Baseline diastolic dysfunction as a predictive factor of trastuzumab-mediated cardiotoxicity after adjuvant anthracycline therapy in breast cancer

Left ventricular diastolic function and cardiotoxic chemotherapy

BACKGROUND

Left ventricular ejection fraction falls when the myocardium has already lost a significant portion of its functional capacity. There are conflicting data on whether diastolic dysfunction precedes systolic dysfunction after cardiotoxic chemotherapy. We aimed to study systolic and diastolic dysfunction after cardiotoxic chemotherapy and whether diastolic dysfunction can predict subsequent risk of systolic dysfunction. It was an observational prospective cohort study, and patients receiving cardiotoxic chemotherapy were included. Baseline, demographic, and clinical details were recorded. Echocardiographic measurements of left ventricular systolic function, global longitudinal strain, and diastolic function were noted at baseline, three months, and 6 months.

RESULTS

We included eighty patients. The mean age of the patients was 54.92 ± 7.6 years, predominantly females (80%). The mean left ventricular ejection fraction fell from 64.92 ± 1.96 to 60.97 ± 4.94 at 6 months. Low ejection fraction was seen in 8 (10%) patients at 6 months. The mean global longitudinal strain (GLS) at baseline was - 18.81 ± 0.797 and fell to - 17.65 ± 2.057 at 6 months, with 12 (15%) patients having low GLS (< - 18). Grade 1 diastolic dysfunction was seen in 22 (27.5%) patients, and grade 2 diastolic dysfunction was seen in 3 (3.8%) patients at 6 months. There was a significant decrease in E/A ratio (inflow early diastolic velocity/Inflow late diastolic velocity), mitral tissue Doppler velocity, and an increase in isovolumic relaxation time, mitral valve deceleration time, and E/e' (inflow early diastolic velocity/tissue Doppler mitral annular velocity), at three months and 6 months. Ejection fraction at 6 months was significantly and negatively correlated with diastolic dysfunction at three months (r = - 0.595, p = 0.02).

CONCLUSIONS

Cardiotoxic chemotherapy is associated with early diastolic dysfunction. Early diastolic dysfunction predicts subsequent left ventricular systolic dysfunction.

Physical and autonomic functionality in women with breast cancer pre and post chemotherapy: a case control study

BACKGROUND

Breast cancer (BC) is one of the most incident types of cancer among women in the world. Although chemotherapy is an effective way to treat several types of cancer, it may also cause serious complications, including cardiotoxicity. This study aimed to identify the impact of chemotherapy on functional capacity, muscle strength and autonomic function.

METHODS

Ten breast cancer patients in therapeutic follow-up (TG) and ten women without comorbidities (CG) participated in the study (46±8.87 years old). Both groups were evaluated at two time points, before and 20 weeks after the start of chemotherapy. Functional capacity and muscle strength were assessed by 6-minute walk test (6MWT) and handgrip test, respectively. Autonomic function was assessed by heart rate variability analysis.

RESULTS

TG presented greater reductions in the handgrip test for the non-dominant hand (TG ↓15.2%; CG: ↑1.1%, p<0.05) compared to GC. However, no significant differences were found regarding VO2max (p>0.05) and 6MWT total distance (p>0.05). Regarding the heart rate variability variables before and after follow-up period, rMSSD (CG= 39.15±37.66; TG= 14.89±8.28, p= 0.01) and SDNN (CG= 55.77±40.03; TG= 26.30±10.37, p= 0.02) showed effect in the group and time interaction, whereas the LF/HF ratio presented significant difference only in the time analysis (CG= 2.24±2.30; TG= 2.84±1.82, p= 0.04).

CONCLUSION

Chemotherapy used in the treatment of breast cancer patients resulted in decreased muscle strength and autonomic imbalance. The data suggests that chemotherapy may carry the risk of developing cardiovascular disease.

TRIAL REGISTRATION

Registration not required.

Early detection of cancer therapy cardiotoxicity by radionuclide angiography: An update

Cancer therapy-induced cardiotoxicity is an emerging clinical and healthcare issue. Myocardial dysfunction and heart failure are mostly responsible for increased cardiovascular mortality in cancer disease survivors. Several imaging surveillance techniques have been proposed for early diagnosis of cancer therapy-induced cardiac dysfunction. Our aim was to provide an update of radionuclide angiography applications in this field. Radionuclide angiography is widely used to assess left ventricular ejection fraction (LVEF) throughout cancer treatment, especially in patients with limited acoustic window. Additional prognostic data may be provided by phase analysis and diastolic function evaluation. Low LVEF and high approximate entropy at baseline seem to be predictors for cancer therapy-induced cardiac dysfunction. A decrease in peak filling rate and/or an increase in time to peak filling rate may be observed in patients undergoing anthracycline and/or trastuzumab administration. Diastolic function impairment may precede or not LVEF decrease. In conclusion, recent studies have provided novel insights into the possible role of radionuclide angiography in the early detection of cancer therapy cardiotoxicity. While interpreting the results of a radionuclide angiography examination, an integrated approach combining the evaluation of LVEF, LV diastolic function, and phase analysis may be useful to improve risk stratification of cancer patients treated with cardiotoxic agents.

Artificial intelligence modelling to assess the risk of cardiovascular disease in oncology patients

Aims

There are no comprehensive machine learning (ML) tools used by oncologists to assist with risk identification and referrals to cardio-oncology. This study applies ML algorithms to identify oncology patients at risk for cardiovascular disease for referrals to cardio-oncology and to generate risk scores to support quality of care.

Methods and results

De-identified patient data were obtained from Vanderbilt University Medical Center. Patients with breast, kidney, and B-cell lymphoma cancers were targeted. Additionally, the study included patients who received immunotherapy drugs for treatment of melanoma, lung cancer, or kidney cancer. Random forest (RF) and artificial neural network (ANN) ML models were applied to analyse each cohort: A total of 20 023 records were analysed (breast cancer, 6299; B-cell lymphoma, 9227; kidney cancer, 2047; and immunotherapy for three covered cancers, 2450). Data were divided randomly into training (80%) and test (20%) data sets. Random forest and ANN performed over 90% for accuracy and area under the curve (AUC). All ANN models performed better than RF models and produced accurate referrals.

Conclusion

Predictive models are ready for translation into oncology practice to identify and care for patients who are at risk of cardiovascular disease. The models are being integrated with electronic health record application as a report of patients who should be referred to cardio-oncology for monitoring and/or tailored treatments. Models operationally support cardio-oncology practice. Limited validation identified 86% of the lymphoma and 58% of the kidney cancer patients with major risk for cardiotoxicity who were not referred to cardio-oncology.

Assessment of left ventricular diastolic dysfunction following anthracyclinebased chemotherapy in breast cancer patients

Cardiotoxicity is a side effect of anthracycline-based chemotherapy. Clinical and prognostic significance of left ventricular diastolic dysfunction in heart failure patients is undeniable.The aim. To assess dynamic changes in the left ventricular diastolic function after anthracycline-based chemotherapy (ANT) in breast cancer patients.Material and methods. The study included 40 women aged 35 to 72 years with breast cancer (BC) undergoing ANT chemotherapy. The main group (n = 40) consisted of women with breast cancer examined at admission, after 6 months the same women (n = 37) were examined again. Women without breast cancer (n = 25) were used as the control group.Results. Dynamic changes in mitral annular velocities were revealed by Doppler tissue imaging. Lateral early diastolic mitral annular velocity (e’ lateral) was significantly lower in breast cancer patients as compared to the control group (p = 0.031). Six months after ANT chemotherapy, there was a definite increase in the lateral late diastolic mitral annular velocity (a’ lateral) (p = 0.033). Average early diastolic transmitral flow velocity to early diastolic velocity (E/e’ lateral) ratio was within the normative values in all groups, but E/e’ lateral in the main group was higher compared to the control group (p = 0.003). In the main group, septal early diastolic mitral annular velocity (e’ septal) was lower compared to the control group (p = 0.0005). Moreover, an increase in the septal mitral annular velocity (a’ septal) (p = 0.01) and higher E/e’ septal ratio (p = 0.011) were revealed during dynamic observation. Multiple logistic regression disclosed that E/A, e’ lateral, e’/a’ lateral, and E/e’ lateral were affected by heart rate, psychological status, age, hypertension, and body mass index, but not anthracycline chemotherapy. The total dose of anthracycline was independently associated with e’ septal and E/e’ septal: F(4.18) = 16.466 (p < 0.001; R2 = 0.775) and F(3.16) = 7.271 (p = 0.004; R2 = 0.627).Conclusion. Left ventricular diastolic function worsens in women undergoing anthracycline-based chemotherapy for breast cancer (lower e’, e’/a’ lateral, and e’ septal, higher E/e’ septal ratio). However, anthracycline does not significantly affect LVEF and LV deformation indicators. E/e’ septalande’ septal are independently associated with the total dose of anthracycline.

Cardio-Oncology Drug Interactions: A Scientific Statement From the American Heart Association

In the cardio-oncology population, drug interactions are of particular importance given the complex pharmacological profile, narrow therapeutic index, and inherent risk of therapies used to manage cardiovascular disease and cancer. Drug interactions may be beneficial or detrimental to the desired therapeutic effect. Clinicians in both cardiology and oncology should be cognizant of these potential drug-drug interactions that may reduce the efficacy or safety of either cardiovascular or cancer therapies. These risks can be mitigated through increased recognition of potential drug-drug interaction, use of alternative medications when possible, and careful monitoring. This scientific statement provides clinicians with an overview of pharmacodynamic and pharmacokinetic drug-drug interactions in patients with cancer exposed to common cardiovascular and cancer medications.

Prevalence and risk factors of trastuzumab induced cardiotoxicity in Tunisian HER2-positive breast cancer patients

INTRODUCTION

Cardiotoxicity is the most important side effect of Trastuzumab treatment. The purpose of this study is to evaluate the prevalence of Trastuzumab induced cardiotoxicity and to analyze risk factors associated with this side effect.

MATERIALS AND METHODS

A retrospective institutional study was carried out from June 2018 to December 2018 at the department of Medical Oncology of Salah Azaiz institute, Tunis, Tunisia. Demographic, clinical characteristics (menopausal status, breast cancer stage, anthracyclines exposure, comorbidities presence…) and left ventricular ejection function (LVEF) measurements, were collected from patient records.

RESULTS

Twenty-three women (20%) had Trastuzumab induced cardiotoxicity.65.2% (N = 15) experienced a decrease in LVEF more than 10% with a decrease below normal value and 34.8% (N = 8) experienced a decrease in LVEF more than 20%. Obesity is a risk factor for the occurrence of Trastuzumab induced cardiotoxicity (adjusted odds ratio (OR) = 2.919 (95% confidence interval (CI) [1.0411-8.186]; p = 0.042).

CONCLUSION

Our study highlighted that obesity is associated with a high risk of cardiotoxicity in women treated with Trastuzumab. Therefore, close monitoring of cardiac function is recommended especially for obese women during Trastuzumab administering.

Cardiotoxicity of Epidermal Growth Factor Receptor 2-Targeted Drugs for Breast Cancer

Breast cancer is the most common form of cancer in women and its incidence has been increasing over the years. Human epidermal growth factor receptor 2 (HER2 or ErbB2) overexpression is responsible for 20 to 25% of invasive breast cancers, and is associated with poor prognosis. HER2-targeted therapy has significantly improved overall survival rates in patients with HER2-positive breast cancer. However, despite the benefits of this therapy, its cardiotoxicity is a major concern, especially when HER2-targeted therapy is used in conjunction with anthracyclines. At present, the mechanism of this cardiotoxicity is not fully understood. It is thought that HER2-targeting drugs inhibit HER2/NRG 1 dimer formation, causing an increase in ROS in the mitochondria of cardiomyocytes and inhibiting the PI3K/Akt and Ras/MAPK pathways, resulting in cell apoptosis. Antioxidants, ACE inhibitors, angiotensin II receptor blockers, β-blockers, statins and other drugs may have a cardioprotective effect when used with ErbB2-targeting drugs. NT-proBNP can be used to monitor trastuzumab-induced cardiotoxicity during HER2-targeted treatment and may serve as a biological marker for clinical prediction of cardiotoxicity. Measuring NT-proBNP is non-invasive, inexpensive and reproducible, therefore is worthy of the attention of clinicians. The aim of this review is to discuss the potential mechanisms, clinical features, diagnostic strategies, and intervention strategies related to cardiotoxicity of ErbB2-targeting drugs.

Equilibrium radionuclide angiography: Intra- and inter-observer repeatability and reproducibility in the assessment of cardiac systolic and diastolic function

BACKGROUND

This study aimed to assess intra- and inter-observer agreement in assessing the systolic and diastolic function with equilibrium radionuclide angiography (ERNA).

MATERIALS AND METHODS

Thirty-two adults underwent baseline and repeat ERNA. An experienced and a trainee operator analyzed the data by assigning regions of interest manually, fully automatically, and semi-automatically. The Bland-Altman statistic (mean ± 1.96 standard deviations of the differences) was used to assess the repeatability (two different assessments of a single acquisition) and reproducibility (assessments of two different acquisitions).

RESULTS

Using the semi-automated technique the intraobserver repeatability and reproducibility of left ventricular ejection fraction for the experienced physician were - 0.1 ± 3.7 and 0.0 ± 3.8 and for the trainee 2.2 ± 10.6 and 1.9 ± 8.4, respectively. The inter-observer repeatability and reproducibility were - 1.8 ± 6.4 and 0.4 ± 9.0, respectively. Among the parameters of diastolic function, the intraobserver repeatability and reproducibility of the peak filling rate for the experienced physician were - 0.0 ± 1.1 and - 0.1 ± 1.1 and for the trainee 0.2 ± 3.5 and 0.4 ± 3.7, respectively. The inter-observer repeatability and reproducibility were 0.3 ± 1.5 and 0.5 ± 4.0, respectively. Similar was the pattern for the other diastolic indices. In all cases the limits of agreement varied according to the quantification approach.

CONCLUSION

A good repeatability but a moderate reproducibility was found in the assessment of the LVEF. Less good were the findings in the assessment of diastolic function.

The role of the Tei index in assessing for cardiotoxicity from anthracycline chemotherapy: a systematic review

Background

Anthracycline agents are known to be effective in treating tumors and hematological malignancies. Although these agents improve survival, their use is associated with cardiotoxic effects, which most commonly manifests as left ventricular systolic dysfunction (LVSD). As such, guidelines recommend the periodic assessment of left ventricular ejection fraction (LVEF). However, as diastolic dysfunction likely proceeds systolic impairment in this setting, the role of Tei index may offer additional benefit in detecting subclinical LVSD.

Methods

We conducted a systematic review to investigate the evidence for the use of Tei index in assessing subclinical cardiotoxicity in patients receiving anticancer agents. A search of Medline and EMBASE was performed and relevant studies were reviewed and narratively synthesized.

Results

A total of 13 studies were included with a total of 800 patients (mean age range 46–62 years, percentage of male participants ranged from 0–86.9%). An increase in Tei index was observed in 11 studies, which suggested a decline in cardiac function following chemotherapy. Out of these, six studies indicated that the Tei index is a useful parameter in predicting cardiotoxic LVSD. Furthermore, five studies indicated Tei index to be superior to LVEF in detecting subclinical cardiotoxicity.

Conclusions

Though there are some studies that suggest that Tei index may be a useful indicator in assessing subclinical anthracycline-related cardiotoxicity, the findings are inconsistent and so more studies are needed before the evaluation of Tei index is performed routinely in patients receiving chemotherapy.

Conventional cardiac risk factors associated with trastuzumab-induced cardiotoxicity in breast cancer: Systematic review and meta-analysis

BACKGROUND

Trastuzumab has had a major impact on the treatment of human epidermal growth factor receptor 2 (HER2) positive breast cancer patients. However, it is associated with cardiotoxicity, expressed as an asymptomatic decrease in left ventricular ejection fraction (LVEF) and less often as clinical HF. The aim of this meta-analysis is to identify the association of conventional cardiovascular risk factors with the development of trastuzumab-induced cardiotoxicity (TIC).

METHODS

A literature search of PubMed was conducted to identify studies examining the association between cardiovascular risk factors and TIC. Data were extracted and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated examining the odds of developing TIC for each of the risk factors.

RESULTS

A total of 35 studies were included in the analysis. Age (OR:0.7; 95%CI 0.318-1.09; P= 0.0004), hypertension (OR:0.69; 95%CI 0.26-1.12; P = 0.001), smoking(OR:0.35; 95%CI 0.01- 0.69; P = 0.038), diabetes mellitus (OR:0.44; 95%CI 0.24- 0.68; P = 0.0001) and family history of CAD (OR:5.51, 95%CI 1.76-17.25; P< 0.00001)were significantly associated with the development of cardiotoxicity. Known history of CAD (OR: 3.72; 95%CI 2.11-6.57; P = 0.0005) was also associated with the development of TIC.

CONCLUSION(S)

Identifying women at risk for TIC have several important potential applications. Clinicians may decide to assess LVEF more frequently in patients at highest risk for TIC in order to detect LV systolic dysfunction earlier. Additionally, this could help identify patients who would benefit most from prophylactic therapy for preventing TIC.

Toxicology of Trastuzumab: An Insight into Mechanisms of Cardiotoxicity

Trastuzumab is a humanized monoclonal antibody that is approved for the treatment of breast and gastric malignancies. Although it has shown promise as a biotherapeutic, its cardiotoxicity remains a major concern. Genotoxic anticancer anthracyclines such as doxorubicin and epirubicin are also known for their cardiotoxic effects. However, trastuzumab and anthracyclines are suggested to mediate cardiotoxicity via different pathways. The available lines of evidence suggest that trastuzumab can exacerbate the cardiotoxic effects of anthracyclines and thus, prior exposure to anthracyclines is regarded as one of the risk factors for trastuzumab-induced cardiotoxcity. Although it is generally believed that the trastuzumab-induced cardiotoxic effects are reversible, various preclinical studies have revealed its apoptotic effects on cardiomyocytes. Thus, the issue of the reversibility of its cardiotoxic effects remains to be fully resolved. This article discusses various mechanisms that have been proposed for the cardiotoxic effects of trastuzumab and the potential risk factors that can lead to cardiotoxicity. The recently approved anti-HER2 monoclonal antibodies including pertuzumab and ado-trastuzumab (T-DM1) are also discussed.

Ventricular peak emptying and filling rates measured by gated tomographic radionuclide angiography using a cadmium-zinc-telluride SPECT camera in chemotherapy-naïve cancer patients

INTRODUCTION

Radionuclide angiography is widely used for left ventricular function assessment. This study establishes normative data and inter-study repeatability on peak ventricular filling and emptying rates obtained by a cadmium-zinc-telluride SPECT camera.

METHOD

Cancer patients (N = 764) without diabetes or cardiovascular diseases referred for baseline assessment of cardiac function were included. Repeatability was assessed in 46 patients where two separate acquisitions were performed. Left and right ventricular emptying rates (LPER, RPER) and filling rates (LPFR, RPFR) were obtained and whenever possible also atrial filling rates (PFRa).

RESULTS

Filling rates were higher in women than men. Emptying rates tended to increase with age, whereas filling rates and the E/A ratio decreased. One patient was excluded from the repeatability analysis due to an unexplained high intra-observer variation. Intraclass correlation coefficients for LPER, RPER, LPFR, and RPFR were 0.99, 0.94, 0.99, and 0.84, no proportional biases were detected.

CONCLUSION

Reference values and relations to age and gender in chemotherapy-naïve cancer patients without cardiopulmonary disease are presented. The CZT camera provides reproducible estimates of peak emptying and filling rates.

Cardiovascular Magnetic Resonance Imaging: Identifying the Effects of Cancer Therapy

The era of modern oncology incorporates an ever-evolving personalized approach to hematological malignancies and solid tumors. As a result, patient survival rates have, in part, substantially improved, depending on the specific type of underlying malignancy. However, systemic therapies may come along with potential cardiotoxic effects resulting in heart failure with increased morbidity and mortality. Ultimately, patients may survive their malignancy but die as a result of cancer treatment. Cardiovascular magnetic resonance imaging has long been in use for the assessment of function and tissue characteristics in patients with various nonischemic cardiac diseases. Besides an introductory overview on the general definition of cardiotoxicity including potential underlying mechanisms, this review provides insight into the application of various cardiovascular magnetic resonance imaging techniques in the setting of cancer therapy-related cardiac and vascular toxicity. Early identification of cardiotoxic effects may allow for on-time therapy adjustment and/or cardioprotective measures to avoid subsequent long-term heart failure with increased mortality.

Trastuzumab cardiotoxicity in HER2-positive breast cancer patients in tertiary health care center, sultanate of Oman

Trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER2), is used to treat breast cancers harboring amplification of the HER2 locus. Cardiotoxicity is a common side effect of trastuzumab that leads to discontinuation of treatment in a significant proportion of cancer patients. In our retrospective study, we evaluate the prevalence and identify the risk factors for cardiotoxicity associated with trastuzumab in HER2-positive breast cancer patients attending to Sultan Qaboos University Hospital between 10/2012 and 10/2017. Using patient records, we collected patients' characteristics (age, menopausal status, lymph nodal status, distant metastasis at presentation, grade of tumor, comorbidities (diabetes mellitus, hypertension, coronary artery disease diseases)), chemotherapy received and total dose of trastuzumab as well as cardiotoxicity (including timing). Cardiotoxicity was defined based on the ejection fraction dropping by 10% of the original value or a drop in the ejection fraction below the normal value. Among the 146 patients included in the study, 35 showed trastuzumab-induced cardiotoxicity (24%). Twenty-nine (83%) of those patients stopped trastuzumab temporarily. Risk of trastuzumab-induced cardiotoxicity was not altered by common cardiac risk factors such as history of coronary artery disease, hypertension and diabetes. Previous anthracyclines therapy exposure increased the risk of trastuzumab-induced cardiotoxicity significantly (p = 0.009). None of the other covariates influenced the incidence of trastuzumab-induced cardiotoxicity, which may be related to the relatively small sample size. Further studies are warranted to establish ways to predict, prevent, and treat trastuzumab-induced cardiotoxicity to provide patients with maximal therapeutic benefit.

Cardiac monitoring in HER2-positive patients on trastuzumab treatment: A review and implications for clinical practice

Trastuzumab prolongs progression-free and overall survival in patients with human epidermal growth factor receptor 2 (HER2) positive breast cancer. However, trastuzumab treatment is hampered by cardiotoxicity, defined as a left ventricular ejection fraction (LVEF) decline with a reported incidence ranging from 3 to 27% depending on variable factors. Early identification of patients at increased risk of trastuzumab-induced myocardial damage is of great importance to prevent deterioration to irreversible cardiotoxicity. Although current cardiac monitoring with multi gated acquisition (MUGA) scanning and/or conventional 2D-echocardiography (2DE) have a high availability, their reproducibility are modest, and more sensitive and reliable techniques are needed such as 3D-echocardiography (3DE) and speckle tracking echocardiography (STE). But which other diagnostic imaging modalities are available for patients before and during trastuzumab treatment? In addition, what is the optimal frequency and duration of cardiac monitoring? At last, which biomarker monitoring strategies are currently available for the identification of cardiotoxicity in patients treated with trastuzumab?

•

Current MUGA is not sensitive and reliable enough to detect cardiotoxicity early.

•

3DE (with STE) is most suitable for cardiac monitoring of patients on trastuzumab.

•

The optimal frequency and duration of cardiac monitoring is not yet established.

•

MPO and hs-troponin are promising biomarkers to detect cardiotoxicity.

Drug-induced myocardial dysfunction - recommendations for assessment in clinical and pre-clinical studies

Introduction: Drug-induced myocardial dysfunction is an important safety concern during drug development. Oncology compounds can cause myocardial dysfunction, leading to decreased left ventricular ejection fraction and heart failure via several mechanisms. Cardiovascular imaging has a major role in the early detection and monitoring of cardiotoxicity. Echocardiography is the method of choice because of its widespread availability, low cost, and absence of radiation exposure. Cardiac magnetic resonance imaging can provide better reliability, reproducibility, and accuracy in the detection of drug-induced myocardial dysfunction. In addition, it enables assessment of myocardial edema, fibrosis, and necrosis. Cardiac serologic biomarkers such as troponins and B-type natriuretic peptides are used in combination with imaging during drug development. This article provides a general overview of each imaging modality and practical guidance for early detection and monitoring of cardiotoxicity.Areas covered: Cardiovascular imaging modalities and cardiac biomarkers for monitoring of cardiac function and early detection of drug-induced myocardial dysfunction in drug development.Expert opinion: Some new drugs especially in the oncology field, can cause myocardial dysfunction. Depending on the strength of pre-clinical or clinical data, CV imaging modalities and cardiac biomarkers play an important role in the early detection and mitigation plans for such drugs during their development.

Doxorubicin-Induced Cardiomyopathy in Children

Doxorubicin-induced cardiotoxicity in childhood cancer survivors is a growing problem. The population of patients at risk for cardiovascular disease is steadily increasing, as five-year survival rates for all types of childhood cancers continue to improve. Doxorubicin affects the developing heart differently from the adult heart and in a subset of exposed patients, childhood exposure leads to late, irreversible cardiomyopathy. Notably, the prevalence of late-onset toxicity is increasing in parallel with improved survival. By the year 2020, it is estimated that there will be 500,000 childhood cancer survivors and over 50,000 of them will suffer from doxorubicin-induced cardiotoxicity. The majority of the research to-date, concentrated on childhood cancer survivors, has focused mostly on clinical outcomes through well-designed epidemiological and retrospective cohort studies. Preclinical studies have elucidated many of the cellular mechanisms that elicit acute toxicity in cardiomyocytes. However, more research is needed in the areas of early- and late-onset cardiotoxicity and more importantly improving the scientific understanding of how other cells present in the cardiac milieu are impacted by doxorubicin exposure. The overall goal of this review is to succinctly summarize the major clinical and preclinical studies focused on doxorubicin-induced cardiotoxicity. As the prevalence of patients affected by doxorubicin exposure continues to increase, it is imperative that the major gaps in existing research are identified and subsequently utilized to develop appropriate research priorities for the coming years. Well-designed preclinical research models will enhance our understanding of the pathophysiology of doxorubicin-induced cardiotoxicity and directly lead to better diagnosis, treatment, and prevention. © 2019 American Physiological Society. Compr Physiol 9:905-931, 2019.

Serial Measurements of Left Ventricular Systolic and Diastolic Function by Cardiac Magnetic Resonance Imaging in Patients with Early Stage Breast Cancer on Trastuzumab

Our aim was to evaluate the temporal changes in left ventricular (LV) diastolic filling in relation to other LV parameters using cardiac MRI (CMR) in patients with HER2 positive breast cancer receiving trastuzumab therapy. Fourty-one women with early stage HER2+ breast cancer underwent serial CMR (baseline, 6, 12, and 18 months) after initiation of trastuzumab therapy. A single, blinded observer measured LV parameters on de-identified CMRs in random order. Linear mixed models were used to investigate temporal changes. Compared to baseline, there were significant decreases in systolic function as measured by both left ventricular ejection fraction (LVEF) (p <0.001 at 6 and 12 months) and peak ejection rate corrected for end-diastolic volume (PER/LVEDV) (p = 0.008 at 6 months, p = 0.01 at 12 months). However, these differences were no longer significant at 18 months. In contrast, significant reductions in diastolic function as measured by LV peak filling rate corrected for end-diastolic volume (PFR/LVEDV) were observed at 6 months (p = 0.012), 12 months (p = 0.031), and up to 18 months (p = 0.034). There were no significant temporal changes in the time to peak filling rate corrected for cardiac cycle (TPF/RR). The reduction in PFR/LVEDV at 18 months was no longer significant when corrected for heart rate. In conclusion, there were significant subclinical deleterious effects on both LV systolic and diastolic function among patients receiving trastuzumab. While there was recovery in LV systolic function after therapy cessation at 18 months, reduction in PFR/LVEDV appeared to persist. Thus, diastolic dysfunction may serve as a marker of trastuzumab-induced cardiotoxicity that needs to be confirmed in a larger study.

Risk Factors Associated with Trastuzumab-induced Cardiotoxicity in Patients with Human Epidermal Growth Factor Receptor 2-positive Breast Cancer

Context:

Although trastuzumab is a highly effective and selective targeted therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer, the drug-induced cardiotoxicity may confine its usefulness in patients.

Aim:

To explore risk factors associated with the development of cardiotoxicity in patients with HER2-positive breast cancer.

Settings and Design:

A retrospective review of medical records and chart review for all patients with breast cancer treated with trastuzumab was conducted at King Abdulaziz Medical City and King Abdullah Specialized Children Hospital in Riyadh, Kingdom of Saudi Arabia, between October 2015 and February 2018. Patients with declined left ventricular ejection fraction, either with or without cardiac symptoms, were recognized as those with cardiotoxicity due to trastuzumab administration.

Results:

A total of 146 patients were included in the study with an average age of 52.7 (standard deviation = 12.2) years. Thirty-two (21.9%) patients developed cardiotoxicity. However, only 24 (16.4%) were symptomatic with an apparent heart failure but it did not necessitate interruption of trastuzumab therapy. The majority of patients had prior underlying cardiovascular diseases. This study identified unilateral tumor site (62.5%), breast surgery (37.5%), and concomitant taxane chemotherapy (62.5%) as the main risk factors associated with significant increase in cardiotoxicity in patients with breast cancer (with P values of 0.0269, 0.0482, and 0.0225, respectively).

Conclusion:

The majority of patients (more than 90%) developed cardiotoxicity after completion of chemotherapy. However, recruiting a larger sample size should be warranted to confirm or negate these findings.

Early diagnosis of cardiotoxic complications of chemotherapy: the possibility of radiation research methods

Oncological diseases are the main causes of death in the world. Modern treatment of cancer patients contributes to an increase in survival rate due to strong chemotherapeutic drugs, the use of which is accompanied by toxic effects on cardiomyocytes. The main manifestations of cardiotoxicity are left ventricular dysfunction, myocardial ischemia, thromboembolic complications, chronic heart failure. As a result, the risk of cardiovascular mortality may be higher than the risk of death from the tumor process. An important task of oncologists and cardiologists is the early diagnosis of cardiotoxic complications in order to start treatment in time and reduce mortality from cardiovascular pathology in cancer patients.

Cardiovascular magnetic resonance left ventricular strain in end-stage renal disease patients after kidney transplantation

BACKGROUND

Cardiovascular disease is a significant cause of morbidity and mortality in patients with end-stage renal disease (ESRD) and kidney transplant (KT) patients. Compared with left ventricular (LV) ejection fraction (LVEF), LV strain has emerged as an important marker of LV function as it is less load dependent. We sought to evaluate changes in LV strain using cardiovascular magnetic resonance imaging (CMR) in ESRD patients who received KT, to determine whether KT may improve LV function.

METHODS

We conducted a prospective multi-centre longitudinal study of 79 ESRD patients (40 on dialysis, 39 underwent KT). CMR was performed at baseline and at 12 months after KT.

RESULTS

Among 79 participants (mean age 55 years; 30% women), KT patients had significant improvement in global circumferential strain (GCS) (p = 0.007) and global radial strain (GRS) (p = 0.003), but a decline in global longitudinal strain (GLS) over 12 months (p = 0.026), while no significant change in any LV strain was observed in the ongoing dialysis group. For KT patients, the improvement in LV strain paralleled improvement in LVEF (57.4 ± 6.4% at baseline, 60.6% ± 6.9% at 12 months; p = 0.001). For entire cohort, over 12 months, change in LVEF was significantly correlated with change in GCS (Spearman's r = - 0.42, p < 0.001), GRS (Spearman's r = 0.64, p < 0.001), and GLS (Spearman's r = - 0.34, p = 0.002). Improvements in GCS and GRS over 12 months were significantly correlated with reductions in LV end-diastolic volume index and LV end-systolic volume index (all p < 0.05), but not with change in blood pressure (all p > 0.10).

CONCLUSIONS

Compared with continuation of dialysis, KT was associated with significant improvements in LV strain metrics of GCS and GRS after 12 months, which did not correlate with blood pressure change. This supports the notion that KT has favorable effects on LV function beyond volume and blood pessure control. Larger studies with longer follow-up are needed to confirm these findings.

Left Ventricular Regional Wall Motion Abnormality is a Strong Predictor of Cardiotoxicity in Breast Cancer Patients Undergoing Chemotherapy

Background

Chemotherapeutic agents of anthracyclines class and humanized monoclonal antibodies are effective treatments for breast cancer, however, they present a potential risk of cardiotoxicity. Several predictors have been recognized as predictors in the development of cardiac toxicity, and the evaluation of left ventricular segmental wall motion abnormalities (LVSWMA) has not been studied.

Objective

To analyze prospectively the role of LVSWMA among echocardiographic parameters in the prediction of development of cardiotoxicity in breast cancer patients undergoing treatment with chemotherapy.

Methods

Prospective cohort of patients diagnosed with breast cancer and in chemotherapy treatment with potential cardiotoxicity medications including doxorubicin and trastuzumab. Transthoracic echocardiograms including speckle tracking strain echocardiography were performed at standard times before, during and after the treatment to assess the presence (or lack thereof) of cardiotoxicity. Cardiotoxicity was defined by a 10% decrease in the left ventricular ejection fraction, on at least one echocardiogram. Multivariate logistic regression models were used to verify the predictors related to the occurrence of cardiotoxicity over time.

Results

Of the 112 patients selected (mean age 51,3 ± 12,9 years), 18 participants (16.1%) had cardiotoxicity. In the multivariate analysis using the logistic regression model, those with LVWMA (OR = 6.25 [CI 95%: 1.03; 37.95], p < 0,05), LV systolic dimension (1.34 [CI 95%: 1.01; 1.79], p < 0,05) and global longitudinal strain by speckle tracking (1.48 [CI 95%: 1.02; 2.12], p < 0,05) were strongly associated with cardiotoxicity.

Conclusion

In the present study, we showed that LVWMA, in addition to global longitudinal strains, were strong predictors of cardiotoxicity and could be useful in the risk stratification of these patients.

Early diastolic strain rate measurements by cardiac MRI in breast cancer patients treated with trastuzumab: a longitudinal study

We evaluated temporal changes in early diastolic strain rates by cardiovascular magnetic resonance (CMR) as an early detector of trastuzumab-induced ventricular dysfunction. We conducted a prospective, multi-centre, longitudinal observational study of 41 trastuzumab-treated breast cancer women who underwent serial CMR (baseline, 6, 12, and 18 months). Two blinded readers independently measured left ventricular ejection fraction (LVEF), peak systolic strain parameters (global longitudinal strain [GLS] and global circumferential strain [GCS]), and early diastolic strain rate parameters (global longitudinal diastolic strain rate [GLSR-E], global circumferential diastolic strain rate [GCSR-E], and global radial diastolic strain rate [GRSR-E]), by feature tracking (FT-CMR) using CMR42. There was a significant decline in peak systolic strain GLS and GCS at 6 months (p = 0.024 and p < 0.001, respectively) and 12 months (p = 0.002 and p < 0.001, respectively), followed by recovery at 18 months, which paralleled decline in LVEF at 6 months (p = 0.034) and 12 months (p = 0.012). Conversely, early diastolic strain rates GLSR-E and GCSR-E did not significantly change over 18 months (p > 0.10), while GRSR-E was marginally significant at 12 months (p = 0.021). There was no significant correlation between changes at 6 months in LVEF and GLSR-E or GRSR-E (p > 0.10), and a marginally significant weak correlation between LVEF and GCSR-E (p = 0.046). Among trastuzumab-treated patients without overt cardiotoxicity, there was no consistent temporal change in FT-CMR-derived diastolic strain rate parameters up to 18 months, in contrast to decline in systolic strain and LVEF. Systolic strains by FT-CMR are likely more useful than diastolic strain rates for monitoring subclinical trastuzumab-related myocardial dysfunction.ClinicalTrials.gov identifier NCT01022086.

Chemotherapy-related cardiac dysfunction: grey area in type I and type II classification

PURPOSE OF REVIEW

The main aim of this review is to address and challenge an old nomenclature of reversible versus irreversible chemotherapy-induced cardiomyopathy.

RECENT FINDINGS

Chemotherapy-related cardiac dysfunction (CRCD) has been often characterized as type I or type II. Type I CRCD (e.g., anthracycline) represents a group of chemotherapeutic agents that has often been correlated with irreversible cardiac dysfunction. Conversely, type II CRCD (e.g., trastuzumab) represents a group of anticancer agents that has been considered as reversible. Recent evidence suggests that this nomenclature may not hold true, thus affecting clinical prognosis as well as timely management. It is prudent to address this concern so that physicians are armed with appropriate information, thus providing our oncological patients with informed care. The purpose is to highlight the grey area in this dichotomous classification.

SUMMARY

Type I CRCD can be reversible if cardioprotective medications are administered in a timely manner. Conversely, a small proportion of type II CRCD may develop irreversible dysfunction and therefore, will require a long-term follow-up. Therefore, every case should be dealt on an individual basis and an appropriate prognosis should be given to patients based on the clinical evidence on hand.

Early Diastolic Dysfunction after Cancer Chemotherapy: Primary Endpoint Results of a Multicenter Cardio-Oncology Study

Asymptomatic diastolic dysfunction (DD) with preserved left ventricular ejection fraction (LVEF) is suspected to precede late cardiac events in cancer survivors treated by chemotherapy. We conducted the first multicenter study of early DD induced by chemotherapy. Patients who were candidates for standard dose chemotherapy were screened for the absence of cardiovascular risk factors, LVEF ≥50%, normal-for-age diastolic function at echocardiography (E/A ratio, E wave deceleration time; DT), normal levels of potential DD biomarkers like Nt-proBNP (≤125 pg/mL), and cardiac troponin I (cTnI, ≤0.05 ng/mL). Mitral Doppler (E/E') was left at the investigator's discretion. Chemotherapy-induced DD with preserved LVEF was diagnosed for patients showing LVEF ≥50% and any of the following: Nt-proBNP > 125 pg/mL, cTnI > 0.05 ng/mL, and out-of-range E/A and DT. Eighty patients (68 females, 12 males, median age 49 years) were evaluated at 1 week after chemotherapy (T1) [corrected]. Thirty-three protocol-defined diastolic events were observed (15 Nt-proBNP > 125 pg/mL, 14 grade I DD by E/A and DT, 4 cTnI > 0.05 ng/mL). The events occurred in 29 asymptomatic patients with LVEF ≥50% (36% incidence of DD with preserved LVEF). Interactions occurred between biomarkers and grade I DD. E/E' abnormalities were not observed. Both anthracycline-based and nonanthracycline regimens induced DD. These findings show that biomarkers and echocardiography intercept early DD in otherwise asymptomatic low-risk cancer patients treated by standard dose chemotherapy. These findings therefore call for the adequate cardiac management of cancer patients.

Incidence, Diagnosis, and Treatment of Cardiac Toxicity from Trastuzumab in Patients with Breast Cancer

Purpose of review

Treatment with trastuzumab is a cornerstone of human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer treatment, but carries an unfortunate risk of toxicity to the cardiovascular system. Here we review recent findings on trastuzumab-associated cardiotoxicity, focusing on its incidence, diagnosis, and treatment.

Recent findings

Screening with multigated acquisition scan (MUGA) or echocardiogram (ECHO) is recommended to assess cardiac function prior to and during trastuzumab therapy. Because trastuzumab-induced cardiotoxicity is typically reversible, cessation of trastuzumab and/or administration of first line heart failure agents effectively restores cardiac function in most cases. Severe trastuzumab-induced cardiotoxicity is rare enough that the risk-benefit ratio still weighs in favor of its use in the vast majority of patients with HER2+ breast cancer.

Summary

An improved understanding of the pathophysiology underlying trastuzumab-induced cardiotoxicity and the identification of patients at highest risk will allow us to continue to safely administer trastuzumab in patients with breast cancer.

Benefits of antihypertensive medications for anthracycline- and trastuzumab-induced cardiotoxicity in patients with breast cancer: Insights from recent clinical trials

Advances in oncologic therapies have allowed many patients with breast cancer to achieve better outcomes and longer survival. However, this progress has been tempered by cardiotoxicity, associated with anticancer therapies, ranging from subclinical abnormalities to irreversible life-threatening complications, such as congestive heart failure or cardiomyopathy. In particular, exposure to chemotherapy (CHT), including anthracyclines and trastuzumab, can lead to cardiac dysfunction with short- or long-term consequences, among patients with breast cancer. The aim of this study is to highlight the potential role of commonly used cardiac medications in the prevention of anthracycline- and trastuzumab-mediated cardiotoxicity, in women with breast cancer, based on evidence from recent clinical trials. This overview is focused on the use of antihypertensive medications, such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, outlining their cardioprotective effects in this patient population. In addition, the importance of biomarkers and modern imaging tests, as potential tools for detection and monitoring of cardiac dysfunction, induced by CHT, as well as some practical preventive and therapeutic strategies for cardio-oncology treatment teams, involved in the management of a growing number of women with breast cancer have been outlined. The content of this overview is based on a literature search of PubMed, within the last 5 years, mostly in relevance to the human epidermal growth factor receptor 2-positive patients with breast cancer, treated with anthracycline or trastuzumab therapy (in addition to surgery and/or radiation therapy [RT] regimen).

Risk factors of trastuzumab-induced cardiotoxicity in breast cancer: A meta-analysis

BACKGROUND

Trastuzumab targets the human epidermal growth factor receptor 2 oncogene and in combination with first-line therapy results in significantly improved survival outcomes and has thus become standard of care in both adjuvant and metastatic settings. While it is estimated that 1% to 4% of patients treated with trastuzumab will develop heart failure and ∼10% will experience a reduction in left ventricular ejection fraction (LVEF), the patient risk factors associated with trastuzumab-induced cardiotoxicity (TIC) are unclear. This meta-analysis aims to consolidate previously published data to identify the risk factors most likely leading to TIC.

METHODS

A search of the MEDLINE literature database using the keywords trastuzumab/Herceptin, risk factors, outcomes, cardiac, cardiotoxicity, cardiomyopathy, LVEF, and chemotherapy was performed. Only prospective/retrospective human studies were included, with additional studies excluded if they reported baseline LVEF > 68%, a cohort of <50 patients, or results that were not stratified based on cardiotoxic events. Pooled odds ratio (OR) and 95% confidence interval (CI) for each potential risk factor were calculated, with heterogeneity of data and samples explored using random-effects modeling.

RESULTS

Data were collected from 17 articles, capturing 6527 patients. Hypertension (OR 1.61, 95% CI 1.14-2.26; P < 0.01), diabetes (OR 1.62; 95% CI 1.10-2.38; P < 0.02), previous anthracycline use (OR 2.14; 95% CI 1.17-3.92; P < 0.02), and older age (P = 0.013) were all shown to be associated with TIC.

CONCLUSION

Cardiac performance should be closely monitored in women treated with trastuzumab. Recognizing potential risk factors along with careful attention to symptoms/LVEF measurements could minimize the occurrence of TIC in this population.

Does diastolic dysfunction precede systolic dysfunction in trastuzumab-induced cardiotoxicity? Assessment with multigated radionuclide angiography (MUGA)

BACKGROUND

Trastuzumab is successfully used for the treatment of HER2-positive breast cancer. Because of its association with cardiotoxicity, LVEF is monitored by MUGA, though this is a relatively late measure of cardiac function. Diastolic dysfunction (DD) is believed to be an early predictor of cardiac impairment. We evaluate the merit of MUGA-derived diastolic function parameters in the early detection of trastuzumab-induced cardiotoxicity (TIC).

METHODS AND RESULTS

77 trastuzumab-treated patients with normal baseline systolic and diastolic function were retrospectively selected (n = 77). All serial MUGA examinations were re-analyzed for systolic and diastolic function parameters. 36 patients (47%) developed SD and 45 patients (58%) DD during treatment. Both systolic and diastolic parameters significantly decreased. Of the patients with SD, 24 (67%) also developed DD. DD developed prior to systolic impairment in 54% of cases, in 42% vice versa, while time to occurrence did not differ significantly (P = .52). This also applied to the subgroup of advanced stage breast cancer patients (P = .1).

CONCLUSIONS

Trastzumab-induced SD and DD can be detected by MUGA. An impairment of MUGA-derived diastolic parameters does not occur prior to SD and therefore cannot be used as earlier predictors of TIC.

A Prospective Cohort Study on Cardiotoxicity of Adjuvant Trastuzumab Therapy in Breast Cancer Patients

Background

Cardiotoxicity is an important side effect of trastuzumab therapy and cardiac surveillance is recommended.

Objectives

The aim of our study was to prospectively assess baseline patients' characteristics, level of N-terminal pro-brain natriuretic peptide (NT-proBNP) and echocardiographic parameters as possible predictors of trastuzumab-related cardiac dysfunction.

Methods

In a prospective cohort study, clinical, echocardiographic and neurohumoral assessment was performed at baseline, after 4, 8 and 12 months in breast cancer patients undergoing post-anthracycline (3-4 cycles) adjuvant therapy with trastuzumab. Trastuzumab-related cardiac dysfunction was defined as a decline of ≥ 10% in left ventricular ejection fraction (LVEF).

Results

92 patients (mean age, 53.6 ± 9.0 years) were included. Patients who developed trastuzumab-related LVEF decline ≥ 10% (20.6%) during treatment had significantly higher baseline LVEF (70.7 ± 4.4%) than those without (64.8 ± 5.5%) (p = 0.0035). All other measured baseline parameters (age, body mass index, arterial hypertension, level of NT-proBNP and other echocardiographic parameters) were not identified as significant.

Conclusions

Our findings suggest that baseline patient' characteristics, level of NT-proBNP and echocardiographic parameters, as long as they are within normal range, are not a reliable tool to predict early trastuzumab-related cardiac dysfunction in patients undergoing post-low dose anthracycline adjuvant trastuzumab therapy. A LVEF decline in patients with high-normal baseline level although statistically significant is not clinically relevant.

Observational study of trastuzumab-related cardiotoxicity in early and metastatic breast cancer

Introduction Trastuzumab-related cardiotoxicity has been a major concern in clinical practice, since observational studies have shown higher incidences than that reported in clinical trials. We aim to measure the incidence of trastuzumab-related cardiotoxicity in patients with early and metastatic breast cancer in the south of Brazil. Methods Multicenter prospective observational study, which included 109 patients with early or metastatic HER-2+ breast cancer undergoing any trastuzumab-based regimen. Cardiac events were measured by transthoracic echocardiography assessments and by signs and symptoms of heart failure. Results Trastuzumab-related cardiotoxicity was observed in 58 patients (53.2%). Emergency and hospitalization admissions were necessary in seven and three patients, respectively, due to symptoms of heart failure. One patient died in consequence of trastuzumab-related cardiotoxicity. In total, trastuzumab was discontinued in 31.2% of patients, of which almost a third could not return to treatment. In this study, no risk factors were significantly associated with the development of cardiotoxicity. Discussion The incidence of TRC and trastuzumab's early discontinuation observed was significantly higher in comparison with other studies. These findings endorse the fact that trastuzumab-related cardiotoxicity is a relevant adverse reaction, and therefore, cardiac dysfunction's monitoring must be highlighted in order to allow a safe use of trastuzumab in this population.

Risk of severe cardiotoxicity following treatment with trastuzumab: a meta-analysis of randomized and cohort studies of 29,000 women with breast cancer

Trastuzumab prolongs survival in women with HER2-positive breast cancer, but may increase the risk of heart disease. The occurrence of severe cardiotoxicity, however, is not defined in real-life settings. We performed a meta-analysis of clinical trials and cohort studies to estimate the frequency of cardiotoxicities following trastuzumab treatment. We searched MEDLINE, EMBASE, and the Cochrane Library (1996-January 2014). The primary outcome was the frequency of severe cardiotoxicities up to 3-years after trastuzumab initiation. Among 58 studies (29,598 patients), severe cardiotoxicity occurred in 3.00% (95% CI 2.41-3.64), 2.62% (95% CI 1.97-3.35), and 3.14% (95% CI 2.12-4.37) of overall, early (EBC) and metastatic (MBC) breast cancer patients, respectively. In EBC, the proportion increased from 2.40% at the first year to a plateau of approximately 3% after the second year. In MBC, the proportion increased from 3.00 to 3.68% when trastuzumab was used as first line or further lines of therapy, respectively. In EBC, cardiotoxicity occurred in 2.90% of patients treated with taxanes and anthracyclines compared to 0.92% in patients treated with taxanes without anthracyclines. The occurrence of cardiotoxicity varied according to age, increasing from 2.31% in individuals <50 years, to 3.46% in those 50-59 years, to 4.91% in those >60 years of age. Cardiotoxicity was higher in smokers (5.3%), dyslipidemic patients (3.9%), BMI ≥25 (6.5%), diabetes (6.2%), hypertension (5.5%), or positive history of cardiac disease (19.1%). RCTs consistently report lower cardiac toxicity rates than observational studies (EBC: 1.7 versus 3.2; MBC: 2.8 versus 4.4). Following trastuzumab initiation, approximately three in 100 patients develop severe cardiotoxicity after 2 years. Patients enrolled in cohort studies, who more closely reflect women treated for breast cancer in real-life settings compared to RCTs, are at higher risk of developing cardiac events.

Cardiotoxicity due to chemotherapy: role of cardiac imaging

The identification of patients at risk of cardiac toxicity (cardiotoxicity) from cancer therapy is challenging. There is an increasing focus on early detection of cardiotoxicity such that interventions can be instituted to prevent advanced heart failure. Clinical risk prediction tools are limited and clinical symptoms are not specific. Direct assessment of myocardial function before and during cancer treatment using cardiac imaging appears to be an objective method to identify patients at risk. Although, multiple imaging modalities and measures of cardiac function are available, the best modality or the optimal measure of function is unknown. Measurement of left ventricular ejection fraction is most commonly used; however, growing literature suggests that it is inadequate for the detection of early cardiac injury. Other measures include left ventricular diastolic function, myocardial deformation, and myocardial tissue characterization. This review will provide an overview of the clinically available measures for the assessment of cardiotoxicity.

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.

Diastolic Dysfunction Occurs Early in HER2-Positive Breast Cancer Patients Treated Concurrently With Radiation Therapy and Trastuzumab

BACKGROUND

Left ventricular ejection fraction (LVEF) is used routinely to monitor cardiac dysfunction associated with breast cancer treatment. In this study the prevalence of early left ventricular diastolic dysfunction (LVDD) and its relationship to the dose-volume of the heart irradiated were evaluated in HER2-positive breast cancer patients undergoing concurrent trastuzumab and adjuvant radiotherapy (RT).

MATERIALS AND METHODS

Data from 40 breast cancer patients treated with concurrent trastuzumab and left-sided adjuvant RT between September 2011 and October 2012 were collected prospectively. For comparison, 32 patients treated with concurrent trastuzumab and right-sided adjuvant RT and 71 patients treated with left-sided RT alone were collected retrospectively. Echocardiography was obtained before RT, immediately following RT, and 3 and 6 months after RT. Doses to the heart and left ventricle (LV) were quantified.

RESULTS

Prior to RT with concurrent trastuzumab, 11 of 29 (left) and 8 of 25 (right) patients with normal baseline left ventricular diastolic function (LVDF) developed LVDD. In patients receiving left-sided RT alone, 12 of 61 patients with normal baseline LVDF developed LVDD. Dmean, D15-D40, D60-D70, and V3-V10 of the LV were significantly higher in patients who developed LVDD after concurrent trastuzumab and left-sided RT. In contrast, only two patients developed grade 1 LVEF decrease after both concurrent treatment and left-sided RT alone.

CONCLUSION

Changes in LVDF compared with LVEF are more sensitive for early detection of cardiotoxicity. The dose-volume of the heart contributes significantly to the risk of LVDD in patients with left-sided breast cancer treated concurrently with trastuzumab.

IMPLICATIONS FOR PRACTICE

Abnormalities in diastolic function are more sensitive than changes in the left ventricular ejection fraction for detecting acute cardiotoxicity and are related to the dose-volume of the heart irradiated in patients with left-sided breast cancer receiving radiotherapy concurrently with trastuzumab. This result highlights the importance of decreasing the dose-volume of heart irradiated as a protective strategy in the treatment setting of concurrent trastuzumab and radiotherapy. Diastolic dysfunction may serve as a more sensitive tool for the early detection of cardiac damage and should be incorporated as a routine parameter in the functional monitoring of cardiotoxicity.

The role of general nuclear medicine in breast cancer

The rising incidence of breast cancer worldwide has prompted many improvements to current care. Routine nuclear medicine is a major contributor to a full gamut of clinical studies such as early lesion detection and stratification; guiding, monitoring, and predicting response to therapy; and monitoring progression, recurrence or metastases. Developments in instrumentation such as the high-resolution dedicated breast device coupled with the diagnostic versatility of conventional cameras have reinserted nuclear medicine as a valuable tool in the broader clinical setting. This review outlines the role of general nuclear medicine, concluding that targeted radiopharmaceuticals and versatile instrumentation position nuclear medicine as a powerful modality for patients with breast cancer.

Cardiac risk in the treatment of breast cancer: assessment and management

As the number of long-term breast cancer survivors has increased, the side effects of adjuvant cancer therapy, such as cardiac toxicity, remain clinically important. Although the cardiac toxicity due to anthracyclines, radiotherapy, or trastuzumab is well-documented, several issues need to be clarified and are the subjects of extensive ongoing clinical research. This review summarizes the incidence of cardiac toxicity due to breast cancer adjuvant therapy and highlights the current trends in early detection and management of cardiac toxicities.

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.

Cardiovascular toxicity associated with adjuvant trastuzumab therapy: prevalence, patient characteristics, and risk factors

Before the advent of the human epidermal growth factor receptor 2 (HER2)-targeted monoclonal antibody trastuzumab, HER2-positive breast cancers were difficult to treat and had a poor prognosis. Adjuvant trastuzumab is now an important part of the treatment regimen for many women with HER2-positive breast cancer and has undoubtedly resulted in a significant improvement in prognosis, but it is associated with a risk for cardiotoxicity. In this review, we describe the prevalence, patient characteristics, and risk factors for cardiotoxicity associated with use of adjuvant trastuzumab. Understanding risk factors for trastuzumab-induced cardiotoxicity and appropriate patient monitoring during trastuzumab treatment allows for safe and effective use of this important adjuvant therapy.

An integrated characterization of serological, pathological, and functional events in doxorubicin-induced cardiotoxicity

Many efficacious cancer treatments cause significant cardiac morbidity, yet biomarkers or functional indices of early damage, which would allow monitoring and intervention, are lacking. In this study, we have utilized a rat model of progressive doxorubicin (DOX)-induced cardiomyopathy, applying multiple approaches, including cardiac magnetic resonance imaging (MRI), to provide the most comprehensive characterization to date of the timecourse of serological, pathological, and functional events underlying this toxicity. Hannover Wistar rats were dosed with 1.25 mg/kg DOX weekly for 8 weeks followed by a 4 week off-dosing "recovery" period. Electron microscopy of the myocardium revealed subcellular degeneration and marked mitochondrial changes after a single dose. Histopathological analysis revealed progressive cardiomyocyte degeneration, hypertrophy/cytomegaly, and extensive vacuolation after two doses. Extensive replacement fibrosis (quantified by Sirius red staining) developed during the off-dosing period. Functional indices assessed by cardiac MRI (including left ventricular ejection fraction (LVEF), cardiac output, and E/A ratio) declined progressively, reaching statistical significance after two doses and culminating in "clinical" LV dysfunction by 12 weeks. Significant increases in peak myocardial contrast enhancement and serological cardiac troponin I (cTnI) emerged after eight doses, importantly preceding the LVEF decline to <50%. Troponin I levels positively correlated with delayed and peak gadolinium contrast enhancement, histopathological grading, and diastolic dysfunction. In summary, subcellular cardiomyocyte degeneration was the earliest marker, followed by progressive functional decline and histopathological manifestations. Myocardial contrast enhancement and elevations in cTnI occurred later. However, all indices predated "clinical" LV dysfunction and thus warrant further evaluation as predictive biomarkers.

Concurrent evolution of cancer cachexia and heart failure: bilateral effects exist

Cancer cachexia is defined as a multifactorial syndrome of involuntary weight loss characterized by an ongoing loss of skeletal muscle mass and progressive functional impairment. It is postulated that cardiac dysfunction/atrophy parallels skeletal muscle atrophy in cancer cachexia. Cardiotoxic chemotherapy may additionally result in cardiac dysfunction and heart failure in some cancer patients. Heart failure thus may be a consequence of either ongoing cachexia or chemotherapy-induced cardiotoxicity; at the same time, heart failure can result in cachexia, especially muscle wasting. Therefore, the subsequent heart failure and cardiac cachexia can exacerbate the existing cancer-induced cachexia. We discuss these bilateral effects between cancer cachexia and heart failure in cancer patients. Since cachectic patients are more susceptible to chemotherapy-induced toxicity overall, this may also include increased cardiotoxicity of antineoplastic agents. Patients with cachexia could thus be doubly unfortunate, with cachexia-related cardiac dysfunction/heart failure and increased susceptibility to cardiotoxicity during treatment. Cardiovascular risk factors as well as pre-existing heart failure seem to exacerbate cardiac susceptibility against cachexia and increase the rate of cardiac cachexia. Hence, chemotherapy-induced cardiotoxicity, cardiovascular risk factors, and pre-existing heart failure may accelerate the vicious cycle of cachexia-heart failure. The impact of cancer cachexia on cardiac dysfunction/heart failure in cancer patients has not been thoroughly studied. A combination of serial echocardiography for detection of cachexia-induced cardiac remodeling and computed tomography image analysis for detection of skeletal muscle wasting would appear a practical and non-invasive approach to develop an understanding of cardiac structural/functional alterations that are directly related to cachexia.

Cardiotoxicity of concomitant radiotherapy and trastuzumab for early breast cancer

BACKGROUND

Trastuzumab therapy given in combination with one of several chemotherapy regimens is currently considered the standard of care for the treatment of early-stage, human epidermal growth factor receptor-2 (HER2) -positive breast cancer. The treatment with trastuzumab is due to a significant impact on the survival part of the standard adjuvant treatment of patients with HER2-positive breast cancer. Patients treated with postoperative breast or chest wall irradiation receive trastuzumab concomitant with radiotherapy. In a small proportion of patients trastuzumab causes cardiotoxicity. Preclinical findings indicate a radiosensibilizing effect of trastuzumab in breast cancer cells, but it is not yet clear whether it radiosensibilizes cells of healthy tissues too.

CONCLUSIONS

Special attention is required when left breast or left thoracic wall is irradiated in patient receiving trastuzumab, because long-term effects of the concurrent treatment with trastuzumab and radiotherapy are not yet known. In an era where more patients are surviving a diagnosis of breast cancer, better understanding and earlier detection of therapy-induced cardiac toxicity will be of paramount importance.

Cardiac side effects of anticancer treatments: new mechanistic insights

Damage to heart cells leading to heart failure is a known complication of well-established cancer therapies including anthracycline antibiotics and radiation therapy, and the cardiovascular complications of these therapies has been controlled in large part through dose limitations and modifications of delivery methods. Recent research into the cellular and molecular mechanisms for the cardiovascular effects of these therapies may lead to other cardioprotective strategies that improve effectiveness of cancer treatments. Newer cancer therapies that have been developed based upon specifically targeting oncogene signaling also have been associated with heart failure. Rapid development of a detailed understanding of how these agents cause cardiac dysfunction promises to improve outcomes in cancer patients, as well as stimulate concepts of cardiovascular homeostasis that will likely accelerate development of cardiovascular therapies.