EXercise to prevent AnthrCycline-based Cardio-Toxicity (EXACT) in individuals with breast or hematological cancers: a feasibility study protocol

Preventing broken hearts in women with breast cancer: a concise review on chemotherapy-mediated cardiotoxicity

Cancer and cardiovascular disease are the leading causes of death for Canadian women. One in eight Canadian women will receive the life-changing diagnosis of breast cancer (BC) in their lifetime, with 1 in 34 dying from the disease. Although doxorubicin (DOX) and trastuzumab (TRZ) have significantly improved survival in women diagnosed with human epidermal growth factor receptor 2 (HER2)-positive BC, approximately one in four women who receive this treatment are at risk of developing chemotherapy-induced cardiotoxicity. Cardiotoxicity is defined as a decline in left ventricular ejection fraction (LVEF) of >10% to an absolute value of <53%. Current guidelines recommend the serial monitoring of LVEF in this patient population using non-invasive cardiac imaging modalities including transthoracic echocardiography or multi-gated acquisition scan; however, this will only allow for the detection of established cardiotoxicity. Recent studies have demonstrated that a reduction in global longitudinal strain by speckle tracking echocardiography can identify pre-clinical systolic dysfunction prior to a decline in overall LVEF. Implementation of early detection techniques would allow for the prompt initiation of cardioprotective strategies. In addition to the early detection of chemotherapy-mediated cardiotoxicity, the prophylactic use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, statins, exercise, and nutraceutical therapies have been studied in the setting of cardio-oncology.

Exercise to Reduce Anthracycline-Mediated Cardiovascular Complications in Breast Cancer Survivors

While developments in cancer therapeutics have greatly reduced morbidity and mortality in females with breast cancer, it comes at a cost of an increased risk of cardiovascular complications. In particular, anthracyclines, like doxorubicin, which are a mainstay of current chemotherapy regimens, are associated with dose-dependent cardiotoxicity. Exercise has been widely accepted as an effective intervention in reducing cardiovascular risk in a variety of different clinical conditions. However, the benefits of exercise in anthracycline-mediated cardiotoxicity are not clearly understood. First, this review discusses the pre-clinical studies which have elucidated the cardioprotective mechanisms of aerobic and resistance exercise in improving cardiovascular function in the setting of anthracycline treatment. Next, it aims to summarize the results of aerobic and resistance exercise clinical trials conducted in females with breast cancer who received anthracycline-based chemotherapy. The review further discusses the current exercise guidelines for women undergoing chemotherapy and contraindications for exercise. Finally, the review addresses gaps in research, specifically the need for further clinical trials to establish a recommended exercise prescription within this patient population.

Efficacy of Physical Exercise to Offset Anthracycline-Induced Cardiotoxicity: A Systematic Review and Meta-Analysis of Clinical and Preclinical Studies

Background

Physical exercise is an intervention that might protect against doxorubicin‐induced cardiotoxicity. In this meta‐analysis and systematic review, we aimed to estimate the effect of exercise on doxorubicin‐induced cardiotoxicity and to evaluate mechanisms underlying exercise‐mediated cardioprotection using (pre)clinical evidence.

Methods and Results

We conducted a systematic search in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Cochrane's and Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk‐of‐bias tools were used to assess the validity of human and animal studies, respectively. Cardiotoxicity outcomes reported by ≥3 studies were pooled and structured around the type of exercise intervention. Forty articles were included, of which 3 were clinical studies. Overall, in humans (sample sizes ranging from 24 to 61), results were indicative of exercise‐mediated cardioprotection, yet they were not sufficient to establish whether physical exercise protects against doxorubicin‐induced cardiotoxicity. In animal studies (n=37), a pooled analysis demonstrated that forced exercise interventions significantly mitigated in vivo and ex vivo doxorubicin‐induced cardiotoxicity compared with nonexercised controls. Similar yet slightly smaller effects were found for voluntary exercise interventions. We identified oxidative stress and related pathways, and less doxorubicin accumulation as mechanisms underlying exercise‐induced cardioprotection, of which the latter could act as an overarching mechanism.

Conclusions

Animal studies indicate that various exercise interventions can protect against doxorubicin‐induced cardiotoxicity in rodents. Less doxorubicin accumulation in cardiac tissue could be a key underlying mechanism. Given the preclinical evidence and limited availability of clinical data, larger and methodologically rigorous clinical studies are needed to clarify the role of physical exercise in preventing cardiotoxicity in patients with cancer.

Registration

URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42019118218.

Exercise, cancer and cardiovascular disease: what should clinicians advise?

Cardiovascular disease is one of the leading causes of morbidity and mortality in persons with cancer. The elevated risk is thought to derive from the combination of cardiovascular risk factors and direct cardiotoxicity from cancer therapies. Exercise may be a potential strategy to counteract these toxicities and maintain cardiovascular reserve. In this article, we review the evidence for the potential cardioprotective effects of exercise training in cancer patients before, during, and following treatment. We also propose a patient-tailored approach for the development of targeted prescriptions based on individual exercise capacity and cardiovascular reserve.

Role of Oxidative Stress in the Mechanisms of Anthracycline-Induced Cardiotoxicity: Effects of Preventive Strategies

Anthracycline-induced cardiotoxicity (AIC) persists as a significant cause of morbidity and mortality in cancer survivors. Although many protective strategies have been evaluated, cardiotoxicity remains an ongoing threat. The mechanisms of AIC remain unclear; however, several pathways have been proposed, suggesting a multifactorial origin. When the central role of topoisomerase 2β in the pathophysiology of AIC was described some years ago, the classical reactive oxygen species (ROS) hypothesis shifted to a secondary position. However, new insights have reemphasized the importance of the role of oxidative stress-mediated signaling as a common pathway and a critical modulator of the different mechanisms involved in AIC. A better understanding of the mechanisms of cardiotoxicity is crucial for the development of treatment strategies. It has been suggested that the available therapeutic interventions for AIC could act on the modulation of oxidative balance, leading to a reduction in oxidative stress injury. These indirect antioxidant effects make them an option for the primary prevention of AIC. In this review, our objective is to provide an update of the accumulated knowledge on the role of oxidative stress in AIC and the modulation of the redox balance by potential preventive strategies.

Prevention of doxorubicin-induced Cardiotoxicity by pharmacological non-hypoxic myocardial preconditioning based on Docosahexaenoic Acid (DHA) and carvedilol direct antioxidant effects: study protocol for a pilot, randomized, double-blind, controlled trial (CarDHA trial)

Background

Anthracycline-induced cardiotoxicity (AIC), a condition associated with multiple mechanisms of damage, including oxidative stress, has been associated with poor clinical outcomes. Carvedilol, a β-blocker with unique antioxidant properties, emerged as a strategy to prevent AIC, but recent trials question its effectiveness. Some evidence suggests that the antioxidant, not the β-blocker effect, could prevent related cardiotoxicity. However, carvedilol’s antioxidant effects are probably not enough to prevent cardiotoxicity manifestations in certain cases. We hypothesize that breast cancer patients taking carvedilol as well as a non-hypoxic myocardial preconditioning based on docosahexaenoic acid (DHA), an enhancer of cardiac endogenous antioxidant capacity, will develop less subclinical cardiotoxicity manifestations than patients randomized to double placebo.

Methods/design

We designed a pilot, randomized controlled, two-arm clinical trial with 32 patients to evaluate the effects of non-hypoxic cardiac preconditioning (DHA) plus carvedilol on subclinical cardiotoxicity in breast cancer patients undergoing anthracycline treatment. The trial includes four co-primary endpoints: changes in left ventricular ejection fraction (LVEF) determined by cardiac magnetic resonance (CMR); changes in global longitudinal strain (GLS) determined by two-dimensional echocardiography (ECHO); elevation in serum biomarkers (hs-cTnT and NT-ProBNP); and one electrocardiographic variable (QTc interval). Secondary endpoints include other imaging, biomarkers and the occurrence of major adverse cardiac events during follow-up. The enrollment and follow-up for clinical outcomes is ongoing.

Discussion

We expect a group of anthracycline-treated breast cancer patients exposed to carvedilol and non-hypoxic myocardial preconditioning with DHA to show less subclinical cardiotoxicity manifestations than a comparable group exposed to placebo.

Trial registration

ISRCTN registry, ID: ISRCTN69560410. Registered on 8 June 2016.

Exercise stimulates beneficial adaptations to diminish doxorubicin-induced cellular toxicity

Doxorubicin (DOX) is a highly effective antitumor agent used for the treatment of a wide range of cancers. Unfortunately, DOX treatment results in cytotoxic side effects due to its accumulation within off-target tissues. DOX-induced cellular toxicity occurs as a result of increased oxidative damage, resulting in apoptosis and cell death. While there is no standard-of-care practice to prevent DOX-induced toxicity to healthy organs, exercise has been shown to prevent cellular dysfunction when combined with DOX chemotherapy. Endurance exercise stimulates numerous biochemical adaptations that promote a healthy phenotype in several vulnerable tissues without affecting the antineoplastic properties of DOX. Therefore, for the development of an effective strategy to combat the pathological effects of DOX, it is important to determine the appropriate exercise regimen to prescribe to cancer patients receiving DOX therapy and to understand the mechanisms responsible for exercise-induced protection against DOX toxicity to noncancer cells. This review summarizes the cytotoxic effects of DOX on the heart, skeletal muscle, liver, and kidneys and discusses the current understanding of the clinical benefits of regular physical activity and the potential mechanisms mediating the positive effects of exercise on each organ system.

Cardiac Complications in the Adult Bone Marrow Transplant Patient

PURPOSE OF REVIEW

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

RECENT FINDINGS

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