Long-term cardiovascular toxicity in children, adolescents, and young adults who receive cancer therapy: pathophysiology, course, monitoring, management, prevention, and research directions: a scientific statement from the American Heart Association

Evaluation, prevention and management of cancer therapy-induced cardiotoxicity: a contemporary approach for clinicians

PURPOSE OF REVIEW

While targeted therapies have improved cancer outcomes, unique cardiovascular toxicities are increasingly recognized, particularly when administered sequentially after anthracyclines or radiation. Patients with cancer therapy-induced cardiotoxicity benefit from collaborative care involving cardiology and oncology, leading to a new interdisciplinary field called cardio-oncology. The present review will highlight contemporary clinical issues in cardio-oncology.

RECENT FINDINGS

Recently, risk factors for cancer therapy-induced cardiotoxicity have been evaluated in real-world rather than in clinical trial patients. Biomarkers and advanced echocardiography are emerging as sensitive tools for preclinical identification of cancer therapy-induced cardiotoxicity. Single-center studies suggest that cancer therapy-induced cardiotoxicity responds to prompt heart failure medical treatment, and such therapy may even prevent cardiotoxicity.

SUMMARY

Modern cancer therapy has short-term cardiac risk that may require collaborative management by clinicians with expertise in cardiology and oncology. The increased effectiveness of modern cancer therapy is resulting in a growing population of cancer survivors who are at long-term risk for cardiovascular disease. The present review of contemporary clinical issues in cardio-oncology will be of interest to healthcare providers who manage cardiotoxicity during cancer therapy, and who follow patients who survive cancer but face increased long-term cardiovascular risk.

Individual prediction of heart failure among childhood cancer survivors

PURPOSE

To create clinically useful models that incorporate readily available demographic and cancer treatment characteristics to predict individual risk of heart failure among 5-year survivors of childhood cancer.

PATIENTS AND METHODS

Survivors in the Childhood Cancer Survivor Study (CCSS) free of significant cardiovascular disease 5 years after cancer diagnosis (n = 13,060) were observed through age 40 years for the development of heart failure (ie, requiring medications or heart transplantation or leading to death). Siblings (n = 4,023) established the baseline population risk. An additional 3,421 survivors from Emma Children's Hospital (Amsterdam, the Netherlands), the National Wilms Tumor Study, and the St Jude Lifetime Cohort Study were used to validate the CCSS prediction models.

RESULTS

Heart failure occurred in 285 CCSS participants. Risk scores based on selected exposures (sex, age at cancer diagnosis, and anthracycline and chest radiotherapy doses) achieved an area under the curve of 0.74 and concordance statistic of 0.76 at or through age 40 years. Validation cohort estimates ranged from 0.68 to 0.82. Risk scores were collapsed to form statistically distinct low-, moderate-, and high-risk groups, corresponding to cumulative incidences of heart failure at age 40 years of 0.5% (95% CI, 0.2% to 0.8%), 2.4% (95% CI, 1.8% to 3.0%), and 11.7% (95% CI, 8.8% to 14.5%), respectively. In comparison, siblings had a cumulative incidence of 0.3% (95% CI, 0.1% to 0.5%).

CONCLUSION

Using information available to clinicians soon after completion of childhood cancer therapy, individual risk for subsequent heart failure can be predicted with reasonable accuracy and discrimination. These validated models provide a framework on which to base future screening strategies and interventions.

Cardiovascular prevention in the cancer survivor

Cancer survivorship should be defined starting not from completion of treatment, but from the time of diagnosis. Assessing and controlling the cancer patient's cardiovascular risk before, during, and after treatment is crucial to improving their overall outcome. There are many cancer therapies, including but not limited to anthracyclines, radiation, and vascular signaling pathway inhibitors which should be considered nontraditional cardiovascular risk factors with significant morbidity. Monitoring novel populations, such as a younger age group, for ischemic coronary disease or congestive heart failure (CHF) is not intuitive to many clinicians. Symptoms of CHF and coronary artery disease overlap with common side effects of cancer and cancer treatment. Cancer survivors may also have fewer typical symptoms of cardiovascular disease. Increased surveillance and aggressive control of cardiovascular disease is important in cancer patients both while undergoing active treatment and in the long term. Despite the increasing interest in cardio-oncology, data-driven guidelines are lacking due to small study sizes and low event rates over a short period of time. Most practice guidelines have been based on clinical practice and expert opinion. The list of cardiotoxic cancer therapies continues to grow each year. This review is not intended to be a comprehensive review of all cancer therapy toxicity, but will focus on recent literature regarding prevention of CHF and coronary artery disease (CAD) during active cancer therapy as well as current screening guidelines for long-term survivors.

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.

Role of echocardiography in the management of cardiac disease in women

The widespread use of echocardiography has contributed to the early recognition of several distinct cardiac diseases in women. During pregnancy, safe monitoring of the disease process, as well as a better understanding of hemodynamics, is possible. During the use of potentially cardiotoxic drugs for breast cancer chemotherapy, echocardiographic patient monitoring is vital. Compared to men, the addition of an imaging modality to routine electrocardiogram monitoring during stress testing is more informative for diagnosing coronary disease in women. This review briefly discusses the role of echocardiography in the management of several women-specific cardiac diseases where echocardiography plays a pivotal role in disease management.

Impact of Cancer Therapy-Related Exposures on Late Mortality in Childhood Cancer Survivors

Survival of children and adolescents diagnosed with cancer has improved dramatically in recent decades, but the substantial burden of late morbidity and mortality (i.e., more than 5 years after cancer diagnosis) associated with pediatric cancer treatments is increasingly being recognized. Progression or recurrence of the initial cancer is a primary cause of death in the initial postdiagnosis period, but as survivors age, there is a dramatic shift in the cause-specific mortality profile. By 15 years postdiagnosis, the death rate attributable to health-related causes other than recurrence or external causes (e.g., accidents, suicide, assault) exceeds that due to primary disease, and by 30 years, these causes account for the largest proportion of cumulative mortality. The two most prominent causes of treatment-related mortality in childhood cancer survivors are subsequent malignant neoplasms and cardiovascular problems, the incidence of which can be largely attributed to the long-term toxicities of radiation and chemotherapy exposures. These late effects of treatment are likely to increase in importance as survivors continue to age, inspiring continued research to better understand their etiology and to inform early detection or prevention efforts.

Increasing cardiomyopathy screening in at-risk adult survivors of pediatric malignancies: a randomized controlled trial

PURPOSE

To determine whether the addition of advanced-practice nurse (APN) telephone counseling to a printed survivorship care plan (SCP) significantly increases the proportion of at-risk survivors who complete cardiomyopathy screening.

PATIENTS AND METHODS

Survivors age ≥ 25 years participating in the Childhood Cancer Survivor Study who received cardiotoxic therapy and reported no history of cardiomyopathy screening in the previous 5 years were eligible for enrollment. The 472 participants (mean age, 40.1 years; range, 25.0 to 59.0; 53.3% women) were randomly assigned to either standard care, consisting of an SCP summarizing cancer treatment and cardiac health screening recommendations (n = 234), or standard care plus two APN telephone counseling sessions (n = 238). The primary outcome-completion of cardiomyopathy screening within 1 year-was validated by medical records and compared between the two arms using adjusted relative risks (RRs) with 95% CIs.

RESULTS

Participants in the standard and APN counseling groups were not statistically different by demographic or clinical characteristics. At the time of 1-year follow-up, 107 (52.2%) of 205 survivors in the APN group completed screening compared with 46 (22.3%) of 206 survivors in the non-APN group (P < .001). With adjustment for sex, age (< 30 v ≥ 30 years), and Children's Oncology Group-recommended screening frequency group (annual, 2 years, or 5 years), survivors in the APN group were > 2× more likely than those in the control group to complete the recommended cardiomyopathy screening (RR, 2.31; 95% CI, 1.74 to 3.07).

CONCLUSION

The addition of telephone counseling to an SCP with cardiac health screening recommendations increases cardiomyopathy screening in at-risk survivors.

Exercise and risk of major cardiovascular events in adult survivors of childhood hodgkin lymphoma: a report from the childhood cancer survivor study

PURPOSE

Survivors of Hodgkin lymphoma (HL) are at increased risk of treatment-related cardiovascular (CV) events; whether exercise modifies this risk is unknown.

METHODS

Survivors of HL (n = 1,187; median age, 31.2 years) completed a questionnaire evaluating vigorous-intensity exercise behavior. CV events were collected in follow-up questionnaires and graded according to Common Terminology Criteria for Adverse Events (version 4.03). The primary end point was incidence of any major (grade 3 to 5) CV event. Poisson regression analyses were used to estimate the association between exercise exposure (metabolic equivalent [MET] hours/week(-1)) and risk of major CV events after adjustment for clinical covariates and cancer treatment.

RESULTS

Median follow-up was 11.9 years (range, 1.7 to 14.3 years). Cumulative incidence of any CV event was 12.2% at 10 years for survivors reporting 0 MET hours/week(-1) compared with 5.2% for those reporting ≥ 9 MET hours/week(-1). In multivariable analyses, the incidence of any CV event decreased across increasing MET categories (Ptrend = .002). Compared with survivors reporting 0 MET hours/week(-1), the adjusted rate ratio for any CV event was 0.87 (95% CI, 0.56 to 1.34) for 3 to 6 MET hours/week(-1), 0.45 (95% CI, 0.26 to 0.80) for 9 to 12 MET hours/week(-1), and 0.47 (95% CI, 0.23 to 0.95) for 15 to 21 MET hours/week(-1). Adherence to national vigorous intensity exercise guidelines (ie, ≥ 9 MET hours/week(-1)) was associated with a 51% reduction in the risk of any CV event in comparison with not meeting the guidelines (P = .002).

CONCLUSION

Vigorous exercise was associated with a lower risk of CV events in a dose-dependent manner independent of CV risk profile and treatment in survivors of HL.

Managing chemotherapy-related cardiotoxicity in survivors of childhood cancers

In the US, children diagnosed with cancer are living longer, but not without consequences from the same drugs that cured their cancer. In these patients, cardiovascular disease is the leading cause of non-cancer-related morbidity and mortality. Although this review focuses on anthracycline-related cardiomyopathy in childhood cancer survivors, the global lifetime risk of other cardiovascular diseases such as atherosclerosis, arrhythmias and intracardiac conduction abnormalities, hypertension, and stroke also are increased. Besides anthracyclines, newer molecularly targeted agents, such as vascular endothelial growth factor receptor and tyrosine kinase inhibitors, also have been associated with acute hypertension, cardiomyopathy, and increased risk of ischemic cardiac events and arrhythmias, and are summarized here. This review also covers other risk factors for chemotherapy-related cardiotoxicity (including both modifiable and non-modifiable factors), monitoring strategies (including both blood and imaging-based biomarkers) during and following cancer treatment, and discusses the management of cardiotoxicity (including prevention strategies such as cardioprotection by use of dexrazoxane).

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.

Cancer treatment-related cardiotoxicity: current state of knowledge and future research priorities

Cardiotoxicity resulting from direct myocyte damage has been a known complication of cancer treatment for decades. More recently, the emergence of hypertension as a clinically significant side effect of several new agents has been recognized as adversely affecting cancer treatment outcomes. With cancer patients living longer, in part because of treatment advances, these adverse events have become increasingly important to address. However, little is known about the cardiovascular pathogenic mechanisms associated with cancer treatment and even less about how to optimally prevent and manage short- and long-term cardiovascular complications, leading to improved patient safety and clinical outcomes. To identify research priorities, allocate resources, and establish infrastructure required to address cardiotoxicity associated with cancer treatment, the National Cancer Institute (NCI) and National Heart, Lung and Blood Institute (NHLBI) sponsored a two-day workshop, "Cancer treatment-related cardiotoxicity: Understanding the current state of knowledge and future research priorities," in March 2013 in Bethesda, MD. Participants included leading oncology and cardiology researchers and health professionals, patient advocates and industry representatives, with expertise ranging from basic to clinical science. Attendees were charged with identifying research opportunities to advance the understanding of cancer treatment-related cardiotoxicity across basic and clinical science. This commentary highlights the key discussion points and overarching recommendations from that workshop.

Can short-term fasting protect against doxorubicin-induced cardiotoxicity?

Doxorubicin (Dox) is one of the most effective chemotherapeutic agents used in the treatment of several types of cancer. However the use is limited by cardiotoxicity. Despite extensive investigation into the mechanisms of toxicity and preventative strategies, Dox-induced cardiotoxicity still remains a major cause of morbidity and mortality in cancer survivors. Thus, continued research into preventative strategies is vital. Short-term fasting has proven to be cardioprotective against a variety of insults. Despite the potential, only a few studies have been conducted investigating its ability to prevent Dox-induced cardiotoxicity. However, all show proof-of-principle that short-term fasting is cardioprotective against Dox. Fasting affects a plethora of cellular processes making it difficult to discern the mechanism(s) translating fasting to cardioprotection, but may involve suppression of insulin and insulin-like growth factor-1 signaling with stimulated autophagy. It is likely that additional mechanisms also contribute. Importantly, the literature suggests that fasting may enhance the antitumor activity of Dox. Thus, fasting is a regimen that warrants further investigation as a potential strategy to prevent Dox-induced cardiotoxicity. Future research should aim to determine the optimal regimen of fasting, confirmation that this regimen does not interfere with the antitumor properties of Dox, as well as the underlying mechanisms exerting the cardioprotective effects.

Pre-existing arterial hypertension as a risk factor for early left ventricular systolic dysfunction following (R)-CHOP chemotherapy in patients with lymphoma

Experimental studies in animals suggest that arterial hypertension may be a specific risk factor predisposing to anthracycline cardiotoxicity. The aim was determination of the effect of pre-existing arterial hypertension on the development of early left ventricular systolic dysfunction (LVSD) directly after rituximab, cyclophosphamide, doxorubicin, vincristin, prednisone ([R]-CHOP) chemotherapy in patients with lymphomas.The study included 208 patients with non-Hodgkin's lymphoma receiving conventional doxorubicin. LVSD was defined as a decrease of left ventricular ejection fraction below 50% and at least by 10 percentage points from baseline value. Patients with pre-existing hypertension more frequently developed new LVSD (19.7% vs. 6.6%; P = .004), pitting edema of the ankles (23.9% vs. 9.5%; P = .005), and nycturia (21.1% vs. 7.3%; P = .004) compared with patients without hypertension. As a consequence, the hypertension subgroup suffered from more delays of subsequent chemotherapy cycles (26.8% vs. 14.6%; P = .03), more reductions of doxorubicin doses (18.3% vs. 8.8%; P = .05), and premature discontinuations of chemotherapy (16.9% vs. 7.3%; P = .03). On logistic regression analyses, hypertension was one of the most important risk factors for developing new LVSD after (R)-CHOP chemotherapy.Arterial hypertension confers a significant risk of early LVSD in lymphoma patients treated with (R)-CHOP chemotherapy, interfering with its recommended schedule of administration.

Left ventricular function in long-term survivors of childhood lymphoma

Survivors of childhood lymphoma (CL) have markedly increased risk of developing heart failure. Echocardiographic studies after cardiotoxic treatment have primarily demonstrated left ventricular (LV) systolic dysfunction. In the present study, we hypothesized that longer follow-up and a more comprehensive echocardiographic examination would reveal more cardiac abnormalities. We conducted a cross-sectional study with echocardiography 20.4 ± 8.6 years after diagnosis in 125 survivors of CL, grouped according to treatment methods, and compared with matched controls. Treatment included mediastinal radiotherapy (median 40.0 Gy) in 66 and anthracyclines (median dose 160 mg/m(2)) in 92 survivors of CL. Abnormal LV function, left-sided valve dysfunction, or both occurred in 62 patients (50%). Diastolic dysfunction occurred in 29%. Compared with control subjects, mitral annular early diastolic velocities (e') were reduced in patients (septal e' 0.09 ± 0.03 vs 0.12 ± 0.03 m/s, p <0.001), and the E/e' ratio was increased, particularly after mediastinal radiotherapy (10.6 ± 6.4 vs 5.6 ± 1.3, p <0.001). Survivors of CL had lower fractional shortening than control subjects (32 ± 6 vs 36 ± 7, p <0.001), but mean ejection fraction was equal and overt systolic dysfunction was infrequent. After mediastinal radiotherapy alone, global longitudinal myocardial strain was lower (p <0.05) compared with other treatment groups. Left-sided valvular dysfunction occurred in 55% of patients after mediastinal radiotherapy. In conclusion, survivors of CL had reduced LV diastolic function assessed by tissue Doppler imaging. This was more pronounced after mediastinal radiotherapy, which also frequently led to valvular disease. Systolic function was normal in most survivors of CL.

Noninvasive imaging of cardiovascular injury related to the treatment of cancer

The introduction of multiple treatments for cancer, including chemotherapeutic agents and radiation therapy, has significantly reduced cancer-related morbidity and mortality. However, these therapies can promote a variety of toxicities, among the most severe being the ones involving the cardiovascular system. Currently, for many surviving cancer patients, cardiovascular (CV) events represent the primary cause of morbidity and mortality. Recent data suggest that CV injury occurs early during cancer treatment, creating a substrate for subsequent cardiovascular events. Researchers have investigated the utility of noninvasive imaging strategies to detect the presence of CV injury during and after completion of cancer treatment because it starts early during cancer therapy, often preceding the development of chemotherapy or cancer therapeutics related cardiac dysfunction. In this State-of-the-Art Paper, we review the utility of current clinical and investigative CV noninvasive modalities for the identification and characterization of cancer treatment-related CV toxicity.

Risks and diagnosis of coronary artery disease in Hodgkin lymphoma survivors

Higher mortality rates are reported because of cardiovascular diseases in individuals living in industrialized areas of the World. In cancer patients, cardiotoxic chemotherapeutic agents and/or mediastinal radiotherapy are additional risk factors for the development of coronary artery disease. An improved survival rate for patients with Hodgkin lymphoma was reported in recent decades. Determining and handling the long-term effects of cancer treatment have become more important nowadays, parallel to the good results reached in survival rates. Mediastinal radiotherapy and cardiotoxic chemotherapeutic agents are routinely used to treat Hodgkin lymphoma but are commonly associated with a variety of cardiovascular complications. Drugs used in cancer treatment and radiotherapy may cause deleterious effects on contractile capacity and conduction system of the heart. Approximately ten years after the completion of all therapies, the cardiovascular disease risk peaks in patients who survived from Hodgkin lymphoma. The value of coronary computed tomography angiography as a diagnostic tool in determining coronary artery disease as early as possible is underlined in this review, in patients who are in remission and carry the risk of coronary artery disease probably because of chemo/radiotherapy used in their treatment. Survivors of Hodgkin lymphoma especially treated with combined chemoradiotherapy at younger ages are candidates for coronary computed tomography angiography.

Screening for cardiac dysfunction in anthracycline-exposed childhood cancer survivors

PURPOSE

To examine the utility and reliability of obtaining early echocardiographic measurements of left ventricular (LV) remodeling as well as blood biomarkers of cardiac injury in asymptomatic childhood cancer survivors at risk for LV dysfunction and congestive heart failure due to past exposure to anthracycline chemotherapy.

EXPERIMENTAL DESIGN

Using a cross-sectional design, anthracycline-exposed childhood cancer survivors with preserved ejection fraction (EF; ≥50%) were evaluated using early echocardiographic indices and blood biomarkers of LV dysfunction. Survivors treated with ≥300 mg/m(2) anthracyclines [high risk (HR): n = 100] were compared with those treated with <300 mg/m(2) anthracyclines [low risk (LR): n = 50] and matched healthy controls (HC: n = 50). All echocardiograms were interpreted by an institutional cardiologist and a study cardiologist blinded to risk status.

RESULTS

Time from diagnosis was comparable for HR (12.0 years) and LR (13.2 years, P = 0.8) survivors. Echocardiograms: HR had lower LV thickness-dimension ratio (Z-score: HR: -0.62, LR: -0.03, HC: -0.02; P < 0.001), increased LV wall stress (HR: 66.7 g/cm(2), LR: 56.6 g/cm(2), HC: 54.2 g/cm(2); P < 0.01), and higher myocardial performance index (HR: 0.51, LR: 0.46, HC: 0.46; P < 0.01). Interobserver correlation (clinical/blinded reading) for all echocardiographic indices was excellent (range: R = 0.76-0.97, P < 0.001). Blood biomarkers: With the exception of NT-proBNP (r = 0.28, P < 0.01), there was no correlation between blood biomarkers (B-type natriuretic peptide, Troponin-T, ST-2, Galectin-3) and LV dysfunction.

CONCLUSION

Childhood cancer survivors with preserved EF 10+ years from anthracycline exposure had dose-dependent changes in echocardiographic markers of LV dysfunction.

Cost-effectiveness of the children's oncology group long-term follow-up screening guidelines for childhood cancer survivors at risk for treatment-related heart failure

BACKGROUND

Childhood cancer survivors treated with anthracyclines are at high risk for asymptomatic left ventricular dysfunction (ALVD), subsequent heart failure, and death. The consensus-based Children's Oncology Group (COG) Long-Term Follow-up Guidelines recommend lifetime echocardiographic screening for ALVD.

OBJECTIVE

To evaluate the efficacy and cost-effectiveness of the COG guidelines and to identify more cost-effective screening strategies.

DESIGN

Simulation of life histories using Markov health states.

DATA SOURCES

Childhood Cancer Survivor Study; published literature.

TARGET POPULATION

Childhood cancer survivors.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Echocardiographic screening followed by angiotensin-converting enzyme (ACE) inhibitor and β-blocker therapies after ALVD diagnosis.

OUTCOME MEASURES

Quality-adjusted life-years (QALYs), costs, incremental cost-effectiveness ratios (ICERs) in dollars per QALY, and cumulative incidence of heart failure.

RESULTS OF BASE-CASE ANALYSIS

The COG guidelines versus no screening have an ICER of $61 500, extend life expectancy by 6 months and QALYs by 1.6 months, and reduce the cumulative incidence of heart failure by 18% at 30 years after cancer diagnosis. However, less frequent screenings are more cost-effective than the guidelines and maintain 80% of the health benefits.

RESULTS OF SENSITIVITY ANALYSIS

The ICER was most sensitive to the magnitude of ALVD treatment efficacy; higher treatment efficacy resulted in lower ICER.

LIMITATION

Lifetime non-heart failure mortality and the cumulative incidence of heart failure more than 20 years after diagnosis were extrapolated; the efficacy of ACE inhibitor and β-blocker therapy in childhood cancer survivors with ALVD is undetermined (or unknown).

CONCLUSION

The COG guidelines could reduce the risk for heart failure in survivors at less than $100 000/QALY. Less frequent screening achieves most of the benefits and would be more cost-effective than the COG guidelines.

Routine echocardiography screening for asymptomatic left ventricular dysfunction in childhood cancer survivors: a model-based estimation of the clinical and economic effects

BACKGROUND

Childhood cancer survivors treated with cardiotoxic therapies are recommended to have routine cardiac assessment every 1 to 5 years, but the long-term benefits are uncertain.

OBJECTIVE

To estimate the cost-effectiveness of routine cardiac assessment to detect asymptomatic left ventricular dysfunction and of angiotensin-converting enzyme inhibitor and β-blocker treatment to reduce congestive heart failure (CHF) incidence in childhood cancer survivors.

DESIGN

Simulation model.

DATA SOURCES

Literature, including data from the Childhood Cancer Survivor Study.

TARGET POPULATION

Childhood cancer survivors.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Interval-based echocardiography assessment every 1, 2, 5, or 10 years, with subsequent angiotensin-converting enzyme inhibitor or β-blocker treatment for patients with positive test results.

OUTCOME MEASURES

Lifetime risk for systolic CHF, lifetime costs, quality-adjusted life expectancy, and incremental cost-effectiveness ratios (ICERs).

RESULTS OF BASE-CASE ANALYSIS

The lifetime risk for systolic CHF among 5-year childhood cancer survivors aged 15 years was 18.8% without routine cardiac assessment (average age at onset, 58.8 years). Routine echocardiography reduced lifetime risk for CHF by 2.3% (with assessment every 10 years) to 8.7% (annual assessment). The ICER for assessment every 10 years was $111 600 per quality-adjusted life-year (QALY) compared with no assessment. Assessment every 5 years had an ICER of $117 900 per QALY, and ICERs for more frequent assessment exceeded $165 000 per QALY.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to treatment effectiveness, absolute excess risk for CHF, and asymptomatic left ventricular dysfunction asymptomatic period. The probability that assessment every 10 or 5 years was preferred at a $100 000-per-QALY threshold was 0.33 for the overall cohort.

LIMITATION

Treatment effectiveness was based on adult data.

CONCLUSION

Current recommendations for cardiac assessment may reduce CHF incidence, but less frequent assessment may be preferable.

Anthracycline-induced cardiotoxicity: a review of pathophysiology, diagnosis, and treatment

OPINION STATEMENT

Anthracyclines have been widely used in children and adults to treat hematologic malignancies, soft-tissue sarcomas, and solid tumors. However, anthracyclines come with both short- and long-term cardiotoxic effects, ranging from occult changes in myocardial structure and function to severe cardiomyopathy and heart failure that may result in cardiac transplantation or death. Here, we review the progress made over the past two decades in understanding the molecular and genetic basis of anthracycline-induced cardiotoxicity; detecting and monitoring myocardial dysfunction; using adjunct cardioprotectant therapies, such as dexrazoxane; and improving cardioprotection with agents such as liposomal and pegylated doxorubicin. Despite this increased understanding, preventing drug-induced cardiotoxicity while maintaining oncologic efficacy to achieve the highest quality of life over a lifespan remain cornerstones of successful anthracycline chemotherapy during childhood.

Carnitine and cardiac dysfunction in childhood cancer survivors treated with anthracyclines

Childhood cancer survivors are at high risk of developing congestive heart failure (CHF) compared with the general population, and there is a dose-dependent increase in CHF risk by anthracycline dose. The mechanism by which this occurs has not been fully elucidated. Metabolomics, the comprehensive profile of small-molecule metabolites, has the potential to provide insight into the pathogenesis of disease states and discover diagnostic markers for therapeutic targets. We performed echocardiographic testing and blood plasma metabolomic analyses (8 pathways; 354 metabolites) in 150 asymptomatic childhood cancer survivors previously treated with anthracyclines. Median time from cancer diagnosis to study participation was 12.4 years (2.6-37.9 years); 64% were treated for a hematologic malignancy; median anthracycline dose was 350 mg/m(2) (25-642 mg/m(2)). Thirty-five (23%) participants had cardiac dysfunction-defined as left ventricular end-systolic wall stress >2SD by echocardiogram. Plasma levels of 15 compounds in three metabolic pathways (carbohydrate, amino acid, and lipid metabolism) were significantly different between individuals with cardiac dysfunction and those with normal systolic function. After adjusting for multiple comparisons, individuals with cardiac dysfunction had significantly lower plasma carnitine levels [relative ratio (RR), 0.89; P < 0.01] in relation to those with normal systolic function. These findings may facilitate the development of primary prevention (treatment of carnitine deficiency before/during anthracycline administration) and secondary prevention strategies (screening and treatment in long-term survivors) in patients at highest risk for CHF. Cancer Epidemiol Biomarkers Prev; 23(6); 1109-14. ©2014 AACR.

Childhood and adolescent cancer statistics, 2014

In this article, the American Cancer Society provides estimates of the number of new cancer cases and deaths for children and adolescents in the United States and summarizes the most recent and comprehensive data on cancer incidence, mortality, and survival from the National Cancer Institute, the Centers for Disease Control and Prevention, and the North American Association of Central Cancer Registries (which are reported in detail for the first time here and include high-quality data from 45 states and the District of Columbia, covering 90% of the US population). In 2014, an estimated 15,780 new cases of cancer will be diagnosed and 1960 deaths from cancer will occur among children and adolescents aged birth to 19 years. The annual incidence rate of cancer in children and adolescents is 186.6 per 1 million children aged birth to 19 years. Approximately 1 in 285 children will be diagnosed with cancer before age 20 years, and approximately 1 in 530 young adults between the ages of 20 and 39 years is a childhood cancer survivor. It is therefore likely that most pediatric and primary care practices will be involved in the diagnosis, treatment, and follow-up of young patients and survivors. In addition to cancer statistics, this article will provide an overview of risk factors, symptoms, treatment, and long-term and late effects for common pediatric cancers.

Doxorubicin-induced carbonylation and degradation of cardiac myosin binding protein C promote cardiotoxicity

Dose-dependent oxidative stress by the anthracycline doxorubicin (Dox) and other chemotherapeutic agents causes irreversible cardiac damage, restricting their clinical effectiveness. We hypothesized that the resultant protein oxidation could be monitored and correlated with physiological functional impairment. We focused on protein carbonylation as an indicator of severe oxidative damage because it is irreversible and results in proteasomal degradation. We identified and investigated a specific high-molecular weight cardiac protein that showed a significant increase in carbonylation under Dox-induced cardiotoxic conditions in a spontaneously hypertensive rat model. We confirmed carbonylation and degradation of this protein under oxidative stress and prevention of such effect in the presence of the iron chelator dexrazoxane. Using MS, the Dox-induced carbonylated protein was identified as the 140-kDa cardiac myosin binding protein C (MyBPC). We confirmed the carbonylation and degradation of MyBPC using HL-1 cardiomyocytes and a purified recombinant untagged cardiac MyBPC under metal-catalyzed oxidative stress conditions. The carbonylation and degradation of MyBPC were time- and drug concentration-dependent. We demonstrated that carbonylated MyBPC undergoes proteasome-mediated degradation under Dox-induced oxidative stress. Cosedimentation, immunoprecipitation, and actin binding assays were used to study the functional consequences of carbonylated MyBPC. Carbonylation of MyBPC showed significant functional impairment associated with its actin binding properties. The dissociation constant of carbonylated recombinant MyBPC for actin was 7.35 ± 1.9 μM compared with 2.7 ± 0.6 μM for native MyBPC. Overall, our findings indicate that MyBPC carbonylation serves as a critical determinant of cardiotoxicity and could serve as a mechanistic indicator for Dox-induced cardiotoxicity.