Iron overload in children undergoing cancer treatments

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.

Risk of transfusion-related iron overload varies based on oncologic diagnosis and associated treatment: Retrospective analysis from a single pediatric cancer center

BACKGROUND

Transfusion-related iron overload (TRIO) is a widely acknowledged late effect of antineoplastic therapy in pediatric cancer survivors, but firm guidelines as to screening protocols or at-risk populations are lacking in the literature.

PROCEDURE

We performed retrospective analysis of all oncology patients diagnosed at our center from 2014 to 2019, who underwent TRIO screening as part of an internal quality improvement project. Correlations of MRI-confirmed TRIO with patient-, disease-, and treatment-specific features were evaluated.

RESULTS

We show that a tiered screening algorithm for TRIO, when followed as intended, led to the identification of the highest proportion of patients with TRIO. We confirm that cardiac TRIO is quite rare in the oncology patient population. However, accepted surrogate markers including red blood cell transfused volume and ferritin only modestly correlated with TRIO in our patient cohort. Instead, we found that older age, leukemia diagnosis, anthracycline exposure, and receipt of stem cell transplant were most strongly associated with risk for TRIO.

CONCLUSIONS

We describe associations between TRIO and patient, disease, and treatment characteristics in a multivariate risk model that could lead to an improved risk stratification of off-therapy patients, and which should be validated in a prospective manner.

Iron Overload Following Hematopoietic Stem Cell Transplantation: Prevalence, Severity, and Management in Children and Adolescents with Malignant and Nonmalignant Diseases

Iron overload (IOL) is a frequently reported complication following hematopoietic stem cell transplantation (HSCT) that has been investigated extensively in the field of hemoglobinopathies but has not been thoroughly characterized after HSCT in pediatric malignancies. Our aim was to assess prevalence, severity, risk factors, and management of IOL, as defined using biochemical (serum ferritin) and radiologic tools (T2*-weighted magnetic resonance imaging [MRI]), in a cohort of pediatric patients who underwent HSCT for either malignant or benign diseases. This monocentric, retrospective, observational study included all the 163 patients alive and in continuous remission at 24 months post-HSCT out of the 219 consecutive children and adolescents who underwent HSCT at our institution between 2012 and 2018, were included in the study. IOL was classified into 4 categories: absent, mild, moderate, and severe. Among the 163 patients, 73% had some degree of IOL (mild in 37%, moderate in 29%, and severe in 7%). Moderate/severe IOL was more frequent among patients diagnosed with a malignant disease versus those with a benign disease (43% versus 19%; P = .0065). Trend lines for serum ferritin showed a "bell-shaped" distribution, with the highest levels recorded during the first 6 months post-HSCT, followed by a spontaneous reduction. Both pre-HSCT (1659 ng/mL versus 617 ng/mL; P < .001) and maximum post-HSCT (2473 ng/mL versus 1591 ng/mL; P < .001) median ferritin levels were statistically higher in the patients with malignancies. Radiologic assessment of IOL confirmed a more severe degree in patients with malignant disorders compared to those with benign disorders (median T2*-MRI, 4.20 msec [interquartile range (IQR), 3.0 to 6.40 msec] versus 7.40 msec [IQR, 4.90 to 11.00 msec]; P = .008). T2* levels were associated with the number of transfusions performed (P = .0006), with a steeper drop in T2* values for the first 20 transfusions and a milder slope for subsequent transfusions. T2* and ferritin values showed a statistically significant negative exponential relationship (P < .0001), although a ferritin level ≥1000 ng/mL showed poor specificity (48%) and low positive predictive value (53%) for discriminating moderate-to-severe IOL from absent-mild IOL as assessed by T2*-MRI, but with high sensitivity (92%) and negative predictive value (91%). In a multivariable model, >20 transfusions (odds ratio [OR], 4.07; 95% confidence interval [CI], 1.61 to 10.68; P = .003) and higher pre-HSCT ferritin level (P < .001) were associated with the risk of developing moderate-to-severe IOL. Use of a sibling donor (OR, .29; 95% CI, .10 to .77; P = .015) and a nonmalignancy (OR, .27; 95% CI, .08 to .82; P = .026) were protective factors. Phlebotomy (66%), low-dose oral chelators (9%), or a combined approach (25%) were started at a median of 12 months after HSCT in 78% of the patients with IOL. Six percent of the patients treated exclusively with phlebotomy (median, 14, significantly higher in patients >40 kg) discontinued phlebotomy owing to poor venous access, lack of compliance, or hypotension, whereas 39% of patients treated with chelators developed mild renal or hepatic side effects that resolved after tapering or discontinuation. Patients with malignancies showed statistically higher pre-HSCT and post-HSCT ferritin levels and lower T2* values. High ferritin level recorded on T2*-MRI showed unsatisfactory diagnostic accuracy in predicting IOL; thus, T2*-MRI should be considered a key tool for confirming IOL after HSCT in patients with an elevated serum ferritin level. IOL treatment is feasible after HSCT.

Estimation of iron overload with T2*MRI in children treated for hematological malignancies

Iron overload may contribute to long-term complications in childhood cancer survivors. There are limited reports of assessment of tissue iron overload in childhood leukemia by magnetic resonance imaging (MRI). A cross-sectional, observational study in children treated for hematological malignancy was undertaken. Patients ≥6 months from the end of therapy who had received ≥5 red-cell transfusions were included. Iron overload was estimated by serum ferritin (SF) and T2*MRI. Forty-five survivors were enrolled among 431 treated for hematological malignancies. The median age at diagnosis was 7-years. A median of 8 red-cell units was transfused. The median duration from the end of treatment was 15 months. An elevated SF (>1,000 ng/ml), elevated liver iron concentration (LIC) and myocardial iron concentration (MIC) were observed in 5 (11.1%), 20 (45.4%), and 2 (4.5%) patients, respectively. All survivors with SF >1,000 ng/ml had elevated LIC. The LIC correlated with SF (p < 0.001). MIC lacked correlation with SF or LIC. Factors including the number of red-cell units transfused and duration from the last transfusion were associated with elevated SF (p = 0.001, 0.002) and elevated LIC (p = 0.012, 0.005) in multiple linear regression. SF >595 ng/ml predicted elevated LIC with a sensitivity of 85% and specificity of 91.6% (AUC 91.2%). A cutoff >9 units of red cell transfusions had poor sensitivity and specificity of 70% and 75% (AUC 76.6%) to predict abnormal LIC. SF >600 ng/ml is a robust tool to predict iron overload, and T2*MRI should be considered in childhood cancer survivors with SF exceeding 600 ng/ml.

Cardiac Dysfunction in Medulloblastoma Survivors Treated with Photon Irradiation

Background

Medulloblastoma is an aggressive central nervous system (CNS) tumor that occurs mostly in the pediatric population. Treatment often includes a combination of surgical resection, craniospinal irradiation (CSI) and chemotherapy. Children who receive standard photon CSI are at risk for cardiac toxicities including coronary artery disease, left ventricular scarring and dysfunction, valvular damage, and atherosclerosis. Current survivorship guidelines recommend routine echocardiogram (ECHO) surveillance. In this multi-institution study, we describe markers of cardiac dysfunction in medulloblastoma survivors.

Methods

A retrospective chart review of medulloblastoma patients who had photon beam CSI followed by ECHO between 1980 and 2010 at Lurie Children’s Hospital and Dana-Farber/Boston Children’s Hospital.

Results

During the 30-year study period, 168 medulloblastoma patient records were identified. Included in this study were the 75 patients who received CSI or spinal radiation and ECHO follow up. The mean age at CSI was 8.6 years (range, 2.9-20), and the mean number of years between radiation (RT) completion and first ECHO was 7.4 (range, 2-16). Mean ejection fraction (EF) was 60.0% and shortening fraction (SF) was 33.8%. Five patients (7%) had abnormal ECHO results: three with EF &lt;50% and two with SF &lt;28%.

Conclusion

Majority of medulloblastoma patients who received CSI have relatively normal ECHOs post treatment, however 7% of patients had abnormal ECHOs. The implication of our study for medulloblastoma survivors is that further investigations are needed in this populations with a more systematic, longitudinal assessment to determine predictors and screenings.

Transfusion-related Iron Overload in Children With Leukemia

BACKGROUND

Children with leukemia commonly receive red blood cell (RBC) transfusions and transfusion-related iron overload (TRIO) is a major complication. However, few studies have evaluated TRIO in children with leukemia and no guidelines for screening exist. This retrospective, observational cohort study in children with acute leukemia evaluates the prevalence of TRIO and its impact on end-organ function.

RESULTS

The study included 139 patients; 60% standard-risk acute lymphoblastic leukemia (ALL), 32% high-risk (HR) ALL, and 9% acute myeloid leukemia (AML). The mean age at diagnosis was 6 years (range: 5 mo to 18 y). Patients with HR-ALL and AML were more likely to be transfused with ≥10 RBC units (59% and 92%, respectively) compared with those with standard-risk ALL (18%) (P<0.0001). Ferritin levels were measured in 68% patients and elevated (>1000 mcg/L) in 23%. Endocrinopathies were the most common end-organ abnormality. Hepatic dysfunction was significantly higher in patients with ≥10 RBC units transfused compared with those with <10 units (P=0.008).

CONCLUSIONS

Although the RBC transfusion burden is highest in patients with AML and HR-ALL, TRIO screening was not commonly performed. Patients who receive ≥10 RBC units are at risk for hepatic and endocrine dysfunction. We recommend routine screening for TRIO in children with leukemia, who are at risk for a higher transfusion burden.

Evaluation of Liver Iron Content by Magnetic Resonance Imaging in Children with Acute Lymphoblastic Leukemia after Cessation of Treatment

Objective

There are a limited number of studies evaluating iron overload in childhood leukemia by magnetic resonance imaging (MRI). The aim of this study was to determine liver iron content (LIC) by MRI in children with acute lymphoblastic leukemia (ALL) who had completed treatment and to compare those values with serum iron parameters.

Materials and Methods

A total of 30 patients between the ages of 7 and 18 who had completed ALL treatment were included in the study. Serum iron parameters (serum iron, serum ferritin [SF], and total iron-binding capacity) and liver function tests were studied. R2 MRI was performed for determining LIC.

Results

Normal LIC was detected in 22 (63.4%) of the cases. Seven (23.3%) had mild and 1 (3.3%) had moderate liver iron deposition. In contrast, severe iron overload was not detected in any of the cases. LIC levels were correlated with the numbers of packed red blood cell (pRBC) transfusions (r=0.637, p<0.001), pRBC transfusion volume (r=0.449, p<0.013), SF levels (r=0.561, p=0.001), and transferrin saturation (r=0.353, p=0.044). In addition, a positive correlation was found between the number of pRBC transfusions and SF levels (r=0.595, p<0.001).

Conclusion

We showed that the frequency of liver iron deposition was low and clinically less significant after the end of treatment in childhood ALL patients. LIC was demonstrated to be related to SF and transfusion history. These findings support that SF and transfusion history may be used as references for monitoring iron accumulation or identifying cases for further examinations such as MRI.

Blood product administration during high risk neuroblastoma therapy

The increasing intensity of high-risk neuroblastoma (HR NB) treatment over the last decades has resulted in improved survival at the expense of prolonging therapy and exposure to additional potentially toxic agents. Anemia and thrombocytopenia requiring transfusion are common during therapy for HR NB. Risks of cumulative red blood cell and platelet transfusions are incompletely defined in pediatric oncology patients, however, risks of transfusional iron overload are well described in other populations. This study aimed to determine the number of packed red blood cell (pRBC) and platelet transfusions throughout treatment for HR NB and how these numbers have changed with modern therapy. We performed a retrospective review of 92 patients with HR NB from June 2002 until September 2017. Patients received a median of 20 pRBC and 32 platelet transfusions. Our results demonstrated large numbers of transfusions with significantly increased blood product exposures among patients who received intensified therapy, either with additional induction chemotherapy, tandem autologous stem cell transplants, or dinutuximab plus cytokines with isotretinoin. Similar volumes of pRBC transfusions have been associated with iron overload in other populations and warrant further discussion of guidelines for long-term follow up of HR NB patients.

Systematic review and meta-analysis of the effect of iron chelation therapy on overall survival and disease progression in patients with lower-risk myelodysplastic syndromes

The impact of iron chelation therapy (ICT) on overall survival (OS) and progression to acute myeloid leukemia (AML) in patients with iron overload and International Prognostic Scoring System low- or intermediate-risk myelodysplastic syndromes (MDS) is not well understood. We conducted a systematic review and meta-analysis of published studies of ICT in patients with MDS to better elucidate these relationships. We searched PubMed, EMBASE, Cochrane databases, and the World Health Organization Clinical Trial Registry for studies reporting the impact of ICT on OS in patients with low- or intermediate-risk MDS. Studies were examined for demographics, effect measures, and potential bias risk. Fixed and random-effects models were used to calculate adjusted OS and adjusted hazards ratio (aHR) estimates, respectively, among the different studies. Nine observational studies (four prospective and five retrospective) were identified. For patients with MDS, ICT was associated with an overall lower risk of mortality compared with no ICT (aHR 0.42; 95% confidence interval (CI) 0.28-0.62; P < 0.01); however, there was significant heterogeneity across the studies. In studies reporting progression to AML, ICT was not associated with decreased risk of progression (odds ratio 0.68; 95% CI 0.31-1.43; P < 0.030). This systematic review and meta-analysis of nine nonrandomized trials demonstrated significant reduction in risk of mortality in patients with iron overload and low- or intermediate-risk MDS treated with ICT; however, a causal relationship cannot be established. Randomized, controlled trials are needed to more definitively evaluate the relationship between ICT and survival in patients with iron overload and low- or intermediate-risk MDS.

Iron Overload in Survivors of Childhood Cancer

BACKGROUND

Patients transfused with packed red blood cells (PRBC), including childhood cancer survivors (CCS), experience complications. We describe iron overload (ferritin>500 ng/mL) prevalence and identify risk factors in CCS.

OBSERVATIONS

Of 116 participants, 3 (2.6%) had elevated ferritin. All were teenagers at cancer diagnosis and received >8000 mL PRBC. Total PRBC volume correlated best with elevated ferritin (r=0.74; P<0.0001). PRBC (8000 mL) had the best positive and negative predictive value (75% and 100%, respectively) for iron overload.

CONCLUSIONS

CCS may have iron overload. Overall prevalence is low. At-risk include teenagers at diagnosis and those receiving higher total PRBC volumes.

Incidentally Detected Transfusion-associated Iron Overload in 3 Children After Cancer Chemotherapy

Iron overload is a potential long-term complication among cancer survivors who received transfusions during treatment. Although there are screening guidelines for iron overload in pediatric survivors of hematopoietic stem cell transplant, these do not call for screening of other pediatric oncology patients. In our practice we incidentally discovered 3 patients in a population of 168 cancer survivors over the span of 17 years who were treated for cancer without hematopoietic stem cell transplant who had iron overload. The 3 patients had elevated liver iron on magnetic resonance imaging T2* and 2 received therapeutic phlebotomy. These cases, and others like them, suggest that collaborative groups should consider revisiting the literature to establish screening and treatment guidelines for iron overload after cancer therapy.

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.

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.

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.