Association of projected transfusional iron burden with treatment intensity in childhood cancer survivors

Transfusional hemosiderosis in childhood cancer patients and survivors

BACKGROUND

Children treated for cancer are at risk for adverse effects of iron due to transfusions administered during prolonged marrow suppression, which may increase exposure to toxic forms of iron, extrahepatic iron accumulation, and long-term organ damage.

OBJECTIVE

This study aimed to characterize the severity and organ distribution of clinically significant, multisystem iron overload (IO) in an at-risk cohort of pediatric cancer patients.

METHODS

This was a retrospective, cross-sectional study of childhood cancer patients who underwent a magnetic resonance imaging (MRI) due to clinical concern for IO. Data regarding cancer type and treatment, transfusion history, MRI and laboratory results, and treatment for IO were collected. Severity of IO was analyzed by non-parametric tests with respect to clinical characteristics.

RESULTS

Of the 103 patients, 98% of whom had a Cancer Intensity Treatment Rating (ITR-3) of 3 or higher, 53% (54/102) had moderate or greater hepatic siderosis, 80% (77/96) had pancreatic siderosis, 4% (3/80) had cardiac siderosis, and 45% (13/29) had pituitary siderosis and/or volume loss. Pancreatic iron was associated with both cardiac (p = .0043) and pituitary iron (p = .0101). In the 73 off-therapy patients, ferritin levels were lower (p = .0008) with higher correlation with liver iron concentration (LIC) (p = .0016) than on-therapy patients. Fifty-eight subjects were treated for IO.

CONCLUSION

In this heavily treated cohort of pediatric cancer patients, more than 80% had extrahepatic iron loading, which occurs with significant exposure to toxic forms of iron related to decreased marrow activity in setting of transfusions. Further studies should examine the effects of exposure to reactive iron on long-term outcomes and potential strategies for management.

Hepatic late adverse effects after antineoplastic treatment for childhood cancer

BACKGROUND

Survival rates have greatly improved as a result of more effective treatments for childhood cancer. Unfortunately, the improved prognosis has been accompanied by the occurrence of late, treatment-related complications. Liver complications are common during and soon after treatment for childhood cancer. However, among long-term childhood cancer survivors, the risk of hepatic late adverse effects is largely unknown. To make informed decisions about future cancer treatment and follow-up policies, it is important to know the risk of, and associated risk factors for, hepatic late adverse effects. This review is an update of a previously published Cochrane review.

OBJECTIVES

To evaluate all the existing evidence on the association between antineoplastic treatment (that is, chemotherapy, radiotherapy involving the liver, surgery involving the liver and BMT) for childhood cancer and hepatic late adverse effects.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2018, Issue 1), MEDLINE (1966 to January 2018) and Embase (1980 to January 2018). In addition, we searched reference lists of relevant articles and scanned the conference proceedings of the International Society of Paediatric Oncology (SIOP) (from 2005 to 2017) and American Society of Pediatric Hematology/Oncology (ASPHO) (from 2013 to 2018) electronically.

SELECTION CRITERIA

All studies, except case reports, case series, and studies including fewer than 10 patients that examined the association between antineoplastic treatment for childhood cancer (aged 18 years or less at diagnosis) and hepatic late adverse effects (one year or more after the end of treatment).

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection and 'risk of bias' assessment. The 'risk of bias' assessment was based on earlier checklists for observational studies. For the original version of the review, two review authors independently performed data extraction. For the update of the review, the data extraction was performed by one reviewer and checked by another reviewer.

MAIN RESULTS

Thirteen new studies were identified for the update of this review. In total, we included 33 cohort studies including 7876 participants investigating hepatic late adverse effects after antineoplastic treatment (especially chemotherapy and radiotherapy) for different types of childhood cancer, both haematological and solid malignancies. All studies had methodological limitations. The prevalence of hepatic late adverse effects, all defined in a biochemical way, varied widely, between 0% and 84.2%. Selecting studies where the outcome of hepatic late adverse effects was well-defined as alanine aminotransferase (ALT) above the upper limit of normal, indicating cellular liver injury, resulted in eight studies. In this subgroup, the prevalence of hepatic late adverse effects ranged from 5.8% to 52.8%, with median follow-up durations varying from three to 23 years since cancer diagnosis in studies that reported the median follow-up duration. A more stringent selection process using the outcome definition of ALT as above twice the upper limit of normal, resulted in five studies, with a prevalence ranging from 0.9% to 44.8%. One study investigated biliary tract injury, defined as gamma-glutamyltransferase (γGT) above the upper limit of normal and above twice the upper limit of normal and reported a prevalence of 5.3% and 0.9%, respectively. Three studies investigated disturbance in biliary function, defined as bilirubin above the upper limit of normal and reported prevalences ranging from 0% to 8.7%. Two studies showed that treatment with radiotherapy involving the liver (especially after a high percentage of the liver irradiated), higher BMI, and longer follow-up time or older age at evaluation increased the risk of cellular liver injury in multivariable analyses. In addition, there was some suggestion that busulfan, thioguanine, hepatic surgery, chronic viral hepatitis C, metabolic syndrome, use of statins, non-Hispanic white ethnicity, and higher alcohol intake (> 14 units per week) increase the risk of cellular liver injury in multivariable analyses. Chronic viral hepatitis was shown to increase the risk of cellular liver injury in six univariable analyses as well. Moreover, one study showed that treatment with radiotherapy involving the liver, higher BMI, higher alcohol intake (> 14 units per week), longer follow-up time, and older age at cancer diagnosis increased the risk of biliary tract injury in a multivariable analysis.

AUTHORS' CONCLUSIONS

The prevalence of hepatic late adverse effects among studies with an adequate outcome definition varied considerably from 1% to 53%. Evidence suggests that radiotherapy involving the liver, higher BMI, chronic viral hepatitis and longer follow-up time or older age at follow-up increase the risk of hepatic late adverse effects. In addition, there may be a suggestion that busulfan, thioguanine, hepatic surgery, higher alcohol intake (>14 units per week), metabolic syndrome, use of statins, non-Hispanic white ethnicity, and older age at cancer diagnosis increase the risk of hepatic late adverse effects. High-quality studies are needed to evaluate the effects of different therapy doses, time trends, and associated risk factors after antineoplastic treatment for childhood cancer.

Change in liver, spleen and bone marrow magnetic resonance imaging signal intensity over time in children with solid abdominal tumors

BACKGROUND

Reticuloendothelial system MRI signal hypointensity is common in pediatric oncology patients with solid abdominal tumors.

OBJECTIVE

To assess changes in liver, spleen and bone marrow T2-weighted MRI signal intensity over time and their relationship to blood transfusion history in children with solid abdominal tumors.

MATERIALS AND METHODS

In this retrospective study we measured liver, spleen and bone marrow signal intensity on axial T2-weighted MR images obtained December 2009 through February 2016 in children with hepatoblastoma, neuroblastoma, ganglioneuroblastoma and Wilms tumor. All signal intensity measurements were normalized to paraspinal muscle signal intensity. We used linear mixed models (including a day*day quadratic term) to determine whether organ signal intensity changed over time and whether change was associated with blood transfusion volume or tumor type.

RESULTS

We included 133 children (mean age at diagnosis =2.9 years); 56 had neuroblastoma, 42 hepatoblastoma, 28 Wilms tumor and 7 ganglioneuroblastoma. Seventy-nine (59.4%) children received transfusions (median: 8 transfusions, range: 1-30; mean volume: 1,148.5 mL). Hepatic, splenic and bone marrow signal intensity ratios changed quadratically over time for the study population, initially decreasing and then increasing (P<0.0001). Children receiving less than the mean blood transfusion volume showed no significant change in tissue signal intensity, while those receiving more than the mean volume showed significant changes in signal intensity over time (P<0.0001). Compared to children with Wilms tumor, those with neuroblastoma exhibited significantly lower hepatic (P=0.03) signal intensity ratios.

CONCLUSION

Liver, spleen and bone marrow T2-weighted MRI signal intensity ratios change over time in some pediatric patients with solid abdominal tumors, likely from tissue iron deposition related to blood transfusions and perhaps because of tumor type.

The relationship between iron bone marrow stores and response to treatment in pediatric acute lymphoblastic leukemia

Iron is an intracellular element whose accumulation in the body is associated with tissue damage. This study examines the effect of iron on pediatric acute lymphoblastic leukemia (ALL) and its "response to treatment." At the end of the first year of treatment, bone marrow iron store (BMIS) was evaluated in children with ALL and the relationship between iron store and minimal residual disease was investigated. Moreover, the 3-year disease-free survival (3-DFS) of patients was determined. Patients' BMIS were compared with that of subjects with normal bone marrow. The study examined 93 children, including 78 Pre-B and 15 T-cell ALL patients. BMIS did not differ between the children with ALL and those with no evidence of cancer. BMIS was increased in 26.6% of patients at the end of the first year of treatment. Drug resistance and BM relapses were more prevalent in cases with high BMIS in both Pre-B and T-cell groups. Bone marrow iron store is not considered a risk factor for childhood ALL. However, high levels of BMIS are associated with poor response to treatment and the risk of relapse. Bone marrow iron store control during treatment can therefore help achieve better outcomes and improve the chances of recovery.

MRI-based evaluation of multiorgan iron overload is a predictor of adverse outcomes in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation

The medical records of 44 pediatric patients who underwent allogeneic transplantation from 2011 to 2015 were retrospectively reviewed. Magnetic resonance imaging was used to measure iron concentrations in the liver, spleen, pancreas and bone. These patients were divided into two groups, 18 with non-elevated (< 100 μmol/g; Group 1) liver iron concentration before transplantation and 26 with elevated (> 100 μmol/g; Group 2) concentration . We compared transplant-related outcomes in the two groups. Iron overload was a negative prognostic risk factor for sinusoidal obstruction syndrome (OR = 17), osteoporosis (OR = 6.8), pancreatic insufficiency (OR = 17) and metabolic syndrome (OR = 15.1). No statistically significant differences in overall survival, disease-free survival, relapse incidence and incidence of acute or chronic graft-versus host disease were observed between the two groups. Mean times to engraftment of platelets (43.0 ± 35.3 days vs. 22.1 ± 9.5 days, p < 0.05) and neutrophils (23.1 ± 10.4 days vs. 17.8 ± 4.6 days, p < 0.05) appear significantly longer in Group 2 than in Group 1. Time to platelet engraftment showed statistically significant correlation with pre-transplant liver (r = 0.5775; p < 0.001) and bone iron concentration (r = 0.7305; p < 0.001). Post-transplant evaluation pointed out that iron concentration analyzed at the first follow-up peaked in all tissues. The iron accumulation was highest in bone, followed by the spleen, liver and pancreas. One year post transplant 9 of 18 (50%) patients in Group 1 and 6 of 22 (27%) in Group 2 presented with bone and/or spleen iron overload, but not with liver overload. Liver iron concentration is not always a reliable indicator of systemic siderosis or of the efficacy of chelation therapy.

HFE gene mutation and iron overload in Egyptian pediatric acute lymphoblastic leukemia survivors: a single-center study

BACKGROUND

Hereditary hemochromatosis gene (HFE) mutations have a role in iron overload in pediatric acute lymphoblastic leukemia (ALL) survivors. We aimed to evaluate the genotype frequency and allelic distribution of the two HFE gene mutations (C282Y and H63D) in a sample of Egyptian pediatric ALL survivors and to detect the impact of these two mutations on their iron profile.

PATIENTS AND METHODS

This study was performed on 35 ALL survivors during their follow-up visits to the Hematology and Oncology Unit, Pediatric Department, Menoufia University Hospitals. Thirty-five healthy children of matched age and sex were chosen as controls. After completing treatment course, ALL survivors were screened for the prevalence of these two mutations by polymerase chain reaction-restriction fragment length polymorphism. Serum ferritin levels were measured by an enzyme-linked immunosorbent assay technique (ELISA).

RESULTS

C282Y mutation cannot be detected in any of the 35 survivors or the 35 controls. The H63D heterozygous state (CG) was detected in 28.6% of the survivors group and in 20% of controls, while the H63D homozygous (GG) state was detected in 17.1% of survivors. No compound heterozygosity (C282Y/H63D) was detected at both groups with high G allele frequency (31.4%) in survivors more than controls (10%). There were significant higher levels of iron parameters in homozygote survivors than heterozygotes and the controls.

CONCLUSION

H63D mutation aggravates the iron overload status in pediatric ALL survivors.

Prevalence and risk factors of iron overload after hematopoietic stem cell transplantation for childhood acute leukemia: a LEA study

Data on post-transplant iron overload (IO) are scarce in pediatrics. We conducted a prospective multicenter cohort study (Leucémie de l'Enfant et de l'Adolescent cohort) to determine the prevalence and risk factors of IO in 384 acute leukemia survivors transplanted during childhood. Prevalence of IO (ferritin level ⩾350 ng/mL) was 42.2% (95%CI 37.2-47.2%). Factors significantly associated with IO were: 1) in univariate analysis: older age at transplant (P<0.001), allogeneic versus autologous transplantation (P<0.001), radiation-based preparative regimen (P=0.035) and recent period of transplantation (P<0.001); 2) in multivariate analysis: older age at transplant in quartiles (Odds Ratio (OR)=7.64, 95% CI: 3.73-15.64 for age >12.7 years and OR=5.36, 95% CI: 2.63-10.95 for age from 8.2 to 12.7 years compared to age < 4.7 years), acute myeloid leukemia (OR=3.23, 95% CI: 1.47-7.13), allogeneic graft (OR=4.34, 95% CI: 2.07-9.12 for alternative donors and OR=2.53, 95% CI: 1.2-5.33 for siblings, compared to autologous graft) and radiation-based conditioning regimen (OR=2.45, 95% CI: 1.09-5.53). Graft-versus-host disease was an additional risk factor for allogeneic graft recipients. In conclusion, IO is a frequent complication in pediatric long-term survivors after transplantation for acute leukemia, more frequently observed in older children, those transplanted from alternative donors or with graft-versus-host disease.

Iron Overload in Survivors of Childhood Cancer

Iron overload is a significant cause of morbidity and mortality for patients who require frequent transfusions. We completed a prospective, cross-sectional study to evaluate the prevalence of iron overload in previously transfused childhood cancer survivors. Survivors recruited from the University of Minnesota Long-Term Follow-Up Clinic were stratified into 3 groups: oncology patients not treated with hematopoietic stem cell transplantation (HSCT) (n=27), patients treated with allogeneic HSCT (n=27), and patients treated with autologous HSCT (n=9). Serum ferritin was collected and hepatic magnetic resonance imaging (FerriScan) was obtained for those with iron overload (defined as ferritin ≥1000 ng/mL). The prevalence of iron overload in subjects with a history of allogeneic HSCT was 25.9% (95% CI, 9.4%-42.5%) compared with only 3.7% (95% CI, 0%-10.8%) in subjects treated without HSCT and 0% in subjects treated with autologous HSCT. No association was found between serum ferritin levels and the presence of cardiac, liver, or endocrine dysfunction. The prevalence of iron overload in subjects who received no HSCT or autologous HSCT is low in our study. A higher prevalence was found in patients receiving allogeneic HSCT, reiterating the importance of screening these patients for iron overload in accordance with the current Children's Oncology Group Long Term Follow-Up Guidelines.

Myocardial iron load and fibrosis in long term survivors of childhood leukemia

BACKGROUND

We sought to assess myocardial iron load and fibrosis, which may potentially affect cardiac function, in adult survivors of childhood leukemias and their relationships with left (LV) and right ventricular (RV) function.

PROCEDURE

Fifty-eight (33 males) adult survivors, aged 24.5 ± 4.4, underwent cardiac magnetic resonance (CMR) at 16.6 ± 5.8 years after completion of treatment. Myocardial iron load and fibrosis were quantified using respectively T2* scan and late gadolinium enhancement. Right and left ventricular ejection fraction (EF) was measured by CMR, while myocardial function was assessed using tissue Doppler imaging.

RESULTS

None of the survivors had significant myocardial iron overload (T2*<20 msec). The prevalence of LV and RV fibrosis was 9% (5/58) and 38% (22/58), respectively. Left ventricular EF was subnormal (EF 45-<55%) in 9% (5/58), while RV EF was abnormal (EF <45%) in 12% (7/58) and subnormal in 34% (20/58) of survivors. Patients with LV fibrosis had significantly lower mitral annular early diastolic velocity (P = 0.01) and smaller LV end-systolic volume (P = 0.02), while those with RV fibrosis had significantly lower tricuspid late diastolic annular velocity (P = 0.02) and early to late diastolic annular velocity ratio (P = 0.02) compared to those without. Cumulative anthracycline dose correlated with early diastolic mitral (r = -0.28, P = 0.038) and tricuspid (r = -0.40, P = 0.002) annular velocities, but not LV and RV EF or fibrosis (all P > 0.05).

CONCLUSION

Ventricular fibrosis may occur in long term survivors of childhood leukemias and is related to diastolic function in the absence of significant myocardial iron overload.

Estimating tissue iron burden: current status and future prospects

Iron overload is becoming an increasing problem as haemoglobinopathy patients gain greater access to good medical care and as therapies for myelodysplastic syndromes improve. Therapeutic options for iron chelation therapy have increased and many patients now receive combination therapies. However, optimal utilization of iron chelation therapy requires knowledge not only of the total body iron burden but the relative iron distribution among the different organs. The physiological basis for extrahepatic iron deposition is presented in order to help identify patients at highest risk for cardiac and endocrine complications. This manuscript reviews the current state of the art for monitoring global iron overload status as well as its compartmentalization. Plasma markers, computerized tomography, liver biopsy, magnetic susceptibility devices and magnetic resonance imaging (MRI) techniques are all discussed but MRI has come to dominate clinical practice. The potential impact of recent pancreatic and pituitary MRI studies on clinical practice are discussed as well as other works-in-progress. Clinical protocols are derived from experience in haemoglobinopathies but may provide useful guiding principles for other iron overload disorders, such as myelodysplastic syndromes.

Iron toxicity and its possible association with treatment of Cancer: lessons from hemoglobinopathies and rare, transfusion-dependent anemias

Exposure to elevated levels of iron causes tissue damage and organ failure, and increases the risk of cancer. The toxicity of iron is mediated through generation of oxidants. There is also solid evidence indicating that oxidant stress plays a significant role in a variety of human disease states, including malignant transformation. Iron toxicity is the main focus when managing thalassemia. However, the short- and long-term toxicities of iron have not been extensively considered in children and adults treated for malignancy, and only recently have begun to draw oncologists' attention. The treatment of malignancy can markedly increase exposure of patients to elevated toxic iron species without the need for excess iron input from transfusion. This under-recognized exposure likely enhances organ toxicity and may contribute to long-term development of secondary malignancy and organ failure. This review discusses the current understanding of iron metabolism, the mechanisms of production of toxic free iron species in humans, and the relation of the clinical marker, transferrin saturation (TS), to the presence of toxic free iron. We will present epidemiological data showing that high TS is associated with poor outcomes and development of cancer, and that lowering free iron may improve outcomes. Finally, we will discuss the possible relation between some late complications seen in survivors of cancer and those due to iron toxicity.

An assessment of iron overload in children treated for cancer and nonmalignant hematologic disorders

Our goal was to assess the natural fate of iron overload (IO) following transfusions of packed red blood cells (PRBCs) in children treated for cancer and nonmalignant disorders according to the intensity level of their treatment. Sixty-six children were followed up from February 2010 to March 2013. The transfusion burden was compared between three treatment intensity groups assigned according to the Intensity of Treatment Rating Scale 3.0 (ITR-3). IO was assessed by serial measurements of serum ferritin (SF) (n= 66) and quantification of tissue iron by magnetic resonance imaging (MRI) (n=12). Of the children studied, 36 % (24/66) received moderately intensive treatment (level 2), 21 % (14/ 66) received very intensive treatment (level 3), and 42 % (28/ 66) received the most intensive treatment (level 4). The number of PRBC (p=0.016), the total transfused volume (p= 0.026), and transfused volume adjusted to body weight (p= 0.004) were significantly higher in the level 4 group. By the median follow-up time of 35.5 months (range 8–133), 21– 29 % of patients (including level 2 and level 3 children) had SF >1,000 μg/l 1 year after cessation of transfusions. The slowest decrease of SF was observed in the level 4 group. Initial MRI examination demonstrated either mild or moderate IO in the liver and spleen. Repetitive MRI showed significant improvement in relaxation time between the initial and follow-up MRI performances in the liver (5.9 vs. 8.6 ms, p= 0.03) and the spleen (4.3 vs. 8.8 ms, p=0.03).

CONCLUSION

IO diminished over time, but in the level 4 patients, it was detectable for years after cessation of transfusions.

Physiology and pathophysiology of iron in hemoglobin-associated diseases

Iron overload and iron toxicity, whether because of increased absorption or iron loading from repeated transfusions, can be major causes of morbidity and mortality in a number of chronic anemias. Significant advances have been made in our understanding of iron homeostasis over the past decade. At the same time, advances in magnetic resonance imaging have allowed clinicians to monitor and quantify iron concentrations noninvasively in specific organs. Furthermore, effective iron chelators are now available, including preparations that can be taken orally. This has resulted in substantial improvement in mortality and morbidity for patients with severe chronic iron overload. This paper reviews the key points of iron homeostasis and attempts to place clinical observations in patients with transfusional iron overload in context with the current understanding of iron homeostasis in humans.

Characterization of transfusion-derived iron deposition in childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) receiving packed red blood cell (PRBC) transfusions may have increased risk for vital organ iron deposition causing serious late effects.

METHODS

This cross-sectional cohort study of a CCS cohort quantified organ iron content by magnetic resonance imaging. Iron status by serum markers and hemochromatosis gene mutation status were assessed.

RESULTS

Seventy-five patients who had received a range (0-392 mL/kg) of cumulative PRBC transfusion volumes were enrolled (median age 14 years, range 8-25.6 years at evaluation). Median follow-up time was 4.4 years, and median time since last transfusion was 4.9 years. Cancer diagnoses included acute lymphoblastic or myelogenous leukemia (ALL/AML; n = 33) and solid tumors (n = 42). Liver and pancreatic iron concentrations were elevated in 36 of 73 (49.3%) and 19 of 72 (26.4%) subjects, respectively. Cardiac iron concentration was not increased in this cohort. In multivariate analysis, cumulative PRBC volume (P < 0.0001) and older age at diagnosis (P < 0.0001) predicted elevated liver iron concentration.

CONCLUSIONS

Iron overload (IO) may occur in children and adolescents/young adults treated for cancer and is associated with cumulative PRBC transfusion volume and age at diagnosis.

IMPACT

These findings have implications for development of monitoring and management guidelines for cancer patients and survivors at risk for IO, exploration of the additive risk of liver/pancreatic damage from chemotherapeutic exposures, and health education to minimize further liver/pancreatic damage from exposures such as excessive alcohol intake and hepatotoxic medications.

Number of erythrocyte transfusions is more predictive than serum ferritin in estimation of cardiac iron loading in pediatric patients with acute lymphoblastic leukemia

BACKGROUND

Transfusions with packed erythrocytes is a common practice in pediatric patients with acute lymphoblastic leukemia (ALL) who are on chemotherapy. Since there is no physiological excretion mechanism for iron, the iron related to erythrocyte transfusions accumulates and may contribute to late cardiac, hepatic and endocrine complications in these patients.

PROCEDURE

In order to evaluate the iron burden among pediatric patients with ALL and define the risk factors associated with higher iron loading, we evaluated 79 pediatric patients with ALL (36 were off-therapy). Cardiac and hepatic T2* were ordered to a total of 22 (28%) patients who were either transfused with erythrocytes ≥ 10 times (n=11; 50%), had serum ferritin (SF) ≥ 1000 ng/ml (n=2; 9.1%) or both (n=9; 40.9%).

RESULTS

Half of the patients who were screened by T2* MRI had hepatic T2*<7 ms and six (27%) of the patients had cardiac T2*<20 ms, indicating iron loading. Patients who had serum ferritin <1000 vs ≥ 1000 ng/ml had median cardiac T2* values of 28.3 ms (15-40) vs 21 (7.9-36), (p=0.324); whereas hepatic T2* of 10.8 (5.32-27) vs 4.7 (2.2-36), (p=0.017). Patients who had erythrocyte transfusion <10 vs ≥ 10 times had median cardiac T2* values of 34 ms (28-38) vs 23 (7.93-40), (p=0.021); whereas hepatic T2* of 13.6 (6.6-36) vs 5.32 (2.2-27), (p=0.046).

CONCLUSIONS

Our results indicate that pediatric patients with ALL should be screened for transfusional iron load and the amount of erythrocyte transfusions seems to be a more reliable indication than serum ferritin levels to detect cardiac iron loading in these patients.

Iron overload in children undergoing cancer treatments

BACKGROUND

Iron overload is responsible for severe morbidity and mortality in polytransfused patients. Although repeated blood transfusions are needed during the treatment of most cancers, pediatric patients are not routinely screened for subsequent iron overload.

PROCEDURE

Seventy-five patients were identified as candidates for cancer treatment and enrolled prospectively in a yearly protocol including a cardiac and liver magnetic resonance imaging coupled with ferritin level measurements. Patients were divided into four groups using the intensity of treatment rating (ITR-3).

RESULTS

Fifty-nine patients reached 1-year of follow-up and liver iron overload was found in up to 66% of them. Such overload correlated with the total volume of red blood cells transfused and persisted at least 2 years after the initiation of therapy. Moderate myocardial overload was also, but less frequently (14%), observed in these patients.

CONCLUSIONS

Our study demonstrated that severe liver iron overload as well as moderate myocardial iron overload can be found 1 year after cancer treatment and that this overload persists overtime. The patients with higher ITR and those who have received more than a liter of blood red cells per square meter, regardless of their diagnosis or ITR, are at risk of iron overload and should be screened carefully.

Tissue iron evaluation in chronically transfused children shows significant levels of iron loading at a very young age

Chronic blood transfusions start at a very young age in subjects with transfusion-dependent anemias, the majority of whom have hereditary anemias. To understand how rapidly iron overload develops, we retrospectively reviewed 308 MRIs for evaluation of liver, pancreatic, or cardiac iron in 125 subjects less than 10 years old. Median age at first MRI evaluation was 6.0 years. Median liver iron concentrations in patients less than 3.5 years old were 14 and 13 mg/g dry weight in thalassemia major (TM) and Diamond-Blackfan anemia (DBA) patients, respectively. At time of first MRI, pancreatic iron was markedly elevated (> 100 Hz) in DBA patients, and cardiac iron ( R₂* >50 Hz) was present in 5/112 subjects (4.5%), including a 2.5 years old subject with DBA. Five of 14 patients (38%) with congenital dyserythropoietic anemia (CDA) developed excess cardiac iron before their 10th birthday. Thus, clinically significant hepatic and cardiac iron accumulation occurs at an early age in patients on chronic transfusions, particularly in those with ineffective or absent erythropoiesis, such as DBA, CDA, and TM, who are at higher risk for iron cardiomyopathy. Performing MRI for iron evaluation in the liver, heart, and pancreas as early as feasible, particularly in those conditions in which there is suppressed bone marrow activity is very important in the management of iron loaded children in order to prescribe appropriate chelation to prevent long-term sequelae. .

Risk factors for hyperferritinemia secondary to red blood cell transfusions in pediatric cancer patients

BACKGROUND

Transfusion of packed red blood cells is common in pediatric cancer patients who receive chemotherapy. This study was done to identify characteristics of pediatric cancer patients at risk of hyperferritinemia secondary to frequent transfusions.

PROCEDURE

In this retrospective chart review, all pediatric cancer patients who completed chemotherapy from January 2007 to January 2012 and had an assessment of serum ferritin 6 months after the end of treatment were included. Variables included: age, sex, type of cancer diagnosis, weight and body surface area (BSA) at the time of diagnosis, number of transfusions, total transfused volume (TTV), total transfused volume per body weight (TVPBW), and weight and BSA change from the time of diagnosis to the time of ferritin check.

RESULTS

Of 109 eligible patients, 85 (78%) received transfusions. Sixteen patients (14.7%) had ferritin levels > 200 µg/L and four (3.7%) had ferritin levels > 1,000 µg/L. Although age, weight and BSA at cancer diagnosis, number of transfusions and TVPBW were correlated with the level of ferritin, independent risk factors were TTV (range 1,961-30,090 ml in patients with hyperferritinemia, P < 0.001) and BSA change from the time of diagnosis to the time of ferritin check (range -0.15 to 0.31 m(2) in patients with hyperferritinemia, P < 0.001). Increase in BSA was correlated with reduction of hyperferritinemia in follow-up ferritin measurements (P = 0.049).

CONCLUSIONS

In addition to TTV, change in BSA is an independent predictor for the degree and possibly persistence of hyperferritinemia in pediatric cancer patients and should be considered in decisions to initiate interventions.

Deferasirox shows in vitro and in vivo antileukemic effects on murine leukemic cell lines regardless of iron status

Numerous studies have shown the antiproliferative effect of iron chelating agents (ICAs), which have been used traditionally in patients with secondary iron overload (SIO). Because the in vivo model for these studies has been animals with normal iron status, the antileukemic effect of ICAs in the SIO condition has not been determined clearly. We investigated the in vitro and in vivo effects of ICAs in murine leukemic cell lines regarding the iron status. The viability of both EL4 cells and L1210 cells incubated with either deferoxamine (DFO) or deferasirox (DFX) decreased in a concentration-dependent manner. This effect was most prominent in L1210 cells treated with DFX. The viability of L1210 cells incubated with both ICAs did not change regardless of the presence of ferric chloride. The percentage of apoptosis in L1210 cells treated with DFO or DFX increased in a concentration-dependent manner; however, the expression of Fas showed no significant change. The non-SIO mice and SIO mice bearing L1210 cells showed longer survival than other groups when treated with DFX, whereas the SIO mice treated with DFO showed shorter survival than the control group. The tumor was significantly smaller in the SIO mice treated with DFX or DFO compared with the control group. The iron content of the liver or the tumor in SIO mice decreased after ICA treatment. This study indicates an antileukemic effect of DFX regardless of iron status and suggests that the use of DFX has a survival benefit for SIO leukemia murine model in terms of iron chelation and antileukemic therapy.

Trends in transfusion burden among long-term survivors of childhood hematological malignancies

The risk from cumulative erythrocyte transfusions is poorly understood in oncology populations. This analysis among long-term survivors explored variation in transfusional burden over progressive eras of treatment identifying those at risk for iron overload. Transfusion records of 982 survivors of hematological malignancies treated at St. Jude were reviewed. After exclusions, 881 (90%) were assessed for cumulative volume, weight-adjusted volume and transfusion number. Treatment intensity was assigned using the Intensity of Treatment Rating Scale version 3.0 (ITR-3). Hematopoietic stem cell transplant and acute myeloid leukemia survivors had greater transfusional burden than conventional therapy recipients and acute lymphoblastic leukemia survivors, respectively. Survivors of 5-10 years were more likely than survivors of > 10 years to receive ≥ 10 transfusions (odds ratio = 2.0, 95% confidence interval 1.5-2.8). Those with higher ITR-3 scores and more recent decades of treatment had a higher transfusional burden. Comprehensive transfusion histories are useful in identifying those at highest risk for iron overload.