Decline in the use of anthracyclines for breast cancer

Risk Stratification for Trastuzumab-Induced Cardiac Dysfunction and Potential Implications for Surveillance

BACKGROUND

Although patient factors and sequential anthracycline use contribute to risk for cancer therapy-related cardiac dysfunction (CTRCD) with HER2-directed cancer therapy, frequent (every 3 months) left ventricular ejection fraction (LVEF) surveillance is recommended irrespective of baseline risk.

OBJECTIVES

The aim of this study was to examine the incidence of trastuzumab-associated CTRCD in a contemporary cohort with HER2-positive breast cancer and assess the performance of a risk assessment tool to identify patients at low risk for CTRCD to guide risk-based surveillance strategies.

METHODS

A retrospective cohort of patients with HER2-positive breast cancer treated with trastuzumab at a tertiary cancer center was examined. Patients were categorized as low, medium, and high or very high risk for CTRCD by Heart Failure Association/International Cardio-Oncology Society risk assessment.

RESULTS

Of 496 patients treated with trastuzumab, 29.8% also received anthracyclines. Over a median follow-up period of 51 months, 8.7% developed CTRCD, but only 1.6% had associated heart failure (HF). CTRCD rates were 3.6%, 12.8%, and 32.1% in low-risk, medium-risk, and high or very high risk groups, respectively. HF incidence was 0.4% in the low-risk group and 2.1% in the medium-risk group, with no HF in patients at low- or medium-risk who received trastuzumab without anthracyclines. HF was observed in 11% of high-risk patients. The risk assessment had a negative predictive value for CTRCD in low vs moderate- or high-risk patients of 96.4% (95% CI: 93.5%-98.3%).

CONCLUSIONS

The findings support the exploration of a prospective personalized risk-based approach to cardiac LVEF surveillance during trastuzumab therapy. Less frequent LVEF monitoring in low-risk patients may optimize resource use and reduce patient burden without compromising safety.

Cardiovascular mortality trends and disparities in U.S. breast cancer patients, 1999-2020: a population-based retrospective study

BACKGROUND

Breast cancer survivors face a higher risk of cardiovascular disease (CVD) compared to non-breast cancer patients, yet contemporary data on CVD-related mortality within this group remains scarce.

OBJECTIVE

To investigate trends and disparities in CVD mortality among breast cancer patients.

METHODS

We queried the Centers for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research (CDC Wonder) and conducted serial cross-sectional analyses on national death certificate data for CVD mortality in breast cancer patients aged 25 and above from 1999 to 2020. We calculated age-adjusted mortality rates (AAMR) per 100,000 individuals and analyzed trends over time using the Joinpoint Regression Program, with further analyses stratified by age, race, census region, and urbanization level.

RESULTS

A total of 74,733 CVDs with comorbid breast cancer in the United States were identified between 1999 and 2020. The AAMR from CVDs with comorbid breast cancer decreased from 2.57 (95% CI [2.50-2.65]) in 1999 to 1.20 (95% CI [1.15-1.24]) in 2020, with an average annual percent change (AAPC) of - 4.3. The three most common causes of CVDs were ischemic heart disease (47.8%), cerebrovascular disease (17.1%), and hypertensive disease (10.6%). Our analysis revealed a significant decrease in AAMR for all CVD subtypes, except for hypertensive diseases and arrhythmias. The decrease in annual percent change (APC) was more pronounced in individuals aged ≥ 65 years compared to those < 65 years (-4.4, 95%CI [-4.9, -3.9] vs. -2.9, 95%CI [-4.1, -1.7], respectively. Notably, non-Hispanic Blacks consistently exhibited the highest AAMR (1.95, 95%CI [1.90-1.99]), whereas Hispanic or Latina patients had the lowest AAMR (0.75, 95% CI [0.72-0.78]). The AAMR was also higher in rural regions than in urban areas (1.64, 95%CI [1.62-1.67] vs. 1.55, 95%CI [1.53-1.56]).

CONCLUSION

The study highlights a significant decline in CVD mortality among breast cancer patients over two decades, with persistent disparities by race and region. Exceptionally, hypertensive diseases and arrhythmias did not follow this declining trend.

Anthracyclines induce cardiotoxicity through a shared gene expression response signature

TOP2 inhibitors (TOP2i) are effective drugs for breast cancer treatment. However, they can cause cardiotoxicity in some women. The most widely used TOP2i include anthracyclines (AC) Doxorubicin (DOX), Daunorubicin (DNR), Epirubicin (EPI), and the anthraquinone Mitoxantrone (MTX). It is unclear whether women would experience the same adverse effects from all drugs in this class, or if specific drugs would be preferable for certain individuals based on their cardiotoxicity risk profile. To investigate this, we studied the effects of treatment of DOX, DNR, EPI, MTX, and an unrelated monoclonal antibody Trastuzumab (TRZ) on iPSC-derived cardiomyocytes (iPSC-CMs) from six healthy females. All TOP2i induce cell death at concentrations observed in cancer patient serum, while TRZ does not. A sub-lethal dose of all TOP2i induces limited cellular stress but affects calcium handling, a function critical for cardiomyocyte contraction. TOP2i induce thousands of gene expression changes over time, giving rise to four distinct gene expression response signatures, denoted as TOP2i early-acute, early-sustained, and late response genes, and non-response genes. There is no drug- or AC-specific signature. TOP2i early response genes are enriched in chromatin regulators, which mediate AC sensitivity across breast cancer patients. However, there is increased transcriptional variability between individuals following AC treatments. To investigate potential genetic effects on response variability, we first identified a reported set of expression quantitative trait loci (eQTLs) uncovered following DOX treatment in iPSC-CMs. Indeed, DOX response eQTLs are enriched in genes that respond to all TOP2i. Next, we identified 38 genes in loci associated with AC toxicity by GWAS or TWAS. Two thirds of the genes that respond to at least one TOP2i, respond to all ACs with the same direction of effect. Our data demonstrate that TOP2i induce thousands of shared gene expression changes in cardiomyocytes, including genes near SNPs associated with inter-individual variation in response to DOX treatment and AC-induced cardiotoxicity.

Cardiotoxicity of anti-cancer drugs: cellular mechanisms and clinical implications

Cardio-oncology is an emerging field that seeks to enhance quality of life and longevity of cancer survivors. It is pertinent for clinicians to understand the cellular mechanisms of prescribed therapies, as this contributes to robust understanding of complex treatments and off-target effects, improved communication with patients, and guides long term care with the goal to minimise or prevent cardiovascular complications. Our aim is to review the cellular mechanisms of cardiotoxicity involved in commonly used anti-cancer treatments and identify gaps in literature and strategies to mitigate cardiotoxicity effects and guide future research endeavours.

Comparison of cardiovascular disease risk in women with and without breast cancer: secondary data analysis with the 2014-2018 korean national health and nutrition examination survey

BACKGROUND

Aging breast cancer survivors may be at an elevated risk of cardiovascular disease (CVD), but little is known about CVD risk assessment and breast cancer in Korean women. We hypothesized that Korean breast cancer survivors would have higher risks of future CVD within the next 10 years (i.e., Framingham Risk Score [FRS]) than women without cancer.

OBJECTIVES

(1) To compare FRS-based CVD risks in women with and without breast cancer based on propensity score matching; and (2) To explore adiposity-related measures in relation to FRS in Korean women with breast cancer.

METHODS

Using the cross-sectional data from the 2014-2018 Korean National Health and National Survey (KNHANES), we identified 136 women with breast cancer aged 30-74 years who had no other cancer and no CVD. The comparison group of 544 women with no cancer were selected by 1:4 nearest-neighbor propensity score matching based on breast cancer diagnosis. CVD risk was assessed by FRS based on multiple traditional risk factors (e.g., cholesterol, blood pressure, diabetes, and smoking). Adiposity was measured by physical examination, including body mass index (BMI) and waist-to-height ratio (WHtR). Physical activity and health behaviors were assessed by self-reports.

RESULTS

Women with breast cancer (mean age of 57 years) had similar FRS levels at a low-risk category (< 10%) to women with no cancer (4.9% vs. 5.5%). Breast cancer survivors (mean 8.5 survival years) presented at significantly lower levels of total cholesterol, BMI, and WHtR (all p values < 0.05) than their counterpart. Within the breast cancer group, WHtR ≥ 0.5 was associated with higher FRS, compared to WHtR < 0.5. FRS was not different by survival < 5 years or ≥ 5 years after breast cancer diagnosis.

CONCLUSIONS

FRS-based CVD risks were not different in Korean, mostly postmenopausal, women by breast cancer status. Whereas breast cancer survivors had even lower levels of lipid and adiposity measures than women without cancer, those values indicating borderline cardiometabolic risk suggest continued screening and management efforts for these aging women. Future studies are needed to examine longitudinal trajectories of CVD risk factors and CVD outcomes among Korean breast cancer survivors.

Targeting the Divergent Roles of STK3 Inhibits Breast Cancer Cell Growth and Opposes Doxorubicin-Induced Cardiotoxicity In Vitro

Breast cancer (BCa) is the most prevalent type of cancer in women. Several therapies used in the treatment of breast cancer are associated with clinically important rates of cardiovascular toxicity during or after treatment exposure, including anthracyclines. There is a need for new BCa therapeutics and treatments that mitigate chemotherapy-induced cardiotoxicity in BCa. In this study, we examine the effects of Serine/Threonine Kinase 3 (STK3) inhibition in the context of BCa therapy and cardioprotection from doxorubicin. STK3 (also known as MST2) is a key member of the Hippo Tumor-Suppressor Pathway, which regulates cell growth and proliferation by inhibiting YAP/TAZ co-transcription factors. Canonically, STK3 should restrict BCa growth; however, we observed that STK3 is amplified in BCa and associated with worse patient outcomes, suggesting a noncanonical pro-tumorigenic role. We found BCa cell lines have varying dependence on STK3. SUM52PE cells had the highest expression and dependence on STK3 in genetic and pharmacological assays. MCF-7 and MDA-MB-231 were less sensitive to STK3 targeting in standard proliferation assays, but were STK3 dependent in colony formation and matrigel invasion assays. In contrast, STK3 inhibition mitigated the toxic effects of doxorubicin in H9C2 rat cardiomyocytes by increasing YAP expression. Importantly, STK3 inhibition in BCa cells did not interfere with the therapeutic effects of doxorubicin. Our studies highlight STK3 is a potential molecular target for BCa with dual therapeutic effects: suppression of BCa growth and progression, and chemoprotection in cardiomyocytes.

High-intensity interval training improves metabolic syndrome in women with breast cancer receiving Anthracyclines

INTRODUCTION

Anthracycline chemotherapy is a frequent treatment for breast cancer, whereas it can increase risk of physiologic side-effects, such as metabolic syndrome (MetS). Exercise has been used as a non-pharmacological strategy to decrease MetS. Specifically, high-intensity interval training (HIIT) has been shown to improve MetS in patients with diabetes or cardiac rehabilitation patients; however, the effects of HIIT on MetS and associated biomarkers in patients with breast cancer receiving anthracycline chemotherapy have not been previously explored. Therefore, we purposed to determine the effects of HIIT on MetS in breast cancer patients undergoing anthracycline chemotherapy.

METHODS

In total, 30 patients with breast cancer were recruited prior to initiating treatment and randomized into HIIT (n = 15) or control (n = 15). The HIIT group attended supervised cycling sessions 3 days/week for 8 weeks. MetS was assessed by waist circumference, blood pressure, fasting levels of high-density lipoprotein cholesterol (HDL-C), triglycerides, and glucose. Circulating levels of MetS-related biomarkers were also measured (total cholesterol, insulin, HbA1c, leptin, adiponectin, and c-reactive protein).

RESULTS

After 8 weeks, MetS z-score was significantly improved in the HIIT group compared with controls (-7.60, 95% CI: -9.08 to -6.13, p < 0.001). MetS variables (HDL-C, glucose, and triglycerides) and circulating levels of MetS-related biomarkers were significantly improved in the HIIT group compared with controls (p < 0.001). Non-significant differences were found in body composition outcomes at the end of the study.

CONCLUSIONS

HIIT may be an effective strategy to improve MetS in breast cancer patients undergoing anthracycline chemotherapy. Furthermore, changes in MetS were independent of changes in body composition.

Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis

Previous evidence on postdiagnosis body fatness and mortality after breast cancer was graded as limited-suggestive. To evaluate the evidence on body mass index (BMI), waist circumference, waist-hip-ratio and weight change in relation to breast cancer prognosis, an updated systematic review was conducted. PubMed and Embase were searched for relevant studies published up to 31 October, 2021. Random-effects meta-analyses were conducted to estimate summary relative risks (RRs). The evidence was judged by an independent Expert Panel using pre-defined grading criteria. One randomized controlled trial and 225 observational studies were reviewed (220 publications). There was strong evidence (likelihood of causality: probable) that higher postdiagnosis BMI was associated with increased all-cause mortality (64 studies, 32 507 deaths), breast cancer-specific mortality (39 studies, 14 106 deaths) and second primary breast cancer (11 studies, 5248 events). The respective summary RRs and 95% confidence intervals per 5 kg/m2 BMI were 1.07 (1.05-1.10), 1.10 (1.06-1.14) and 1.14 (1.04-1.26), with high between-study heterogeneity (I2  = 56%, 60%, 66%), but generally consistent positive associations. Positive associations were also observed for waist circumference, waist-hip-ratio and all-cause and breast cancer-specific mortality. There was limited-suggestive evidence that postdiagnosis BMI was associated with higher risk of recurrence, nonbreast cancer deaths and cardiovascular deaths. The evidence for postdiagnosis (unexplained) weight or BMI change and all outcomes was graded as limited-no conclusion. The RCT showed potential beneficial effect of intentional weight loss on disease-free-survival, but more intervention trials and well-designed observational studies in diverse populations are needed to elucidate the impact of body composition and their changes on breast cancer outcomes.

Nicorandil Ameliorates Doxorubicin-Induced Cardiotoxicity in Rats, as Evaluated by 7 T Cardiovascular Magnetic Resonance Imaging

PURPOSE

Doxorubicin-induced cardiotoxicity (DIC) is a common side effect of doxorubicin chemotherapy, and a major mechanism of DIC is inflammation. However, no effective method exists to prevent DIC. In the present study, we investigated the cardioprotective effects of nicorandil against DIC using multiparametric cardiac magnetic resonance (CMR) imaging and elucidated the anti-inflammatory properties of nicorandil in rat models.

METHODS

Male Sprague-Dawley rats received four weekly intraperitoneal doxorubicin doses (4 mg/kg/injection) to establish the DIC model. After treatment with or without nicorandil (3 mg/kg/day) or diazoxide (10 mg/kg/day) orally, all the groups underwent weekly CMR examinations, including cardiac function and strain assessment and T2 mapping, for 6 weeks. Additionally, blood samples and hearts were collected to examine inflammation and histopathology.

RESULTS

According to our results, the earliest DIC CMR parameter in the doxorubicin group was T2 mapping time prolongation compared with the DIC rats treated with nicorandil (doxorubicin+nicorandil group) at week 2. Subsequently, the left ventricular ejection fraction (LVEF) and global peak systolic myocardial strain in the doxorubicin group were significantly reduced, and nicorandil effectively inhibited these effects at week 6. Our results were confirmed by histopathological evaluations. Furthermore, nicorandil treatment had a protective effect against the doxorubicin-induced inflammatory response. Interestingly, similar protective results were obtained using the KATP channel opener diazoxide.

CONCLUSION

Collectively, our findings indicate that nicorandil application ameliorates DIC in rats with significantly higher cardiac function and myocardial strain and less fibrosis, apoptosis and inflammatory cytokine production. Nicorandil prevents T2 abnormalities in the early stages of DIC, showing a high clinical value for early nicorandil treatment in chemotherapy patients.

Serum sodium ions and chloride ions associated with taxane-induced peripheral neuropathy in Chinese patients with early-stage breast cancer: A nation-wide multicenter study

BACKGROUND

Taxane-induced peripheral neuropathy (TIPN) is a debilitating adverse effect of cancer treatments with taxanes which may require a reduction or discontinuation chemotherapy and affect clinical and survival outcomes. A number of factors have contributed to the increasing prevalence of TIPN. Nonetheless, limited knowledge exists of potential prechemotherapy blood-based biochemical factors associated with TIPN development.

METHODS

We recruited breast cancer patients at seven cancer institutions in China. Participants aged 18 years or older with stage I to III breast cancer who scheduled to undergo primary neoadjuvant and adjuvant chemotherapy with taxanes were eligible. Eligible patients underwent patient-reported neuropathy assessments using the EORTC-CIPN20 questionnaire. Patients completed the questionnaire before commencing treatment and after every cycle. For every patient, we selected the highest TIPN toxicity score for analysis since the first cycle. The posttreatment TIPN severity was compared with blood-based biochemical factors within 30 days before commencing treatment. Independent samples t tests, Mann-Whitney U tests and linear regression were used to identify blood-based and clinical associations with TIPN development.

RESULTS

The study included 873 breast cancer participants who received paclitaxel, docetaxel or nanoparticle albumin-bound (nab)-paclitaxel. In the whole cohort, factors associated with higher TIPN toxicity scores were higher cumulative chemotherapy dose (β = 0.005; 95% CI, 0.004 to 0.006; P < .001), lower sodium ions (β = -0.24; 95% CI, -0.39 to -0.09; P = .002) and higher chloride ions (β = 0.30; 95% CI, 0.16 to 0.44; P < .001).

CONCLUSIONS

The findings suggest that breast cancer patients with a higher cumulative chemotherapy dose, lower pretreatment sodium ions, and higher pretreatment chloride ions receiving taxanes should receive closer monitoring to mitigate the development of short-term and long-term TIPN.

Early myocardial oedema can predict subsequent cardiomyopathy in high-dose anthracycline therapy

AIMS

This study aims to assess subclinical changes in functional and morphologic myocardial MR parameters very early into a repetitive high-dose anthracycline treatment (planned cumulative dose >650 mg/m² ), which may predict subsequent development of anthracycline-induced cardiomyopathy (aCMP).

METHODS

Thirty sarcoma patients with previous exposition of 300-360 mg/m² doxorubicin-equivalent chemotherapy who were planned for a second treatment of anthracycline-based chemotherapy (360 mg/m² doxorubicin-equivalent) were recruited. Enrolled individuals received three CMR studies (before treatment, 48 h after first anthracycline treatment and upon completion of treatment). Native T1 mapping (MOLLI 5s(3s)3s), T2 mapping, and extracellular volume (ECV) maps were acquired in addition to a conventional CMR with SSFP-cine imaging at 1.5 T. Patients were given 0.2 mmol/kg gadoteridol for ECV quantification and LGE imaging. Blood samples for cardiac biomarkers were obtained before each scan. Development of relevant aCMP was defined as drop of left ventricular ejection fraction (LVEF) by >10% compared with baseline.

RESULTS

Twenty-three complete datasets were available for analysis. Median treatment time was 20.7 ± 3.0 weeks. Eight patients developed aCMP with LVEF reduction >10% until end of chemotherapy. Baseline LVEF was not different between patients with and without subsequent aCMP. Patients with aCMP had decreased LV mass upon completion of therapy (99.4 ± 26.5 g vs. 90.3 ± 24.8 g; P = 0.02), whereas patients without aCMP did not show a change in LV mass (91.5 ± 20.0 g vs. 89.0 ± 23.6 g; P > 0.05). On strain analysis, GLS (-15.3 ± 1.3 vs. -13.4 ± 1.6; P = 0.02) and GCS (-16.7 ± 2.1 vs. -14.9 ± 2.6; P = 0.04) were decreased in aCMP patients upon completion of therapy, whereas non-aCMP individuals showed no change in GLS (-15.4 ± 3.3 vs. -15.4 ± 3.4; P = 0.97). When assessed 48 h after first dose of anthracyclines, patients with subsequent aCMP had significantly elevated myocardial T2 times compared with before therapy (53.0 ± 2.8 ms vs. 49.3 ± 5.2 ms, P = 0.02) than patients who did not develop aCMP (50.7 ± 5.1 ms vs. 51.1 ± 3.9 ms, P > 0.05). Native T1 times decreased at 48 h after first dose irrespective of development of subsequent aCMP (1020.2 ± 28.4 ms vs. 973.5 ± 40.3 ms). Upon completion of therapy, patients with aCMP had increased native T1 compared with baseline (1050.8 ± 17.9 ms vs. 1022.4 ± 22.0 ms; P = 0.01), whereas non-aCMP patients did not (1034.5 ± 46.6 ms vs. 1018.4 ± 29.7 ms; P = 0.15). No patient developed new myocardial scars or compact myocardial fibrosis under chemotherapy. Cardiac biomarkers were elevated independent of development of aCMP.

CONCLUSIONS

With high cumulative anthracycline doses, early increase of T2 times 48 h after first treatment with anthracyclines can predict the development of subsequent aCMP after completion of chemotherapy. Early drop of native T1 times occurs irrespective of development of aCMP in high-dose anthracycline therapy.

Cardio-oncology: Implications for Clinical Practice for Women

PURPOSE OF REVIEW

Clinical cardio-oncology considerations specific to women span across many areas and are particularly relevant for management of patients with sex-specific cancers, such as breast cancer.

RECENT FINDINGS

Major improvement in breast cancer survivorship over the last decade and the recognition of CV disease as the second leading cause of death among survivors point to the relevance of long-term cardiovascular (CV) safety. This review summarizes the CV effects associated with multimodality breast cancer treatments and contemporary approach to CV risk stratification, prevention, early detection, monitoring, and management at the time of cancer diagnosis, during and after completion of treatment. We highlight the growing role of a multidisciplinary, team-based approach for comprehensive CV and oncology care through the entire cancer treatment continuum, from diagnosis through survivorship.

Anthracycline-induced cardiotoxicity: From pathobiology to identification of molecular targets for nuclear imaging

Anthracyclines are a widely used class of chemotherapy in pediatric and adult cancers, however, their use is hampered by the development of cardiotoxic side-effects and ensuing complications, primarily heart failure. Clinically used imaging modalities to screen for cardiotoxicity are mostly echocardiography and occasionally cardiac magnetic resonance imaging. However, the assessment of diastolic and global or segmental systolic function may not be sensitive to detect subclinical or early stages of cardiotoxicity. Multiple studies have scrutinized molecular nuclear imaging strategies to improve the detection of anthracycline-induced cardiotoxicity. Anthracyclines can activate all forms of cell death in cardiomyocytes. Injury mechanisms associated with anthracycline usage include apoptosis, necrosis, autophagy, ferroptosis, pyroptosis, reactive oxygen species, mitochondrial dysfunction, as well as cardiac fibrosis and perturbation in sympathetic drive and myocardial blood flow; some of which have been targeted using nuclear probes. This review retraces the pathobiology of anthracycline-induced cardiac injury, details the evidence to date supporting a molecular nuclear imaging strategy, explores disease mechanisms which have not yet been targeted, and proposes a clinical strategy incorporating molecular imaging to improve patient management.

Chemotherapy Regimens Received by Women With BRCA1/2 Pathogenic Variants for Early Stage Breast Cancer Treatment

BACKGROUND

Genetic testing is widespread among breast cancer patients; however, no guideline recommends using germline genetic testing results to select a chemotherapy regimen. It is unknown whether breast cancer patients who carry pathogenic variants (PVs) in BRCA1 and/or 2 (BRCA1/2) or other cancer-associated genes receive different chemotherapy regimens than noncarriers.

METHODS

We linked Surveillance, Epidemiology, and End Results registry records from Georgia and California to germline genetic testing results from 4 clinical laboratories. Patients who 1) had stages I-III breast cancer, either hormone receptor (HR) positive and HER2 negative or triple negative (TNBC), diagnosed in 2013-2017; 2) received chemotherapy; and 3) were linked to genetic results were included. Chemotherapy details were extracted from Surveillance, Epidemiology, and End Results text fields completed by registrars. We examined whether PV carriers received more intensive regimens (HR-positive,HER2-negative: ≥3 drugs including an anthracycline; TNBC: ≥4 drugs including an anthracycline and platinum) and/or less standard breast cancer agents (a platinum). All statistical tests were 2-sided.

RESULTS

Among 2293 patients, 1451 had HR-positive, HER2-negative disease, and 842 had TNBC. On multivariable analysis of women with HR-positive, HER2-negative disease, receipt of a more intensive chemotherapy regimen varied statistically significantly by genetic results (P = .02), with platinum receipt more common among BRCA1/2 PV carriers (odds ratio = 2.44, 95% confidence interval = 1.36 to 4.38; P < .001). Among women with TNBC, chemotherapy agents did not vary significantly by genetic results.

CONCLUSION

BRCA1/2 PV carriers with HR-positive, HER2-negative breast cancer had twofold higher odds than noncarriers of receiving a platinum, as part of a more intensive chemotherapy regimen. This likely represents overtreatment and emphasizes the need to monitor how genetic testing results are managed in oncology practice.

New Insights on the Toxicity on Heart and Vessels of Breast Cancer Therapies

Cardiovascular diseases are largely represented in patients with cancer and appear to be important side effects of cancer treatments, heavily affecting quality of life and leading to premature morbidity and death among cancer survivors. In particular, treatments for breast cancer have been shown to potentially play serious detrimental effects on cardiovascular health. This review aims to explore the available literature on breast cancer therapy-induced side effects on heart and vessels, illustrating the molecular mechanisms of cardiotoxicity known so far. Moreover, principles of cardiovascular risk assessment and management of cardiotoxicity in clinical practice will also be elucidated. Chemotherapy (anthracycline, taxanes, cyclophosphamide and 5-fluorouracil), hormonal therapy (estrogen receptor modulator and gonadotropin or luteinizing releasing hormone agonists) and targeted therapy (epidermal growth factor receptor 2 and Cyclin-dependent kinases 4 and 6 inhibitors) adverse events include arterial and pulmonary hypertension, supraventricular and ventricular arrhythmias, systolic and diastolic cardiac dysfunction and coronary artery diseases due to different and still not well-dissected molecular pathways. Therefore, cardiovascular prevention programs and treatment of cardiotoxicity appear to be crucial to improve morbidity and mortality of cancer survivors.

Structural Characterization and Anti-breast Cancer Activity in vitro of a Novel Polysaccharide From Cymbopogon citratus

Cymbopogon citratus is an important functional food, widely used for flavoring in Africa and South America. In this study, a novel high-molecular-weight polysaccharide (CCP) from C. citratus was extracted, and its structural characteristics and anti-breast cancer activity in vitro were investigated. CCP contained both α and β configurations and mainly composed of galactose (36.89%), arabinose (23.97%), glucose (18.35%) and rhamnose (9.36%) with an average molecular weight of 1.98 × 10⁶ Da. The main glycosyl residues of CCP detected by methylation analysis were 1,3,6-linked Galp, 1,3-linked Glcp, 1,5-linked Araf , T-Araf , and T-Rhap. In vitro experiments suggested that CCP significantly inhibited the proliferation of MDA-MB-231 cells, decreased the expressions of cyclin D1 and CDK4 and stocked cells at G₀/G₁ phase. Meanwhile, the typical morphological features of apoptotic cells were also observed. Combining with the consequences of Annexin V-FITC/PI staining, Hoechst 33258 staining and western blot analysis, CCP induced apoptosis of MDA-MB-231 cells by triggering the Fas/FasL-mediated death receptor pathway. Overall, these results provide a theoretical basis for the application of C. citratus polysaccharide as a potential anti-breast cancer agent in functional food and medicine.

Elabela ameliorates doxorubicin-induced cardiotoxicity by promoting autophagic flux through TFEB pathway

Doxorubicin (DOX) is a widely used and effective antineoplastic drug; however, its clinical application is limited by cardiotoxicity. A safe and effective strategy to prevent from doxorubicin-induced cardiotoxicity (DIC) is still beyond reach. Elabela (ELA), a new APJ ligand, has exerted cardioprotective effect against multiple cardiovascular diseases. Here, we asked whether ELA alleviates DIC. Mice were injected with DOX to established acute DIC. In vivo studies were assessed with echocardiography, serum cTnT and CK-MB, HW/BW ratio and WGA staining. Cell death and atrophy were measured by AM/PI staining and phalloidin staining respectively in vitro. Autophagic flux was monitored with Transmission electron microscopy in vivo, as well as LysoSensor and mRFP-GFP-LC3 puncta in vitro. Our results showed that ELA improved cardiac dysfunction in DIC mice. ELA administration also attenuated cell death and atrophy in DOX-challenged neonatal rat cardiomyocytes (NRCs). Additionally, we found that ELA restored DOX-induced autophagic flux blockage, which was evidenced by the reverse of p62 and LC3II, improvement of lysosome function and accelerated degradation of accumulated autolysosomes. Chloroquine, a classical autophagic flux inhibitor, blunted the improvement of ELA on cardiac dysfunction. At last, we revealed that ELA reversed DOX-induced downregulation of transcription factor EB (TFEB), and silencing TFEB by siRNA abrogated the effects of ELA on autophagic flux as well as cell death and atrophy in NRCs. In conclusion, this study indicated that ELA ameliorated DIC through enhancing autophagic flux via activating TFEB. ELA may become a potential target against DIC.

At the Intersection of Cardiology and Oncology: TGFβ as a Clinically Translatable Therapy for TNBC Treatment and as a Major Regulator of Post-Chemotherapy Cardiomyopathy

Triple-negative breast cancer (TNBC) is a subtype of breast cancer that accounts for the majority of breast cancer-related deaths due to the lack of specific targets for effective treatments. While there is immense focus on the development of novel therapies for TNBC treatment, a persistent and critical issue is the rate of heart failure and cardiomyopathy, which is a leading cause of mortality and morbidity amongst cancer survivors. In this review, we highlight mechanisms of post-chemotherapeutic cardiotoxicity exposure, evaluate how this is assessed clinically and highlight the transforming growth factor-beta family (TGF-β) pathway and its significance as a mediator of cardiomyopathy. We also highlight recent findings demonstrating TGF-β inhibition as a potent method to prevent cardiac remodeling, fibrosis and cardiomyopathy. We describe how dysregulation of the TGF-β pathway is associated with negative patient outcomes across 32 types of cancer, including TNBC. We then highlight how TGF-β modulation may be a potent method to target mesenchymal (CD44+/CD24-) and epithelial (ALDHhigh) cancer stem cell (CSC) populations in TNBC models. CSCs are associated with tumorigenesis, metastasis, relapse, resistance and diminished patient prognosis; however, due to plasticity and differential regulation, these populations remain difficult to target and continue to present a major barrier to successful therapy. TGF-β inhibition represents an intersection of two fields: cardiology and oncology. Through the inhibition of cardiomyopathy, cardiac damage and heart failure may be prevented, and through CSC targeting, patient prognoses may be improved. Together, both approaches, if successfully implemented, would target the two greatest causes of cancer-related morbidity in patients and potentially lead to a breakthrough therapy.

Real-time exercise reduces impaired cardiac function in breast cancer patients undergoing chemotherapy: A randomized controlled trial

BACKGROUND

Previous studies have reported that chemotherapy results in substantial long-term risk of heart failure. Exercise ameliorates exercise responses and exercise tolerance in patients receiving chemotherapy. The cardioprotective effect of real-time exercise in breast cancer is still unclear.

OBJECTIVES

The aim of the present study was to determine the effect of real-time moderate-to-high-intensity exercise training in women with breast cancer undergoing chemotherapy and to follow up on parameters of cardiac function and exercise capacity at different times. We hypothesized that early moderate-to-high-intensity exercise training has beneficial effects on cardiac function in women with breast cancer undergoing chemotherapy.

METHODS

This was a randomized controlled study that included 32 women randomly allocated into the control or exercise group. Exercise began with the first cycle of chemotherapy, and the training program was maintained during chemotherapy with 2 to 3 sessions per week for 3 months. Patients were instructed to perform moderate-to-high-intensity training with aerobic and resistance training. Outcome measurements were echocardiography and cardiopulmonary exercise test. The primary outcome was the change in left ventricle ejection fraction (LVEF). The secondary outcome was peak oxygen consumption (peak VO2).

RESULTS

The control group showed lower cardiac systolic function than the exercise group [mean (SD) LVEF 62% (2) and 70% (5), P<0.05], reduced cardiac diastolic function, and cardiac hypertrophy at 3, 6 and 12 months after chemotherapy. At 6 months after chemotherapy, the exercise group exhibited relatively higher exercise capacity than controls [mean (SD) VO2 12.1 (2.2) and 13.6 (2.2) mL/kg/min, P<0.05]. The main effect size of the study based on echocardiography outcomes was 0.25 (95% confidence interval 0.23 to 0.27), a medium effect size.

CONCLUSIONS

Moderate-to-high-intensity exercise training in breast cancer patients undergoing chemotherapy may prevent impaired cardiac function.

CLINICAL TRIAL REGISTRATION

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in.th (Identifier TCTR20190330002).

Trends in heart disease mortality among breast cancer survivors in the US, 1975-2017

Purpose

Heart disease is a significant concern among breast cancer survivors, in part due to cardiotoxic treatments including chemotherapy and radiotherapy. Long-term trends in heart disease mortality have not been well characterized. We examined heart disease mortality trends among US breast cancer survivors by treatment type.

Methods

We included first primary invasive breast cancer survivors diagnosed between 1975 and 2016 (aged 18–84; survived 12 + months; received initial chemotherapy, radiotherapy, or surgery) in the SEER-9 Database. Standardized mortality ratios (SMRs) and 10-year cumulative heart disease mortality estimates accounting for competing events were calculated by calendar year of diagnosis and initial treatment regimen. P_trends were assessed using Poisson regression. All statistical tests were 2-sided.

Results

Of 516,916 breast cancer survivors, 40,812 died of heart disease through 2017. Heart disease SMRs declined overall from 1975–1979 to 2010–2016 (SMR 1.01 [95%CI: 0.98, 1.03] to 0.74 [0.69, 0.79], p_trend < 0.001). This decline was also observed for survivors treated with radiotherapy alone and chemotherapy plus radiotherapy. A sharper decline in heart disease SMRs was observed from 1975 to 1989 for left-sided radiotherapy, compared to right-sided. In contrast, there was a non-significant increasing trend in SMRs for chemotherapy alone, and significant by regional stage (p_trend = 0.036). Largest declines in 10-year cumulative mortality were observed from 1975–1984 to 2005–2016 among surgery only: 7.02% (95%CI: 6.80%, 7.23%) to 4.68% (95%CI: 4.39%, 4.99%) and radiotherapy alone: 6.35% (95%CI: 5.95%, 6.77%) to 2.94% (95%CI: 2.73%, 3.16%).

Conclusions

We observed declining heart disease mortality trends by most treatment types yet increasing for regional stage patients treated with chemotherapy alone, highlighting a need for additional studies with detailed treatment data and cardiovascular management throughout cancer survivorship.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-022-06515-5.

Profile, treatment patterns, and influencing factors of anthracycline use in breast cancer patients in China: A nation-wide multicenter study

Background

Anthracycline‐based chemotherapy (ABC) is one of the standard therapies against breast cancer. However, few guidelines are currently available to optimize the use of ABC. Therefore, the present analysis aimed at determining the profile and treatment patterns of ABC and the association of clinicopathological characteristics with ABC selection.

Methods

We retrospectively analyzed the data of a nation‐wide multicenter epidemiological study, which collected the medical records of breast cancer patients receiving chemotherapy in different settings from seven geographic regions in China (NCT03047889).

Results

In total, 3393 patients were included, with 2917 treated with ABC. Among them, 553 (89.8%), 2165 (81.7%), and 814 (25.7%) were subjected to ABC as neoadjuvant, adjuvant, and advanced chemotherapy, respectively. The most frequently used regimens were anthracycline‐taxane‐based combinations for neo‐ and adjuvant chemotherapy, along with taxanes and oral fluorouracils for the palliative stages. In the overall cohort, patients aged < 40 or 40‐65 (p < 0.001), in premenopause (p < 0.001), without comorbidities (p = 0.016), with invasive ductal carcinoma (p= 0.001), high lymph node involvement (p < 0.001), in the pTNM stage II, III, or IV versus stage I (p < 0.001), subjected to mastectomy (p < 0.001) or subjected to sentinel lymph node biopsy combined with axillary lymph node dissection (p = 0.044), or with a decreased disease‐free survival (p < 0.001) were more likely to be recommended to ABC.

Conclusion

Taken together, ABC remained the mainstay of breast cancer treatment, especially in neo and adjuvant therapy. ABC was mainly used as a combination therapy, and the correlation between influencing factors and ABC choice varied during different settings, indicating the preference and different perspectives of medication considered by medical oncologists regarding the use ABC in China.

Dantrolene Prevents the Lymphostasis Caused by Doxorubicin in the Rat Mesenteric Circulation

Background and Purpose: Doxorubicin (DOX) is a risk factor for arm lymphedema in breast cancer patients. We reported that DOX opens ryanodine receptors (RYRs) to enact "calcium leak," which disrupts the rhythmic contractions of lymph vessels (LVs) to attenuate lymph flow. Here, we evaluated whether dantrolene, a clinically available RYR1 subtype antagonist, prevents the detrimental effects of DOX on lymphatic function. Experimental Approach: Isolated rat mesenteric LVs were cannulated, pressurized (4-5 mm Hg) and equilibrated in physiological salt solution and Fura-2AM. Video microscopy recorded changes in diameter and Fura-2AM fluorescence tracked cytosolic free calcium ([Ca2+ i]). High-speed in vivo microscopy assessed mesenteric lymph flow in anesthetized rats. Flow cytometry evaluated RYR1 expression in freshly isolated mesenteric lymphatic muscle cells (LMCs). Key Results: DOX (10 μmol/L) increased resting [Ca2+ i] by 17.5 ± 3.7% in isolated LVs (n = 11). The rise in [Ca2+ i] was prevented by dantrolene (3 μmol/L; n = 10). A single rapid infusion of DOX (10 mg/kg i.v.) reduced positive volumetric lymph flow to 29.7 ± 10.8% (n = 7) of baseline in mesenteric LVs in vivo. In contrast, flow in LVs superfused with dantrolene (10 μmol/L) only decreased to 76.3 ± 14.0% (n = 7) of baseline in response to DOX infusion. Subsequently, expression of the RYR1 subtype protein as the presumed dantrolene binding site was confirm in isolated mesenteric LMCs by flow cytometry. Conclusion and Implications: We conclude that dantrolene attenuates the acute impairment of lymph flow by DOX and suggest that its prophylactic use in patients subjected to DOX chemotherapy may lower lymphedema risk.

Decision Science Can Inform Clinical Trade-Offs Regarding Cardiotoxic Cancer Treatments

Cancer treatment-related cardiotoxicity (ie, heart failure, coronary artery disease, vascular diseases, arrhythmia) is a growing cancer survivorship concern within oncology practice; heart disease is the leading cause of noncancer death in cancer survivors and surpasses cancer as the leading cause of death for some cancers with higher survival rates. The issue of cardiotoxicity introduces a critical tradeoff that must be acknowledged and reconciled in clinical oncology practice: treating cancer aggressively and effectively in the present vs preventing future cardiotoxicity. Although many cancers must be treated as aggressively as possible, for others, multiple treatment options are available. Yet even when effective and less cardiotoxic treatments are available, they are not always chosen. Wariness to choose equally effective but less cardiotoxic treatment options may result in part from providers' and patients' reliance on "cognitive heuristics," or mental shortcuts that people (including, research shows, medical professionals) use to simplify complex judgments. These heuristics include delay discounting, availability and affect heuristics, and default bias. In the current commentary, we describe relevant research that illuminates how use of heuristics leads to biased medical decision making and translate how this research may apply when the tradeoff between aggressive cancer treatment and preventing future cardiotoxicity is considered. We discuss the implications of these biases in oncology practice, offer potential solutions to reduce bias, and call for future research in this area.

Design, Synthesis and Biological Evaluation of Novel Pyrazolo[1,2,4]triazolopyrimidine Derivatives as Potential Anticancer Agents

Three novel pyrazolo-[4,3-e][1,2,4]triazolopyrimidine derivatives (1, 2, and 3) were designed, synthesized, and evaluated for their in vitro biological activity. All three compounds exhibited different levels of cytotoxicity against cervical and breast cancer cell lines. However, compound 1 showed the best antiproliferative activity against all tested tumor cell lines, including HCC1937 and HeLa cells, which express high levels of wild-type epidermal growth factor receptor (EGFR). Western blot analyses demonstrated that compound 1 inhibited the activation of EGFR, protein kinase B (Akt), and extracellular signal-regulated kinase (Erk)1/2 in breast and cervical cancer cells at concentrations of 7 and 11 µM, respectively. The results from docking experiments with EGFR suggested the binding of compound 1 at the ATP binding site of EGFR. Furthermore, the crystal structure of compound 3 (7-(4-bromophenyl)-9-(pyridin-4-yl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine) was determined by single crystal X-ray analysis. Our work represents a promising starting point for the development of a new series of compounds targeting EGFR.

Breast cancer: Muscarinic receptors as new targets for tumor therapy

The development of breast cancer is a complex process that involves the participation of different factors. Several authors have demonstrated the overexpression of muscarinic acetylcholine receptors (mAChRs) in different tumor tissues and their role in the modulation of tumor biology, positioning them as therapeutic targets in cancer. The conventional treatment for breast cancer involves surgery, radiotherapy, and/or chemotherapy. The latter presents disadvantages such as limited specificity, the appearance of resistance to treatment and other side effects. To prevent these side effects, several schedules of drug administration, like metronomic therapy, have been developed. Metronomic therapy is a type of chemotherapy in which one or more drugs are administered at low concentrations repetitively. Recently, two chemotherapeutic agents usually used to treat breast cancer have been considered able to activate mAChRs. The combination of low concentrations of these chemotherapeutic agents with muscarinic agonists could be a useful option to be applied in breast cancer treatment, since this combination not only reduces tumor cell survival without affecting normal cells, but also decreases pathological neo-angiogenesis, the expression of drug extrusion proteins and the cancer stem cell fraction. In this review, we focus on the previous evidences that have positioned mAChRs as relevant therapeutic targets in breast cancer and analyze the effects of administering muscarinic agonists in combination with conventional chemotherapeutic agents in a metronomic schedule.

Molecular mechanisms of anthracycline cardiovascular toxicity

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

Effect of high-intensity interval training on patient-reported outcomes and physical function in women with breast cancer receiving anthracycline-based chemotherapy

PURPOSE

The purpose of this study was to determine the effects of an 8-week HIIT intervention on patient-reported outcomes and physical function in breast cancer patients undergoing anthracycline-based chemotherapy.

METHODS

Thirty breast cancer patients were recruited prior to initiating treatment and randomized into the HIIT group (n = 15) or control (CON) group (n = 15). The HIIT group attended HIIT sessions three days per week for eight weeks. The CON group was asked to maintain their current level of physical activity. Patient-reported outcomes were assessed by the Functional Assessment of Cancer Therapy-Breast Cancer (FACT-B), Multidimensional Fatigue Inventory with 20 questions (MFI-20), and the 15-item Five-Facet Mindfulness Questionnaire (FFMQ-15). Physical function was assessed using the timed up and go (TUG), 30-s sit-to-stand (30STS), Margaria-Kalamen stair climb test, and 6-min walk test (6MWT). Repeated measures ANCOVA and paired t-tests were performed to assess group differences.

RESULTS

All patients completed the 8-week study with 82.3% adherence to the intervention among the HIIT group. Post-intervention, significant improvements were found for the Margaria-Kalamen stair climb test (- 3.39%; P = 0.013) and 6MWT (+ 11.6%; P = 0.008) in the HIIT group compared to baseline and CON group. No changes in patient-reported outcomes, TUG, and 30STS were observed following the 8-week study period in both groups (P  > 0.05).

CONCLUSIONS

HIIT may be an effective strategy to improve physical function and possibly maintain QOL in breast cancer patients undergoing the anthracycline-based chemotherapy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT02454777.

The effect of eIF3a on anthracycline-based chemotherapy resistance by regulating DSB DNA repair

BACKGROUND

Anthracycline are inhibitors of topoisomerase II leading to DNA double strand breaks, and it is widely used for treatment of breast cancer. eIF3a is the largest subunit of eukaryotic translation initiation factor 3 (eIF3) and highly expressed in breast cancer. In this study, we investigated the role of eIF3a in DSB DNA repair and the response of breast cancer patients to anthracycline-based chemotherapy.

METHODS

MTT assay was used to detect anthracycline sensitivity in cell lines. Real-time reverse transcriptase PCR, western blotting and immunofluorescence were performed to assess changes in gene expression levels. Cometassay and end-joining activity assay were conducted to explore the effect of eIF3a in NHEJ repair. Luciferase reporter assay was performed to detect LIG4 5'UTR activity. Immunohistochemistry was used to detect eIF3a, LIG4 and DNA-PKcs expression levels in breast cancer tissues.

RESULTS

The results showed that eIF3a increased cellular response to anthracyclines by regulating DSB repair activity via influencing the expression of LIG4 and DNA-PKcs at translational level. Breast cancer patients with high level of eIF3a or low level of LIG4 or low level of DNA-PKcs had better anthracycline-based chemotherapy prognosis compared. Moreover, Combined expressions of eIF3a, LIG4 and DNA-PKcs could be better to predict PFS in breast cancer patients with anthracycline-based chemotherapy.

CONCLUSION

Our findings suggest that eIF3a effects anthracycline-based chemotherapy response by regulating DSB DNA repair.

Risks of subsequent primary cancers among breast cancer survivors according to hormone receptor status

BACKGROUND

This study was aimed at examining the risks of subsequent primary cancers (SPCs) among breast cancer survivors by hormone receptor (HR) status and age at diagnosis.

METHODS

Data from 12 Surveillance, Epidemiology, and End Results registries were used to identify 431,222 breast cancer survivors (at least 1 year) diagnosed between the ages of 20 and 84 years from 1992 to 2015. Risks of SPCs were measured as the standardized incidence ratio (SIR) and the excess absolute risk (EAR) per 10,000 person-years. Poisson regression was used to test the difference in SIRs by HR status.

RESULTS

In comparison with the general population, the risk of new cancer diagnoses among survivors was 20% higher for those with HR-positive cancers (SIR, 1.20; 95% confidence interval [CI], 1.19-1.21; EAR, 23.3/10,000 person-years) and 44% higher for those with HR-negative cancers (SIR, 1.44; 95% CI, 1.41-1.47; EAR, 45.2/10,000 person-years), with the risk difference between HR statuses statistically significant. The higher risk after HR-negative cancer was driven by acute nonlymphocytic leukemia and breast, ovarian, peritoneal, and lung cancers. By age at diagnosis, the total EAR per 10,000 person-years ranged from 15.8 (95% CI, 14.1-17.5; SIR, 1.11) among late-onset (age, 50-84 years) HR-positive survivors to 69.4 (95% CI, 65.1-73.7; SIR, 2.24) among early-onset (age, 20-49 years) HR-negative survivors, with subsequent breast cancer representing 73% to 80% of the total EAR. After breast cancer, the greatest EARs were for ovarian cancer among early-onset HR-negative survivors, lung cancer among early- and late-onset HR-negative survivors, and uterine corpus cancer among late-onset HR-positive survivors.

CONCLUSIONS

Risks of SPCs after breast cancer differ substantially by subtype and age. This suggests that more targeted approaches for cancer prevention and early-detection strategies are needed in survivorship care planning.

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.

Structural and Electrophysiological Changes in a Model of Cardiotoxicity Induced by Anthracycline Combined With Trastuzumab

Background

Combined treatment with anthracyclines (e.g., doxorubicin; Dox) and trastuzumab (Trz), a humanized anti-human epidermal growth factor receptor 2 (HER2; ErbB2) antibody, in patients with HER2-positive cancer is limited by cardiotoxicity, as manifested by contractile dysfunction and arrhythmia. The respective roles of the two agents in the cardiotoxicity of the combined therapy are incompletely understood.

Objective

To assess cardiac performance, T-tubule organization, electrophysiological changes and intracellular Ca²⁺ handling in cardiac myocytes (CMs) using an in vivo rat model of Dox/Trz-related cardiotoxicity.

Methods and Results

Adult rats received 6 doses of either Dox or Trz, or the two agents sequentially. Dox-mediated left ventricular (LV) dysfunction was aggravated by Trz administration. Dox treatment, but not Trz, induced T-tubule disarray. Moreover, Dox, but not Trz monotherapy, induced prolonged action potential duration (APD), increased incidence of delayed afterdepolarizations (DADs) and beat-to-beat variability of repolarization (BVR), and slower Ca²⁺ transient decay. Although APD, DADs, BVR and Ca²⁺ transient decay recovered over time after the cessation of Dox treatment, subsequent Trz administration exacerbated these abnormalities. Trz, but not Dox, reduced Ca²⁺ transient amplitude and SR Ca²⁺ content, although only Dox treatment was associated with SERCA downregulation. Finally, Dox treatment increased Ca²⁺ spark frequency, resting Ca²⁺ waves, sarcoplasmic reticulum (SR) Ca²⁺ leak, and long-lasting Ca²⁺ release events (so-called Ca²⁺ “embers”), partially reproduced by Trz treatment.

Conclusion

These results suggest that in vivo Dox but not Trz administration causes T-tubule disarray and pronounced changes in electrical activity of CMs. While adaptive changes may account for normal AP shape and reduced DADs late after Dox administration, subsequent Trz administration interferes with such adaptive changes. Intracellular Ca²⁺ handling was differently affected by Dox and Trz treatment, leading to SR instability in both cases. These findings illustrate the specific roles of Dox and Trz, and their interactions in cardiotoxicity and arrhythmogenicity.

Topoisomerases inhibition and DNA binding mode of daunomycin-oligoarginine conjugate

Cancer is a major health issue adsorbing the attention of a biomedical research. To fight this disease, new drugs are developed, specifically tailored to target biological pathways or peculiar components of the tumour cells. Particularly interesting is the use of intercalating agents as drugs capable to bind DNA and inhibit enzymes involved in DNA metabolism. Anthracyclines are the most commonly used anticancer drugs. In particular, daunomycin is used to cancer treatment by exploiting its ability to intercalate DNA and inhibit the activity of DNA topoisomerases implicated in the replication processes. Unfortunately, clinical application of anthracyclines is limited by their side effects. The conjugation with specific carriers could affect the selectivity and reduce side effect by improving stability and/or cellular uptake properties. We here report the biochemical characterisation of a daunomycin oligopeptide conjugate containing six residues of arginine, by the analysis of its fluorescence properties, DNA interaction and topoisomerases inhibitory effects.

Risk of contralateral breast cancer according to first breast cancer characteristics among women in the USA, 1992-2016

Background

Estimates of contralateral breast cancer (CBC) risk in the modern treatment era by year of diagnosis and characteristics of the first breast cancer are needed to assess the impact of recent advances in breast cancer treatment and inform clinical decision making.

Methods

We examined CBC risk among 419,818 women (age 30–84 years) who were diagnosed with a first unilateral invasive breast cancer and survived ≥ 1 year in the US Surveillance, Epidemiology, and End Results program cancer registries from 1992 to 2015 (follow-up through 2016). CBC was defined as a second invasive breast cancer in the contralateral breast ≥ 12 months after the first breast cancer. We estimated standardized incidence ratios (SIRs) of CBC by year of diagnosis, age at diagnosis, and tumor characteristics for the first breast cancer. Cumulative incidence of CBC was calculated for women diagnosed with a first breast cancer in the recent treatment era (2004–2015, follow-up through 2016).

Results

Over a median follow-up of 8 years (range 1–25 years), 12,986 breast cancer patients developed CBC. Overall, breast cancer patients had approximately twice the risk of developing cancer in the contralateral breast when compared to that expected in the general population (SIR = 2.21, 95% CI = 2.17–2.25). SIRs for CBC declined by year of first diagnosis, irrespective of age at diagnosis and estrogen receptor (ER) status (p-trends < 0.001), but the strongest decline was after an ER-positive tumor. The 5-year cumulative incidence of CBC ranged from 1.01% (95% CI = 0.90–1.14%) in younger women (age < 50 years) with a first ER-positive tumor to 1.89% (95% CI = 1.61–2.21%) in younger women with a first ER-negative tumor.

Conclusion

Declines in CBC risk are consistent with continued advances in breast cancer treatment. The updated estimates of cumulative incidence inform breast cancer patients and clinicians on the risk of CBC and may help guide treatment decisions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01400-3.

Drug Combination in Cancer Treatment-From Cocktails to Conjugated Combinations

It is well recognized today that anticancer drugs often are most effective when used in combination. However, the establishment of chemotherapy as key modality in clinical oncology began with sporadic discoveries of chemicals that showed antiproliferative properties and which as a first attempt were used as single agents. In this review we describe the development of chemotherapy from its origins as a single drug treatment with cytotoxic agents to polydrug therapy that includes targeted drugs. We discuss the limitations of the first chemotherapeutic drugs as a motivation for the establishment of combined drug treatment as standard practice in spite of concerns about frequent severe, dose limiting toxicities. Next, we introduce the development of targeted treatment as a concept for advancement within the broader field of small-molecule drug combination therapy in cancer and its accelerating progress that was boosted by recent scientific and technological progresses. Finally, we describe an alternative strategy of drug combinations using drug-conjugates for selective delivery of cytotoxic drugs to tumor cells that potentiates future improvement of drug combinations in cancer treatment. Overall, in this review we outline the development of chemotherapy from a pharmacological perspective, from its early stages to modern concepts of using targeted therapies for combinational treatment.

Clinical utilization of long-acting granulocyte colony-stimulating factor (pegfilgrastim) prophylaxis in breast cancer patients with adjuvant docetaxel-cyclophosphamide chemotherapy

Purpose

Treatment with 4 cycles of docetaxel and cyclophosphamide (TC) in the adjuvant setting is associated with better outcomes than treatment with doxorubicin and cyclophosphamide (AC). However, Western guidelines have indicated that TC confers a high risk (>20%) of febrile neutropenia (FN), while AC confers an intermediate risk (10%-20%) of FN. Threrefore, we evaluated the incidence of FN and the clinical utilization of pegfilgrastim prophylaxis after adjuvant TC chemotherapy.

Methods

We categorized 201 patients who received adjuvant TC chemotherapy into 3 groups according to the method of prophylaxis and compared neutropenic events, other adverse events, and hospital care costs in the 3 groups.

Results

The incidence of grade 4 neutropenia decreased from 93.0% in patients without prophylaxis to 82.4% in those who received secondary prophylaxis and 16.7% in those who received primary prophylaxis. Although the incidence of FN was not different between patients without prophylaxis and patients who received secondary prophylaxis (15.7% and 14.9%), none of the patients who received primary prophylaxis developed FN. Moreover, a decrease in neutropenic events resulted in a significant decrease in the mean duration of neutropenia (2.50 days to 0.08 days, P < 0.001), the risk of hospitalization (29.8% to 2.2%, P < 0.001), and the mean total hospital care cost for all chemotherapy cycles (790.80 to 486.00 US dollars, P < 0.001).

Conclusion

The use of pegfilgrastim prophylaxis during adjuvant TC chemotherapy is associated with significant decreases in the incidence of neutropenic events, hospitalization, and hospital care cost compared to those seen in patients without prophylaxis.

Simulation of Chemotherapy Effects in Older Breast Cancer Patients With High Recurrence Scores

BACKGROUND

Tumor genomic expression profile data are used to guide chemotherapy choice, but there are gaps in evidence for women aged 65 years and older. We estimate chemotherapy effects by age and comorbidity level among women with early-stage, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancers and Oncotype DX scores of 26 or higher.

METHODS

A discrete-time stochastic state transition simulation model synthesized data from population studies and clinical trials to estimate outcomes over a 25-year horizon for subgroups based on age (65-69, 70-74, 75-79, and 80-89 years) and comorbidity levels (no or low, moderate, severe). Outcomes were discounted at 3%, and included quality-adjusted life-years (QALYs), life-years, and breast cancer and other-cause mortality with chemoendocrine vs endocrine therapy. Sensitivity analysis tested the effect of varying uncertain parameters.

RESULTS

Women aged 65-69 years with no or low comorbidity gained 0.16 QALYs with chemo-endocrine and reduced breast cancer mortality from 34.8% to 29.7%, for an absolute difference of 5.1%; this benefit was associated with a 12.8% rate of grade 3-4 toxicity. Women aged 65-69 years with no or low or moderate comorbidity levels, and women aged 70-74 years with no or low comorbidity had small chemotherapy benefits. All women aged 75 years and older experienced net losses in QALYs with chemo-endocrine therapy. The results were robust in sensitivity analyses. Chemotherapy had greater benefits as treatment effectiveness increased, but toxicity reduced the QALYs gained.

CONCLUSION

Among women aged 65-89 years whose tumors indicate a high recurrence risk, only those aged 65-74 years with no or low or moderate comorbidity have small benefits from adding chemotherapy to endocrine therapy. Genomic expression profile testing (and chemotherapy use) should be reserved for women aged younger than 75 years without severe comorbidity.

Drug Repurposing in Medulloblastoma: Challenges and Recommendations

OPINION STATEMENT

Medulloblastoma is the most frequently diagnosed primary malignant brain tumor among children. Currently available therapeutic strategies are based on surgical resection, chemotherapy, and/or radiotherapy. However, majority of patients quickly develop therapeutic resistance and are often left with long-term therapy-related side effects and sequelae. Therefore, there remains a dire need to develop more effective therapeutics to overcome the acquired resistance to currently available therapies. Unfortunately, the process of developing novel anti-neoplastic drugs from bench to bedside is highly time-consuming and very expensive. A wide range of drugs that are already in clinical use for treating non-cancerous diseases might commonly target tumor-associated signaling pathways as well and hence be of interest in treating different cancers. This is referred to as drug repurposing or repositioning. In medulloblastoma, drug repurposing has recently gained a remarkable interest as an alternative therapy to overcome therapy resistance, wherein existing non-tumor drugs are being tested for their potential anti-neoplastic effects outside the scope of their original use.

Albumin-Albumin/Lactosylated Core-Shell Nanoparticles: Therapy to Treat Hepatocellular Carcinoma for Controlled Delivery of Doxorubicin

Doxorubicin (Dox) is the most widely used chemotherapeutic agent and is considered a highly powerful and broad-spectrum for cancer treatment. However, its application is compromised by the cumulative side effect of dose-dependent cardiotoxicity. Because of this, targeted drug delivery systems (DDS) are currently being explored in an attempt to reduce Dox systemic side-effects. In this study, DDS targeting hepatocellular carcinoma (HCC) has been designed, specifically to the asialoglycoprotein receptor (ASGPR). Dox-loaded albumin-albumin/lactosylated (core-shell) nanoparticles (tBSA/BSALac NPs) with low (LC) and high (HC) crosslink using glutaraldehyde were synthesized. Nanoparticles presented spherical shapes with a size distribution of 257 ± 14 nm and 254 ± 14 nm, as well as an estimated surface charge of -28.0 ± 0.1 mV and -26.0 ± 0.2 mV, respectively. The encapsulation efficiency of Dox for the two types of nanoparticles was higher than 80%. The in vitro drug release results showed a sustained and controlled release profile. Additionally, the nanoparticles were revealed to be biocompatible with red blood cells (RBCs) and human liver cancer cells (HepG2 cells). In cytotoxicity assays, Dox-loaded nanoparticles decrease cell viability more efficiently than free Dox. Specific biorecognition assays confirmed the interaction between nanoparticles and HepG2 cells, especially with ASGPRs. Both types of nanoparticles may be possible DDS specifically targeting HCC, thus reducing side effects, mainly cardiotoxicity. Therefore, improving the quality of life from patients during chemotherapy.

The Role of Biomarkers to Evaluate Cardiotoxicity

OPINION STATEMENT

Moderate-level evidence suggests that cardiac troponin and natriuretic peptides are useful for risk stratification and early identification of anthracycline cardiotoxicity; however, many of these studies used older chemotherapy regimens, and thus, the applicability to current anthracycline treatment regimens is uncertain. Further research is needed to determine optimal timing and thresholds for troponin and natriuretic peptides in anthracycline-treated patients and evaluate these and other promising biomarkers for anti-HER2 therapies, thoracic radiation, anti-VEGF therapy, and fluoropyrimidine therapy-related cardiotoxicity. Risk tools that combine cardiac risk factors, cancer treatment variables, biomarkers, and imaging parameters are most likely to accurately identify individuals at highest risk for cancer therapy cardiotoxicity. Clinical trials focusing cardioprotective strategies on high-risk individuals are more likely to result in clinically significant results compared with primary prevention cardioprotective approaches.

Heart Failure in Relation to Anthracyclines and Other Chemotherapies

Anthracyclines are the cornerstone of therapy for a wide range of solid and hematologic malignancies; however, their use is limited by the risk of chemotherapy-induced cardiotoxicity leading to cardiomyopathy and heart failure. The incidence of cardiotoxicity in the literature depends on the definition being used, anthracycline dose, duration of follow-up, and surveillance methods used to identify cardiac injury. The reported risk of clinical heart failure has been around 2% to 4% with low-dose anthracycline regimens, whereas the incidence of cardiac injury defined by an abnormal increase in cardiac biomarkers has been reported as high as 35%. Multiple mechanisms have been proposed for anthracycline cardiotoxicity, including the deleterious effects of oxidative stress and reactive oxygen species and the inhibition of topoisomerase II beta, which leads to cardiomyocyte death. In addition, genetic susceptibility is an emerging field that is currently generating active research. The risk factors associated with anthracycline cardiotoxicity include lifetime cumulative dose, age, prior cardiac dysfunction, and the presence of cardiovascular risk factors, in particular hypertension. In this review, we summarize the incidence, mechanisms, and risk factors for anthracycline-mediated left ventricular dysfunction and discuss the role of risk stratification and early detection in patient management.

Real-world impact of postmastectomy radiotherapy in T1-2 breast cancer with one to three positive lymph nodes

Background

The utility of postmastectomy radiotherapy (PMRT) in breast cancer patients with T1-2 (tumor size ≤5 cm) and N1 (one to three lymph nodes involved) disease remains controversial. The aim of this population-based study was to investigate the effectiveness of PMRT in this patient subset in the current clinical practice.

Methods

We included T1-2N1 breast cancer patients treated with mastectomy from 2004 to 2012 using the data form the Surveillance, Epidemiology, and End Results program. The association of PMRT administration with breast cancer-specific survival was determined using multivariable Cox analysis.

Results

We identified 10,248 patients of this study, including 3,725 (36.3%) received PMRT and 6,523 (63.7%) patients did not receive PMRT. Use of PMRT showed increase from 2008 onward; the percentage of patients receiving PMRT was 30.6% in 2004 and was 47.1% in 2012 (P<0.001). Patients diagnosis after 2008, aged <50 years, high tumor grade, T2 stage, and ≥2 positive lymph nodes were independently related to PMRT receipt. Multivariate analysis indicated that PMRT was not related to better breast cancer-specific survival compared to those without PMRT both before (P=0.186) and after propensity score matching (P=0.137).

Conclusions

In breast cancer with T1-2N1 disease, PMRT does not appear to improve survival in the era of modern systemic therapy.

The Role of AMPK Activation for Cardioprotection in Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a commonly used chemotherapeutic agent for the treatment of a range of cancers, but despite its success in improving cancer survival rates, doxorubicin is cardiotoxic and can lead to congestive heart failure. Therapeutic options for this patient group are limited to standard heart failure medications with the only drug specific for doxorubicin cardiotoxicity to reach FDA approval being dexrazoxane, an iron-chelating agent targeting oxidative stress. However, dexrazoxane has failed to live up to its expectations from preclinical studies while also bringing up concerns about its safety. Despite decades of research, the molecular mechanisms of doxorubicin cardiotoxicity are still poorly understood and oxidative stress is no longer considered to be the sole evil. Mitochondrial impairment, increased apoptosis, dysregulated autophagy and increased fibrosis have also been shown to be crucial players in doxorubicin cardiotoxicity. These cellular processes are all linked by one highly conserved intracellular kinase: adenosine monophosphate-activated protein kinase (AMPK). AMPK regulates mitochondrial biogenesis via PGC1α signalling, increases oxidative mitochondrial metabolism, decreases apoptosis through inhibition of mTOR signalling, increases autophagy through ULK1 and decreases fibrosis through inhibition of TGFβ signalling. AMPK therefore sits at the control point of many mechanisms shown to be involved in doxorubicin cardiotoxicity and cardiac AMPK signalling itself has been shown to be impaired by doxorubicin. In this review, we introduce different agents known to activate AMPK (metformin, statins, resveratrol, thiazolidinediones, AICAR, specific AMPK activators) as well as exercise and dietary restriction, and we discuss the existing evidence for their potential role in cardioprotection from doxorubicin cardiotoxicity.

Impact of chemotherapy schedule modification on breast cancer patients: a single-centre retrospective study

Background Nonconformity to chemotherapy schedules is common in clinical practice. Multiple clinical studies have established the negative prognostic impact of dose delay on survival outcome. Objective This study investigated the prevalence and reason for chemotherapy schedule modifications of breast cancer patients. This study also investigated the impact of schedule modifications on overall survival (OS). Setting This retrospective cohort study was done among breast cancer patient receiving chemotherapy from 2013 to 2017 and patients were followed until 31 Dec 2018. Methods Medical records of patients with cancer were reviewed. Female patients over eighteen years old were included, with primary carcinoma of the breast, who received anthracycline or taxane based chemotherapy regime and completed more than two cycles of chemotherapy. Patients were categorized into three groups of (1) no schedule modification, (2) with schedule modification and (3) incomplete schedule. The Kaplan-Meier was used to test for survival differences in the univariate setting and Cox regression model was used in the multivariate setting. Main outcome measure Prevalence, overall survival rates and hazard ratio of three schedule group Results Among 171 patient who were included in the final analysis, 28 (16.4%) had no schedule modification, 118 (69.0%) with schedule modification and 25 (14.6%) had incomplete schedule with OS of 75.0%, 59.3% and 52.0% respectively. 94% (189) of all cycle rescheduling happened because of constitutional symptoms (70), for non-medical reasons (61) and blood/bone marrow toxicity (58). When compared to patients with no schedule modification, patients with schedule modification had a 2.34-times higher risk of death (HR 2.34, 95% CI 1.03-5.32; p = 0.043). Conclusion Nonconformity to the chemotherapy schedule is common in clinical practice because of treatment complications, patients' social schedule conflicts, and facility administrative reasons. Cumulative delays of ≥ 14 days are likely to have negative prognostic effect on patient survival. Thus, the duration of the delays between cycles should be reduced whenever possible to achieve the maximum chemotherapeutic benefit.

DNA inhibitors for the treatment of brain tumors

Introduction: The worldwide incidence of central nervous system (CNS) primary tumors is increasing. Most of the chemotherapeutic agents used for treating these cancer types induce DNA damage, and their activity is affected by the functional status of repair systems involved in the detection or correction of DNA lesions. Unfortunately, treatment of malignant high-grade tumors is still an unmet medical need.Areas covered: We summarize the action mechanisms of the main DNA inhibitors used for the treatment of brain tumors. In addition, studies on new agents or drug combinations investigated for this indication are reviewed, focusing our attention on clinical trials that in the last 3 years have been completed, terminated or are still recruiting patients.Expert opinion: Much still needs to be done to render aggressive CNS tumors curable or at least to transform them from lethal to chronic diseases, as it is possible for other cancer types. Drugs with improved penetration in the CNS, toxicity profile, and activity against primary and recurrent tumors are eagerly needed. Targeted agents with innovative mechanisms of action and ability to harness the cells of the tumor microenvironment against cancer cells represent a promising approach for improving the clinical outcome of CNS tumors.

Neuromuscular ultrasound for taxane peripheral neuropathy in breast cancer

BACKGROUND

Our study aim was to evaluate neuromuscular ultrasound (NMUS) for the assessment of taxane chemotherapy-induced peripheral neuropathy (CIPN), the dose-limiting toxicity of this agent.

METHODS

This cross-sectional study of breast cancer patients with taxane CIPN measured nerve cross-sectional area (CSA) by NMUS and compared with healthy historical controls. Correlations were determined between CSA and symptom scale, nerve conduction studies, and intraepidermal nerve fiber density (IENFD).

RESULTS

A total of 20 participants reported moderate CIPN symptoms at a median of 3.8 months following the last taxane dose. Sural nerve CSA was 1.2 mm² smaller than healthy controls (P ≤ .01). Older age and time since taxane were associated with smaller sural nerve CSA. For each 1 mm² decrease in sural nerve CSA, distal IENFD decreased by 2.1 nerve/mm (R² 0.30; P = .04).

CONCLUSIONS

These data support a sensory predominant taxane neuropathy or neuronopathy and warrant future research on longitudinal NMUS assessment of CIPN.

The Yield of Routine Cardiac Imaging in Breast Cancer Patients Receiving Trastuzumab-Based Treatment: A Retrospective Cohort Study

BACKGROUND

There are limited data on the yield of routine cardiac imaging for trastuzumab-treated patients with breast cancer.

METHODS

We conducted a retrospective cohort study of patients with breast cancer treated with adjuvant trastuzumab between 2007 and 2012 at Princess Margaret Cancer Centre (Toronto, Canada). We classified imaging tests as clinically prompted or routinely ordered and determined whether each test led to changes in patient care. A generalized estimating equation model was used to determine if patient characteristics predicted routine studies more likely to change care. We analysed routine tests that were exclusively preceded by consecutive tests that did not change care to determine if their yield differed by time since trastuzumab start and the number of prior tests that did not change care.

RESULTS

We identified 448 patients who received 1735 cardiac imaging studies after trastuzumab initiation. Of 1555 routine tests, 44 led to changes in care (2.8%) for 43 patients, whereas 50 of 180 clinically prompted tests (27.8%) altered care in 29 patients (P-value < 0.001). Earlier stage cancer, diabetes, prior anthracyclines, and prior cardiovascular disease were associated with a higher likelihood of changes in care following routine tests (P-value < 0.05). Among routine tests that were exclusively preceded by consecutive tests that did not change care, tests ordered outside months 3-9 and those that followed ≥ 3 tests were even less likely to change care.

CONCLUSIONS

Routine cardiac imaging tests rarely changed care for trastuzumab-treated patients with breast cancer, particularly among lower risk anthracycline-naïve women who had multiple prior tests that did not change care.

Remote Ischemic Pre-Conditioning Attenuates Adverse Cardiac Remodeling and Mortality Following Doxorubicin Administration in Mice

Objectives

Because of its multifaceted cardioprotective effects, remote ischemic pre-conditioning (RIPC) was examined as a strategy to attenuate doxorubicin (DOX) cardiotoxicity.

Background

The use of DOX is limited by dose-dependent cardiotoxicity and heart failure. Oxidative stress, mitochondrial dysfunction, inflammation, and autophagy modulation have been proposed as mediators of DOX cardiotoxicity.

Methods

After baseline echocardiography, adult male CD1 mice were randomized to either sham or RIPC protocol (3 cycles of 5 min femoral artery occlusion followed by 5 min reperfusion) 1 h before receiving DOX (20 mg/kg, intraperitoneal). The mice were observed primarily for survival over 85 days (86 mice). An additional cohort of 50 mice was randomized to either sham or RIPC 1 h before DOX treatment and was followed for 25 days, at which time cardiac fibrosis, apoptosis, and mitochondrial oxidative phosphorylation were assessed, as well as the expression profiles of apoptosis and autophagy markers.

Results

Survival was significantly improved in the RIPC cohort compared with the sham cohort (p = 0.007). DOX-induced cardiac fibrosis and apoptosis were significantly attenuated with RIPC compared with sham (p < 0.05 and p < 0.001, respectively). Although no mitochondrial dysfunction was detected at 25 days, there was a significant increase in autophagy markers with DOX that was attenuated with RIPC. Moreover, DOX caused a 49% decline in cardiac BCL2/BAX expression, which was restored with RIPC (p < 0.05 vs. DOX). DOX also resulted in a 17% reduction in left ventricular mass at 25 days, which was prevented with RIPC (p < 0.01), despite the lack of significant changes in left ventricular ejection fraction.

Conclusions

Our preclinical results suggested that RIPC before DOX administration might be a promising approach for attenuating DOX cardiotoxicity.