The Preventive role of Regular Physical Training in Ventricular Remodeling, Serum Cardiac Markers, and Exercise Performance Changes in Breast Cancer in Women Undergoing Trastuzumab Therapy-An REH-HER Study

Effects of aerobic combined with resistance exercise on cardiorespiratory fitness and cardiometabolic health in breast cancer survivors: A Systematic Review, meta-analysis and meta-regression

Background

Cardiotoxicity from chemotherapy is a serious risk to the quality of survival of breast cancer survivors (BCS), and aerobic combined with resistance exercise (CE) has the potential to combat this cardiac damage. However, there is a lack of high-quality studies to assess the specific effects of CE. This study aimed to investigate the effects of CE on cardiopulmonary function (CRF) and cardiometabolic health in BCS.

Methods

A comprehensively searched of the 4 databases (PubMed, Embase, Web of Science, Cochrane Library) from the database construction until March 1, 2023. The included studies were randomized controlled trials (RCTs) reporting the effects of CE on CRF and cardiometabolic health in BCS. The quality of the literature was assessed by two independent reviewers using the Cochrane Collaboration Risk of Bias Tool. Weight means difference (WMD), or standardized mean difference (SMD), were combined using random or fixed effects models. Subgroup and meta-regression explored heterogeneity as well as covariate effects.

Results

40 studies were included in the meta-analysis, with 2849 participants. Results showed that CE significantly increased maximal oxygen uptake (VO2max) (WMD:4.55; 95% CI:2.84, 6.26; I2 = 91.90%, P < 0.001) and reduced body weight (BW) (WMD: 1.61; 95% CI: 2.44, -0.78; I2 = 38.60%, P = 0.032) and body mass index (BMI) (WMD: 0.86; 95% CI: 1.43, -0.29; I2 = 70.50%, P < 0.001) in BCS. Subgroup analysis showed that BMI (WMD: 1.15; 95% CI: 1.89, -0.41; I2 = 76.90%, P < 0.001) and VO2max (WMD:4.21; 95% CI:2.40, 6.02; I2 = 96.4%, P < 0.001) were more effective with supervision. Meta-regression analysis showed that sample size had a significant moderating effect on BW (Coeff: 0.03, 95% CI: 0.00, 0.06).

Conclusions

CE significantly increases CRF in BCS and improves most cardiometabolic health-related outcomes. In addition, there will be a need for many larger RCTs to explore the effects of CE on inflammatory biomarkers in BCS.

The efficacy and safety of exercise regimens to mitigate chemotherapy cardiotoxicity: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Cardiotoxicity is one of the most common adverse events of the chemotherapy. Physical exercise was shown to be cardioprotective. We aim to estimate the efficacy and safety of exercise in cancer patients receiving cardiotoxic chemotherapy.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, Web of Science, SCOPUS, Cochrane, Clinical Trials.gov, and MedRxiv through July 17th, 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD), with a 95% confidence interval (CI).

PROSPERO ID

CRD42023460902.

RESULTS

We included thirteen RCTs with a total of 952 patients. Exercise significantly increased VO2 peak (MD: 1.95 with 95% CI [0.59, 3.32], P = 0.005). However, there was no significant effect regarding left ventricular ejection fraction, global longitudinal strain, cardiac output, stroke volume, left ventricular end-diastolic volume, left ventricular end-systolic volume, E/A ratio, resting heart rate, peak heart rate, resting systolic blood pressure, and resting diastolic blood pressure. Also, there was no significant difference regarding any adverse events (AEs) (RR: 4.44 with 95% CI [0.47, 41.56], P = 0.19), AEs leading to withdrawal (RR: 2.87 with 95% CI [0.79, 10.43], P = 0.11), serious AEs (RR: 3.00 with 95% CI [0.14, 65.90], P = 0.49), or all-cause mortality (RR: 0.25 with 95% CI [0.03, 2.22], P = 0.21).

CONCLUSION

Exercise is associated with increased VO2 peak in cancer patients receiving cardiotoxic chemotherapy. However, there was no significant difference between exercise and usual care regarding the echocardiographic and safety outcomes.

Exercise-based cardio-oncology rehabilitation for cardiotoxicity prevention during breast cancer chemotherapy: The ONCORE randomized controlled trial

BACKGROUND

Breast cancer (BC) treatment with anthracyclines and/or anti-human epidermal growth factor receptor-2 (HER2) antibodies is associated with an increased risk of cardiovascular disease complications, including cancer therapy-related cardiac dysfunction (CTRCD). While Cardio-Oncology Rehabilitation (CORe) programs including exercise have emerged to minimize these risks, its role in preventing CTRCD is unclear.

OBJECTIVES

We investigated the effectiveness of an exercise-based CORe program in preventing CTRCD [left ventricular ejection fraction (LVEF) drop ≥10% to a value <53% or a decrease >15% in global longitudinal strain (GLS)]. Secondary outcomes examined changes in cardiac biomarkers, physical performance including peak oxygen consumption, psychometric and lifestyle outcomes. Safety, adherence, and patient satisfaction were also assessed.

METHODS

This is a randomized controlled trial including 122 early-stage BC women receiving anthracyclines and/or anti-HER2 antibodies, randomized to CORe (n = 60) or usual care with exercise recommendation (n = 62). Comprehensive assessments were performed at baseline and after cardiotoxic treatment completion. The average duration of the intervention was 5.8 months.

RESULTS

No cases of CTRCD were identified during the study. LVEF decreased in both groups, but was significantly attenuated in the CORe group [-1.5% (-2.9, -0.1); p = 0.006], with no changes detected in GLS or cardiac biomarkers. The CORe intervention led to significant body mass index (BMI) reduction (p = 0.037), especially in obese patients [3.1 kg/m2 (1.3, 4.8)]. Physical performance and quality-of-life remained stable, while physical activity level increased in both groups. No adverse events were detected.

CONCLUSIONS

This study suggests that CORe programs are safe and may help attenuate LVEF decline in BC women receiving cardiotoxic therapy and reduce BMI in obese patients.

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.

Incorporating Exercise Training into Cardio-Oncology Care: Current Evidence and Opportunities: JACC: CardioOncology State-of-the-Art Review

Cancer treatment-induced cardiotoxicities are an ongoing concern throughout the cancer care continuum from treatment initiation to survivorship. Several "standard-of-care" primary, secondary, and tertiary prevention strategies are available to prevent the development or further progression of cancer treatment-induced cardiotoxicities and their risk factors. Despite exercise's established benefits on the cardiovascular system, it has not been widely adopted as a nonpharmacologic cardioprotective strategy within cardio-oncology care. In this state-of-the-art review, the authors discuss cancer treatment-induced cardiotoxicities, review the existing evidence supporting the role of exercise in preventing and managing these sequelae in at-risk and affected individuals living after cancer diagnoses, and propose considerations for implementing exercise-based services in cardio-oncology practice.

Risk and Management of Patients with Cancer and Heart Disease

Cancer and cardiovascular disease are two of the leading causes of global mortality and morbidity. Medical research has generated powerful lifesaving treatments for patients with cancer; however, such treatments may sometimes be at the expense of the patient's myocardium, leading to heart failure. Anti-cancer drugs, including anthracyclines, can result in deleterious cardiac effects, significantly impacting patients' functional capacity, mental well-being, and quality of life. Recognizing this, recent international guidelines and expert papers published recommendations on risk stratification and care delivery, including that of cardio-oncology services. This review will summarize key evidence with a focus on anthracycline therapy, providing clinical guidance for the non-oncology professional caring for a patient with cancer and heart failure.

Feasibility of Aerobic Exercise Training to Mitigate Cardiotoxicity of Breast Cancer Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

Current anticancer treatments for breast cancer (BC) may cause cardiotoxicity. This study aimed to investigate the effectiveness of aerobic exercise in mitigating cardiotoxicity caused by BC therapy.

MATERIALS AND METHODS

PubMed, Embase, Cochrane Library, Web of Science, and the Physiotherapy Evidence Database were searched until February 7, 2023. Clinical trials investigating the effectiveness of exercise training, including aerobic exercise, in BC patients receiving treatments that could cause cardiotoxicity were eligible. Outcome measures included cardiorespiratory fitness (CRF) (peak oxygen consumption, VO₂peak), left ventricular ejection fraction, and peak oxygen pulse. Intergroup differences were determined by standard mean differences (SMD) and 95% confidence intervals (CIs). Trial sequential analysis (TSA) was utilized to ensure whether the current evidence was conclusive.

RESULTS

Sixteen trials involving 876 participants were included. Aerobic exercise significantly improved CRF measured by VO₂peak in mL/kg/min (SMD 1.79, 95% CI 0.99-2.59) when compared to usual care. This result was confirmed through TSA. Subgroup analyses revealed that aerobic exercise given during BC therapy significantly improved VO₂peak (SMD 1.84, 95% CI 0.74-2.94). Exercise prescriptions at a frequency of up to 3 times per week, an intensity of moderate to vigorous, and a >30-minute session length also improved VO₂peak.

CONCLUSION

Aerobic exercise is effective in improving CRF when compared to usual care. Exercise performed up to 3 times per week, at a moderate-to-vigorous intensity, and having a session length >30 minutes is considered effective. Future high-quality research is needed to determine the effectiveness of exercise intervention in preventing cardiotoxicity caused by BC therapy.

Mechanisms of trastuzumab induced cardiotoxicity - is exercise a potential treatment?

The use of the adjuvant therapeutic antibody trastuzumab in breast cancer is associated with a range of cardiotoxic side effects despite successfully reducing the severity of outcomes cancer patients,. The most common cardiac effect, a reduction in left ventricular ejection fraction (LVEF), is a known precursor to heart failure and often requires interruption of chemotherapy to avoid endangering patients further. An understanding of trastuzumab's cardiac-specific interactions is therefore critical in devising new methods to not only avoid permanent cardiac damage, but also prolong treatment time, and therefore effectiveness, for breast cancer patients. Increasingly, the use of exercise as a treatment has been indicated across the field of cardio-oncology due to encouraging evidence that it can protect against LVEF reductions and heart failure. This review explores the mechanisms of trastuzumab-mediated cardiotoxicity, as well as the physiological effects of exercise on the heart, in order to assess the suitability of exercise intervention for breast cancer patients on trastuzumab antibody-therapy. We furthermore draw comparison to existing evidence for exercise intervention as a cardioprotective treatment in doxorubicin-induced cardiotoxicity. Although preclinical evidence seems to support exercise-based approaches also in trastuzumab-cardiotoxicity, current clinical evidence is too limited to confidently recommend it as a treatment, largely owing to issues of adherence. Future studies should therefore examine how the variety and duration of exercise can be adjusted to improve treatment effectiveness at a more personalised level.

Potential Role of Global Longitudinal Strain in Cardiac and Oncological Patients Undergoing Cardio-Oncology Rehabilitation (CORE)

Although shown to be effective in improving survival and quality of life in patients with cancer, some treatments are well-known causes of cardiotoxicity, such as anthracyclines, monoclonal antibodies against human epidermal growth factor receptor 2 (HER2) and radiotherapy. To prevent cardiovascular disease (CVD) in patients living with cancer, cardiologists and oncologists promoted the development of cardio-oncology, an interdisciplinary field which aims to further improving life expectancy in these patients. Cardio-oncology rehabilitation (CORE), through correction of risk factors, prescription of drug therapies and structured exercise programs, tries to improve symptoms, quality of life, cardiorespiratory fitness (CRF) and survival in patients with cancer. Different imaging modalities can be used to evaluate the real effectiveness of exercise training on cardiac function. Among these, the global longitudinal strain (GLS) has recently aroused interest, thanks to its high sensitivity and specificity for cardiac dysfunction detection due to advanced ultrasound programs. This review summarizes the evidence on the usefulness of GLS in patients with cancer undergoing cardiac rehabilitation programs.

Antioxidant Protection against Trastuzumab Cardiotoxicity in Breast Cancer Therapy

Breast cancer is the most frequent malignant neoplastic disease in women, with an estimated 2.3 million cases in 2020 worldwide. Its treatment depends on characteristics of the patient and the tumor. In the latter, characteristics include cell type and morphology, anatomical location, and immunophenotype. Concerning this latter aspect, the overexpression of the HER2 receptor, expressed in 15-25% of tumors, is associated with greater aggressiveness and worse prognosis. In recent times some monoclonal antibodies have been developed in order to target HER2 receptor overexpression. Trastuzumab is part of the monoclonal antibodies used as targeted therapy against HER2 receptor, whose major problem is its cardiac safety profile, where it has been associated with cardiotoxicity. The appearance of cardiotoxicity is an indication to stop therapy. Although the pathophysiological mechanism is poorly known, evidence indicates that oxidative stress plays a fundamental role causing DNA damage, increased cytosolic and mitochondrial ROS production, changes in mitochondrial membrane potential, intracellular calcium dysregulation, and the consequent cell death through different pathways. The aim of this review was to explore the use of antioxidants as adjuvant therapy to trastuzumab to prevent its cardiac toxicity, thus leading to ameliorate its safety profile in its administration.

Comparative clinical-related outcomes of Chinese patent medicines for cardiac hypertrophy: A systematic review and network meta-analysis of randomized clinical trials

Background: Persistent pathological cardiac hypertrophy has been associated with increased risk of heart failure and even sudden death. Multiple Chinese patent medicines (CPMs) have gained attention as alternative and complementary remedies due to their high efficiency and few side effects. However, the effects of CPM-related treatment regimens for cardiac hypertrophy had not been systematically evaluated. Aim: The objective of this study was to estimate and compare the effectiveness of different mechanisms of CPMs to improve clinical outcomes, including clinical efficacy and echocardiographic indices, in the treatment of cardiac hypertrophy patents. Methods: A network meta-analysis was conducted on CPM-related randomized controlled trials (RCTs) published between 2012 and 2022 involving cardiac hypertrophy patients from four foreign and four Chinese databases. The outcomes concerned efficacy and related indicators, including echocardiographic indices, cardiac biomarkers, and functional exercise capacity, which were evaluated as odds ratios, mean differences, and 95% credible intervals. Network plots, league tables, surface-under-the-cumulative ranking (SUCRA), and funnel plots were created for each outcome, and all analyses were conducted using Stata 16.0 software. Results: A total of 25 RCTs were evaluated; these involved 2395 patients in a network meta-analysis (NMA). The results from existing evidence indicate that blood-activating and stasis-removing Chinese patent medicine (BASR-CPM) + Western medicine (WM) showed a good improvement in clinical efficacy (OR = 8.27; 95%CI = 0.97, 70.73). A combined treatment regimen of CPM with a function of qi-replenishing, blood-activating and stasis-removing, and Western medicine was an effective treatment regimen for echocardiographic indices such as decreasing left ventricular end-systolic dimension (LVESD) (SMD = -2.35; 95%CI = -3.09, -1.62) and left ventricular mass index (LVMI) (SMD = -1.73; 95%CI = -2.92, -0.54). Furthermore, KWYR-CPM + WM and BASR-CPM also showed good improvement for echocardiographic indices of LVEDD (SMD = -1.84; 95%CI = -3.46, -0.22) and left ventricular ejection fraction (SMD = 1.90; 95%CI = -0.46, -3.35), respectively. Conclusion: The study showed that BASR-CPM + WM may be the potentially superior treatment regimen for improving clinical efficacy among cardiac hypertrophy patients. QR&BASR-CPM + WM might be the optimal treatment for decreasing LVESD and LVMI. However, due to potential risks from bias and limited RCTs, further studies with larger samples and high-quality RCTs are needed to support these findings. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=329589],identifier [CRD42022329589].

Redox Status Response of Physical Exercise Training in Women with Breast Cancer during Trastuzumab Therapy

Trastuzumab is indicated in the adjuvant setting for the early and intermediate stages of breast cancer (BC) positive for epidermal growth factor receptor 2 (HER2). Although HER2 in BC patients tends to disrupt pro-oxidant and inflammatory signaling, the influence of trastuzumab in modulating this process remains unknown. Due to the absence of any chemotherapeutic or chemoprophylactic agents for trastuzumab-induced side effects, this study investigated the potential role of regular physical exercise in modulating the antioxidant defenses, oxidative stress, and nitrosative damage in BC patients during trastuzumab treatment.

AIM

The study aimed to analyze the relationship between regular physical activity and the redox status in women with BC during trastuzumab therapy.

MATERIALS AND METHODS

We observed 50 BC patients during trastuzumab therapy in two groups: one that undertook moderately intensive supervised physical exercises, and a second that performed physical activity according to the recommendations for cancer patients, along with a third (control) group of healthy women.

RESULTS

The antioxidant enzyme and non-enzymatic antioxidant activities were significantly higher in the exercised group compared with the other participants. The concentrations of lipid and protein oxidative damage and nitrosative stress products were significantly higher in both BC groups than in the healthy controls.

CONCLUSIONS

Trastuzumab treatment stimulates a redox response in BC patients. The results highlight the oxidative imbalance in parallel with regular physical training in women with BC during trastuzumab therapy. Further studies are needed to analyze different intensities and levels of physical training in women with BC during trastuzumab treatment.

Cardiotoxicity is mitigated after a supervised exercise program in HER2-positive breast cancer undergoing adjuvant trastuzumab

Background

Trastuzumab is used, alone or in conjunction with standard chemotherapy, to treat HER2-positive breast cancer (BC). Although it improves cancer outcomes, trastuzumab. can lead to cardiotoxicity. Physical exercise is a safe and effective supportive therapy in the management of side effects, but the cardioprotective effects of exercise are still unclear.

Objectives

The primary aim of this study was to test whether trastuzumab-induced cardiotoxicity [left ventricular ejection fraction (LVEF) under 50%, or an absolute drop in LVEF of 10%] was reduced after a supervised exercise program of 3 months in patients with HER2-positive breast cancer. Secondary endpoints were to evaluate (i) cardiotoxicity rates using other criteria, (ii) cardiac parameters, (iii) cardiorespiratory fitness and (iv) whether a change in LVEF influences the cardiorespiratory fitness.

Methods

89 women were randomized to receive adjuvant trastuzumab in combination with a training program (training group: TG; n = 46) or trastuzumab alone (control group: CG; n = 43). The primary and secondary endpoints were evaluated at the end of the supervised exercise program of 3 months (T3).

Results

After exercise program, 90.5 % of TG patients and 81.8% of CG patients did not exhibit cardiotoxicity. Furthermore, whatever the used criterion, percentage of patients without cardiotoxicity were greater in TG (97.6 and 100% respectively) than in CG (90.9 and 93.9% respectively). LVEF and GLS values remained stable in both groups without any difference between the groups. In contrast, at T3, peak VO2 (+2.6 mL.min−1.kg−1; 95%CI, 1.8 to 3.4) and maximal power (+21.3 W; 95%CI, 17.3 to 25.3) increased significantly in TG, whereas they were unchanged in CG (peak VO2: +0.2 mL.min−1.kg−1; 95%CI, −0.5 to 0.9 and maximal power: +0.7 W, 95%CI, −3.6 to 5.1) compared to values measured at T0. No correlation between LVEF changes and peak VO2 or maximal power was observed.

Conclusion

A 12-week supervised exercise regimen was safe and improved the cardiopulmonary fitness in particular peak VO2, in HER2-positive BC patients treated with adjuvant trastuzumab therapy. The study is under powered to come to any conclusion regarding the effect on cardiotoxicity.

Clinical trial registration

www.ClinicalTrials.gov, identifier: NCT02433067.

Effectiveness of different types, delivery modes and extensiveness of exercise in patients with breast cancer receiving systemic treatment - A systematic review and meta-analysis

BACKGROUND

Effects of exercise in patients with breast cancer have been thoroughly investigated. The aim was to explore differences in effects regarding type, delivery mode and extensiveness (e.g. intensity; volume) of the interventions.

METHODS

We searched for randomised controlled trials including patients with breast cancer receiving systemic treatment, exercise-based interventions, and measures on patient reported- and objectively measured outcomes.

RESULTS

Exercise showed significant and moderate effects on the primary outcomes quality of life and physical function, Standardised Mean Difference: 0.52 (95 % CI 0.38-0.65) and 0.52 (95 % CI 0.38-0.66), respectively. Type of exercise had little influence on the effects, however combined aerobic- and resistance exercise seemed superior for increasing physical function, compared to aerobic or resistance exercise. Supervised interventions were superior to partly and unsupervised. Extensiveness of the intervention only influenced physical function.

CONCLUSIONS

Supervised interventions, more than type or extensiveness of interventions, seem to increase effects.

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.

A randomized trial to evaluate the impact of exercise-based cardiac rehabilitation for the prevention of chemotherapy-induced cardiotoxicity in patients with breast cancer: ONCORE study protocol

Background

Anthracyclines and monoclonal antibodies against human epidermal growth factor receptor-2 (HER2) are frequently used to treat breast cancer but they are associated with risk of developing cardiotoxicity. Implementation of cardioprotective strategies as part of breast cancer treatment are needed. To date, a limited number of studies have examined the effectiveness of cardiac rehabilitation programs or exercise programs in the prevention of cardiotoxicity through an integral assessment of cardiac function. The ONCORE study proposes an exercise-based cardiac rehabilitation program as a non-pharmacological tool for the management of chemotherapy-induced cardiotoxicity.

Methods

The study protocol describes a prospective, randomized controlled trial aimed to determine whether an intervention through an exercise-based CR program can effectively prevent cardiotoxicity induced by anthracyclines and/or anti-HER2 antibodies in women with breast cancer. Three hundred and forty women with breast cancer at early stages scheduled to receive cardiotoxic chemotherapy will be randomly assigned (1:1) to participation in an exercise-based CR program (intervention group) or to usual care and physical activity recommendation (control group). Primary outcomes include changes in left ventricular ejection fraction and global longitudinal strain as markers of cardiac dysfunction assessed by transthoracic echocardiography. Secondary outcomes comprise levels of cardiovascular biomarkers and cardiopulmonary function through peak oxygen uptake determination, physical performance and psychosocial status. Supervised exercise program-related outcomes including safety, adherence/compliance, expectations and physical exercise in- and out-of-hospital are studied as exploratory outcomes. Transthoracic echocardiography, clinical test and questionnaires will be performed at the beginning and two weeks after completion of chemotherapy.

Discussion

The growing incidence of breast cancer and the risk of cardiotoxicity derived from cancer treatments demand adjuvant cardioprotective strategies. The proposed study may determine if an exercise-based CR program is effective in minimizing chemotherapy-induced cardiotoxicity in this population of women with early-stage breast cancer. The proposed research question is concrete, with relevant clinical implications, transferable to clinical practice and achievable with low risk.

Trial registration ClinicalTrials.gov Identifier: NCT03964142. Registered on 28 May 2019. Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03964142

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-01970-2.

Six-Minute Walk Distance in Breast Cancer Survivors-A Systematic Review with Meta-Analysis

The six-minute walk test (6MWT) is a widely used test for the indirect measurement of cardiorespiratory fitness in various cancer populations. Although the 6MWT is a simple test, there are no normative values for breast cancer survivors (BCS) or comparisons of results with healthy counterparts. A systematic review with a meta-analysis was carried out, which included studies from 2007 to 2020. Ninety-one studies were found, 21 of which were included in the quantitative synthesis. Among them were 9 randomized controlled trials (RCT), 8 prospective cohort studies and 4 cross-sectional studies. A total of 1084 BCS were included. Our results revealed that healthy subjects (n = 878) covered a significantly greater distance than BCS during the 6MWT (589.9 m vs. 477.4 m, p < 0.001), and the results of the meta-regression analysis showed that the 6MWD was predicted by the participants’ BMI (p < 0.001), but not by their age (p = 0.070). After adjustment for BMI, the healthy subjects also covered greater distances than the BCS (103 m; p < 0.001). The normative values of 6MWT were presented for BCS. Besides, 6MWT distances distinguish between their healthy counterparts, therefore, the 6MWT distance is a relevant parameter for the assessment and monitoring of cardiorespiratory fitness in medical and exercise interventions for BCS.

Attenuating Treatment-Related Cardiotoxicity in Women Recently Diagnosed With Breast Cancer via a Tailored Therapeutic Exercise Program: Protocol of the ATOPE Trial

OBJECTIVE

Therapeutic exercise is already used to ameliorate some of the side effects of cancer treatment. Recent studies examined its preventive potential regarding treatment-related toxicity, which can increase the risk of functional decline and lead to disease recurrence and death. This trial will examine whether the Tailored Therapeutic Exercise and Recovery Strategies (ATOPE) program, performed before treatment, can mitigate the onset and extent of cardiotoxicity beyond that achieved when the program is followed during treatment in recently diagnosed breast cancer patients.

METHODS

The intervention has a preparatory phase plus 12 to 18 sessions of tailored, high-intensity exercise, and post-exercise recovery strategies. A total of 120 women recently diagnosed with breast cancer, at risk of cardiotoxicity due to anticancer treatment awaiting surgery followed by chemotherapy and/or radiotherapy, will be randomized to either group. In a feasibility study, measurements related to recruitment rate, satisfaction with the program, adherence to them, the retention of participants, safety, and adverse effects will be explored. In the main trial, the efficacy of these interventions will be examined. The major outcome will be cardiotoxicity, assessed echocardiographically via the left ventricular ejection fraction. Other clinical, physical, and anthropometric outcomes and biological and hormonal variables will also be assessed after diagnosis, after treatment, 1 year after treatment ends, and 3 years after treatment ends.

CONCLUSION

Given its potential effect on patient survival, the mitigation of cardiotoxicity is a priority, and physical therapists have an important role in this mitigation. If the ATOPE intervention performed before treatment returns better cardioprotection results, it may be recommendable that patients recently diagnosed follow this program.

IMPACT

The ATOPE program will highlight the need for a physical therapist intervention from the moment of diagnosis, in the prevention or mitigation of cardiotoxicity, in women with breast cancer. It could help physical therapists to establish an adequate therapeutic exercise dose adapted to breast cancer patients and to propose correct therapeutic exercise prescription according to the assimilation of the sessions.

Consideration of Sex as a Biological Variable in the Development of Doxorubicin Myotoxicity and the Efficacy of Exercise as a Therapeutic Intervention

Doxorubicin (DOX) is an anthracycline antibiotic used to treat a wide variety of hematological and solid tumor cancers. While DOX is highly effective at reducing tumor burden, its clinical use is limited by the development of adverse effects to both cardiac and skeletal muscle. The detrimental effects of DOX to muscle tissue are associated with the increased incidence of heart failure, dyspnea, exercise intolerance, and reduced quality of life, which have been reported in both patients actively receiving chemotherapy and cancer survivors. A variety of factors elevate the probability of DOX-related morbidity in patients; however, the role of sex as a biological variable to calculate patient risk remains unclear. Uncertainty regarding sexual dimorphism in the presentation of DOX myotoxicity stems from inadequate study design to address this issue. Currently, the majority of clinical data on DOX myotoxicity come from studies where the ratio of males to females is unbalanced, one sex is omitted, and/or the patient cohort include a broad age range. Furthermore, lack of consensus on standard outcome measures, difficulties in long-term evaluation of patient outcomes, and other confounding factors (i.e., cancer type, drug combinations, adjuvant therapies, etc.) preclude a definitive answer as to whether differences exist in the incidence of DOX myotoxicity between sexes. This review summarizes the current clinical and preclinical literature relevant to sex differences in the incidence and severity of DOX myotoxicity, the proposed mechanisms for DOX sexual dimorphism, and the potential for exercise training to serve as an effective therapeutic countermeasure to preserve muscle strength and function in males and females.