We systematically reviewed and synthesized evidence on the impact of physical activity/exercise on cancer treatment efficacy. We included six preclinical and seven clinical studies. Exercise significantly enhanced the efficacy of chemotherapy and tamoxifen in seven of eight rodent models in either an additive, sensitizing, or synergistic manner. In clinical studies, preliminary evidence indicates that exercise during neoadjuvant, primary, and adjuvant treatment may enhance efficacy of cancer therapies; however, no clinical study was designed for this purpose. Here we discuss the biological mechanisms of exercise-associated enhancement of therapeutic efficacy and propose future research directions to definitively examine the effects of exercise on cancer treatment and patient outcomes.

An improved understanding of the pathophysiology of trastuzumab-mediated cardiotoxicity is required to improve outcomes of patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We aimed to characterize the cardiac and cardiometabolic phenotype of trastuzumab-mediated toxicity and potential interactions with cardiac pharmacotherapy. This study was an analysis of serial magnetic resonance imaging (MRI) and circulating biomarker data acquired from patients with HER2-positive early-stage breast cancer participating in a randomized-controlled clinical trial for the pharmaco-prevention of trastuzumab-associated cardiotoxicity. Circulating biomarkers (B-type natriuretic peptide, troponin I, MMP-2 and -9, GDF-15, neuregulin-1, and IGF-1) and MRI of cardiac structure and function and abdominal fat distribution were acquired prior to trastuzumab, post-cycle 4 and post-cycle 17. Ninety-four participants (51 ± 8 years) completed the study with 30 on placebo, 33 on perindopril, and 31 on bisoprolol. Post-cycle 4, global longitudinal strain deteriorated from baseline in both placebo (+2.0 ± 2.7%, P = 0.002) and perindopril (+0.9 ± 2.5%, P = 0.04), but not with bisoprolol (−0.2 ± 2.1%, P = 0.55). In all groups combined, extracellular volume fraction and GDF-15 increased post-cycle 4 (+1.3 ± 4.4%, P = 0.004; +130 ± 150%, P ≤ 0.001, respectively). However, no significant change in troponin I was detected throughout trastuzumab. In all groups combined, visceral and intermuscular fat volume increased post-cycle 4 (+7 ± 17%, P = 0.02, +8 ± 23%, P = 0.02, respectively), while muscle volume and IGF-1 decreased from post-cycle 4 to 17 (−2 ± 10%, P = 0.008, -18 ± 28%, P < 0.001, respectively). Trastuzumab results in impaired cardiac function and early myocardial inflammation. Trastuzumab is also associated with deleterious changes to the cardiometabolic phenotype which may contribute to the increased cardiovascular risk in this population.

Background: An underlying cause of solid tumor resistance to chemotherapy treatment is diminished tumor blood supply, which leads to a hypoxic microenvironment, dependence on anaerobic energy metabolism, and impaired delivery of intravenous treatments. Preclinical data suggest that dietary strategies of caloric restriction and low-carbohydrate intake can inhibit glycolysis, while acute exercise can transiently enhance blood flow to the tumor and reduce hypoxia. The Diet Restriction and Exercise-induced Adaptations in Metastatic Breast Cancer (DREAM) study will compare the effects of a short-term, 50% calorie-restricted and ketogenic diet combined with aerobic exercise performed during intravenous chemotherapy treatment to usual care on changes in tumor burden, treatment side effects, and quality of life. Methods: Fifty patients with measurable metastases and primary breast cancer starting a new line of intravenous chemotherapy will be randomly assigned to usual care or the combined diet and exercise intervention. Participants assigned to the intervention group will be provided with food consisting of 50% of measured calorie needs with 80% of calories from fat and ≤ 10% from carbohydrates for 48–72 h prior to each chemotherapy treatment and will perform 30–60 min of moderate-intensity cycle ergometer exercise during each chemotherapy infusion, for up to six treatment cycles. The diet and exercise durations will be adapted for each chemotherapy protocol. Tumor burden will be assessed by change in target lesion size using axial computed tomography (primary outcome) and magnetic resonance imaging (MRI)-derived apparent diffusion coefficient (secondary outcome) after up to six treatments. Tertiary outcomes will include quantitative MRI markers of treatment toxicity to the heart, thigh skeletal muscle, and liver, and patient-reported symptoms and quality of life. Exploratory outcome measures include progression-free and overall survival. Discussion: The DREAM study will test a novel, short-term diet and exercise intervention that is targeted to mechanisms of tumor resistance to chemotherapy. A reduction in lesion size is likely to translate to improved cancer outcomes including disease progression and overall survival. Furthermore, a lifestyle intervention may empower patients with metastatic breast cancer by actively engaging them to play a key role in their treatment. Trial registration: ClinicalTrials.gov, NCT03795493, registered 7 January, 2019.

Cardiac rehabilitation (CR) modeled care is recommended for patients with breast cancer to mitigate risk of cardiotoxicity. However, the cardiovascular impact of CR-modeled interventions has not been studied. The purpose of this study was to evaluate if a multidisciplinary model of CR reduces cardiotoxicity and improves cardiovascular risk in patients undergoing breast cancer treatment. We randomly assigned patients with stage I to III breast cancer scheduled to receive anthracycline and/or trastuzumab-based chemotherapy to the CR intervention (n = 37) or usual care (n = 37). The intervention included guideline-directed management of cardiovascular risk factors, dietary counselling, and supervised exercise for 52 weeks. Cardiac magnetic resonance imaging, cardiopulmonary exercise testing, dual-energy x-ray absorptiometry, and serum biomarkers were acquired at baseline and 52 weeks. There was no difference in the primary outcome, left ventricular ejection fraction (LVEF), between groups at 52 weeks (61% ± 6%). Other markers of cardiotoxicity, including high-sensitivity troponin I and brain natriuretic peptide, were similar between groups. However, total cholesterol (5.2 ± 0.8 mmol/L to 4.7 ± 0.8 mmol/L, P = 0.002) and low-density lipoprotein (3.0 ± 0.7 mmol/L to 2.4 ± 0.7 mmol/L, P < 0.001) decreased in the intervention group at 52 weeks and were unchanged in usual care. In all patients, adverse cardiac and metabolic changes occurred over 52 weeks including reductions in LVEF, left ventricular mass, high-density lipoprotein, lean body mass, insulin-like growth factor-1, as well as increased triglycerides, whole-body and truncal fat mass (all P < 0.050). The CR-modeled intervention had no effect on LVEF or biomarkers of cardiotoxicity. Future lifestyle intervention trials in patients with breast cancer should consider targeting other risk factors associated with incident cardiovascular disease. (Multidisciplinary Team IntervenTion in CArdio-ONcology [TITAN Study] [TITAN]; NCT01621659)

There is substantial overlap in risk factors for the pathogenesis and progression of breast cancer (BC) and cardiovascular disease (CVD), including obesity, metabolic disturbances, and chronic inflammation. These unifying features remain prevalent after a BC diagnosis and are exacerbated by BC treatment, resulting in elevated CVD risk among survivors. Thus, therapies that target these risk factors or mechanisms are likely to be effective for the prevention or progression of both conditions. In this narrative review, we propose time-restricted eating (TRE) as a simple lifestyle therapy to address many upstream causative factors associated with both BC and CVD. TRE is simple dietary strategy that typically involves the consumption of ad libitum energy intake within 8 h, followed by a 16-h fast. We describe the feasibility and safety of TRE and the available evidence for the impact of TRE on metabolic, cardiovascular, and cancer-specific health benefits. We also highlight potential solutions for overcoming barriers to adoption and adherence and areas requiring future research. In composite, we make the case for the use of TRE as a novel, safe, and feasible intervention for primary and secondary BC prevention, as well as tertiary prevention as it relates to CVD in BC survivors.