Late Cardiac Toxic Effects Associated With Treatment Protocols for Hodgkin Lymphoma in Children

Importance

Contemporary North American trials for children with Hodgkin lymphoma (HL) have decreased radiation therapy (RT) use and increased pharmacologic cardioprotection but also increased the cumulative doxorubicin dose, making overall treatment consequences for late cardiac toxic effects uncertain.

Objective

To estimate the risk of cardiac toxic effects associated with treatments used in modern pediatric HL clinical trials.

Design, Setting, and Participants

For this cohort study, Fine and Gray models were fitted using survivors in the Childhood Cancer Survivor Study who were diagnosed with HL between January 1, 1970, and December 31, 1999, and were followed for a median of 23.5 (range, 5.0-46.3) years. These models were applied to the exposures in the study population to estimate the 30-year cumulative incidence of cardiac disease. The study population comprised patients with intermediate-risk or high-risk HL treated in 4 consecutive Children's Oncology Group clinical trials from September 2002 to October 2022: AHOD0031, AHOD0831, AHOD1331, and S1826. Data analysis was performed from April 2020 to February 2023.

Exposures

All patients received chemotherapy including doxorubicin, and some patients received mediastinal RT, dexrazoxane, or mediastinal RT and dexrazoxane.

Main Outcomes and Measures

Estimated 30-year cumulative incidence of grade 3 to 5 cardiac disease.

Results

The study cohort comprised 2563 patients, with a median age at diagnosis of 15 (range, 1-22) years. More than half of the patients were male (1357 [52.9%]). All 2563 patients received doxorubicin, 1362 patients (53.1%) received mediastinal RT, and 307 patients (12.0%) received dexrazoxane. Radiation therapy use and the median mean heart dose among patients receiving RT decreased, whereas the planned cumulative dose of doxorubicin and use of dexrazoxane cardioprotection increased. For patients treated at age 15 years, the estimated 30-year cumulative incidence of severe or fatal cardiac disease was 9.6% (95% CI, 4.2%-16.4%) in the AHOD0031 standard treatment group (enrolled 2002-2009), 8.6% (95% CI, 3.8%-14.9%) in the AHOD0831 trial (enrolled 2009-2012), 8.2% (95% CI, 3.6%-14.3%) in the AHOD1331 trial (enrolled 2015-2019), and 6.2% (95% CI, 2.7%-10.9%) in the S1826 trial (enrolled 2019-2022), whereas the expected rate in an untreated population was 5.0% (95% CI, 2.1%-9.3%). Despite the estimated reduction in late cardiac morbidity, the frequency of recommended echocardiographic screening among survivors will increase based on current guidelines.

Conclusions and Relevance

In this cohort study of sequential HL trials, reductions in the proportion of children receiving mediastinal RT and increases in dexrazoxane use were estimated to offset the increased doxorubicin dose and produce a net reduction in late cardiac disease. Further studies on dexrazoxane are warranted to confirm whether its role in reducing cardiac toxic effects is maintained long term. These findings suggest that survivorship follow-up guidelines should be refined to align with the risks associated with treatment.

Primary cardioprotection with dexrazoxane in patients with childhood cancer who are expected to receive anthracyclines: recommendations from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Survivors of childhood cancer are at risk of anthracycline-induced cardiotoxicity, which might be prevented by dexrazoxane. However, concerns exist about the safety of dexrazoxane, and little guidance is available on its use in children. To facilitate global consensus, a working group within the International Late Effects of Childhood Cancer Guideline Harmonization Group reviewed the existing literature and used evidence-based methodology to develop a guideline for dexrazoxane administration in children with cancer who are expected to receive anthracyclines. Recommendations were made in consideration of evidence supporting the balance of potential benefits and harms, and clinical judgement by the expert panel. Given the dose-dependent risk of anthracycline-induced cardiotoxicity, we concluded that the benefits of dexrazoxane probably outweigh the risk of subsequent neoplasms when the cumulative doxorubicin or equivalent dose is at least 250 mg/m² (moderate recommendation). No recommendation could be formulated for cumulative doxorubicin or equivalent doses of lower than 250 mg/m², due to insufficient evidence to determine whether the risk of cardiotoxicity outweighs the possible risk of subsequent neoplasms. Further research is encouraged to determine the long-term efficacy and safety of dexrazoxane in children with cancer.

Dexrazoxane for preventing or reducing cardiotoxicity in adults and children with cancer receiving anthracyclines

BACKGROUND

This review is the third update of a previously published Cochrane Review. The original review, looking at all possible cardioprotective agents, was split and this part now focuses on dexrazoxane only. Anthracyclines are effective chemotherapeutic agents in the treatment of numerous malignancies. Unfortunately, their use is limited by a dose-dependent cardiotoxicity. In an effort to prevent or reduce this cardiotoxicity, different cardioprotective agents have been studied, including dexrazoxane.

OBJECTIVES

To assess the efficacy of dexrazoxane to prevent or reduce cardiotoxicity and determine possible effects of dexrazoxane on antitumour efficacy, quality of life and toxicities other than cardiac damage in adults and children with cancer receiving anthracyclines when compared to placebo or no additional treatment.

SEARCH METHODS

We searched CENTRAL, MEDLINE and Embase to May 2021. We also handsearched reference lists, the proceedings of relevant conferences and ongoing trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which dexrazoxane was compared to no additional therapy or placebo in adults and children with cancer receiving anthracyclines.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, data extraction, risk of bias and GRADE assessment of included studies. We analysed results in adults and children separately. We performed analyses according to the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

For this update, we identified 548 unique records. We included three additional RCTs: two paediatric and one adult. Therefore, we included a total of 13 eligible RCTs (five paediatric and eight adult). The studies enrolled 1252 children with leukaemia, lymphoma or a solid tumour and 1269 participants, who were mostly diagnosed with breast cancer. In adults, moderate-quality evidence showed that there was less clinical heart failure with the use of dexrazoxane (risk ratio (RR) 0.22, 95% confidence interval (CI) 0.11 to 0.43; 7 studies, 1221 adults). In children, we identified no difference in clinical heart failure risk between treatment groups (RR 0.20, 95% CI 0.01 to 4.19; 3 studies, 885 children; low-quality evidence). In three paediatric studies assessing cardiomyopathy/heart failure as the primary cause of death, none of the children had this outcome (1008 children, low-quality evidence). In the adult studies, different definitions for subclinical myocardial dysfunction and clinical heart failure combined were used, but pooled analyses were possible: there was a benefit in favour of the use of dexrazoxane (RR 0.37, 95% CI 0.24 to 0.56; 3 studies, 417 adults and RR 0.46, 95% CI 0.33 to 0.66; 2 studies, 534 adults, respectively, moderate-quality evidence). In the paediatric studies, definitions of subclinical myocardial dysfunction and clinical heart failure combined were incomparable, making pooling impossible. One paediatric study showed a benefit in favour of dexrazoxane (RR 0.33, 95% CI 0.13 to 0.85; 33 children; low-quality evidence), whereas another study showed no difference between treatment groups (Fischer exact P = 0.12; 537 children; very low-quality evidence). Overall survival (OS) was reported in adults and overall mortality in children. The meta-analyses of both outcomes showed no difference between treatment groups (hazard ratio (HR) 1.04, 95% 0.88 to 1.23; 4 studies; moderate-quality evidence; and HR 1.01, 95% CI 0.72 to 1.42; 3 studies, 1008 children; low-quality evidence, respectively). Progression-free survival (PFS) was only reported in adults. We subdivided PFS into three analyses based on the comparability of definitions, and identified a longer PFS in favour of dexrazoxane in one study (HR 0.62, 95% CI 0.43 to 0.90; 164 adults; low-quality evidence). There was no difference between treatment groups in the other two analyses (HR 0.95, 95% CI 0.64 to 1.40; 1 study; low-quality evidence; and HR 1.18, 95% CI 0.97 to 1.43; 2 studies; moderate-quality evidence, respectively). In adults, there was no difference in tumour response rate between treatment groups (RR 0.91, 95% CI 0.79 to 1.04; 6 studies, 956 adults; moderate-quality evidence). We subdivided tumour response rate in children into two analyses based on the comparability of definitions, and identified no difference between treatment groups (RR 1.01, 95% CI 0.95 to 1.07; 1 study, 206 children; very low-quality evidence; and RR 0.92, 95% CI 0.84 to 1.01; 1 study, 200 children; low-quality evidence, respectively). The occurrence of secondary malignant neoplasms (SMN) was only assessed in children. The available and worst-case analyses were identical and showed a difference in favour of the control group (RR 3.08, 95% CI 1.13 to 8.38; 3 studies, 1015 children; low-quality evidence). In the best-case analysis, the direction of effect was the same, but there was no difference between treatment groups (RR 2.51, 95% CI 0.96 to 6.53; 4 studies, 1220 children; low-quality evidence). For other adverse effects, results also varied. None of the studies evaluated quality of life. If not reported, the number of participants for an analysis was unclear.

AUTHORS' CONCLUSIONS

Our meta-analyses showed the efficacy of dexrazoxane in preventing or reducing cardiotoxicity in adults treated with anthracyclines. In children, there was a difference between treatment groups for one cardiac outcome (i.e. for one of the definitions used for clinical heart failure and subclinical myocardial dysfunction combined) in favour of dexrazoxane. In adults, no evidence of a negative effect on tumour response rate, OS and PFS was identified; and in children, no evidence of a negative effect on tumour response rate and overall mortality was identified. The results for adverse effects varied. In children, dexrazoxane may be associated with a higher risk of SMN; in adults this was not addressed. In adults, the quality of the evidence ranged between moderate and low; in children, it ranged between low and very low. Before definitive conclusions on the use of dexrazoxane can be made, especially in children, more high-quality research is needed. We conclude that if the risk of cardiac damage is expected to be high, it might be justified to use dexrazoxane in children and adults with cancer who are treated with anthracyclines. However, clinicians and patients should weigh the cardioprotective effect of dexrazoxane against the possible risk of adverse effects, including SMN, for each individual. For children, the International Late Effects of Childhood Cancer Guideline Harmonization Group has developed a clinical practice guideline.

Late health outcomes after dexrazoxane treatment: A report from the Children's Oncology Group

BACKGROUND

The objective of this study was to examine long-term outcomes among children newly diagnosed with cancer who were treated in dexrazoxane-containing clinical trials.

METHODS

P9404 (acute lymphoblastic leukemia/lymphoma [ALL]), P9425 and P9426 (Hodgkin lymphoma), P9754 (osteosarcoma), and Dana-Farber Cancer Institute 95-01 (ALL) enrolled 1308 patients between 1996 and 2001: 1066 were randomized (1:1) to doxorubicin with or without dexrazoxane, and 242 (from P9754) were nonrandomly assigned to receive dexrazoxane. Trial data were linked with the National Death Index, the Organ Procurement and Transplantation Network, the Pediatric Health Information System (PHIS), and Medicaid. Osteosarcoma survivors from the Childhood Cancer Survivor Study (CCSS; n = 495; no dexrazoxane) served as comparators in subanalyses. Follow-up events were assessed with cumulative incidence, Cox regression, and Fine-Gray methods.

RESULTS

In randomized trials (cumulative prescribed doxorubicin dose, 100-360 mg/m² ; median follow-up, 18.6 years), dexrazoxane was not associated with relapse (hazard ratio [HR], 0.84; 95% confidence interval [CI], 0.63-1.13), second cancers (HR, 1.19; 95% CI, 0.62-2.30), all-cause mortality (HR, 1.07; 95% CI, 0.78-1.47), or cardiovascular mortality (HR, 1.45; 95% CI, 0.41-5.16). Among P9754 patients (all exposed to dexrazoxane; cumulative doxorubicin, 450-600 mg/m² ; median follow-up, 16.6-18.4 years), no cardiovascular deaths or heart transplantation occurred. The 20-year heart transplantation rate among CCSS osteosarcoma survivors (mean doxorubicin, 377 ± 145 mg/m² ) was 1.6% (vs 0% in P9754; P = .13). Among randomized patients, serious cardiovascular outcomes (cardiomyopathy, ischemic heart disease, and stroke) ascertained by PHIS/Medicaid occurred less commonly with dexrazoxane (5.6%) than without it (17.6%; P = .02), although cardiomyopathy rates alone did not differ (4.4% vs 8.1%; P = .35).

CONCLUSIONS

Dexrazoxane did not appear to adversely affect long-term mortality, event-free survival, or second cancer risk.

Minimizing cardiac toxicity in children with acute myeloid leukemia

Anthracycline chemotherapy remains an integral component of modern pediatric acute myeloid leukemia (AML) regimens and is often delivered at high doses to maximize cancer survival. Unfortunately, high-dose anthracyclines are associated with a significant risk of cardiotoxicity, which may result in early and/or long-term left ventricular systolic dysfunction and heart failure. Moreover, the development of cardiotoxicity during pediatric AML therapy is associated with lower event-free and overall survival, which may be partially attributable to incomplete anthracycline delivery. A combined strategy of primary cardioprotection and close cardiac monitoring can maximize chemotherapy delivery while reducing the toxicity of intensive AML therapy. Primary cardioprotection using dexrazoxane reduces short-term cardiotoxicity without compromising cancer survival. Liposomal anthracycline formulations, which are under active investigation, have the potential to mitigate cardiotoxicity while also improving antitumor efficacy. Primary cardioprotective strategies may reduce but not eliminate the risk of cardiotoxicity; therefore, close cardiac monitoring is also needed. Standard cardiac monitoring consists of serial echocardiographic assessments for left ventricular ejection fraction decline. Global longitudinal strain has prognostic utility in cancer therapy-related cardiotoxicity and may be used as an adjunct assessment. Additional cardioprotective measures should be considered in response to significant cardiotoxicity; these include cardiac remodeling medications to support cardiac recovery and anthracycline dose interruption and/or regimen modifications. However, the withholding of anthracyclines should be limited to avoid compromising cancer survival. A careful approach to cardioprotection during AML therapy is critical to maximize the efficacy of leukemia treatment while minimizing the short- and long-term risks of cardiotoxicity.

Evaluation of dexrazoxane effect on preventing acute cardiac arrhythmia in patients with breast cancer treated with neoadjuvant/adjuvant anthracycline-based chemotherapy

INTRODUCTION

Adding dexrazoxane to the treatment during neoadjuvant/adjuvant anthracycline-based chemotherapy in patients with breast cancer prevents the development of heart failure. In this study, we investigated whether dexrazoxane has a protective effect on arrhythmia resulting from chemotherapy.

METHODS

Patients with breast cancer who received neoadjuvant/adjuvant anthracycline-based chemotherapy in the medical oncology polyclinic between 2017 and 2020 were included in the study. To investigate the effect of dexrazoxane on arrhythmia, this retrospective study included 70 patients, whose 12-lead surface electrocardiograms (ECGs) and echocardiography were obtained before receiving anthracycline-based treatment and after receiving four cycles of chemotherapy. Thirty-two patients received anthracycline only, and 38 patients received anthracycline and dexrazoxane. Arrhythmia parameters such as QT interval, QTc interval, Tp-e interval, Tp-e/QT, Tp-e/QTc and frontal QRS-T angle were calculated from 12-lead ECGs.

RESULTS

Arrhythmia parameters such as frontal QRS-T angle , QT , QTc and heart rate were significantly increased after chemotherapy in both the groups that received dexrazoxane and did not receive dexrazoxane (P < .05). Contrary to the ECG parameters, ejection fraction was decreased in the dexrazoxane group (60.5 ± 2.2 vs 60.1 ± 2.0; P = .038) and the other group (60.4 ± 1.3 vs 60.0 ± 2.6; P = .043) after the chemotherapy.

CONCLUSION

This study demonstrated that dexrazoxane may not have a protective effect on ECG parameters which are predictors of arrhythmia, at breast cancer patients who received anthracyclines.

3D-STI evaluation of the effect of dexrazoxane on the mechanical properties of right ventricular myocardium in breast cancer patients treated with pirarubicin

BACKGROUND

Observation indexes used to evaluate the effect of dexrazoxane-anthracycline combinations in breast cancer often only take into account the clinical symptoms, or left ventricular ejection fraction (LVEF), biomarkers [such as creatine kinase MB (CK-MB), brain natriuretic peptide (BNP) and cardiac troponin T (cTnT)], or tumor recurrence rate, improvement of autonomic nerve function or economic benefits. This study aimed to evaluate the effect of dexrazoxane on the changes of mechanical properties of right ventricular myocardium in patients who underwent pirarubicin chemotherapy with three-dimensional speckle-tracking imaging (3D-STI).

METHODS

A total of 64 breast cancer post-operation patients who received pirarubicin chemotherapy were randomly divided into two groups: the experimental group (with dexrazoxane added) and the control group (without dexrazoxane). The mechanical properties of the right ventricular myocardium were monitored by 3D-STI before and after chemotherapy. The levels of serum hypersensitive troponin I (hs-cTnI) and N-terminal B-type pro-natriuretic peptide (NT-proBNP) as well as conventional echocardiographic parameters were also measured.

RESULTS

After chemotherapy, right ventricular global longitudinal strain (RVGLS) and right ventricular global area strain (RVGAS) were significantly reduced in both groups (P<0.05). There was a significant difference between the two groups (P<0.05).

CONCLUSIONS

Dexrazoxane can alleviate the toxicity of pirarubicin in the right ventricular myocardium. 3D-STI is a potential new method for early and accurate evaluation of the mechanical properties and functional changes of the right ventricular myocardium.

Successful management of doxorubicin overdose and extravasation in a dog with lymphoma

A dog was hospitalized after accidental overdose and extravasation of doxorubicin. With supportive care and dexrazoxane, systemic toxicity resolved by Day 9 and extravasation injury by Day 36. This case demonstrates that, with treatment, dogs can survive doxorubicin overdose and extravasation. The report also highlights the importance of checking the dose of chemotherapeutic agents and preventing extravasation.

[Effectiveness of Dexrazoxane for Extravasation of Anthracycline Antitumor Antibiotics - Reporting Measures Developed against Extravasation in the Hospital]

Dexrazoxane(DXZ)is a drug used for treating extravasation(EV)of anthracycline antitumor antibiotics based on 2 of its mechanisms of action through Topo II. In Japan, it has been used in approximately 150 patients as of January 2016, but there is no detailed report. Three DXZ treatments were carried out for 2 cases in our facilities. One case involved a patient's right forearm while 2 cases occurred involved the left and right forearms of each of the patients, and both were Grade 2(CTCAE v4.0). The EV healed in all cases, and surgical procedures were not needed. Moreover, chemotherapy was performed without extending the treatment period. One year 8 months after administration there was no recurrence in both cases, and skin disorders did not develop. In our hospital, DXZ is managed based on the regimen as well as the anticancer agents, and administration within 6 hours from extravasation was made possible by the cooperation of pharmaceutical wholesalers. Nurses and pharmacists who engage in chemotherapy are encouraged to participate in the study sessions of the hospital, it has been the effort to learn the day-to-day knowledge and technology. DXZ is effective in treating the EV of anthracycline antitumor antibiotics and may be well tolerated. To properly use DXZ by integrating these cases, it is necessary to verify its effectiveness and safety.

Dexrazoxane improves cardiac autonomic function in epirubicin-treated breast cancer patients with type 2 diabetes

OBJECTIVE

The study objective was to investigate the protective effects of dexrazoxane (DRZ) on the cardiac autonomic nervous system (ANS) activity in anthracycline-treated breast cancer patients with diabetes.

METHODS

A total of 110 early stage breast cancer patients with type 2 diabetes were divided randomly into 2 even groups: chemotherapy alone (Chemo) and chemotherapy + DRZ (Chemo + DRZ). All patients underwent adjuvant chemotherapy (80 mg/m epirubicin and 500 mg/m cyclophosphamide) for a total of 6 cycles with 21 days/cycle. The Chemo + DRZ group patients were treated intravenously with 800 mg/m DRZ 30 minutes prior to the administration of epirubicin, while the Chemo group patients were given saline. The cardiac ANS function was evaluated for each patient before and after 6 cycles of chemotherapy by resting heart rate (RHR) and heart rate variability (HRV), which was evaluated by both time and frequency domains.

RESULTS

Before and after chemotherapy, patients in both groups showed significant decreases in HRV indices and increases in RHR and the low-frequency/high-frequency ratio. There were no significant differences between Chemo and Chemo + DRZ groups in terms of RHR and HRV indices before chemotherapy; however, after chemotherapy, patients in the Chemo group had a higher average RHR and lower HRV indices compared with patients in the Chemo + DRZ group.

CONCLUSION

DRZ protects the cardiac ANS in epirubicin-treated early stage breast cancer patients with diabetes.

Impaired mitochondrial function is abrogated by dexrazoxane in doxorubicin-treated childhood acute lymphoblastic leukemia survivors

BACKGROUND

Impaired cardiac function in doxorubicin-treated childhood cancer survivors is partly mediated by the disruption of mitochondrial energy production. Doxorubicin intercalates into mitochondrial DNA (mtDNA) and disrupts genes encoding for polypeptides that make adenosine triphosphate.

METHODS

This cross-sectional study examined mtDNA copy numbers per cell and oxidative phosphorylation (OXPHOS) in peripheral blood mononuclear cells (PBMCs) in 64 childhood survivors of high-risk acute lymphoblastic leukemia (ALL) who had been treated on Dana-Farber Cancer Institute childhood ALL protocols and had received doxorubicin alone (42%) or doxorubicin with the cardioprotectant dexrazoxane (58%). The number of mtDNA copies per cell and the OXPHOS enzyme activity of nicotinamide adenine dinucleotide dehydrogenase (complex I [CI]) and cytochrome c oxidase (complex IV [CIV]) were measured with quantitative real-time polymerase chain reaction immunoassays and thin-layer chromatography, respectively.

RESULTS

At a median follow-up of 7.8 years after treatment, the median number of mtDNA copies per cell for patients treated with doxorubicin alone (1106.3) was significantly higher than the median number for those who had also received dexrazoxane (310.5; P = .001). No significant differences were detected between the groups for CI or CIV activity.

CONCLUSIONS

Doxorubicin-treated survivors had an increased number of PBMC mtDNA copies per cell, and concomitant use of dexrazoxane was associated with a lower number of mtDNA copies per cell. Because of a possible compensatory increase in mtDNA copies per cell to maintain mitochondrial function in the setting of mitochondrial dysfunction, overall OXPHOS activity was not different between the groups. The long-term sustainability of this compensatory response in these survivors at risk for cardiac dysfunction over their lifespan is concerning.

Dexrazoxane Diminishes Doxorubicin-Induced Acute Ovarian Damage and Preserves Ovarian Function and Fecundity in Mice

Advances in cancer treatment utilizing multiple chemotherapies have dramatically increased cancer survivorship. Female cancer survivors treated with doxorubicin (DXR) chemotherapy often suffer from an acute impairment of ovarian function, which can persist as long-term, permanent ovarian insufficiency. Dexrazoxane (Dexra) pretreatment reduces DXR-induced insult in the heart, and protects in vitro cultured murine and non-human primate ovaries, demonstrating a drug-based shield to prevent DXR insult. The present study tested the ability of Dexra pretreatment to mitigate acute DXR chemotherapy ovarian toxicity in mice through the first 24 hours post-treatment, and improve subsequent long-term fertility throughout the reproductive lifespan. Adolescent CD-1 mice were treated with Dexra 1 hour prior to DXR treatment in a 1:1 mg or 10:1 mg Dexra:DXR ratio. During the acute injury period (2-24 hours post-injection), Dexra pretreatment at a 1:1 mg ratio decreased the extent of double strand DNA breaks, diminished γH2FAX activation, and reduced subsequent follicular cellular demise caused by DXR. In fertility and fecundity studies, dams pretreated with either Dexra:DXR dose ratio exhibited litter sizes larger than DXR-treated dams, and mice treated with a 1:1 mg Dexra:DXR ratio delivered pups with birth weights greater than DXR-treated females. While DXR significantly increased the "infertility index" (quantifying the percentage of dams failing to achieve pregnancy) through 6 gestations following treatment, Dexra pretreatment significantly reduced the infertility index following DXR treatment, improving fecundity. Low dose Dexra not only protected the ovaries, but also bestowed a considerable survival advantage following exposure to DXR chemotherapy. Mouse survivorship increased from 25% post-DXR treatment to over 80% with Dexra pretreatment. These data demonstrate that Dexra provides acute ovarian protection from DXR toxicity, improving reproductive health in a mouse model, suggesting this clinically available drug may provide ovarian protection for cancer patients.

Cardiovascular disease in adult survivors of childhood cancer

Treatment advances have increased survival in children with cancer, but subclinical, progressive, irreversible, and sometimes fatal treatment-related cardiovascular effects may appear years later. Cardio-oncologists have identified promising preventive and treatment strategies. Dexrazoxane provides long-term cardioprotection from doxorubicin-associated cardiotoxicity without compromising the efficacy of anticancer treatment. Continuous infusion of doxorubicin is as effective as bolus administration in leukemia treatment, but no evidence has indicated that it provides long-term cardioprotection; continuous infusions should be eliminated from pediatric cancer treatment. Angiotensin-converting enzyme inhibitors can delay the progression of subclinical and clinical cardiotoxicity. All survivors, regardless of whether they were treated with anthracyclines or radiation, should be monitored for systemic inflammation and the risk of premature cardiovascular disease. Echocardiographic screening must be supplemented with screening for biomarkers of cardiotoxicity and perhaps by identification of genetic susceptibilities to cardiovascular diseases; optimal strategies need to be identified. The health burden related to cancer treatment will increase as this population expands and ages.

[Prevention against and treatment of doxorubicin-induced acute cardiotoxicity by dexrazoxane and schisandrin B]

In this study, it is to compare the effectiveness of prevention against and treatment of doxorubicin (DOX) induced cardiotoxicity by dexrazoxane and schisandrin B (Sch B) in rats. Sprague-Dawley (SD) rats were randomly divided into the following 6 groups: normal saline group, DOX group, DOX+DEX group, DOX+Sch B (80 mg x kg(-1)) group, DOX+Sch B (40 mg x kg(-1)) group and DOX+Sch B (20 mg x kg(-1)) group. The results showed that Sch B could combat the increase of myocardial enzymes in peripheral blood, decrease of the enzyme activity of myocardial tissue antioxidant enzymes and disorders of systolic and diastolic function of heart in rats intravenously injected with doxorubicin (15 mg x kg(-1)). Sch B was better than DEX in protecting rat against DOX-induced the symptoms. Sch B could protect rat against DOX-induced acute cardiomyopathy and has clinical potential applications.

Treatment of anthracycline extravasations using dexrazoxane

Extravasation of cytotoxic agents is a true medical emergency. Dexrazoxane is the only licensed drug for the treatment of anthracycline extravasations. Dexrazoxane proved to be effective and moderately well tolerated. However, alternative approaches for the management of anthracycline extravasations are available such as topical DMSO and cooling. There appears to be general agreement about dexrazoxane usefulness when extravasations involve large volumes of anthracycline and/or central venous access device. Nevertheless, the non-invasive combination of DMSO and cooling is the most commonly described therapy, particularly in small anthracycline extravasations. Further research is still needed to establish unequivocal situations where dexrazoxane must be initiated.

Mito-tempol and dexrazoxane exhibit cardioprotective and chemotherapeutic effects through specific protein oxidation and autophagy in a syngeneic breast tumor preclinical model

Several front-line chemotherapeutics cause mitochondria-derived, oxidative stress-mediated cardiotoxicity. Iron chelators and other antioxidants have not completely succeeded in mitigating this effect. One hindrance to the development of cardioprotectants is the lack of physiologically-relevant animal models to simultaneously study antitumor activity and cardioprotection. Therefore, we optimized a syngeneic rat model and examined the mechanisms by which oxidative stress affects outcome. Immune-competent spontaneously hypertensive rats (SHRs) were implanted with passaged, SHR-derived, breast tumor cell line, SST-2. Tumor growth and cytokine responses (IL-1A, MCP-1, TNF-α) were observed for two weeks post-implantation. To demonstrate the utility of the SHR/SST-2 model for monitoring both anticancer efficacy and cardiotoxicity, we tested cardiotoxic doxorubicin alone and in combination with an established cardioprotectant, dexrazoxane, or a nitroxide conjugated to a triphenylphosphonium cation, Mito-Tempol (4) [Mito-T (4)]. As predicted, tumor reduction and cardiomyopathy were demonstrated by doxorubicin. We confirmed mitochondrial accumulation of Mito-T (4) in tumor and cardiac tissue. Dexrazoxane and Mito-T (4) ameliorated doxorubicin-induced cardiomyopathy without altering the antitumor activity. Both agents increased the pro-survival autophagy marker LC3-II and decreased the apoptosis marker caspase-3 in the heart, independently and in combination with doxorubicin. Histopathology and transmission electron microscopy demonstrated apoptosis, autophagy, and necrosis corresponding to cytotoxicity in the tumor and cardioprotection in the heart. Changes in serum levels of 8-oxo-dG-modified DNA and total protein carbonylation corresponded to cardioprotective activity. Finally, 2D-electrophoresis/mass spectrometry identified specific serum proteins oxidized under cardiotoxic conditions. Our results demonstrate the utility of the SHR/SST-2 model and the potential of mitochondrially-directed agents to mitigate oxidative stress-induced cardiotoxicity. Our findings also emphasize the novel role of specific protein oxidation markers and autophagic mechanisms for cardioprotection.