Diagnostic and Therapeutic Approaches for Heart Failure in Long-Term Survivors of Childhood Cancer

The improvement in survival rates in pediatric malignancies has led to an increase in the number of cancer survivors who are at risk of developing cardiotoxicity and heart failure. Cardiac dysfunction in these patients can occur asymptomatically, and the diagnosis in a symptomatic phase is associated with reduced treatment response and worse prognosis. For this reason, it is essential to establish protocols to follow up on these patients and identify those at risk of cardiotoxicity in order to start early and effective therapies. This review aims to summarize the latest findings in the diagnosis and treatment of cancer therapy-related cardiac disease in long-term survivors of childhood cancer, with a focus on heart failure.

Effect of Radiotherapy on the Right Ventricular Function in Lung Cancer Patients

BACKGROUND

Anticancer treatment is associated with many side effects, including those involving the cardiovascular system. While many studies are available on the effects of radiotherapy (RT) on the left ventricle (LV), studies are lacking on the early effects of RT on the structure and function of the right ventricle (RV). Our study aims to assess, using modern echocardiographic techniques, the effect of irradiation on RV systolic function in the mid-term follow-up of patients undergoing RT for lung cancer (LC).

METHODS

This single-center, prospective study included consecutive patients with LC who were referred for treatment with definite radiotherapy and chemotherapy (study group) or chemotherapy only (control group).

RESULTS

The study included 43 patients with a mean age of 64.9 ± 8.1 years. Cancer treatment-related RV toxicity (CTR-RVT) was found in 17 patients (40%). Early reductions in TAPSE values were observed among patients in the study group (20.3 mm vs. 22.1 mm, p = 0.021). Compared to baseline, there was a significant reduction in RV global longitudinal strain (RV GLS) in the study group immediately after the treatment (-21.1% vs. -18.4%, p = 0.02) and also at 3 months after RT (-21.1% vs. -19.1%, p = 0.021). A significant reduction in the RV FWLS value was also observed at 3 months after the end of the treatment (-23.8% vs. -21.8, p = 0.046). There were no significant changes in the three-dimensional right ventricular ejection fraction (3DRVEF) during the follow-up. We found a correlation (p = 0.003) between the mean dose of radiation to the RV and 3DRVEF when assessed immediately after RT. The mean dose of radiation to the heart correlated with RV free-wall longitudinal strain (RV FWLS) immediately after RT (p = 0.03).

CONCLUSIONS

RV cardiotoxicity occurs in nearly half of patients treated for lung cancer. TAPSE is an important marker of deterioration of RV function under LC treatment. Compared to 3DRVEF, speckle tracking echocardiography is more useful in revealing deterioration of RV systolic function after radiotherapy.

Survivors of Pediatric Hematopoietic Stem Cell Transplantation Exhibit Progressive Diastolic Dysfunction Over Years of Follow-Up

Patients who have undergone hematopoietic stem cell transplantation (HSCT) in childhood have a higher risk of diastolic heart failure (HF). The rate of progression of diastolic dysfunction in aging pediatric patients is unknown and is more difficult to assess in young patients secondary to changes in diastolic indices as they grow. HSCT recipients at our center were previously found to have decline in diastolic function indices at 1 year after HSCT. This study provides follow-up of this cohort, using age-normalized z-scores to assess whether the decline in diastolic function noted at 1-year post-HSCT persists, worsens, or improves over time. Patients age <21 years who underwent HSCT at Boston Children's Hospital/Dana-Farber Cancer Center between 2005 and 2008 with ≥3 surveillance echocardiograms, including 1 performed pre-HSCT, were included. Diastolic measures included mitral inflow (E/A ratio) and Doppler tissue imaging of left ventricular lateral wall (LV lateral e'), LV septal wall (septal e') and right ventricular free wall (RV e'). Systolic function was measured by LV ejection fraction (LVEF). Normalization by age was done using z-scores, and >±2 SD was defined as abnormal in linear modeling of diastolic dysfunction and systolic dysfunction over time. In a subset of patients with adequate post-HSCT images of the entire left atrium (LA), LA volume and LA strain analyses also were performed. The study cohort comprised 61 patients (41% female; median age at HSCT, 10.7 years; median follow-up, 7.4 years). Diastolic index z-scores declined by -.045/year for LV lateral e', -.06/year for LV septal e', and -.14/year for RV e' (P < .01). The E/A ratio z-score increased by .034/year (P = .028). Linear modeling demonstrated that LV lateral e' and LV septal e' would become abnormal at 25 and 20 years post-HSCT, respectively, whereas RV e' would become abnormal sooner, at 12.6 years. LVEF z-score declined by -.04/year (P < .01) and was estimated to become abnormal at 40 years post-HSCT. Exposure to total body irradiation (TBI) was associated with worsening diastolic indices, lower LVEF (P ≤ .002), and decreased LA reservoir strain (42.0% versus 45.0%; P = .016) and conduit strain (-31.5% versus -35.1%; P = .029), although there was significant overlap between TBI and anthracycline exposure. Treatment with anthracyclines even at low doses (median, 150 mg/m2) was associated with declining LVEF but not with changes in diastolic indices. Long-term survivors of childhood HSCT exhibit declines in both LV and RV diastolic function indices. These results inform the rate of progression of LV and RV diastolic dysfunction indices over time in long-term survivors of pediatric HSCT. A significant association was observed between TBI and diastolic dysfunction and a decline in LVEF. Treatment with anthracyclines even at low doses was associated with a mild decline in LVEF. Our results can inform a lifespan perspective on disease management in this population, encourage clinicians and patients to be vigilant in following guideline-directed surveillance echocardiography, and inform anticipatory responses by clinicians as patients transition from pediatric care to adult care.

Right Ventricular Function in Long-Term Survivors of Childhood Acute Lymphoblastic Leukemia: From the CTOXALL Study

There are limited data regarding right ventricle (RV) impairment in long-term survivors of childhood acute lymphoblastic leukemia (CLS). The aim of this study was to assess RV function in these patients using echocardiographic conventional measurements and automated RV strain. Echocardiographic recordings of 90 CLS and 58 healthy siblings from the CTOXALL cohort were analyzed. For group comparisons, inverse probability weighting was used to reduce confounding. The CLS group (24.6 ± 9.7 years, 37.8% women) underwent an echocardiographic evaluation 18 (11-26) years after the diagnosis. RV systolic dysfunction was found in 16.7% of CLS individuals using RV free-wall strain (RVFWS) compared to 2.2 to 4.4% with conventional measurements. RV systolic function measurements were lower in the CLS than in the control group: TAPSE (23.3 ± 4.0 vs. 25.2 ± 3.4, p = 0.004) and RVFWS (24.9 ± 4.6 vs. 26.8 ± 4.7, p = 0.032). Modifiable cardiovascular risk factors such as obesity (p = 0.022) and smoking (p = 0.028) were independently associated with reduced RVFWS. In conclusion, RV systolic function impairment was frequent in long-term survivors of childhood leukemia, underscoring the importance of RV assessment, including RVFWS, in the cardiac surveillance of these patients.

Systolic myocardial function measured by echocardiographic speckle-tracking and peak oxygen consumption in pediatric childhood cancer survivors-a PACCS study

Background

Cancer therapy-related cardiotoxicity is a major cause of cardiovascular morbidity in childhood cancer survivors. The aims of this study were to investigate systolic myocardial function and its association to cardiorespiratory fitness in pediatric childhood cancer survivors.

Methods

In this sub-study of the international study "Physical Activity and fitness in Childhood Cancer Survivors" (PACCS), echocardiographic measures of left ventricular global longitudinal strain (LV-GLS) and right ventricular longitudinal strain (RV-LS) were measured in 128 childhood cancer survivors aged 9-18 years and in 23 age- and sex-matched controls. Cardiorespiratory fitness was measured as peak oxygen consumption achieved on treadmill and correlated to myocardial function.

Results

Mean LV-GLS was reduced in the childhood cancer survivors compared to the controls, -19.7% [95% confidence interval (CI) -20.1% to -19.3%] vs. -21.3% (95% CI: -22.2% to -20.3%) (p = 0.004), however, mainly within normal range. Only 13% of the childhood cancer survivors had reduced LV longitudinal strain z-score. Mean RV-LS was similar in the childhood cancer survivors and the controls, -23.2% (95% CI: -23.7% to -22.6%) vs. -23.3% (95% CI: -24.6% to -22.0%) (p = 0.8). In the childhood cancer survivors, lower myocardial function was associated with lower peak oxygen consumption [correlation coefficient (r) = -0.3 for LV-GLS]. Higher doses of anthracyclines (r = 0.5 for LV-GLS and 0.2 for RV-LS) and increasing time after treatment (r = 0.3 for LV-GLS and 0.2 for RV-LS) were associated with lower myocardial function.

Conclusions

Left ventricular function, but not right ventricular function, was reduced in pediatric childhood cancer survivors compared to controls, and a lower left ventricular myocardial function was associated with lower peak oxygen consumption. Furthermore, higher anthracycline doses and increasing time after treatment were associated with lower myocardial function, implying that long-term follow-up is important in this population at risk.

Cardiac Imaging in Childhood Cancer Survivors: A State-of-the-Art Review

Childhood cancer survival has improved significantly in the past few decades, reaching rates of 80% or more at 5 years. However, with improved survival, early- and late-occurring complications of chemotherapy and radiotherapy exposure are becoming progressively more evident. Cardiovascular diseases represent the leading cause of non-oncological morbidity and mortality in this highly vulnerable population. Therefore, the necessity of reliable, noninvasive screening tools able to early identify cardiac complications early is now pre-eminent in order to implement prevention strategies and mitigate disease progression. Echocardiography, may allow identification of myocardial dysfunction, pericardial complications, and valvular heart diseases. However, additional imaging modalities may be necessary in selected cases. This manuscript provides an in-depth review of noninvasive imaging parameters studied in childhood cancer survivors. Furthermore, we will illustrate brief surveillance recommendations according to available evidence and future perspectives in this expanding field.

Evaluation of Right Ventricular Function in Patients with Propionic Acidemia-A Cross-Sectional Study

(1) Background: In propionic acidemia (PA), myocardial involvement often leads to progressive cardiac dysfunction of the left ventricle (LV). Cardiomyopathy (CM) is an important contributor to mortality. Although known to be of prognostic value in CM, there are no published data on right ventricular (RV) function in PA patients. (2) Methods: In this cross-sectional single-center study, systolic and diastolic RV function of PA patients was assessed by echocardiography, including frequency, onset, and combinations of echocardiographic parameters, as well as correlations to LV size and function. (3) Results: N = 18 patients were enrolled. Tricuspid annulus S' was abnormal in 16.7%, RV-longitudinal strain in 11.1%, tricuspid annular plane systolic excursion (TAPSE) in 11.1%, Tricuspid valve (TV) E/e' in 33.3%, and TV E/A in 16.7%. The most prevalent combinations of pathological parameters were TV E/A + TV E/e' and TAPSE + TV S'. With age, the probability of developing abnormal RV function increases according to age-dependent normative data. There is a significant correlation between TAPSE and mitral annular plane systolic excursion (MAPSE), and RV/LV-longitudinal strain (p ≤ 0.05). N = 5 individuals died 1.94 years (mean) after cardiac evaluation for this study, and all had abnormal RV functional parameters. (4) Conclusions: Signs of diastolic RV dysfunction can be found in up to one third of individuals, and systolic RV dysfunction in 16.7% of individuals in our cohort. RV function is impaired in PA patients with a poor outcome. RV functional parameters should be used to complement clinical and left ventricular echocardiographic findings.

Right Ventricle and Radiotherapy: More Questions than Answers

The injury of the left ventricle (LV) during anticancer therapy has long been recognized, and guidelines recommend a specific set of parameters for determination of LV impairment. The influence of anticancer therapy on the right ventricle (RV) has been insufficiently investigated, and there are only a few studies that have considered the effect of radiotherapy on RV remodeling. On the other hand, large number of patients with different types of cancers located in the chest are treated with radiotherapy, and the negative clinical effects of this treatment such as accelerated coronary artery disease, valve degeneration and heart failure have been documented. The anatomical position of the RV, which is in the front of the chest, is responsible for its large exposure during radiation treatment, particularly in patients with left-sided breast and lung cancers and mediastinal cancers (hematological malignancies, esophagus cancers, thymomas, etc.). For the same reason, but also due to its anatomical complexity, the RV remains under-investigated during echocardiographic examination, which remains the cornerstone of cardiac imaging in everyday practice. In the last decade many new echocardiographic imaging techniques that enable better evaluation of RV structure, function and mechanics appeared, and they have been used in detection of early and late signs of RV injuries in oncological patients. These investigations are related to some important restrictions that include limited numbers of patients, used parameters and imaging techniques. Many questions about the potential impact of these changes and possible predictions of adverse events remain to be evaluated in future large longitudinal studies. The current body of evidence indicates an important role of radiotherapy in RV remodeling, and therefore, the aim of this review is to summarize currently available data regarding RV changes in patients with various oncological conditions and help clinicians in the assessment of possible cardiac damage.

Mitigating, monitoring, and managing long-term chemotherapy- and radiation-induced cardiac toxicity

Five-year survival for childhood cancer now exceeds 85%. However, for many patients, treatment requires the use of intensive anthracycline-based chemotherapy and radiotherapy, both of which are associated with significant long-term cardiovascular toxicity. As such, late cardiovascular disease is now one of the leading causes of premature morbidity and mortality among childhood cancer survivors. Recent advances over the past decade have refined the cardiotoxic potential of various chemotherapeutics, and ongoing work seeks to determine the efficacy of various cardioprotective strategies in children receiving active cancer therapy. The development of risk prediction models offers an additional strategy to define risk for both newly treated and long-term survivors. Current screening strategies are primarily based on echocardiography, although there is active research investigating methods to further optimize screening through myocardial strain, cardiac magnetic resonance imaging, blood biomarkers, and genetics, along with the cost-effectiveness of different screening strategies. Active research is also underway investigating the efficacy of prevention strategies for childhood cancer survivors who have completed cancer therapy. This ranges from the use of medications to mitigate potential pathologic ventricular remodeling to reducing adverse and modifiable cardiovascular risk factors (eg, hypertension, dyslipidemia, insulin resistance, physical inactivity, tobacco exposure), many of which may be more common in cancer survivors vs the general population and are often underrecognized and undertreated in relatively young adult-aged survivors of childhood cancer.

Assessment of Cardiovascular Function in Childhood Leukemia Survivors: The Role of the Right Heart

Childhood acute lymphoblastic leukemia (ALL) survivors who underwent chemotherapy with anthracyclines have an increased cardiovascular risk. The aim of the study was to evaluate left and right cardiac chamber performances and vascular endothelial function in childhood ALL survivors. Fifty-four ALL survivors and 37 healthy controls were enrolled. All patients underwent auxological evaluation, blood pressure measurements, biochemical parameters of endothelial dysfunction, flow-mediated dilatation (FMD) of the brachial artery, mean common carotid intima-media thickness (c-IMT), antero-posterior diameter of the infra-renal abdominal aorta (APAO), and echocardiographic assessment. The ALL subjects had significantly lower FMD (p = 0.0041), higher left (p = 0.0057) and right (p = 0.0021) echocardiographic/Doppler Tei index (the non-invasive index for combined systolic and diastolic ventricular function) as compared to controls. Tricuspid annular plane excursion (TAPSE) was 16.9 ± 1.2 mm vs. 24.5 ± 3.7 mm, p < 0.0001. Cumulative anthracycline doses were related to TAPSE (p < 0.001). The ALL survivors treated with anthracyclines demonstrated systo/diastolic alterations of the right ventricle and reduced endothelial function compared with healthy controls. The early recognition of subclinical cardiac and vascular impairment during follow up is of utmost importance for the cardiologist to implement strategies preventing overt cardiovascular disease considering the growing number of young adults cured after childhood ALL.

Radiotherapy-Induced Cardiotoxicity: The Role of Multimodality Cardiovascular Imaging

Radiotherapy (RT) is one of the pillars of cancer therapy. High-dose radiation exposure on the thorax is mainly used in the context of adjuvant RT after breast surgery, in lung and esophageal cancer, and as a complement to systemic treatment in lymphoma. Due to the anatomical proximity, the heart inevitably receives some radiation that can result in acute and chronic cardiotoxicity, leading to heart failure, coronary artery disease, pericardial and valvular heart disease. Current evidence suggests there is no safe radiation dose to the heart, which poses a need for early recognition of RT-induced cardiac injury to initiate cardioprotective treatment and prevent further damage. Multimodality cardiac imaging provides a powerful tool to screen for structural and functional abnormalities secondary to RT. Left ventricular ejection fraction, preferably with three-dimensional echocardiography or cardiovascular magnetic resonance (CMR), and global longitudinal strain with speckle-tracking echocardiography are currently the key parameters to detect cardiotoxicity. However, several novel imaging parameters are tested in the ongoing clinical trials. CMR parametric imaging holds much promise as T1, T2 mapping and extracellular volume quantification allow us to monitor edema, inflammation and fibrosis, which are fundamental processes in RT-induced cardiotoxicity. Moreover, the association between serum biomarkers, genetic polymorphisms and the risk of developing cardiovascular disease after chest RT has been demonstrated, providing a platform for an integrative screening approach for cardiotoxicity. The present review summarizes contemporary evidence of RT-induced cardiac injury obtained from multimodality imaging—echocardiography, cardiovascular computed tomography, CMR and nuclear cardiology. Moreover, it identifies gaps in our current knowledge and highlights future perspectives to screen for RT-induced cardiotoxicity.

Assessment of late cardiotoxic effects in patients treated for cancer in childhood

Graphical AbstractThe aim was to assess the late cardiotoxic effects in young adults treated for various cancer types in childhood using echocardiography and 24-h ECG Holter monitoring.

Myocardial Deformation Imaging by Speckle Tracking Echocardiography for Assessment of Cardiotoxicity in Children During and After Chemotherapy: A Systematic Review and Meta-analysis

BACKGROUND

Childhood cancer patients and childhood cancer survivors (CCS) are at risk of developing chemotherapy-induced cardiomyopathy. Myocardial deformation imaging has shown potential in the early detection of subclinical myocardial damage with implications on therapeutic interventions and improvement of outcomes. We aimed to perform a systemic review and meta-analysis of literature on the assessment of left (LV) and right ventricular (RV) myocardial deformation by speckle tracking echocardiography (STE) at rest and during stress in childhood cancer patients during and in survivors after chemotherapy.

METHODS

A systematic review was performed through searching MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, and Scopus. Search hedges were created to cover the concepts of childhood cancer, chemotherapy, radiotherapy, anthracycline, cardiotoxicity, speckle tracking, myocardial strain, and myocardial deformation. Two independent investigators reviewed the eligibility of the articles for inclusion. Weighted mean difference in ventricular strain between pre-and post-chemotherapy treatment and that between long-term CCS and healthy subjects were estimated by random-effect models with 95% confidence intervals. Heterogeneity and publication bias were assessed by I2 statistics and Egger test, respectively.

RESULTS

Of the total of 8703 records initially identified, 42 studies with a total of 430 childhood cancer patients were included. Of these 42 studies that showed heterogeneities, 9 assessed early myocardial injury during chemotherapy, 30 assessed late myocardial injury after chemotherapy with no publication bias, and 3 studied myocardial mechanics during stress. The main findings were 1) impairment of LV systolic deformation in childhood cancer patients during the initial treatment phase and among long-term CCS, while data on changes in RV deformation are limited and inconclusive, 2) the predictive value of early reduction of myocardial strain imaging in forecasting subsequent development of cardiotoxicity is unknown as it has not been studied, 3) limited data suggest possibility of impaired LV contractile mechanics during stress in CCS, and 4) cumulative anthracycline dose and chest-directed radiotherapy are consistently identified as factors associated with impaired myocardial deformation.results CONCLUSIONS: Myocardial strain imaging by STE unveils early evidence of myocardial injury in childhood cancer patients and long-term CCS. To support its adoption for clinical use, more data are required for the better understating of myocardial deformation parameters in the risk stratification of childhood cancer patients and prediction of development of cardiomyopathy among CCS.

Impaired right ventricular function in long-term survivors of allogeneic haematopoietic stem-cell transplantation

AIMS

Survivors of allogeneic haematopoietic stem-cell transplantation (allo-HSCT) are at higher risk of cardiovascular disease. We aimed to describe right ventricular (RV) systolic function and risk factors for RV dysfunction in long-term survivors of allo-HSCT performed in their youth.

METHODS AND RESULTS

This cohort included 103 survivors (53% female), aged (mean±SD) 17.6±9.5 years at allo-HSCT, with a follow-up time of 17.2±5.5 years. Anthracyclines were used as first-line therapy for 44.7% of the survivors. The RV was evaluated with echocardiography, and found survivors to have reduced RV function in comparison to a group of healthy control subjects: Tricuspid annular plane systolic excursion, (TAPSE, 20.8±3.7 mm vs 24.6±3.8 mm, p<0.001), RV peak systolic velocity (RV-s', 11.2±2.3 cm/s vs 12.3±2.3 cm/s, p=0.001), fractional area change (FAC, 41.0±5.2% vs 42.2±5.1%, p=0.047) and RV free-wall strain (RVFWS, -27.1±4.2% vs -28.5±3.3%, p=0.043). RV systolic dysfunction (RVSD) was diagnosed in 14 (13.6%), and was strongly associated with progressive left ventricular systolic dysfunction (LVSD). High dosages of anthracyclines were associated with greater reductions in RV and LV function. Multivariable linear regressions confirmed global longitudinal strain to be a significant independent predictor for reduced RV function.

CONCLUSION

Impaired RV function was found in long-term survivors of allo-HSCT who were treated in their youth. This was associated with progressive left ventricle dysfunction, and pretransplant therapies with anthracyclines. The occurrence of RVSD was less frequent and was milder than coexisting LVSD in this cohort.

The Utility of Advanced Cardiovascular Imaging in Cancer Patients-When, Why, How, and the Latest Developments

Cardio-oncology encompasses the risk stratification, prognostication, identification and management of cancer therapeutics related cardiac dysfunction (CTRCD). Cardiovascular imaging (CVI) plays a significant role in each of these scenarios and has broadened from predominantly quantifying left ventricular function (specifically ejection fraction) to the identification of earlier bio-signatures of CTRCD. Recent data also demonstrate the impact of chemotherapy on the right ventricle, left atrium and pericardium and highlight a possible role for CVI in the identification of CTRCD through tissue characterization and assessment of these cardiac chambers. This review aims to provide a contemporary perspective on the role of multi-modal advanced cardiac imaging in cardio-oncology.

Echocardiographic evaluation of patients undergoing cancer therapy

As advances in oncology therapies lead to significant improvement in life expectancy of many cancer entities, short-, and long-term cardiac side effects of oncology treatments gain increasing importance. In search of new screening modalities, echocardiography currently presents the best established and clinically easily feasible tool to detect cardiotoxicity in patients undergoing cancer therapy. This review focusses on the most commonly used oncology therapies and aims to give a practical approach to guide clinicians caring for this growing number of patients.

Long-term prognostic value of right ventricular dysfunction on cardiovascular magnetic resonance imaging in anthracycline-treated cancer survivors

AIMS

We aimed to determine the prevalence of right ventricular (RV) systolic dysfunction on cardiovascular magnetic resonance imaging (CMR) and its impact on long-term adverse outcomes in a large cohort of cancer survivors treated with anthracycline-based chemotherapy.

METHODS AND RESULTS

Consecutive cancer survivors treated with anthracyclines who underwent clinical CMR for suspected anthracycline-related cardiomyopathy were studied. The primary endpoint was a composite of all-cause death or major adverse cardiac events (MACE): heart failure hospitalization, heart transplantation, ventricular assist device implantation, resuscitated cardiac arrest, or life-threatening ventricular arrhythmia. The secondary endpoints were all-cause death, and cardiac death or MACE. Among 249 survivors who underwent CMR at a median of 2.9 years after cancer treatment, RV systolic dysfunction was present in 54 (21.7%). Of these, 50 (92.6%) had an abnormal left ventricular ejection fraction (LVEF). At a median follow-up time after the CMR of 2.7 years, 105 survivors experienced the primary endpoint. On Kaplan-Meier analyses, the cumulative incidence of the primary endpoint was significantly higher in survivors with abnormal RVEF compared with those with normal RVEF (P = 0.002). However, on Cox multivariable analyses, RVEF was not associated with the primary endpoint (HR 1.04 per 5% decrease; 95% CI 0.93-1.17; P = 0.46) after adjustment for non-imaging variables and LVEF. RVEF was also not associated with the secondary endpoints.

CONCLUSION

Among anthracycline-treated cancer survivors undergoing CMR for suspected cardiotoxicity, RV systolic dysfunction was present in one in five cases, accompanied by LV systolic dysfunction in nearly all cases, and was not independently associated with long-term outcomes.

All for one, though not one for all: team players in normal tissue radiobiology

PURPOSE

As part of the special issue on 'Women in Science', this review offers a perspective on past and ongoing work in the field of normal (non-cancer) tissue radiation biology, highlighting the work of many of the leading contributors to this field of research. We discuss some of the hypotheses that have guided investigations, with a focus on some of the critical organs considered dose-limiting with respect to radiation therapy, and speculate on where the field needs to go in the future.

CONCLUSIONS

The scope of work that makes up normal tissue radiation biology has and continues to play a pivotal role in the radiation sciences, ensuring the most effective application of radiation in imaging and therapy, as well as contributing to radiation protection efforts. However, despite the proven historical value of preclinical findings, recent decades have seen clinical practice move ahead with altered fractionation scheduling based on empirical observations, with little to no (or even negative) supporting scientific data. Given our current appreciation of the complexity of normal tissue radiation responses and their temporal variability, with tissue- and/or organ-specific mechanisms that include intra-, inter- and extracellular messaging, as well as contributions from systemic compartments, such as the immune system, the need to maintain a positive therapeutic ratio has never been more urgent. Importantly, mitigation and treatment strategies, whether for the clinic, emergency use following accidental or deliberate releases, or reducing occupational risk, will likely require multi-targeted approaches that involve both local and systemic intervention. From our personal perspective as five 'Women in Science', we would like to acknowledge and applaud the role that many female scientists have played in this field. We stand on the shoulders of those who have gone before, some of whom are fellow contributors to this special issue.

Right ventricular dysfunction in patients with diffuse large B-cell lymphoma undergoing anthracycline-based chemotherapy: a 2D strain and 3D echocardiography study

To investigate whether 2D strain and 3D echocardiography could early identify the impaired right ventricular (RV) function after anthracycline exposure. Sixty-one patients with diffuse large B-cell lymphoma treated with anthracycline were studied. Echocardiography was conducted at baseline, after the third cycle of the chemotherapy, after the completion of the chemotherapy, and follow-up at 10 months after the initiation of chemotherapy. RV global longitudinal strain (RV GLS) and RV free wall longitudinal strain (RV FWLS) were calculated using speckle tracking echocardiography. RV ejection fraction (RVEF) was analyzed by 3D echocardiography. RV systolic dysfunction was defined by ≥ 2 RV parameters below the threshold value, and cardiotoxicity was defined as a reduction in left ventricular EF > 10 to < 53%. After the third cycle of chemotherapy, only RV GLS was significantly decreased, while after the completion of the chemotherapy, RV GLS, RV FWLS, and RVEF were all significantly decreased compared with baseline measurements. At the end of follow-up, 9 patients (14.8%) were diagnosed with RV systolic dysfunction, and 16 patients (26.2%) had at least 1 abnormal RV function parameter. The proportion of RV systolic dysfunction was significantly higher in patients with cardiotoxicity than in patients without cardiotoxicity, yielding an odds ratio of 5.143. A percentage decrease in RV FWLS and RVEF were independent predictors of RV systolic dysfunction. Two-dimensional strain and 3D echocardiography are valuable methods for evaluating anthracycline-related impairment of RV function in DLBCL patients receiving chemotherapy. RV FWLS and RVEF are reliable predictors of RV systolic dysfunction.

Childhood cancer survivors: The integral role of the cardiologist and cardiovascular imaging

IMPORTANCE

With 80% of childhood cancer survivors (CCS) alive 30 years after diagnosis, preventable causes of death, such as cardiovascular disease resulting from initial cancer therapy, becomes an important metric. This leads to a more pronounced role for cardiologists in the care of CCS.

OBSERVATIONS

While routine cardiovascular screening has been traditionally performed by the hematologist/oncologist or primary care provider, our understanding of cardiovascular disease in CCS has advanced. The measurement of left ventricular ejection fraction (LVEF) can now be complemented with additional assessments of strain, LV mass, right ventricular function, diastolic function, valve function, the pericardium, coronary perfusion, and biomarkers. Risk factor modification, prophylaxis, and timing of treatment are also critical.

CONCLUSIONS AND RELEVANCE

Early cardiovascular screening and treatment in asymptomatic CCS can be nuanced and complex. As a result, there is a renewed opportunity for the cardiologist to play an integral role in the care of CCS.

KEY POINTS

Question/Purpose: Review cardiovascular disease and the role of the cardiologist in the care of asymptomatic childhood cancer survivors (CCS).

FINDINGS

Cardiovascular care in CCS benefits from a multi-faceted approach that does not overly rely on LVEF. Meaning: Adequate screening and treatment of cardiovascular disease in asymptomatic CCS may often be optimized by the involvement of a cardiologist.

Right ventricular involvement in cancer therapy-related cardiotoxicity: the emerging role of strain echocardiography

The involvement of the right ventricle (RV) in various cardiovascular pathologies is usually explored and demonstrated after thorough research of the left ventricle (LV). This is also true in cardio-oncology, where multimodality imaging with cardiac magnetic resonance and nuclear imaging is essential, but echocardiography plays pivotal role in everyday clinical practice. Chemotherapy and radiotherapy effect on RV has been studied mainly in breast cancer patients and survivors from childhood cancer. Right ventricular geometry and shape limit the ability of classical echocardiographic indices like RV ejection fraction (RVEF), RV fractional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE) to identify reliably subtle changes in RV systolic function in cancer patients. The assessment of diastolic function of the RV in various timepoints during or after chemotherapy leads to conflicting results too. However, longitudinal strain of the RV (RV LS) seems to detect myocardial injury with consistent results. Remarkably, cardiotoxicity of the RV is identified by RV LS almost simultaneously with LV cardiotoxicity and with similar cutoff percent change suggesting the uniform effect of cancer and its treatments on myocardium. The prognostic value of cardiotoxic effects on the RV needs to be investigated by large prospective studies.

Advances in Preclinical Research Models of Radiation-Induced Cardiac Toxicity

Radiation therapy (RT) is an important component of cancer therapy, with >50% of cancer patients receiving RT. As the number of cancer survivors increases, the short- and long-term side effects of cancer therapy are of growing concern. Side effects of RT for thoracic tumors, notably cardiac and pulmonary toxicities, can cause morbidity and mortality in long-term cancer survivors. An understanding of the biological pathways and mechanisms involved in normal tissue toxicity from RT will improve future cancer treatments by reducing the risk of long-term side effects. Many of these mechanistic studies are performed in animal models of radiation exposure. In this area of research, the use of small animal image-guided RT with treatment planning systems that allow more accurate dose determination has the potential to revolutionize knowledge of clinically relevant tumor and normal tissue radiobiology. However, there are still a number of challenges to overcome to optimize such radiation delivery, including dose verification and calibration, determination of doses received by adjacent normal tissues that can affect outcomes, and motion management and identifying variation in doses due to animal heterogeneity. In addition, recent studies have begun to determine how animal strain and sex affect normal tissue radiation injuries. This review article discusses the known and potential benefits and caveats of newer technologies and methods used for small animal radiation delivery, as well as how the choice of animal models, including variables such as species, strain, and age, can alter the severity of cardiac radiation toxicities and impact their clinical relevance.

Chemotherapy-Induced Cardiotoxicity in Adolescent After Heart Transplant: Do Not Forget the Right Ventricle

The evaluation of oncologic patients at risk of chemotherapy-induced cardiotoxicity usually focuses on left ventricular function. However, recent studies have demonstrated that right ventricle impairment often coexists (and in some cases precedes) left-side affectation. We present the case of a 19-year-old heart transplant recipient who developed severe right ventricular dysfunction secondary to treatment of an abdominal lymphoma.

Is health status impaired in childhood cancer survivors? A systematic review and meta-analysis

BACKGROUND

An increase in survival rates of childhood cancer is associated with long-term health issues in survivors.

METHODS

We conducted a systematic review and meta-analysis comparing health status-related endpoints in childhood cancer survivors (CCS) versus controls.

RESULTS

Eighty-six studies (n = 98,480 participants, 62% CCS) were included in the review. Of these, 73 studies (n = 96,550, 63% CCS) could be meta-analyzed. CCS showed a lower left ventricular ejection and fractional shortening (SMD=-0.59 and -0.55, respectively, both p < 0.01 [n=1,824 and 1,880]), a lower HDL-cholesterol concentration (SMD=-0.48, p<0.001, n=1,378) and a higher waist-to-hip ratio (SMD=0.61, p < 0.01, n=229) than their healthy peers. No significant differences were found for the remaining endpoints.

CONCLUSIONS

CCS is associated with a lower left ventricular function and HDL-cholesterol level, and a higher waist-to-hip ratio than healthy controls. These findings support the need to closely monitor the cardiometabolic health status of CCS and to implement preventive lifestyle interventions for this population.

Cardiovascular Evaluation of Children With Malignancies

PURPOSE OF REVIEW

The anthracycline (AC) group of drugs is widely used for cancer chemotherapy and has improved outcomes in many childhood malignancies. However, cardiovascular complications are major causes of morbidity and mortality in AC recipients, with the greatest risk factor being a higher cumulative dosage. The purpose of this review is to describe the etio-pathogenesis and risk factors of AC induced cardiotoxicity, with emphasis on currently available and emerging modalities of non-invasive imaging in its surveillance, and to review guidelines on its prevention and treatment.

RECENT FINDINGS

Presently, ejection fraction and shortening fraction derived from two-dimensional echocardiography are the most widely used parameter for monitoring of cardiac function in childhood cancer survivors. The newer speckle tracking echocardiography has shown potential to detect abnormalities in ventricular function prior to the conventional measures such as ejection fraction and shortening fraction. When available, three-dimensional echocardiography should be used as it allows for more accurate estimation of ejection fraction. Newer magnetic resonance imaging (MRI) techniques, such as delayed enhancement and T1 mapping, are useful adjuncts for cardiac evaluation in cancer survivors, especially in patients with poor echocardiographic windows. Early detection and management of cardiovascular diseases is one of the major goals in the long-term follow-up of childhood cancer survivors. In addition to conventional two-dimensional echocardiography, newer techniques such as speckle tracking echocardiography and three-dimensional echocardiography should be incorporated due to its ability to detect early changes in anthracycline-induced cardiotoxicity. However further research are needed to guide changes in management due to abnormalities in speckle tracking echocardiography.

Left and Right Ventricular Systolic and Diastolic Functional Reserves Are Impaired in Anthracycline-Treated Long-Term Survivors of Childhood Cancers

BACKGROUND

The aim of this study was to test the hypothesis that left ventricular (LV) and right ventricular (RV) functional reserves are altered in anthracycline-treated long-term survivors of childhood cancers.

METHODS

One hundred three survivors (55% men) aged 25.0 ± 5.8 years at 15.2 ± 5.8 years after chemotherapy and 61 healthy control subjects (52% men) were studied. Tissue Doppler-derived mitral and tricuspid systolic (s) and early diastolic (e) velocities and LV myocardial acceleration during isovolumic contraction (IVA) were determined at rest and during bicycle exercise. The slope of the LV force-frequency relationship was derived from changes in IVA with heart rate during exercise (ΔIVA/Δ[heart rate]). LV and RV functional reserves were further assessed by the systolic functional reserve index (Δs × [1 - 1/s at baseline]) and diastolic functional reserve index (Δe × [1 - 1/e at baseline]).

RESULTS

At baseline, mitral annular tissue Doppler indices were similar between survivors and control subjects (P > .05 for all), while tricuspid s and e velocities were significantly lower in survivors (P < .05 for both). The force-frequency relationship slope (P < .001), LV systolic functional reserve index (P < .001), and RV systolic functional reserve index (P = .001) were significantly lower in survivors than control subjects. For diastolic functional reserve, LV but not RV diastolic functional reserve index was significantly lower in survivors (P < .001). Multivariate analysis revealed survivor status (β = -0.39, P < .001) and baseline LV IVA (β = 0.15, P < .044) as significant determinants of the LV force-frequency relationship.

CONCLUSIONS

LV and RV functional reserves during exercise are impaired in anthracycline-treated long-term survivors of childhood cancer.

Right ventricular function and mechanics in chemotherapy- and radiotherapy-naïve cancer patients

The present research evaluated right ventricular (RV) structure, function and mechanics in the cancer patients before initiation of chemo- or radiotherapy, and the association between cancer and decreased RV longitudinal strain. This retrospective investigation included 101 chemo- and radiotherapy-naïve patients with solid cancer and 38 age- and gender-matched controls with similar cardiovascular risk profile. Echocardiographic examination and strain evaluation was performed in all participants. RV structure and RV systolic and diastolic function estimated with conventional echocardiographic parameters were similar between the cancer patients and controls. However, RV global longitudinal strain (- 22.7 ± 2.6% vs. - 21.1 ± 2.4%, p < 0.001) was significantly decreased in the cancer patients than in controls. The same was revealed for RV free wall endocardial (- 33.6 ± 4.3% vs. - 31.4 ± 4.0%, p = 0.006) and mid-myocardial (- 25.2 ± 3.6% vs. - 23.7 ± 3.8%, p = 0.035) longitudinal RV strains, whereas difference was not found in RV free wall epicardial longitudinal strain. The presence of cancer was independently of age, gender, body mass index, left ventricular hypertrophy, diabetes, hypertension and pulmonary pressure associated with reduced RV global longitudinal strain (OR 3.79; 95% CI 2.18-10.92, p < 0.001), as well as with decreased free wall RV longitudinal strain (OR 5.73; 95% CI 3.17-9.85, p < 0.001). RV strain is deteriorated in the chemo- and radiotherapy-naïve cancer patients. Endocardial and mid-myocardial layers are more affected than epicardial strain in the cancer patients. The presence of cancer is independently of other clinical parameters associated with reduced RV longitudinal strain.