but its clinical use is limited by uncertain cardioprotective mechanism and by concerns of interference with cancer response to anthracyclines and of long-term safety.

METHODS

We investigated the effects of DRZ on the stability of topoisomerases IIα (TOP2A) and IIβ (TOP2B) and on the DNA damage generated by poisoning these enzymes by the anthracycline doxorubicin (DOX).

RESULTS

DRZ given i.p. transiently depleted in mice the predominant cardiac isoform Top2b. The depletion was also seen in H9C2 cardiomyocytes and it was attenuated by mutating the bisdioxopiperazine binding site of TOP2B. Consistently, the accumulation of DOX-induced DNA double strand breaks (DSB) by wild-type, although not by mutant TOP2B, was reduced by DRZ. In contrast, the DRZ analogue ICRF-161, which is capable of iron chelation but not of TOP2B binding and cardiac protection, did not deplete TOP2B and did not prevent the accumulation of DOX-induced DSB. TOP2A, re-expressed in cultured cardiomyocytes by fresh serum, was depleted by DRZ along with TOP2B. DRZ depleted TOP2A also from fibrosarcoma-derived cells, but not from lung cancer-derived and human embryo-derived cells. DRZ-mediated TOP2A depletion reduced the accumulation of DOX-induced DSB.

CONCLUSIONS

Taken together, our data support a model of anthracycline-induced heart failure caused by TOP2B-mediated DSB and of its prevention by DRZ via TOP2B degradation rather than via iron chelation. The depletion of TOP2B and TOP2A suggests an explanation for the reported DRZ interference with cancer response to anthracyclines and for DRZ side-effects.

Dexrazoxane

Anthracyclines are a fundamental part of many childhood cancer therapy regimens; however, the discovery of anthracycline-induced cardiotoxicity has raised concern and led to dose limitation. The cardiotoxicity of anthracyclines has resulted in an increased demand for cardioprotectants. Dexrazoxane is the only cardioprotectant that has proven efficacy in reducing cardiotoxic effects when given prior to the administration of anthracyclines. Currently, it is still considered an “off-label” use due to a paucity of data in the literature on dexrazoxane administration in children. Nevertheless, through evaluation of the available data, dexrazoxane is observed to be safe, tolerable, and efficacious in mitigating the cardiotoxic effects of anthracycline in children, without jeopardizing its antineoplastic activity or increasing the risk of developing secondary malignant neoplasms.

An update on cardio-oncology

Over the past decades, there have been great advancements in the survival outcome of patients with cancer. As a consequence, treatment regimens are being extended to patient populations that would not have qualified in the past based on comorbidities and age. Furthermore, the anti-cancer regimens, which have been and are being used, can cause considerable morbidity and even mortality. In fact, new drugs such as tyrosine kinase inhibitors have yielded unanticipated side effects in frequency and severity. The cardiovascular disease spectrum is an important element in all of these. In order to optimize the outcome of cancer patients with cardiovascular diseases existing prior to cancer treatment or developing as a consequence of it, a new discipline called "cardio-oncology" has evolved over the past few years. Herein, we review the latest developments in this field including cardiotoxicities, vascular toxicities, and arrhythmias. This field is taking on more shape as cardiologists, oncologists, and hematologists are forming alliances, programs, and clinics, supported by the development of expert consensus statements on best management approaches and care of the cancer patient with cardiovascular diseases.