Subclinical Anthracycline Cardiotoxicity in Patients With Acute Promyelocytic Leukemia in Long-Term Remission After the AIDA Protocol

All-trans retinoic acid (ATRA) regulates key genes in the RARG-TOP2B pathway and reduces anthracycline-induced cardiotoxicity

The effectiveness of anthracycline chemotherapeutics (e.g., doxorubicin) is limited by anthracycline-induced cardiotoxicity (ACT). A nonsynonymous variant (S427L) in the retinoic acid receptor-γ (RARG) gene has been associated with ACT. This variant causes reduced RARG activity, which is hypothesized to lead to increased susceptibility to ACT through reduced activation of the retinoic acid pathway. This study explored the effects of activating the retinoic acid pathway using a RAR-agonist, all-trans retinoic acid (ATRA), in human cardiomyocytes and mice treated with doxorubicin. In human cardiomyocytes, ATRA induced the gene expression of RARs (RARG, RARB) and repressed the expression of topoisomerase II enzyme genes (TOP2A, TOP2B), which encode for the molecular targets of anthracyclines and repressed downstream ACT response genes. Importantly, ATRA enhanced cell survival of human cardiomyocytes exposed to doxorubicin. The protective effect of ATRA was also observed in a mouse model (B6C3F1/J) of ACT, in which ATRA treatment improved heart function compared to doxorubicin-only treated mice. Histological analyses of the heart also indicated that ATRA treatment reduced the pathology associated with ACT. These findings provide additional evidence for the retinoic acid pathway's role in ACT and suggest that the RAR activator ATRA can modulate this pathway to reduce ACT.

An Outcome Analysis of Childhood Acute Promyelocytic Leukemia Treated with Atra and Arsenic Trioxide, and Limited Dose Anthracycline

The overall survival of Acute Promyelocytic Leukemia (APL), reported in recent studies, is approaching to 90% wherein, arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) are used as the mainstay of treatment with either limited or no use of anthracycline and cytarabine. This study is aimed to ascertain the outcome of children with APL using similar approach. A total of 30 patients with APL, registered from January 2015 to December 2018, were reviewed. Diagnosis was established on bone marrow aspirate and confirmed by the presence of PML-RARA translocation. Treatment protocol was based on Australian APML 4 study performed by Australian Leukemia Lymphoma Group (ALLG). Lumbar puncture was not performed as it was not part of the protocol due to the risk of bleeding. The mean age in current cohort was 9 years with 53% males. Seven (23.3%) patients died and three (10%) abandoned treatment during induction. Twenty patients completed the intensive phase of chemotherapy and all (100%) of them attained molecular remission (MR). One patient dropped out after MR whereas, 19 remain on follow up with no evidence of disease, reflecting disease free survival (DFS) of 95%. With a median follow up of 2.5 years (range 2.1-4.8 years) the 5 years Kaplan-Meier estimate of OS was 63% and 73%, with and without abandonment, respectively. Analysis of outcome according to risk groups revealed inferior outcome of high risk (HR) group (38% and 50% with and without abandonment, respectively) in contrast to standard risk (SR) group which showed better outcome (82% and 88% with and without abandonment, respectively). The attainment of 100% molecular remission and absence of relapse supports the effectiveness of this regimen. Moreover, it is found to be less toxic and therefore, can be conveniently managed in day-care settings.

All-trans retinoic acid in anticancer therapy: how nanotechnology can enhance its efficacy and resolve its drawbacks

Introduction: All-trans retinoic acid (ATRA, tretinoin) is the main drug used in the treatment of acute promyelocytic leukemia (APL). Despite its impressive activity against APL, the same could not be clinically observed in other types of cancer. Nanotechnology can be a tool to enhance ATRA anticancer efficacy and resolve its drawbacks in APL as well as in other malignancies.Areas covered: This review covers ATRA use in APL and non-APL cancers, the problems that were found in ATRA therapy and how nanoencapsulation can aid to circumvent them. Pre-clinical results obtained with nanoencapsulated ATRA are shown as well as the two ATRA products based on nanotechnology that were clinically tested: ATRA-IV® and Apealea®.Expert opinion: ATRA presents interesting properties to be used in anticancer therapy with a notorious differentiation and antimetastatic activity. Bioavailability and resistance limitations impair the use of ATRA in non-APL cancers. Nanotechnology can circumvent these issues and provide tools to enhance its anticancer activities, such as co-loading of multiple drug and active targeting to tumor site.

Prevention of adverse drug effects: a pharmacogenomic approach

PURPOSE OF REVIEW

Adverse drug reactions (ADRs) are a serious burden and can negatively impact patient quality of life. One of these ADRs, anthracycline-induced cardiotoxicity (ACT), occurs in up to 65% of treated patients and can lead to congestive heart failure. Pharmacogenetic studies have helped to reveal the mechanisms of ACT and, consequently, inform current strategies to prevent ACT in the clinic.

RECENT FINDINGS

Many pharmacogenetic studies have been conducted for ACT, but few have led to the development of clinical practice guidelines and clinical genetic testing for ACT. This is, in part, because of lack of replication in independent patient cohorts and/or validation of an affected biological pathway. Recent advances in pharmacogenetic studies have been made through the use of novel methods that directly implicate dysregulated genes and perturbed biological pathways in response to anthracycline treatment.

SUMMARY

Furthering the understanding of the genetics and altered biological pathways of ACT through these novel methods can inform clinical treatment strategies and enable refinement of current clinical practice guidelines. This can therefore lead to improvement in clinical pharmacogenetic testing for further reduction of the incidence of ACT in pediatric cancer patients taking anthracyclines.

Novel self-nanoemulsifying drug-delivery system enhances antileukemic properties of all-trans retinoic acid

Aim: All- trans retinoic acid (ATRA) shows erratic oral bioavailability when administered orally against leukemia, which can be solved through its incorporation in self-nanoemulsifying drug-delivery systems (SEDDS). The SEDDS developed contained a hydrophobic ion pair between benzathine (BZT) and ATRA and was enriched with tocotrienols by the input of a palm oil tocotrienol rich fraction (TRF) in its composition. Results: SEDDS-TRF-ATRA-BZT allowed the formation of emulsions with nanometric size that retained ATRA within their core after dispersion. Pharmacokinetic parameters after oral administration of SEDDS-TRF-ATRA-BZT in mice were improved compared with what was seen for an ATRA solution. Moreover, SEDDS-TRF-ATRA-BZT had improved activity against HL-60 cells compared with SEDDS without TRF. Conclusion: SEDDS-TRF-ATRA-BZT is a promising therapeutic choice over ATRA conventional medicine.

Advances in Pediatric Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) is a rare disease accounting for only 5%-10% of pediatric acute myeloid leukemia (AML) and fewer than 1000 cases occur annually in the United States across all age groups. Characterized by t (15; 17), with a resultant PML-RARA gene fusion driving leukemia development, advances in therapy have improved outcomes for APL significantly in the past several decades, now making APL the most curable form of AML in both children and adults. Cure rates in APL are now comparable to pediatric B-lymphoid leukemias. The success of APL treatment is due, in part, to the breadth of understanding of the driver PML-RARA mutation as well as collaborative efforts to quickly introduce and maximize the benefit of new therapies. Here, we review the presentation, clinical features, pathogenesis, and treatment advances in pediatric APL.

Acute Promyelocytic Leukemia: A History over 60 Years-From the Most Malignant to the most Curable Form of Acute Leukemia

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) that is cytogenetically characterized by a balanced reciprocal translocation between chromosomes 15 and 17, which results in the fusion of the promyelocytic leukemia (PML) and retinoic acid receptor alpha (RARα) genes. Because patients with APL present a tendency for severe bleeding, often resulting in an early fatal course, APL was historically considered to be one of the most fatal forms of acute leukemia. However, therapeutic advances, including anthracycline- and cytarabine-based chemotherapy, have significantly improved the outcomes of APL patients. Due to the further introduction of all-trans retinoic acid (ATRA) and-more recently-the development of arsenic trioxide (ATO)-containing regimens, APL is currently the most curable form of AML in adults. Treatment with these new agents has introduced the concept of cure through targeted therapy. With the advent of revolutionary ATRA-ATO combination therapies, chemotherapy can now be safely omitted from the treatment of low-risk APL patients. In this article, we review the six-decade history of APL, from its initial characterization to the era of chemotherapy-free ATRA-ATO, a model of cancer-targeted therapy.

Heart failure following blood cancer therapy in pediatric and adult populations

AIM

The link between chemotherapy treatment and cardiotoxicity is well established, particularly for adults with blood cancers. However, it is less clear for children. This analysis aimed to compare the trajectory and mortality of children and adults who received chemotherapy for blood cancers and were subsequently hospitalized for heart failure.

METHODS

Linked data from the Queensland Cancer Registry, Death Registry and Hospital Administration records for initial chemotherapy and later heart failure were reviewed (1996-2009). Of all identified blood cancer patients (N = 23 434), 8339 received chemotherapy, including 817 children (aged ≤18 years at time of cancer diagnosis) and 7522 adults. Time-varying Cox proportional hazards regression models were used to compare the characteristics and survival between the two groups.

RESULTS

Of those who were subsequently hospitalized for heart failure, 70% of children and 46% of adults had the index admission within 12 months of their cancer diagnosis. Of these, 53% of the pediatric heart failure population and 71% of the adult heart failure population died within the study period. Following adjustment for age, sex and chemotherapy admissions, children with heart failure had an increased mortality risk compared to their non-heart failure counterparts, a difference which was much greater than that between the adult groups.

CONCLUSION

The impact of heart failure on children previously treated for blood cancer is more severe than for adults, with earlier morbidity and greater mortality. Improved strategies are needed for the prevention and management of cardiotoxicity in this population.

Early anthracycline-induced cardiotoxicity monitored by echocardiographic Doppler parameters combined with serum hs-cTnT

PURPOSE

As growing numbers of long-term cancer survivors faced with the cardiac side effects by anthracycline treatment, it is necessary to explore the optimal monitoring method for the early detection of cardiac toxicity.

METHODS

We conducted a retrospective analysis of 82 consecutive patients with diffuse large B-cell lymphoma treated with chemotherapy. Echocardiographic Doppler imaging-derived Tei index and mitral annular peak systolic velocity (Sm) measured by tissue Doppler imaging TDI, serum high-sensitivity cardiac troponin T (hs-cTnT) levels, and left ventricular ejection fraction (LVEF) by multigated radionuclide angiography (MUGA) were obtained before, after 2-4, and after 6-8 chemotherapy cycles. Cardiotoxicity was defined as a relative reduction of LVEF ≥10% from the baseline or LVEF <50% as measured by MUGA.

RESULTS

Following chemotherapy, 24 (29.3%) patients developed detectable cardiac abnormality during the treatment. Five (6.1%) patients' cardiac function changed from normal baseline LVEF to <50% after the chemotherapy. Echocardiographic pulse wave Doppler Tei index (PW Tei index) (baseline 0.347 ± 0.115 vs 2-4 cycles 0.459 ± 0.161 vs 6-8 cycles 0.424 ± 0.139, P = .000) inversely correlated with systolic (P < .001) and diastolic dysfunction (P < .001). Serum hs-cTnT levels increased significantly following chemotherapy after 2-4 cycles of chemotherapy with anthracycline. The increase in PW Tei index of 0.095 [sensitivity, 69.2%; specificity, 64.5%; area under the curve (AUC) = 0.697; P = .005] and the Sm < 13.65 cm/s (sensitivity, 66.7%; specificity, 71%; AUC = 0.682; P = .009) combined with elevation of serum hs-cTnT level of 0.0075 ng/mL (sensitivity, 69.2%; specificity, 83.9%; AUC = 0.790; P < .001) after 2-4 chemotherapy cycles from the baseline values can reliably predict cardiotoxicity.

CONCLUSIONS

We demonstrated that echocardiographic PW Doppler-derived Tei index, and TDI-derived Sm, combined with serum hs-cTnT level can be obtained in outpatient settings to monitor early cardiac toxicity induced by anthracycline therapy.

Long-term cardiovascular health in adult cancer survivors

The number of cancer survivors has tremendously increased over the past decades as a result of aging of the population and improvements in early cancer detection and treatment. Ongoing successes in cancer treatment are expected to result in a further increase in the number of long-term survivors. However, cancer treatment can have detrimental cardiovascular side-effects that impact morbidity and mortality, reducing quality of life in cancer survivors. The spectrum of radiotherapy- and chemotherapy-induced cardiovascular disease is broad, varying from subclinical valvular dysfunction to overt congestive heart failure, and such effects may not be apparent for more than twenty years after the initial cancer treatment. Awareness of these long-term side-effects is of crucial value in the management of these patients, in order to reduce the impact of cardiovascular morbidity and mortality. This review provides a comprehensive overview of the long-term cardiovascular complications of cancer treatments (radiotherapy and chemotherapy) in adult cancer survivors.

Assessment of late cardiomyopathy by magnetic resonance imaging in patients with acute promyelocytic leukaemia treated with all-trans retinoic acid and idarubicin

Late cardiomyopathy CMP is regarded as a potential severe long-term complication after anthracycline-based regimens for acute promyelocitic leukaemia (APL). We assess by MRI the incidence and severity of clinical and subclinical long-term CMP in a cohort of adult APL patients in first complete remission with PETHEMA trials. Adult patients diagnosed with APL in first complete remission lasting ≥2 years underwent anamnesis and physical examination and were asked to perform a cardiac MRI. Clinical CMP was defined as radiographic and physical signs of heart failure accompanied by symptoms or by left ventricle ejection fraction (LVEF) <45% by MRI with or without symptoms. Subclinical CMP was defined as the following MRI abnormalities: LVEF 45-50% or late gadolinium enhancement or two or more of LVEF ≤55%, left ventricle end-diastolic volume index ≥98 ml/m², left ventricle end-systolic volume index ≥38 ml/m², right ventricle end-diastolic volume index ≥106 ml/m² and regional wall motion abnormalities. Of the 82 patients enrolled in the study, median cumulative dose of anthracyclines (doxorubicin equivalence) was 650 mg/m², and median time from APL diagnosis to the study was 87 months (range, 24-195). Seven out of 57 patients with available MRI (12%) had subclinical CMP (all of them showed late gadolinium enhancement in MRI), and none had clinical CMP. Among the 25 patients without MRI, none had CMP by chest X-ray and physical assessment. In summary, we found 12% of subclinical and no clinical late CMP assessed by MRI in APL patients treated with PETHEMA protocols. Due to the low number of patients, we must interpret our results cautiously.

Retinoic acid and arsenic trioxide in the treatment of acute promyelocytic leukemia: current perspectives

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) with a unique morphological appearance, associated coagulopathy and canonical balanced translocation of genetic material between chromosomes 15 and 17. APL was first described as a distinct subtype of AML in 1957 by Dr Leif Hillestad who recognized the pattern of an acute leukemia associated with fibrinolysis, hypofibrinogenemia and catastrophic hemorrhage. In the intervening years, the characteristic morphology of APL has been described fully with both classical hypergranular and variant microgranular forms. Both are characterized by a balanced translocation between the long arms of chromosomes 15 and 17, [t(15;17)(q24;q21)], giving rise to a unique fusion gene PML-RARA and an abnormal chimeric transcription factor (PML-RARA), which disrupts normal myeloid differentiation programs. The success of current treatments for APL is in marked contrast to the vast majority of patients with non-promyelocytic AML. The overall prognosis in non-promyelocytic AML is poor, and although there has been an improvement in overall survival in patients aged <60 years, only 30%-40% of younger patients are still alive 5 years after diagnosis. APL therapy has diverged from standard AML therapy through the empirical discovery of two agents that directly target the molecular basis of the disease. The evolution of treatment over the last 4 decades to include all-trans retinoic acid and arsenic trioxide, with chemotherapy limited to patients with high-risk disease, has led to complete remission in 90%-100% of patients in trials and rates of overall survival between 86% and 97%.

Acute promyelocytic leukemia: preventing early complications and late toxicities

Acute promyelocytic leukemia (APL) is a unique subtype of acute myeloid leukemia (AML), which presents with a distinct coagulopathy. Therapeutic advances have made APL one of the true success stories in oncology, transforming this once lethal disease into the most curable form of AML. For many patients, cure will now be achieved without the use of chemotherapy. It is hoped that limiting chemotherapy will reduce mortality even further, particularly among more vulnerable older adults whose survival lagged behind that of younger patients. It should be noted that early death persists in patients with APL and continues to negatively affect survival. Further, among survivors treated with chemotherapy or even arsenic trioxide (ATO), there remains the potential for long-term toxicities that must be monitored. Understanding the management of these issues is an important complement to ensure maximal survival for patients with APL.

Early change in left atrial function in patients treated with anthracyclines assessed by real-time three-dimensional echocardiography

Real-time three-dimensional echocardiography(RT-3DE) has allowed a better assessment of LA volumes and function. We sought to assess the early change in left atrial size and function in patients treated with anthracyclines using RT-3DE. 61 patients aged 44.9 ± 11.9 years with large B-cell non-Hodgkin lymphoma treated with doxorubicin were studied. Blood collection and echocardiography were performed at baseline and 1 day after completion of the chemotherapy. Global longitudinal strain (GLS), maximum, minimum and pre-atrial contraction LA volumes were measured and reservoir, conduit and booster pump function were assessed. Despite normal LVEF, passive emptying percent of total emptying (0.51 ± 0.14 vs. 0.40 ± 0.12, P < 0.001) and passive emptying index (0.29 ± 0.10 vs. 0.23 ± 0.06, P < 0.001) were remarkably reduced compared to baseline values, while active emptying percent of total emptying (0.49 ± 0.14 vs. 0.60 ± 0.12, P < 0.001) and active emptying index (0.41 ± 0.16 vs. 0.47 ± 0.16, P = 0.048) were increased. GLS (−21.64 ± 2.83 vs. −17.30 ± 2.50) was markedly reduced, cTnT levels was elevated from 0.005 ± 0.004 to 0.020 ± 0.026 ng/mL at the completion of chemotherapy (P all  < 0.001). Early LA functional change occur after doxorubicin exposure in patients with preserved LVEF, which could be detected by RT-3DE.

Mitoxantrone-Induced Cardiotoxicity in Acute Myeloid Leukemia-A Velocity Vector Imaging Analysis

BACKGROUND

The purpose of this investigation was to: (1) determine incidence and predictors of mitoxantrone-induced early cardiotoxicity and (2) study left ventricular mechanics before and after receiving mitoxantrone.

METHOD AND RESULTS

We retrospectively analyzed 80 subjects diagnosed with acute myeloid leukemia (AML) who underwent chemotherapy with bolus high-dose mitoxantrone. Echocardiographic measurements were taken at baseline and at a median interval of 55 days after receiving mitoxantrone. Thirty-five (44%) of the patients developed clinically defined early cardiotoxicity, 29 (36%) of which developed heart failure. There was a significant decrease in the ejection fraction (EF) not only in the cardiotoxicity group (17.6 ± 14.8%, P < 0.001) but also in the noncardiotoxicity group (5.3 ± 8.4%, P < 0.001). Decrease in global longitudinal strain (GLS) (-3.7 ± 4.5, P < 0.001 vs. -2.4 ± 4.3, P = 0.01) and global circumferential strain (GCS) (-5.6 ± 9, P = 0.003 vs. -5.3 ± 8.7, P < 0.001) was significant in both the cardiotoxicity and noncardiotoxicity group, respectively. A multivariate model including baseline left ventricular end-systolic diameter, baseline pre-E/A ratio, and baseline pre-E/e' ratio was found to be the best-fitted model for prediction of mitoxantrone-induced early clinical cardiotoxicity.

CONCLUSION

High-dose mitoxantrone therapy is associated with an excellent remission rate but with a significantly increased risk of clinical and subclinical early cardiotoxicity and heart failure. Mitoxantrone-induced systolic dysfunction is evident from reduction in EF, increase in Tei index, and significant reduction in GLS and GCS. Baseline impaired ventricular relaxation evident from higher E/e' ratio and lower E/A ratio independently predicts increased risk of mitoxantrone-induced early cardiotoxicity.

Cardiotoxicity of anthracycline therapy: current perspectives

Anthracyclines, especially doxorubicin and daunorubicin, are the drugs of first choice in the treatment of patients with hematologic malignancies, soft-tissue sarcomas, and solid tumors. Unfortunately, the use of anthracyclines is limited by their dose-dependent and cumulative cardiotoxicity. The molecular mechanism responsible for anthracycline-induced cardiotoxicity remains poorly understood, although experimental and clinical studies have shown that oxidative stress plays the main role. Hence, antioxidant agents, especially dexrazoxane, and also other drug classes (statins, β-blockers) proved to have a beneficial effect in protecting against anthracycline-induced cardiotoxicity. According to previous clinical trials, the major high-risk factors for anthracycline-induced cardiotoxicity are age, body weight, female gender, radiotherapy, and other diseases such as Down syndrome, familial dilated cardiomyopathy, diabetes and hypertension. Consequently, further studies are needed to elucidate the molecular pathogenesis of anthracycline-induced cardiotoxicity and also to discover new cardioprotective agents against anthracycline-induced cardiotoxicity.

A coding variant in RARG confers susceptibility to anthracycline-induced cardiotoxicity in childhood cancer

Anthracyclines are used in over 50% of childhood cancer treatment protocols, but their clinical usefulness is limited by anthracycline-induced cardiotoxicity (ACT) manifesting as asymptomatic cardiac dysfunction and congestive heart failure in up to 57% and 16% of patients, respectively. Candidate gene studies have reported genetic associations with ACT, but these studies have in general lacked robust patient numbers, independent replication or functional validation. Thus, the individual variability in ACT susceptibility remains largely unexplained. We performed a genome-wide association study in 280 patients of European ancestry treated for childhood cancer, with independent replication in similarly treated cohorts of 96 European and 80 non-European patients. We identified a nonsynonymous variant (rs2229774, p.Ser427Leu) in RARG highly associated with ACT (P = 5.9 × 10(-8), odds ratio (95% confidence interval) = 4.7 (2.7-8.3)). This variant alters RARG function, leading to derepression of the key ACT genetic determinant Top2b, and provides new insight into the pathophysiology of this severe adverse drug reaction.

Multimodality Imaging in Cardiooncology

Cardiotoxicity represents a rising problem influencing prognosis and quality of life of chemotherapy-treated patients. Anthracyclines and trastuzumab are the drugs most commonly associated with development of a cardiotoxic effect. Heart failure, myocardial ischemia, hypertension, myocarditis, and thrombosis are typical manifestation of cardiotoxicity by chemotherapeutic agents. Diagnosis and monitoring of cardiac side-effects of cancer treatment is of paramount importance. Echocardiography and nuclear medicine methods are widely used in clinical practice and left ventricular ejection fraction is the most important parameter to asses myocardial damage secondary to chemotherapy. However, left ventricular ejection decrease is a delayed phenomenon, occurring after a long stage of silent myocardial damage that classic imaging methods are not able to detect. New imaging techniques including three-dimensional echocardiography, speckle tracking echocardiography, and cardiac magnetic resonance have demonstrated high sensitivity in detecting the earliest alteration of left ventricular function associated with future development of chemotherapy-induced cardiomyopathy. Early diagnosis of cardiac involvement in cancer patients can allow for timely and adequate treatment management and the introduction of cardioprotective strategies.

Acute promyelocytic leukemia: where did we start, where are we now, and the future

Historically, acute promyelocytic leukemia (APL) was considered to be one of the most fatal forms of acute leukemia with poor outcomes before the introduction of the vitamin A derivative all-trans retinoic acid (ATRA). With considerable advances in therapy, including the introduction of ATRA initially as a single agent and then in combination with anthracyclines, and more recently by development of arsenic trioxide (ATO)-containing regimens, APL is now characterized by complete remission rates of 90% and cure rates of ∼80%, even higher among low-risk patients. Furthermore, with ATRA-ATO combinations, chemotherapy may safely be omitted in low-risk patients. The disease is now considered to be the most curable subtype of acute myeloid leukemia (AML) in adults. Nevertheless, APL remains associated with a significant incidence of early death related to the characteristic bleeding diathesis. Early death, rather than resistant disease so common in all other subtypes of AML, has emerged as the major cause of treatment failure.

Acute Promyelocytic Leukemia (APL): Comparison Between Children and Adults

The outcome of adults and children with Acute Promyelocytic Leukemia (APL) has dramatically changed since the introduction of all trans retinoic acid (ATRA) therapy. Based on the results of several multicenter trials, the current recommendations for the treatment of patients with APL include ATRA and anthracycline-based chemotherapy for the remission induction and consolidation, and ATRA combined with low-dose chemotherapy for maintenance. This has improved the prognosis of APL by increasing the complete remission (CR) rate, actually > 90%, decreasing the induction deaths and by reducing the relapse rate, leading to cure rates nowadays exceeding 80% considering both adults and children.1-9 More recently the combination of ATRA and arsenic trioxide (ATO) as induction and consolidation therapy has been shown to be at least not inferior and possibly superior to ATRA plus chemotherapy in adult patients with APL conventionally defined as non-high risk (Sanz score).10 Childhood APL has customarily been treated on adult protocols. Data from several trials have shown that the overall outcome in pediatric APL appears similar to that reported for the adult population; however, some clinical and therapeutic aspects differ in the two cohorts which require some important considerations and treatment adjustments.

How I treat children and adolescents with acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APL) is a rare subtype of acute myeloid leukaemia. The outcome of paediatric APL has improved substantially over the past 20 years; cure rates above 80% are expected when all-trans retinoic acid (ATRA) is given with anthracycline-based regimens. The presenting features of paediatric APL may include severe bleeding and thrombotic complications, which contribute to the high early death rate. The incidence of leucocytosis and the microgranular subtype is greater in paediatric than adult APL, and children experience greater ATRA-related toxicity. It is crucial to begin ATRA therapy and intensive platelet and fibrinogen replacement on first suspicion of APL. Recent risk-adapted therapeutic trials have shown that patients at greater risk of relapse benefit from the introduction of high-dose cytarabine during consolidation. Combination therapy with ATRA and arsenic trioxide provides very effective frontline treatment and may reduce the need for subsequent anthracycline therapy.

Treatment-related cardiotoxicity in survivors of childhood cancer

Treatment advances and higher participation rates in clinical trials have rapidly increased the number of survivors of childhood cancer. However, chemotherapy and radiation treatments are cardiotoxic and can cause cardiomyopathy, conduction defects, myocardial infarction, hypertension, stroke, pulmonary oedema, dyspnoea and exercise intolerance later in life. These cardiotoxic effects are often progressive and irreversible, emphasizing a need for effective prevention and treatment to reduce or avoid cardiotoxicity. Medical interventions, such as angiotensin-converting enzyme inhibitors, β-blockers, and growth hormone therapy, might be used to treat cardiotoxicity in childhood cancer survivors. Preventative strategies should include the use of dexrazoxane, which provides cardioprotection without reducing the oncological efficacy of doxorubicin chemotherapy; less-toxic anthracycline derivatives and the use of antioxidant nutritional supplements might also be beneficial. Continuous-infusion doxorubicin provides no benefit over bolus infusion in children. Identifying patient-related (for example, obesity and hypertension) and drug-related (for example, cumulative dose) risk factors for cardiotoxicity could help tailor treatments to individual patients. However, all survivors of childhood cancer are at increased risk of cardiotoxicity, suggesting that survivor screening recommendations for assessment of global risk of premature cardiovascular disease should apply to all survivors. Optimal, evidence-based monitoring strategies and multiagent preventative treatments still need to be identified.

An expert opinion on pharmacologic approaches to reducing the cardiotoxicity of childhood acute lymphoblastic leukemia therapies

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children. Treatment-related cardiac damage is progressive and often difficult to reverse. Strategies to minimize cardiotoxicity during treatment are crucial to prevent severe lasting effects on health and quality of life.

AREAS COVERED

This comprehensive review covers the pathophysiology and various presentations, both clinical and subclinical, of treatment-induced cardiotoxicity and characteristics associated with increased risk of cardiac dysfunction in childhood ALL survivors. Additionally, contemporary prevention strategies such as limiting cumulative anthracycline dose, altering drug administration schedule, the use of anthracycline structural analogs, liposomal encapsulated anthracyclines, cardioprotective agents and nutritional supplements are critically analyzed. Finally, this review covers the management options of chemotherapy-induced damage and other treatment-related cardiotoxicity.

EXPERT OPINION

Higher lifetime cumulative doses of anthracyclines, younger age at diagnosis, longer follow-up, female sex, higher dose rates and cranial irradiation are associated with more severe cardiotoxic effects. Long-term adverse effects of both anthracycline and non-anthracycline chemotherapeutic agents are becoming an increasing focus during treatment of childhood malignancies. There must be a careful balance between achieving remission of childhood ALL while avoiding the development of another often-fatal illness, heart failure.