Review Article Cardiomyopathy Associated With Cancer Therapy ANTHONY F. YU, MD, 1 RICHARD M. STEINGART, MD, 1 AND VALENTIN FUSTER, MD, PhD 2 New York, New York ABSTRACT Chemotherapy-associated cardiomyopathy is a well known cardiotoxicity of contemporary cancer treat- ment and a cause of increasing concern for both cardiologists and oncologists. As cancer outcomes improve, cardiovascular disease has become a leading cause of morbidity and mortality among cancer survivors. Asymptomatic or symptomatic left ventricular systolic dysfunction in the setting of cardiotoxic chemotherapy is an important entity to recognize. Early diagnosis of cardiac injury through the use of novel blood-based biomarkers or noninvasive imaging modalities may allow for the initiation of cardio- protective medications or modification of chemotherapy regimen to minimize or prevent further damage. Several clinical trials are currently underway to determine the efficacy of cardioprotective medications for the prevention of chemotherapy-associated cardiomyopathy. Implementing a strategy that includes both early detection and prevention of cardiotoxicity will likely have a significant impact on the overall prognosis of cancer survivors. Continued coordination of care between cardiologists and oncologists remains critical to maximizing the oncologic benefit of cancer therapy while minimizing any early or late cardiovascular effects. (J Cardiac Fail 2014;20:841e852) Key Words: Cardiotoxicity, chemotherapy, congestive heart failure. The landscape of cancer care has evolved over the past 20 years with the development of more aggressive cancer screening programs, improvements in diagnostic testing, and more effective treatment options. As a result, cancer death rates have declined 20% from 1991 (215.1 per 100,000 population) to 2009 (173.1 per 100,000 popula- tion), and the population of cancer survivors is projected to increase to nearly 18 million by 2022. 1 What has become clear, however, is that the benefit of many successful anti- cancer therapies is attenuated by adverse cardiotoxic ef- fects. As cancer survival increases in the new era of improved chemotherapeutics, competing cardiac causes of morbidity and mortality will have a significant impact on long-term patient outcomes. This is an area of growing concern for both oncologists and cardiologists and has led to the development of a new field of cardio-oncology which focuses on the treatment and prevention of cardiovascular disease among cancer patients. Chemotherapy-associated cardiomyopathy is a well known cardiotoxicity and is the primary focus of this review. A list of chemotherapeutic agents associated with cardiomyopathy is summarized in Table 1. Anthracyclines are among the oldest chemotherapeutic agents, and their car- diotoxic effects have been studied for O30 years. 16e18 Several other classes of chemotherapeutic agents also have been identified to cause significant cardiac toxicity, including alkylating agents, tyrosine kinase inhibitors, antimicrotubule agents, and monoclonal antibodyebased targeted therapies. Attempts to develop improved strategies for the diag- nosis of cardiotoxicity beyond measurement of left ventric- ular ejection fraction (LVEF) have been a major focus of recent investigation. Biomarkers and noninvasive imaging modalities (ie, tissue Doppler imaging, speckle-tracking strain echocardiography, and cardiac magnetic resonance imaging [MRI]) have been proposed for the early detection of cardiotoxicity. Small clinical trials have shown modest success with the use of standard heart failure pharmaco- therapy, including beta-blockers and angiotensin- converting enzyme inhibitors (ACE-Is), to prevent left From the 1 Cardiology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York and 2 Zena and Michael A. Wiener Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York. Manuscript received June 6, 2014; revised manuscript received August 8, 2014; revised manuscript accepted August 14, 2014. Reprint requests: Anthony F. Yu, MD, Department of Medicine, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 43, New York, NY 10065. Tel: 212-639-7932; Fax: 212-639-2275. E-mail: [email protected]See page 849 for disclosure information. 1071-9164/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.cardfail.2014.08.004 841 Journal of Cardiac Failure Vol. 20 No. 11 2014
12
Embed
Cardiomyopathy Associated With Cancer Therapy · 2015. 11. 25. · anthracycline-induced cardiomyopathy, use of endomyo-cardial biopsy is limited in clinical practice owing to its
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Journal of Cardiac Failure Vol. 20 No. 11 2014
Review Article
Cardiomyopathy Associated With Cancer Therapy
ANTHONY F. YU, MD,1 RICHARD M. STEINGART, MD,1 AND VALENTIN FUSTER, MD, PhD2
New York, New York
From the 1CarSloan Kettering CMichael A. Wieneat Mount Sinai, NManuscript rece
8, 2014; revised mReprint reques
Memorial Sloan KNew York, NY [email protected] page 849 fo1071-9164/$ - s� 2014 Elseviehttp://dx.doi.org
ABSTRACT
Chemotherapy-associated cardiomyopathy is a well known cardiotoxicity of contemporary cancer treat-ment and a cause of increasing concern for both cardiologists and oncologists. As cancer outcomesimprove, cardiovascular disease has become a leading cause of morbidity and mortality among cancersurvivors. Asymptomatic or symptomatic left ventricular systolic dysfunction in the setting of cardiotoxicchemotherapy is an important entity to recognize. Early diagnosis of cardiac injury through the use ofnovel blood-based biomarkers or noninvasive imaging modalities may allow for the initiation of cardio-protective medications or modification of chemotherapy regimen to minimize or prevent further damage.Several clinical trials are currently underway to determine the efficacy of cardioprotective medications forthe prevention of chemotherapy-associated cardiomyopathy. Implementing a strategy that includes bothearly detection and prevention of cardiotoxicity will likely have a significant impact on the overallprognosis of cancer survivors. Continued coordination of care between cardiologists and oncologistsremains critical to maximizing the oncologic benefit of cancer therapy while minimizing any early orlate cardiovascular effects. (J Cardiac Fail 2014;20:841e852)Key Words: Cardiotoxicity, chemotherapy, congestive heart failure.
The landscape of cancer care has evolved over the past20 years with the development of more aggressive cancerscreening programs, improvements in diagnostic testing,and more effective treatment options. As a result, cancerdeath rates have declined 20% from 1991 (215.1 per100,000 population) to 2009 (173.1 per 100,000 popula-tion), and the population of cancer survivors is projectedto increase to nearly 18 million by 2022.1 What has becomeclear, however, is that the benefit of many successful anti-cancer therapies is attenuated by adverse cardiotoxic ef-fects. As cancer survival increases in the new era ofimproved chemotherapeutics, competing cardiac causes ofmorbidity and mortality will have a significant impact on
diology Service, Department of Medicine, Memorialancer Center, New York, New York and 2Zena andr Cardiovascular Institute, Icahn School of Medicineew York, New York.ived June 6, 2014; revised manuscript received Augustanuscript accepted August 14, 2014.ts: Anthony F. Yu, MD, Department of Medicine,ettering Cancer Center, 1275 York Avenue, Box 43,
r disclosure information.ee front matterr Inc. All rights reserved./10.1016/j.cardfail.2014.08.004
841
long-term patient outcomes. This is an area of growingconcern for both oncologists and cardiologists and has ledto the development of a new field of cardio-oncology whichfocuses on the treatment and prevention of cardiovasculardisease among cancer patients.
Chemotherapy-associated cardiomyopathy is a wellknown cardiotoxicity and is the primary focus of thisreview. A list of chemotherapeutic agents associated withcardiomyopathy is summarized in Table 1. Anthracyclinesare among the oldest chemotherapeutic agents, and their car-diotoxic effects have been studied for O30 years.16e18
Several other classes of chemotherapeutic agents also havebeen identified to cause significant cardiac toxicity, includingalkylating agents, tyrosine kinase inhibitors, antimicrotubuleagents, and monoclonal antibodyebased targeted therapies.
Attempts to develop improved strategies for the diag-nosis of cardiotoxicity beyond measurement of left ventric-ular ejection fraction (LVEF) have been a major focus ofrecent investigation. Biomarkers and noninvasive imagingmodalities (ie, tissue Doppler imaging, speckle-trackingstrain echocardiography, and cardiac magnetic resonanceimaging [MRI]) have been proposed for the early detectionof cardiotoxicity. Small clinical trials have shown modestsuccess with the use of standard heart failure pharmaco-therapy, including beta-blockers and angiotensin-converting enzyme inhibitors (ACE-Is), to prevent left
Table 1. Chemotherapeutic Agents Associated With Cardiomyopathy
Chemotherapeutic Agent Incidence (%)2 Proposed Mechanism of Action Comments
AnthracyclinesDoxorubicin 3e26 Free radical formation and increased oxidative
stress, leading to apoptosis and cell death;potentially mediated by topoisomerase-II-b3
Acute cardiotoxicity, a rare complication, occursimmediately after infusion (!1%). Chroniccardiotoxicity can first be detected manyyears after exposure but not uncommonlyoccurs within the 1st year of treatment. Riskis dose dependent and increases withcumulative dosing O400 mg/m2.
Liposomal doxorubicin 6e134e6
Epirubicin 0.9e3.3Idarubicin 5e18
Alkylating agentsCyclophosphamide 7e28 Increase in free oxygen radicals; direct
endothelial injury7Acute cardiac toxicity is associated withhigh dose conditioning regimens (120e180 mg/kg) commonly used for bone marrowtransplantation.
Ifosfamide 17
Monoclonal antibodiesTrastuzumab 2e28 Inhibition of ERBB2 signaling, activation of
dysfunctionMost commonly seen in elderly patients withunderlying cardiac risk factors (eg, diabetes,hypertension, coronary artery disease, andarrhythmia)10
Dasatanib 2e4
Multikinase inhibitorsSunitinib 15e2011 Off-target kinase inhibition Cardiomyopathy may be exacerbated by
sunitinib induced hypertension.12
ERBB2 inhibitorsLapatinib 1.5e2.2 Inhibition of ERBB2 and EGFR Lower incidence of cardiomyopathy and heart
failure compared with trastuzumab13
AntimicrotubulesDocetaxel 2.3e8 Increased microtubule density leading to
contractile dysfunction14; histamine release;induction of myocyte damage by affectingsubcellular organelles7
Potentiates the cardiotoxicity of anthracyclineswhen given concurrentlyPaclitaxel d
Proteasome inhibitorsBortezomib 2e5 Interference with the ubiquitin proteasome
system, resulting in accumulation of toxicproteins within cardiomyocytes
dCarfilzomib 415
LVEF, left ventricular ejection fraction; CHF, congestive heart failure.
842 Journal of Cardiac Failure Vol. 20 No. 11 November 2014
ventricular (LV) dysfunction associated with cancer ther-apy. However, there remains no clear consensus on theappropriate use of these therapies in the cancer setting.We will review the current evidence relating to the earlydetection, treatment, and prevention of cancer therapyeassociated cardiomyopathy.
Clinical Criteria for Chemotherapy-AssociatedCardiomyopathy
The term ‘‘cardiotoxicity’’ refers broadly to any cardio-vascular side effect related to cancer therapy (ie, heart fail-ure, cardiomyopathy, arrhythmias, ischemia, valvulardisease, pericardial disease, hypertension, or thrombosis).For the purposes of this review, however, cardiotoxicitywill be used to refer to LV dysfunction that develops as aresult of chemotherapy-induced myocardial injury.Anthracycline-induced cardiomyopathy was first describedin the 1970s and was defined in early trials by the presenceof clinical signs and symptoms of heart failure thought to
be secondary to anthracycline exposure.19 The diagnosiscan be confirmed by endomyocardial biopsy, which showsseveral characteristic findings including myofibrillardropout, distortion and disruption of Z-lines, mitochondrialdisruption, and intramyocyte vacuolization.20,21 Although itis considered to be the most sensitive and specific test foranthracycline-induced cardiomyopathy, use of endomyo-cardial biopsy is limited in clinical practice owing to itsinvasive nature.
More recently, inconsistencies in the literature on thedefinition and criteria for cardiotoxicity pose a major chal-lenge to the field of cardio-oncology, especially in thecontext of newer targeted therapies (eg, trastuzumab) thatare associated with adverse cardiac effects. In 2002 a Car-diac Review and Evaluation Committee (CREC) wasformed to obtain independent and unbiased estimates oftrastuzumab-associated cardiac dysfunction, and thefollowing criteria for cardiotoxicity were proposed22: (1)cardiomyopathy characterized by a decrease in cardiacLVEF (global or septal predominance), (2) symptoms of
Table 2. Chemotherapy-Associated Cardiomyopathy Data From Adjuvant Trastuzumab Clinical Trials
Trial NameImaging Modality forLVEF Determination Frequency of Monitoring
Criteria for WithholdingTrastuzumab Cardiac Event Rates
NSABP B-3123 MUGA Baseline, after AC, and at 6, 9,and 18 months
LVEF decrease of $16%, ordecrease of 10%e15% below theLLN (defined by each institution)
Discontinuation of trastuzumab in14% of patients owing toasymptomatic decrease in LVEF;NYHA functional class III or IVheart failure or death from cardiaccauses occurred in 1.3% in controlvs 4% in trastuzumab arm after7-year follow-up.8
HERA24 Echo or MUGA Baseline and 3, 6, 12, 18, 24,30, 36, and 60 months afterrandomization
Symptomatic heart failure withLVEF !45%, or LVEF decreaseof $10% to !50%
During median follow-up of3.6 years, NYHA functional classIII or IV heart failure occurred in0% of control vs 0.8% oftrastuzumab group; significantdecrease in LVEF occurred in2.9% of control vs 9.8% oftrastuzumab group.25
N-983126,27 Echo or MUGA Baseline, after AC, and at 6, 9,and 18 months
LVEF decrease of $16%, ordecrease of 10%e15% below theLLN (defined by each institution)
NYHA functional class III or IVheart failure or death from cardiaccauses at 3 years: 0.3% in controlvs 3.3% in concurrenttrastuzumab-paclitaxel group.28
FinHer29 Echo or MUGA Before chemotherapy, after FEC,and 12 and 36 months afterchemotherapy
None No patients receiving trastuzumabdeveloped heart failure or adecline in LVEFO10% to!50%.
BCIRG 00630 Echo or MUGA Seven time points throughoutstudy period
LVEF decrease of $16%, ordecrease of 10%e15% below theLLN (defined by each institution),or decrease of !10% to $6%below the LLN
NYHA functional class III or IVheart failure occurred in 0% ofAC-T, 0.4% of TCH, and 2% AC-T þ trastuzumab group; O10%decrease in LVEF occurred in11.2% AC-T, 9.4% of TCH, and18.6% of AC-T þ trastuzumabgroup.
NSABP, National Surgical Adjuvant Breast and Bowel Project; HERA, Herceptin Adjuvant; FinHer, Finland Herceptin; BCIRG, Breast Cancer Interna-tional Research Group; MUGA, multiple-gated acquisition scan; AC, doxorubicin and cyclophosphamide; FEC, 5-fluorouracil, epirubicin, and cyclophos-phamide; LVEF, left ventricular ejection fraction; LLN, lower limit of normal; NYHA, New York Heart Association; T, docetaxel; TCH, docetaxel,carboplatin, and trastuzumab.
Cardiomyopathy Associated With Cancer Therapy � Yu et al 843
congestive heart failure (CHF), (3) associated signs of CHF(ie, S3 gallop, tachycardia, or both), or (4) a decline inLVEF of $5% to !55% with signs/symptoms of CHF,or decline of 10% to !55% without symptoms. Despitethis effort, significant heterogeneity exists in the criteriafor cardiotoxicity in subsequent clinical trials (Table 2),leading to significant variability in the reported incidenceof chemotherapy associated cardiac dysfunction.
Imaging for Early Detection of Cardiotoxicity
Radionuclide Ventriculography and Echocardiography
Measurement of LVEF is the most commonly usedmethod to evaluate for cardiotoxicity, and a baselineLVEF is routinely obtained before the initiation of cardio-toxic chemotherapy. Repeated serial LVEF assessmentsare recommended in the setting of certain cardiotoxicagents, such as trastuzumab,31e33 and can also be per-formed as needed if signs or symptoms of CHF develop.Radionuclide ventriculography, or multiple-gated acquisi-tion scan, has been validated as an accurate and reproduc-ible method for LVEF estimation,34 but it exposespatients to w6e7 mSv ionizing radiation per examination.Echocardiography is often preferred because it is a readily
accessible and safe technology that does not involve the useof ionizing radiation. Although 2-dimensional (2D) echo-cardiography can be limited by significant variability andpoor agreement with reference methods, it has significantlyimproved with the use of ultrasound contrast agents. In astudy of 110 patients by Malm et al, LVEF by unenhancedechocardiography and cardiac MRI differed by$10% in 23patients (26%) versus 0 with contrast echocardiography.35
Three-dimensional (3D) echocardiography offers additionalincremental benefit over 2D techniques for determination ofLVEF.36 Moreover, among cancer patients undergoing se-rial monitoring of LVEF, noncontrast 3D echocardiographyis feasible, accurate, and reproducible.37,38 Although somestudies suggest that diastolic dysfunction may be an earlysign of cardiotoxicity, the utility of diastolic functionassessment during cancer treatment remains uncertain.39,40
Although 2D echocardiography is routinely used forsurveillance of LVEF, this modality can be limited by sub-optimal image quality as well as significant inter- and intra-observer variability. A change in LVEF of w10% is theminimum that can be recognized with 95% confidence,37
but this degree of change is commonly used as the thresholdto define cardiotoxicity. In addition, LVEF abnormalitieslikely represent a late manifestation of cardiotoxicity and
844 Journal of Cardiac Failure Vol. 20 No. 11 November 2014
may indicate the presence of irreversible myocardial dam-age. An earlier study by Ewer et al showed that biopsy-proven abnormalities due to anthracycline cardiotoxicitycorrelated poorly with LVEF, suggesting that LVEF is aninsensitive marker for cardiotoxicity.41 More sensitive andspecific noninvasive markers of LV dysfunction would beuseful for identifying patients at increased risk fortreatment-associated LV dysfunction, thereby allowing on-cologists and cardiologists to tailor the treatment regimenfor optimal efficacy while minimizing cardiac toxicity.
Myocardial Strain Imaging
Tissue Doppler and speckle-tracking strain imaging haveemerged as 2 quantitative techniques for estimating globaland regional myocardial mechanical function and have thepotential to detect early signs of LV dysfunction.42 The firstdescription of strain was derived from tissue Doppler imag-ing (TDI) for assessment of regional myocardial functionand was validated in an ischemia model.43,44 However,the technique is both user and angle dependent and is un-able to differentiate translational motion or tethering effectsfrom myocardial contractility. Speckle-tracking echocardi-ography is an angle-independent technique that uses animage-processing algorithm for analyzing motion of‘‘speckles’’ or ‘‘fingerprints’’ within a 2D echo image,and it has replaced TDI strain as the preferred method forquantitative assessment of cardiac deformation (Fig. 1).45,46
Several studies have evaluated the utility of strain imag-ing for the detection of chemotherapy-associated cardiotox-icity. Fallah-Rad et al47 evaluated 42 patients with breastcancer overexpressing human epidermal growth factor re-ceptor 2 (HER2) receiving trastuzumab in the adjuvantsetting after anthracycline therapy. Within 3 months, peakglobal longitudinal and radial strain detected preclinicalchanges in LV systolic function before a decrease inLVEF observed several months later. A more recent pro-spective multicenter study by Sawaya et al demonstratedthat global longitudinal strain!19% was predictive of sub-sequent cardiotoxicity as defined by CREC criteria and waspresent in all patients who later developed symptoms ofheart failure.48 Negishi et al similarly showed that a$11% relative reduction in global longitudinal strain waspredictive of subsequent trastuzumab-associated cardiotox-icity.49 Abnormalities in strain parameters can also be seenseveral years after a cardiotoxic exposure. This wasreported in a study among 75 asymptomatic breast cancersurvivors who received anthracycline with or without adju-vant trastuzumab, in which global longitudinal strain wassignificantly decreased in the chemotherapy group up to6 years after therapy compared with control subjects.50
Although these novel echocardiographic markers of sub-clinical LV dysfunction may allow for earlier detection ofpatients at increased risk for developing cardiotoxicity,the clinical significance of these changes remains unclear.Further studies are required to determine which patientswould benefit most from this additional testing, when the
testing should occur, and whether changes in these earlyechocardiographic markers are of sufficient clinical rele-vance to warrant an alteration in the oncologic treatmentplan or intervention with cardioprotective medication.
Cardiac Magnetic Resonance Imaging
Cardiac MRI provides accurate measurements of LV di-mensions and is considered to be the criterion standard withwhich other imaging modalities are compared for LVEFdetermination. Unlike echocardiography, cardiac MRIdoes not rely on geometric assumptions for calculating vol-umes and is not hindered by poor acoustic windows. As aresult, it has been shown to have superior intra- and inter-observer reproducibility and accuracy compared with echo-cardiography.51 The use of echocardiography and cardiacMRI for evaluation of LV structure and function wascompared in 114 adult survivors of childhood cancer byArmstrong et al.52 Compared with cardiac MRI, 2D and3D echocardiography were less sensitive (25% and 53%,respectively) for the detection of LVEF !50%. However,the use of a higher LVEF cutoff of !60% by echocardiog-raphy increased the sensitivity to 75% for detecting LVEF!50% by cardiac MRI. These results suggest that the prev-alence of cardiotoxicity may be underestimated by 2Dechocardiography compared with more sensitive volumetricmeasures of LVEF such as cardiac MRI.
Beyond cardiac function and remodeling, cardiac MRIcan directly assess myocardial tissue characteristics thatare potentially useful for the identification of cardiotoxicityduring or after cancer therapy. Several studies have shownthe presence of myocardial fibrosis with the detection oflate gadolinium enhancement (LGE) during and soon aftercompletion of cancer therapy,47,53 although the prevalenceof LGE appears to be low (!10%) during long-termfollow-up.54,55 New tissue characterization methods, suchas T1 mapping, enable quantification of extracellular vol-umes, and preliminary studies have shown this to beelevated among patients with anthracycline-associated car-diotoxicity.56,57 Additional studies are needed to determinethe role that cardiac MRI will play in the surveillance anddiagnostic algorithm for cardiotoxicity. Evaluation ofchemotherapy-associated cardiomyopathy and quantifica-tion of LV function are both approved indications for car-diac MRI based on the 2006 American College ofCardiology (ACC)/American Heart Association (AHA)appropriate use guidelines,58 but key disadvantages of car-diac MRI are high cost and limited availability of cardiacMRI scanners and trained personnel.
Biomarkers for Prediction of Cardiotoxicity
Cardiac biomarkers may serve a role as an alternate diag-nostic tool for the detection of chemotherapy-associatedcardiotoxicity. A biomarker strategy would allow for earlyintervention with cardioprotective medications or alterationin the cancer treatment regimen to minimize the risk
Fig. 1. Two-dimensional myocardial strain measurement. Example of assessment of longitudinal myocardial strain in the apical 4-chamberview: (A) normal longitudinal strain in a healthy patient; (B) abnormal longitudinal strain in a Hodgkin lymphoma survivor previouslytreated with anthracycline chemotherapy and mediastinal radiotherapy. The colored lines represent measurements of regional myocardialdeformation. The white dotted line represents the global average of all segments in each view.
Cardiomyopathy Associated With Cancer Therapy � Yu et al 845
of cardiac dysfunction. Several biomarkers have beenproposed, including troponin, natriuretic peptide, andC-reactive protein (CRP).
Troponin
Cardiac troponins T and I (TnT and TnI), long known forthe important role they play in the diagnosis of acutecoronary syndromes, are sensitive and specific markersfor myocardial injury. Multiple studies have investigatedthe role of troponin as a promising biomarker for thediagnosis of chemotherapy-associated cardiomyopathy
(Table 3). In one study of 204 patients receiving high-dose chemotherapy, TnI was elevated in 32% of patientsand occurred O50% of the time soon after the end ofdrug administration. LVEF was also significantly reducedamong patients with positive TnI.60 A follow-up study toinvestigate the time course of TnI elevation and its impacton clinical outcome showed that patients with negative TnI(!0.08 ng/mL), immediately and 1 month after chemo-therapy, showed no reduction in LVEF and a very low inci-dence of cardiac events.61 In contrast, patients with positiveTnI had a higher incidence of adverse cardiac events, con-sisting mostly of heart failure and asymptomatic LV
Table 3. Utility of Troponin as a Biomarker for Predicting Chemotherapy-Associated Cardiomyopathy
Author
Criteria forBiomarkerPositivity Patient Population n Frequency of Monitoring Outcome
Broeyeret al59
TnT $0.01 ng/mL Recipients of doxorubicinchemotherapy
26 Before, at completion, and24 h after chemotherapyadministration
TnT below limit of detection inmost cases
Cardinaleet al60
TnI O0.4 ng/mL Recipients of HDC 204 Before, immediately after,and 12, 24, 36, and 72 hafter each cycle
LVEF !50% observed in 19/65(29%) TnIþ and 0/139TnI� patients (P ! .001)
Cardinaleet al61
TnI $0.08 ng/mL Recipients of HDC 703 Before, immediately after, 12,24, 36, and 72 h after eachcycle (early TnI), and 1 monthafter (late TnI) lastadministration of HDC
Higher cardiac event rate inpatients with TnI positivity
Cardinaleet al62
TnI $0.08 ng/mL Early, advanced, and metastaticHER2þ breast cancer patientstreated with receivingtrastuzumab
251 Before and soon after eachtrastuzumab treatment
Trastuzumab-inducedcardiotoxicity was morefrequent in patients withelevated TnI (62% vs 5%;P ! .001); LVEF recoveryoccurred less frequentlyin patients with elevatedTnI (35% vs 100%; P ! .001)
Fallah-Radet al47
TnT $0.01 ng/mL HER2þ breast cancer patientsreceiving adjuvant trastuzumab
42 Before initiation of anthracycline,before initiation of trastuzumab,and 3, 6, 9, and 12 months afterinitiation of trastuzumab
TnT remained within normallimits for both the normalcohort and those who developedtrastuzumab-mediatedcardiomyopathy
Sawayaet al63
hsTnI O0.015 mg/L HER2þ breast cancer treated withanthracyclines and trastuzumab
43 Before chemotherapy and after3 and 6 months of treatment
Elevated hsTnI at 3 mo is anindependent predictor oflater cardiotoxicity (P ! .02)
Sawayaet al48
hsTnI O30pg/mL HER2þ breast cancer patientstreated with adjuvantanthracyclines, taxanes, andtrastuzumab
81 Before chemotherapy and after3, 6, 9, 12, and 15 months
Elevated hsTnI at the completionof anthracycline therapy ispredictive of subsequentcardiotoxicity
TnT, troponin T; TnI, troponin I; HDC, high-dose chemotherapy; LVEF, left ventricular ejection fraction; hsTnI, high-sensitivity troponin I.
846 Journal of Cardiac Failure Vol. 20 No. 11 November 2014
dysfunction. Elevated troponin may also identify those whoare less likely to recover despite maximal heart failure ther-apy, whereas negative troponin may suggest that any inci-dent LV dysfunction will be transient.62 This informationcould help clinicians to risk stratify patients and minimizeunnecessary interruption of cancer treatment.
More sensitive troponin assays have recently been devel-opedwhich allow for detection of troponin release at an earlierstage of myocyte stress. Several studies have demonstratedbetter diagnostic accuracy of these newer assays in the earlydiagnosis of acute coronary syndrome,64e66 but their role inthe detection of cardiotoxicity is still unclear. Sawaya et alevaluated the utility of ultrasensitive TnI for predicting subse-quent cardiotoxicity among 81 patients with HER2þ breastcancer and found that ultrasensitive TnI O30 pg/mL com-bined with global longitudinal strain !19% was associatedwith subsequent decline in LVEF and symptomatic CHF.48
Natriuretic Peptide
Natriuretic peptides have been studied extensively fortheir diagnostic and prognostic role in cardiovascular dis-ease. Both A-type and B-type natriuretic peptides (ANPand BNP) are important for salt and water handling andare produced by the heart in response to high ventricularfilling pressure, as is typically seen with heart failure. Severalstudies have looked at the value of both ANP and BNP levels
for monitoring and/or prediction of chemotherapy-inducedcardiotoxicity, but the results have been inconclusive. Anearly study by Suzuki et al suggested the possible role ofBNP in the assessment of cardiac function after anthracy-cline administration for hematologic malignancies.67 How-ever, other studies performed in patients of varying agesand different malignancies have failed to show an associationbetween BNP and risk of cardiotoxicity.47,68 Daugard et alstudied 107 patients receiving anthracycline for a varietyof cancer diagnoses, including breast cancer, sarcoma, andlymphoma, and concluded that neither baseline levels nor achange in ANP or BNP were predictive of a change inLVEF.69 More recently, in a homogeneous group of 81women with HER2þ breast cancer treated with anthracy-clines followed by taxanes and trastuzumab, Sawaya et alfound that elevated N-terminal pro-BNP was not predictiveof subsequent LVEF decline or symptomatic heart failure.48
At present, there are insufficient data to recommend theroutine measurement of natriuretic peptides in the assess-ment of cardiotoxicity in clinical practice.
C-Reactive Protein and Other Novel Biomarkers
Few studies have evaluated the association between CRPand cardiotoxicity, perhaps owing to the confounding effectof concurrent infectious or inflammatory processes thataffect CRP levels and often occur with malignancy. A
Cardiomyopathy Associated With Cancer Therapy � Yu et al 847
recent single-center clinical trial demonstrated that high-sensitivity CRP had a high sensitivity (92.9%) and negativepredictive value (94.1%) for predicting trastuzumab-induced cardiotoxicity.70 Another study by Ky et al investi-gated the association of multiple conventional and novelbiomarkers with cardiotoxicity, including growth differenti-ation factor 15, myeloperoxidase (MPO), placental growthfactor, soluble Fms-like tyrosine kinase receptor 1, and ga-lectin-3.71 Among 78 breast cancer patients treated withdoxorubicin and trastuzumab, changes in TnI and MPObut not CRP were associated with subsequent cardiacdysfunction. Additional studies are needed to validate theutility of candidate biomarkers before application in clin-ical practice.
Management of Cardiotoxicity
In 2005, ACC/AHA introduced a new classification sys-tem of heart failure that emphasized the preventable natureof heart failure, and this was accompanied by recommenda-tions to treat cardiovascular risk factors to prevent or delaythe onset of heart failure.72 Based on this new classificationsystem, patients with chemotherapy-associated cardiomy-opathy and asymptomatic LV dysfunction are classifiedwith stage B heart failure. According to the 2013 ACC/AHA Guideline for the Management of Heart Failure, pa-tients with stage B heart failure should be treated withACE-Is (Class I, Level of Evidence A) and beta blockers(Class I, Level of Evidence C).73 The use of therapiessuch as implantable cardioverter-defibrillators or cardiac re-synchronization therapy for more advanced stages of heartfailure should take into consideration the patient’s overallprognosis and quality of life. A proposed diagnostic andtreatment algorithm for patients exposed to cardiotoxictherapy is shown in Figure 2.Evidence supporting the use of contemporary heart fail-
ure therapies is largely based on studies in patients withischemic or nonischemic dilated cardiomyopathies, andlimited data exist regarding the treatment of patients withchemotherapy-associated cardiomyopathy.74e76 Cardinaleet al evaluated the response of anthracycline-induced car-diomyopathy to modern heart failure therapy and included201 patients with a LVEF #45%.77 Enalapril and, whenpossible, carvedilol were initiated at the time of detectionof LVEF impairment and up-titrated to the maximal toler-ated dose, and LVEF was followed serially with the useof echocardiography. A total of 85 patients (42%) normal-ized their LVEF, 26 patients (13%) showed an increase inLVEF of O10% but remaining !50%, and 90 patients(45%) showed !10% increase in LVEF. A short time toinitiation of heart failure therapy was an important predic-tor of LVEF recovery. This was one of the first prospectivestudies to show the efficacy of ACE-Is and beta-blockersfor the treatment of anthracycline-mediated cardiomyopa-thy, suggesting that early treatment may be important to in-crease the likelihood of LVEF recovery. Several questionsremain unanswered, including which specific medication
to use, how much, and for what duration. Additional studiesare needed to address these gaps in knowledge and betterinform the optimal heart failure management ofchemotherapy-associated cardiomyopathy.
Strategies for Prevention of Cardiotoxicity
Current management strategies have relied on earlydetection of myocardial injury through serial monitoringof LVEF or cardiac biomarker testing during treatment, fol-lowed by temporary or permanent discontinuation offurther cardiotoxic exposures. A major goal of cardio-oncology is to prevent the development of cardiotoxicity,either by modification of the cardiotoxic exposure or byinitiation of cardioprotective medications. Here we reviewsome of the preventive strategies that have been proposed.
Chemotherapy Modification
Anthracycline cardiotoxicity is related to cumulativedose,78 and cumulative doxorubicin doses should be limitedto 450e500 mg/m2 in adults. However, given that the sensi-tivity to cardiotoxic effects of anthracycline can vary by pa-tient, routine surveillance of cardiac function is critical forthe prevention of cardiotoxicity, even at lower anthracy-cline dose ranges. Prolonged infusion schedules havebeen shown to lower the incidence of cardiotoxicitycompared with bolus therapy.79 In a Cochrane database re-view of 6 randomized controlled trials in which differentanthracycline dosage schedules were used in cancer pa-tients, the rate of heart failure was significantly lowerwith a long infusion ($6 h) compared with shorter (relativerisk [RR] 0.27, 95% confidence interval [CI] 0.09e0.81).80
This strategy has not been shown to adversely affect thecancer response rate or overall survival.
Liposomal preparations of anthracyclines, first used inthe early 1990s for the treatment of AIDS-associatedKaposi sarcoma, are associated with a lower incidence ofcardiotoxicity compared with standard anthracycline prepa-rations.81 Liposomal preparations of anthracyclines werefound to be effective in a variety of malignancies, includingbreast cancer, ovarian cancer, and multiple myeloma, whileassociated with less cardiac toxicity.4,5,82e84 Less severecardiac changes were seen on endomyocardial biopsyamong patients receiving pegylated liposomal doxorubicincompared with patients receiving non-liposomal doxoru-bicin.85 Liposomal anthracycline preparations are currentlyin use for the treatment of ovarian cancer and multiplemyeloma.
Dexrazoxane
Dexrazoxane is an EDTA-like chelator that binds to ironand reduces the formation of superhydroxide radicals thatcan cause oxidative damage of cardiac tissue. The efficacyof dexrazoxane was recently addressed in a Cochrane data-base review that included 10 randomized clinical trials of1,619 patients.86 The majority of patients included in the
Fig. 2. Proposed diagnostic, preventive, and treatment strategies for patients at risk for chemotherapy-associated cardiomyopathy. ACE-I,angiotensin-converting enzyme inhibitor; EKG, electrocardiography; LVEF, left ventricular ejection fraction; MUGA, multiple-gatedacquisition scan.
848 Journal of Cardiac Failure Vol. 20 No. 11 November 2014
studies were adults with advanced breast cancer treatedwith either doxorubicin or epirubicin, and treatment withdexrazoxane significantly reduced the incidence of heartfailure (RR 0.29, 95% CI 0.20e0.41; P ! .00001).Although there have been some concerns that dexrazoxanemay compromise tumor response to chemotherapy,87 thismeta-analysis showed no significant difference in tumorresponse rate, progression-free survival, overall survival,adverse effects, or secondary malignant disease with dexra-zoxane treatment.
The American Society of Clinical Oncology (ASCO)published guidelines in 2008 for the use of dexrazoxanein patients with breast cancer and other malignancies andrecommended the following.88 (1) Dexrazoxane should beconsidered for patients with metastatic breast cancer orother malignancies who have received O300 mg/m2 doxo-rubicin in the metastatic setting and who may benefit fromcontinued doxorubicin therapy. (2) Dexrazoxane can beconsidered for patients with non-breast malignancies whohave received $300 mg/m2 of doxorubicin-based therapy.Caution should be exercised in settings wheredoxorubicin-based therapy has been shown to improve sur-vival. (3) The use of dexrazoxane in the adjuvant setting isnot recommended outside of a clinical trial. (4) There isinsufficient evidence to support routine use of dexrazoxaneamong patients with cardiac risk factors or underlyingstructural heart disease. Despite the current ASCO guide-lines, dexrazoxane is not routinely used in clinical practiceowing to continued concern regarding its interference withconventional cancer treatment. Several clinical trials are
currently underway to evaluate the efficacy of dexrazoxanein other cancer patient populations.
Prophylaxis With Cardioprotective Medications
One of the first clinical trials to investigate the role ofcardioprotective medical therapy in preventing cardiotoxic-ity was performed by Kalay et al.89 In that small study, 50patients with planned anthracycline treatment (doxorubicinor epirubicin) were randomized to 12.5 mg carvedilol oncedaily versus placebo. LV systolic and diastolic function wasevaluated with the use of echocardiography before and afterexposure to anthracycline treatment. At 6-month follow-up,patients in the control group had a significantly lower LVEFand larger LV systolic and diastolic dimensions comparedwith the carvedilol group. A retrospective study by Seiceanet al also showed that beta-blocker use was associated witha lower incidence of heart failure among patients withbreast cancer receiving anthracycline and trastuzumab ther-apy.90 One of the proposed mechanisms for the protectiveeffect of carvedilol is its ability to reduce free oxygen rad-icals, which have been implicated in the pathogenesis ofanthracycline-mediated toxicity.91 More recently, a studyby Zhang et al showed that topoisomerase-II-beta playsan important role in the pathogenesis of doxorubicin-induced cardiotoxicity through the mediation of structuraland functional changes in mitochondria of cardiomyocytesas well as generation of reactive oxygen species.3
The role of angiotensin antagonists for the prevention ofcardiotoxicity was investigated in a randomized trial by
Cardiomyopathy Associated With Cancer Therapy � Yu et al 849
Cardinale et al.92 Among patients with elevated TnI(O0.07 ng/mL) after high-dose chemotherapy, early treat-ment with 20 mg enalapril daily, started 1 month afterchemotherapy and continued for 1 year, prevented thedevelopment of cardiotoxicity (defined as an absolutedecrease in LVEF of O10% to !50%). Although themechanism by which enalapril prevents cardiotoxicity re-mains unclear, it is postulated that ACE-Is block cardiac-associated renin-angiotensin system activity, reduce LVremodeling, and decrease oxidative stress. This was the firststudy to implement a prophylactic cardioprotective strategyamong patients at high risk of cardiotoxicity with the use ofa biomarker-directed approach. The Prevention of Left Ven-tricular Dysfunction During Chemotherapy (OVERCOME)study recently evaluated the effects of combined enalapriland carvedilol in patients with hematologic malignanciestreated with intensive chemotherapy and found that LVEFdid not change in the enalapril and carvedilol group butsignificantly decreased in those treated with placebo(P 5 .04).93 These results show that the combination ofenalapril and carvedilol may be effective in preventingLV dysfunction during intensive chemotherapy and couldhave important clinical implications.Statins, well known for the protective effects in patients
treated for coronary artery disease, also have been investi-gated for their potential to attenuate cardiotoxicity. Riadet al showed that mice pretreated with fluvastatin showedimproved LV function compared with untreated mice afterexposure to doxorubicin.94 Observational data from Sei-cean et al also showed that statin therapy appears to beassociated with a reduced risk of heart failure andcardiac-related mortality among breast cancer patientstreated with anthracycline,95 but prospective clinical trialsare needed to further evaluate any association betweenstatin therapy and risk of cardiotoxicity.Several clinical trials are currently underway to further
investigate the efficacy of prophylactic cardioprotectivemedications among patients treated with cardiotoxicchemotherapy. The Multidisciplinary Approach to NovelTherapies in Cardiology Oncology Research Trial(MANTICORE 101-Breast) is a randomized trial amongHER2þ early breast cancer patients to determine if peri-ndopril or bisoprolol therapy can prevent trastuzumab-associated LV remodeling as measured by LV volumeindices with the use of cardiac MRI.96 A similar trial spon-sored by the National Cancer Institute is studying the effectof lisinopril and carvedilol on trastuzumab-induced cardio-toxicity as measured by LVEF (clinicaltrials.gov no.NCT01009918).
Exercise Training
Aerobic exercise training has been proposed as a non-pharmacologic therapy that may attenuate the deleteriouseffects of heart failure.97,98 It has been shown to correctendothelial dysfunction by both improving nitric oxide(NO) formation and endothelium-dependent vasodilation
of the skeletal muscle vasculature,99 improve cardiac andskeletal muscle energy metabolism and function,100 andimprove diastolic filling and increase stroke volume.101
All of these adaptations lead to an improvement in systolicand diastolic function with augmentation of cardiac outputand increase in maximal oxygen uptake (VO2max), resultingin improved exercise tolerance and decreased fatigability inheart failure.102 Several animal studies have investigatedthe effects of aerobic exercise training before and duringdoxorubicin therapy and shown that exercise preventsdoxorubicin-induced impairments in LV function.103,104
Exercise training represents a promising strategy for pre-vention and/or treatment of chemotherapy-associated car-diomyopathy, but additional studies are required to betterunderstand the mechanism of this benefit and to informfuture recommendations for exercise training among cancerpatients.
Conclusion
Given the potential interaction between cancer therapyand the cardiovascular system, cardiologists and oncolo-gists must collaborate to ensure the best long-term clinicaloutcome for cancer patients. Newer targeted therapies arechanging the landscape of cancer care, and the impact ofcardiotoxicity on overall morbidity and mortality will in-crease as cancer outcomes improve. Future diagnostic stra-tegies will likely incorporate the use of novel imagingtechniques (eg, speckle-tracking strain or cardiac MRI)and biomarker testing to identify patients with early or sub-clinical signs of cardiotoxicity. Translational studies areneeded to better understand the mechanism in which cardi-otoxic agents cause myocardial injury, and this may help toinform the design of future trials investigating the use ofcardioprotective medications for the prevention ofchemotherapy-associated cardiomyopathy. A continuedinterdisciplinary cardio-oncology approach is critical tomaintain a balance between the oncologic benefit of cancertreatment and its associated cardiac toxicities.
Disclosures
None.
References
1. Siegel R, Naishadham D, Jemal A. Cancer statistics, 2012. CA Can-
cer J Clin 2012;62:10e29.
2. Yeh ET, Bickford CL. Cardiovascular complications of cancer ther-
apy: incidence, pathogenesis, diagnosis, and management. J Am
Coll Cardiol 2009;53:2231e47.
3. Zhang S, Liu X, Bawa-Khalfe T, Lu LS, Lyu YL, Liu LF, et al. Iden-
tification of the molecular basis of doxorubicin-induced cardiotoxic-
ity. Nat Med 2012;18:1639e42.
4. Harris L, Batist G, Belt R, Rovira D, Navari R, Azarnia N, et al.
Liposome-encapsulated doxorubicin compared with conventional