Impact of age on outcome of pediatric acute myeloid leukemia: a report from 2 institutions

Association of the social disorganization index with time to first septic shock event in children with acute myeloid leukemia

BACKGROUND

Pediatric acute myeloid leukemia (AML) chemotherapy increases the risk of life-threatening complications, including septic shock (SS). An area-based measure of social determinants of health, the social disorganization index (SDI), was hypothesized to be associated with SS and SS-associated death (SS-death).

METHODS

Children treated for de novo AML on two Children's Oncology Group trials at institutions contributing to the Pediatric Health Information System (PHIS) database were included. The SDI was calculated via residential zip code data from the US Census Bureau. SS was identified via PHIS resource utilization codes. SS-death was defined as death within 2 weeks of an antecedent SS event. Patients were followed from 7 days after the start of chemotherapy until the first of end of front-line therapy, death, relapse, or removal from study. Multivariable-adjusted Cox regressions estimated hazard ratios (HRs) comparing time to first SS by SDI group.

RESULTS

The assembled cohort included 700 patients, with 207 (29.6%) sustaining at least one SS event. There were 233 (33%) in the SDI-5 group (highest disorganization). Adjusted time to incident SS did not statistically significantly differ by SDI (reference, SDI-1; SDI-2: HR, 0.84 [95% confidence interval (CI), 0.51-1.41]; SDI-3: HR, 0.70 [95% CI, 0.42-1.16]; SDI-4: HR, 0.97 [95% CI, 0.61-1.53]; SDI-5: HR, 0.72 [95% CI, 0.45-1.14]). Nine patients (4.4%) with SS experienced SS-death; seven of these patients (78%) were in SDI-4 or SDI-5.

CONCLUSIONS

In a large, nationally representative cohort of trial-enrolled pediatric patients with AML, there was no significant association between the SDI and time to SS.

Increased survival disparities among children and adolescents & young adults with acute myeloid leukemia: A Dutch population-based study

For many cancers, adolescents and young adults (AYAs) have a poorer prognosis than pediatric patients. Our study evaluates survival outcomes of children (0‐17 years) and AYAs (18‐39 years) diagnosed with acute myeloid leukemia (AML) in the Netherlands between 1990 and 2015 (N = 2058) utilizing the population‐based Netherlands Cancer Registry, which includes information on therapy and site of primary treatment. Five‐ and 10‐year relative (disease‐specific) survival were estimated for all patients, children and AYAs. Multivariable analyses were performed using generalized linear models (excess mortality) and logistic regression (early mortality). AYAs with AML had a substantially lower 5‐ and 10‐year relative survival than children (5‐year: 43% vs 58%; 10‐year: 37% vs 51%). The gap in 5‐year relative survival was largest (nearly 20 percent‐points) in 2010 to 2015, despite survival improvements over time across all ages. The multivariable‐adjusted excess risk of dying was 60% higher in AYAs (95% CI: 37%‐86%). Early mortality (death within 30 days of diagnosis) declined over time, and did not differ between children and AYAs. In conclusion, AYAs diagnosed with AML in the Netherlands had a worse prognosis than pediatric patients. The survival gap seemed most pronounced in recent years, suggesting that improvements in care resulting in better outcome for children have not led to equal benefits for AYAs.

Adolescents and young adult acute myeloid leukemia outcomes at pediatric versus adult centers: A population-based study

BACKGROUND

Adolescents and young adult (AYA) acute myeloid leukemia (AML) outcomes remain poor. The impact of locus of care (LOC; adult vs pediatric) in this population is unknown.

PROCEDURE

The IMPACT cohort comprises detailed data for all Ontario, Canada, AYA aged 15-21 years diagnosed with AML between 1992 and 2012, linked to population-based health administrative data. We determined the impact of LOC on event-free survival (EFS) and overall survival (OS), treatment-related mortality (TRM), and relapse/progression.

RESULTS

Among 140 AYA, 51 (36.4%) received therapy at pediatric centers. The five-year EFS and OS for the whole cohort were 35.0% ± 4.0% and 53.6% ± 4.2%. Cumulative doses of anthracycline were higher among pediatric center AYA [median 355 mg/m² , interquartile range (IQR) 135-492 vs 202 mg/m² , IQR 140-364; P = 0.003]. In multivariable analyses, LOC was not predictive of either EFS [adult vs pediatric center hazard ratio (HR) 1.3, 95% confidence interval (CI) 0.8-2.2, P = 0.27] or OS (HR 1.0, CI 0.6-1.6, P = 0.97). However, patterns of treatment failure varied; higher two-year incidence of TRM in pediatric centers (23.5% ± 6.0% vs.10.1% ± 3.2%; P = 0.046) was balanced by lower five-year incidence of relapse/progression (33.3% ± 6.7% vs 56.2% ± 5.3%; P = 0.002).

CONCLUSIONS

AYA AML survival outcomes did not vary between pediatric and adult settings. Causes of treatment failure were different, with higher intensity pediatric protocols associated with higher TRM but lower relapse/progression. Careful risk stratification and enhanced supportive care may be of substantial benefit to AYA with AML by allocating maximal treatment intensity to patients who most benefit while minimizing the risk of TRM.

Comparable on-therapy mortality and supportive care requirements in Black and White patients following initial induction for pediatric acute myeloid leukemia

BACKGROUND

Black patients with acute myeloid leukemia (AML) are more likely to present with high acuity and consequently experience higher rates of induction mortality than white patients. Given the consistently identified racial disparities in overall survival (OS) among patients with AML, we aimed to evaluate whether there were sustained on-therapy racial differences in inpatient mortality, intensive care unit (ICU) requirements, or supportive care beyond initial induction.

PROCEDURE

Within a retrospective cohort of 1239 children diagnosed with AML between 2004 and 2014 in the Pediatric Health Information System (PHIS) database who survived their initial course of induction chemotherapy, we compared on-therapy inpatient mortality, ICU-level care requirements, treatment course duration, cumulative length of hospital stay (LOS), and resource utilization after induction I by race.

RESULTS

Over the period from the start of induction II through completion of frontline chemotherapy, there were no significant differences in mortality (adjusted odds ratios [OR], 1.01; 95% confidence intervals [CI], 0.41-2.48), ICU-level care requirements (adjusted OR, 0.93; 95% CI, 0.69-1.26), LOS (adjusted mean difference, 3.2 days; 95% CI, -2.3-9.6), or supportive care resource utilization for black patients relative to white patients. Course-specific analyses also demonstrated no differences by race.

CONCLUSION

Although black patients have higher acuity at presentation and higher induction mortality, such disparities do not persist over subsequent frontline chemotherapy treatment. This finding allows interventions aimed at reducing disparities to be directed at presentation and induction.

High incidence of acute kidney injury during chemotherapy for childhood acute myeloid leukemia

BACKGROUND/OBJECTIVES

Childhood acute myeloid leukemia (AML) is a rare and heterogeneous disease. Pediatric data on the epidemiology of acute kidney injury (AKI) in AML are limited. We report on the incidence of AKI in childhood AML and the risk factors associated with AKI episodes.

METHODS

A retrospective cohort of 53 patients (≤18 years), with de novo AML, receiving chemotherapy over a 10-year period. All serum creatinine (SCr) levels during therapy-related hospitalizations were assessed to stage AKI episodes as per Kidney Disease: Improving Global Outcomes criteria. Severe AKI was defined as AKI stages 2 or 3 and urine output criteria were not used. AKI risk factors were assessed independently in both cycle 1 alone and combining all chemotherapy cycles.

RESULTS

AKI developed in 34 patients (64%) with multiple AKI episodes in 10 patients (46 total episodes). Twenty-four severe AKI episodes occurred in 23 patients (43.4%) with a mean duration of 26.1 days (SD 7.3). In cycle 1, hyperleukocytosis was not predictive of AKI, but severe sepsis was an independent risk factor of severe AKI (odds ratio [OR]: 13.4; 95% CI 1.9-94.9). With cycles combined, all subjects with AKI had severe sepsis and older age (≥10 years) was associated with severe AKI (OR: 20.8; 95% CI 3.8-112.2).

CONCLUSION

There was a high incidence of AKI in our AML cohort with a strong association with older age (≥10 years) and severe sepsis. Larger prospective studies are needed to confirm the high burden of AKI and risk factors in this susceptible population.

Survival differences in childhood and young adult acute myeloid leukemia: A cross-national study using US and England data

BACKGROUND

Acute myeloid leukemia (AML) is a serious disease with complex etiology and marked variation in survival. Known prognostic factors include AML subtypes, age at diagnosis and sex. However, survival outcomes may vary across healthcare systems. In this study, we evaluated the survival patterns in individuals diagnosed with AML at ages 0-24 years in the US and England between prognostic features and across countries.

METHODS

We obtained data on 4387 and 2194 subjects from the US Surveillance Epidemiology and End Result registries and UK National Cancer Data Repository. Subjects were diagnosed and followed in 1995-2014. Kaplan-Meier curve and stratified Cox proportional hazards regression were used in the analysis.

RESULTS

Overall risk of mortality was 23% lower in English patients compared to that in the US patients (adjusted hazard ratio (aHR), 95% confidence Interval (CI): 0.77, 0.71-0.84). Survival difference of similar extent was observed in subgroups of sex and age at diagnosis. However, mortality risks between two countries varied substantially across AML subtypes, especially in AML inv(16) (1.81, 0.61-5.34), AML with minimal differentiation (0.54, 0.25-1.17), AML without maturation (0.38, 0.20-0.74) and AML with maturation (0.52, 0.31-0.86).

CONCLUSIONS

Similar to the population trend, mortality risk across sex, age at diagnosis, and most AML subtypes was lower in England. Survival outcome for AML with and without maturation in England was better than the population trend, while that for AML inv(16) was worse. Our findings suggest that future etiologic and policy research may uncover the underlying mechanisms and contribute to closing these morality gaps.

Impact of age on the survival of pediatric leukemia: an analysis of 15083 children in the SEER database

BACKGROUND & AIMS

Age at diagnosis is a key factor for predicting the prognosis of pediatric leukemia especially regarding the survivorship assessment. In this study, we aimed to assess the impact of this prognostic factor such as age in children with pediatric leukemia.

METHODS

In this study, Surveillance, Epidemiology, and End Results Program-registered children with leukemia during 1988-2013 were analyzed. All patients were divided into five groups according to the age at the time of diagnosis (<1, 1-4, 5-9, 10-15, >15 years old). Kaplan-Meier and multivariable Cox regression models were used to evaluate leukemia survival outcomes and risk factors.

RESULTS

There was significant variability in pediatric leukemia survival by age at diagnosis including ALL, AML and CML subtypes. According to the survival curves in each group, survival rate were peaked among children diagnosed at 1–4 years and steadily declined among those diagnosed at older ages in children with ALL. Infants (<1 year) had the lowest survivorship in children with either ALL or AML. However, children (1-4 years) harbored the worst prognosis suffering from CML. A stratified analysis of the effect of age at diagnosis was validated as independent predictors for the prognosis of pediatric leukemia.

CONCLUSIONS

Age at diagnosis remained to be a crucial determinant of the survival variability of pediatric leukemia patients.

Salvaged allogeneic hematopoietic stem cell transplantation for pediatric chemotherapy refractory acute leukemia

There is an ongoing debate concerning the performance of salvaged allogeneic hematopoietic stem cell transplantation (allo-HSCT) in pediatric patients with acute refractory leukemia, in whom the prognosis is quite dismal. Few studies have ever been conducted on this subject. This may be partly due to missed opportunities by majority of the patients in such situations. To investigate the feasibility, evaluate the efficiency, and identify the prognostic factors of allo-HSCT in this sub-setting, the authors performed a single institution-based retrospective analysis. A total of 44 patients, of whom 28 had acute myeloid leukemia (AML), 13 had acute lymphocytic leukemia (ALL), and 3 had mixed phenotype leukemia (MPL), were enrolled in this study. With a median follow-up of 19 months, the estimated 2-year overall survival (OS) and progression free survival (PFS) were 34.3% (95% CI, 17.9–51.4%) and 33.6% (95% CI, 18.0–50.1%), respectively. The estimated 2-year incidence rates of relapse and non-relapse mortality (NRM) were 43.8% (95% CI 26.4–60.0%) and 19.6% (95% CI 9.1–32.9%), respectively. The estimated 100-day cumulative incidence of acute graft versus host disease (aGvHD) was 43.6% (95% CI 28.7–57.5%), and the 1-year cumulative incidence of chronic GvHD (cGvHD) was 45.5% (95% CI 30.5–59.3%). Compared with the previous studies, the multivariate analysis in this study additionally identified that female donors and cGvHD were associated with lower relapse and better PFS and OS. Male recipients, age younger than 10 years, a diagnosis of ALL, and the intermediate-adverse cytogenetic risk group were associated with increased relapse. On the contrary, extramedullary disease (EMD) and aGvHD were only linked to worse PFS. These data suggested that although only one-third of the patients would obtain PFS over 2 years, salvaged allo-HSCT is still the most reliable and best therapeutic strategy for refractory pediatric acute leukemia. If probable, choosing a female donor, better management of aGvHD, and induction of cGvHD promotes patient survival.

The role of acuity of illness at presentation in early mortality in black children with acute myeloid leukemia

Black patients with acute myeloid leukemia (AML) experience higher mortality than White patients. We compared induction mortality, acuity of illness prior to chemotherapy, and insurance type between Black and White patients to assess whether acuity of presentation mediates the disparity. Within a retrospective cohort of 1,122 children with AML treated with two courses of standard induction chemotherapy between 2004 and 2014 in the Pediatric Health Information System (PHIS) database, the association between race (Black versus White) and inpatient mortality during induction was examined. Intensive Care Unit (ICU)-level resource utilization during the first 72 hours following admission for initial AML chemotherapy was evaluated as a potential mediator. The total effect of race on mortality during Induction I revealed a strong association (unadjusted HR 2.75, CI: 1.18, 6.41). Black patients had a significantly higher unadjusted risk of requiring ICU-level resources within the first 72 hours after initial presentation (17% versus 11%; RR 1.52, CI: 1.04, 2.24). Mediation analyses revealed the indirect effect of race through acuity accounted for 61% of the relative excess mortality during Induction I. Publicly insured patients experienced greater induction mortality than privately insured patients regardless of race. Black patients with AML have significantly greater risk of induction mortality and are at increased risk for requiring ICU-level resources soon after presentation. Higher acuity amongst Black patients accounts for a substantial portion of the relative excess mortality during Induction I. Targeting factors affecting acuity of illness at presentation may lessen racial disparities in AML induction mortality.

Outcome of Adolescents and Young Adults Compared With Pediatric Patients With Acute Myeloid and Promyelocytic Leukemia

BACKGROUND

Studies on the outcome of adolescents and young adults (AYAs) with acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL) are limited.

METHODS

We compared the outcome of AYA (19-30 years) patients with AML and PML and pediatric (0-18 years) patients with AML (pAMLs) and APL (pAPLs) utilizing the Surveillance Epidemiology and End Results-18 registry. Early mortality rate (EMR), defined as mortality within 1 month of diagnosis, was used as a surrogate for treatment-related mortality. Survival statistics were computed using the Kaplan-Meier method. Multivariate analysis was done using logistic regression and the Cox proportional hazard regression model.

RESULTS

A total of 6343 patients with AML were identified; 44.7% were AYAs. pAMLs had lower EMR (6.2% vs. 9.2%; P < .01) and higher overall survival (OS) (1-year, 70.3% vs. 62.1%; 5-year, 48.2% vs. 36.4%; P < .01). Nine hundred twenty patients with APL were also identified; 59.5% were AYAs. No statistically significant difference was found between AYAs with APL and pAPLs in EMR (11.4% vs. 14.1%; P = .23) and OS (1-year, 83.8% vs. 81.2%; P = .31 and 5-year, 68.2% vs. 73.1%; P = .11]. Comparing all patients with AML and APL, AYAs with APL and pAPLs had higher EMR (11.4% and 14.1% vs. 6.2% and 9.2%; P ≤ .01) but better OS than AYAs with AML and pAMLs (5-year OS, 68.2% and 73.1% vs. 48.2% and 36.4%; P ≤ .01).

CONCLUSION

Our analysis shows AYAs with AML have worse EMR and OS compared with pAMLs. AYAs with APL and pAPLs have similar outcomes. To our knowledge, this is the first study reporting outcomes of AYAs with APL and pAPLs using a large population-based registry and their comparison with same age patients with AML.

Racial disparities in the survival of American children, adolescents, and young adults with acute lymphoblastic leukemia, acute myelogenous leukemia, and Hodgkin lymphoma

BACKGROUND

Race-based survival in children and adolescents with hematologic malignancies has been a national challenge for decades. Large-scale investigations of age- and race-based survival trends over time in these patients have not previously been reported. The objective of this study was to investigate whether race- and age-related differences in pediatric and adolescent and young adult (AYA) leukemia and lymphoma survival persist and to what extent these differences have changed over time.

METHODS

Using the Surveillance, Epidemiology, and End Results program, this study investigated the outcomes of black and white (1975-2012; n = 27,369) and white and Hispanic (1992-2012; n = 20,574) children (0-14 years old) and AYAs (15-39 years old) with acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), and Hodgkin lymphoma (HL). Estimates of 5- and 10-year relative survival were compared over time.

RESULTS

Trends showed a convergence of survival for white and black children with ALL but a divergence in survival for AYA patients. Hispanic children and AYAs both suffered inferior outcomes. Trends for AML revealed persistent survival differences between black and white children and suggested worsening disparities for AYAs. Survival trends in HL revealed sustained survival differences between black and white AYA patients, whereas no differences were found in Hispanic and white patient outcomes for AML or HL.

CONCLUSIONS

Although survival for children and AYAs with ALL, AML, and HL has improved over the past 4 decades, differences persist between black, white, and Hispanic children and AYAs; survival disparities between black and white children with ALL have been nearly eliminated. Strategies aimed at identifying causality and reducing disparities are warranted. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2723-2730. © 2016 American Cancer Society.

Effect of age and body weight on toxicity and survival in pediatric acute myeloid leukemia: results from NOPHO-AML 2004

Treatment for pediatric acute myeloid leukemia is very toxic and the association between outcome and age and Body Mass Index is unclear. We investigated effect of age and Body Mass Index on toxicity and survival in pediatric acute myeloid leukemia. We studied all patients who completed first induction course of NOPHO-AML 2004 (n=318). Toxicity following induction and consolidation courses (n=6) was analyzed. The probabilities of toxicity and death were determined using time-to-event analyses with Cox multivariate proportional hazard regression for comparative analyses. Age 10-17 years was associated with sepsis with hypotension [hazard ratio 2.3 (95% confidence interval 1.1-4.6)]. Being overweight (>1 standard deviation) was associated with requiring supplemental oxygen [1.9 (1.0-3.5)]. The 5-year event-free and overall survival were 47% and 71%. Children aged 10-17 years showed a trend for inferior 5-year overall survival compared to children aged 2-9 (64% vs. 76%; P=0.07). Infants showed a trend for superior 5-year event-free survival (66% vs. 43%; P=0.06). Overweight children aged 10-17 years showed a trend for superior survival [5-year event-free survival 59% vs. 40% (P=0.09) and 5-year overall survival 78% vs. 56% (P=0.06)] compared to healthy weight children aged 10-17 years. In conclusion, children aged 10-17 years and overweight children had a higher risk of grade 3-4 toxicity. Children aged 10-17 years showed inferior survival, but, unexpectedly, in this age group overweight children tended to have increased survival. This suggests different pharmacokinetics of chemotherapeutic drugs in adolescents and warrants further studies.

Predictors of early death and survival among children, adolescents and young adults with acute myeloid leukaemia in California, 1988-2011: a population-based study

A better understanding of factors associated with early death and survival among children, adolescents and young adults with acute myeloid leukaemia (AML) may guide health policy aimed at improving outcomes in these patients. We examined trends in early death and survival among 3935 patients aged 0-39 years with de novo AML in California during 1988-2011 and investigated the associations between sociodemographic and selected clinical factors and outcomes. Early death declined from 9·7% in 1988-1995 to 7·1% in 2004-2011 (P = 0·062), and survival improved substantially over time. However, 5-year survival was still only 50% (95% confidence interval 47-53%) even in the most recent treatment period (2004-2011). Overall, the main factors associated with poor outcomes were older age at diagnosis, treatment at hospitals not affiliated with National Cancer Institute-designated cancer centres, and black race/ethnicity. For patients diagnosed during 1996-2011, survival was lower among those who lacked health insurance compared to those with public or private insurance. We conclude that mortality after AML remained strikingly high in California and increased with age. Possible strategies to improve outcomes include wider insurance coverage and treatment at specialized cancer centres.

Acute Myeloid Leukemia in Adolescents and Young Adults Treated in Pediatric and Adult Departments in the Nordic Countries

BACKGROUND

Studies on adolescents and young adults with acute lymphoblastic leukemia suggest better results when using pediatric protocols for adult patients, while corresponding data for acute myeloid leukemia (AML) are limited.

PROCEDURE

We investigated disease characteristics and outcome for de novo AML patients 10-30 years old treated in pediatric or adult departments. We included 166 patients 10-18 years of age with AML treated according to the pediatric NOPHO-protocols (1993-2009) compared with 253 patients aged 15-30 years treated in hematology departments (1996-2009) in the Nordic countries.

RESULTS

The incidence of AML was 4.9/million/year for the age group 10-14 years, 6.5 for 15-18 years, and 6.9 for 19-30 years. Acute promyelocytic leukemia (APL) was more frequent in adults and in females of all ages. Pediatric patients with APL had similar overall survival as pediatric patients without APL. Overall survival at 5 years was 60% (52-68%) for pediatric patients compared to 65% (58-70%) for adult patients. Cytogenetics and presenting white blood cell count were the only independent prognostic factors for overall survival. Age was not an independent prognostic factor.

CONCLUSIONS

No difference was found in outcome for AML patients age 10-30 years treated according to pediatric as compared to adult protocols.

Sex disparity in childhood and young adult acute myeloid leukemia (AML) survival: Evidence from US population data

Sex variation has been persistently investigated in studies concerning acute myeloid leukemia (AML) survival outcomes but has not been fully explored among pediatric and young adult AML patients. We detected sex difference in the survival of AML patients diagnosed at ages 0-24 years and explored distinct effects of sex across subgroups of age at diagnosis, race-ethnicity and AML subtypes utilizing the United States Surveillance Epidemiology and End Results (SEER) population based dataset of 4865 patients diagnosed with AML between 1973 and 2012. Kaplan-Meier survival function, propensity scores and stratified Cox proportional hazards regression were used for data analyses. After controlling for other prognostic factors, females showed a significant survival advantage over their male counterparts, adjusted hazard ratio (aHR, 95% confidence interval (CI): 1.09, 1.00-1.18). Compared to females, male patients had substantially increased risk of mortality in the following subgroups of: ages 20-24 years at diagnosis (aHR1.30), Caucasian (1.14), acute promyelocytic leukemia (APL) (1.35), acute erythroid leukemia (AEL) (1.39), AML with inv(16)(p13.1q22) (2.57), AML with minimum differentiation (1.47); and had substantially decreased aHR in AML t(9;11)(p22;q23) (0.57) and AML with maturation (0.82). Overall, females demonstrated increased survival over males and this disparity was considerably large in patients ages 20-24 years at diagnosis, Caucasians, and in AML subtypes of AML inv(16), APL and AEL. In contrast, males with AML t(9;11)(p22;q23), AML with maturation and age at diagnosis of 10-14 years showed survival benefit. Further investigations are needed to detect the biological processes influencing the mechanisms of these interactions.

Prognostic factors of childhood and adolescent acute myeloid leukemia (AML) survival: evidence from four decades of US population data

Growing insight into prognosis of pediatric acute myeloid leukemia (AML) survival has led to improved outcome over time and could be further enhanced through investigation using a large number of patients. To characterize the extent of the association of pediatric AML survival with its identified prognostic factors, we analyzed the United States population-based Surveillance Epidemiology and End Results (SEER) large dataset of 3442 pediatric AML patients diagnosed and followed between 1973 and 2011 using a Cox proportional hazards model stratified by year of diagnosis. Patients diagnosed between 10 and 19 years of age were at a higher risk of death compared to those diagnosed before age 10 (adjusted hazard ratio (aHR): 1.30, 95% confidence interval (CI): 1.17-1.44). African Americans (1.27, 1.09-1.48) and Hispanics (1.15, 1.00-1.32) had an elevated risk of mortality than Caucasians. Compared to the subtype acute promyelocytic leukemia, AML with minimal differentiation (2.44, 1.78-3.35); acute erythroid leukemia (2.34, 1.60-3.40); AML without maturation (1.87, 1.35-2.59); and most other AML subtypes had a higher risk of mortality, whereas AML with inv(16) had a substantially lower risk. Age at diagnosis, race-ethnicity, AML subtype, county level poverty and geographic region appeared as significant prognostic factors of pediatric AML survival in the US. Contrary to previous findings, the subtypes of AML with t(9;11)(p22;q23)MLLT3-MLL, AML without maturation and acute myelomonocytic leukemia emerged to be indicative of poor outcome.

Toxicity of Cancer Therapy in Adolescents and Young Adults (AYAs)

OBJECTIVES

To identify treatment-related toxicities that are either more frequent or more severe in the adolescent and young adult (AYA) oncology population. To explore differences in drug pharmacology and patient physiology that contribute to toxicities in the AYA population and to describe the impact of treatment-related toxicities on outcomes for AYA patients.

DATA SOURCES

A PubMed search was undertaken using the key words Adolescent Young Adult Oncology, AYA, toxicity, bone marrow transplant, late effects, and chemotherapy. Additional toxicity information was also obtained from recent publications from cancer cooperative groups treating AYA patients.

CONCLUSION

AYA patients often experience more severe toxicities than children when treated with identical chemotherapy regimens, which can interfere with successful administration of planned treatment, as well as have profound effects on quality of life. AYA patients with cancer face the dual challenge of disease biology associated with inferior response to treatment, thus necessitating treatment intensification, while at the same time suffering higher rates of specific toxicities such as vincristine-induced neuropathy, osteonecrosis, and treatment-related mortality caused by infection.

IMPLICATIONS FOR NURSING PRACTICE

AYA patients are at a higher risk for toxicities from regimens that may be tolerated by younger patients. Staff should be aware of toxicities facing this population so that appropriate supportive care measures can be utilized. Future research on the pharmacology of drugs in adolescence, hormonal effects on drug-metabolizing enzymes, cumulative exposure to different drugs in combination, and risk and severity of specific toxicities will be critical to improving the treatment of AYA patients.

Characterization of pediatric acute lymphoblastic leukemia survival patterns by age at diagnosis

Age at diagnosis is a key prognostic factor in pediatric acute lymphoblastic leukemia (ALL) survivorship. However, literature providing adequate assessment of the survival variability by age at diagnosis is scarce. The aim of this study is to assess the impact of this prognostic factor in pediatric ALL survival. We estimated incidence rate of mortality, 5-year survival rate, Kaplan-Meier survival function, and hazard ratio using the Surveillance Epidemiology and End Results (SEER) data during 1973-2009. There was significant variability in pediatric ALL survival by age at diagnosis. Survival peaked among children diagnosed at 1-4 years and steadily declined among those diagnosed at older ages. Infants (<1 year) had the lowest survivorship. In a multivariable Cox proportional hazard model stratified by year of diagnosis, those diagnosed in age groups 1-4, 5-9, 10-14, and 15-19 years were 82%, 75%, 57%, and 32% less likely to die compared to children diagnosed in infancy, respectively. Age at diagnosis remained to be a crucial determinant of the survival variability of pediatric ALL patients, after adjusting for sex, race, radiation therapy, primary tumor sites, immunophenotype, and year of diagnosis. Further research is warranted to disentangle the effects of age-dependent biological and environmental processes on this association.

Outcome of pediatric acute myeloid leukemia patients receiving intensive care in the United States

OBJECTIVE

Children with acute myeloid leukemia are at risk for sepsis and organ failure. Outcomes associated with intensive care support have not been studied in a large pediatric acute myeloid leukemia population. Our objective was to determine hospital mortality of pediatric acute myeloid leukemia patients requiring intensive care.

DESIGN

Retrospective cohort study of children hospitalized between 1999 and 2010. Use of intensive care was defined by utilization of specific procedures and resources. The primary endpoint was hospital mortality.

SETTING

Forty-three children's hospitals contributing data to the Pediatric Health Information System database.

PATIENTS

Patients who are newly diagnosed with acute myeloid leukemia and who are 28 days through 18 years old (n = 1,673) hospitalized any time from initial diagnosis through 9 months following diagnosis or until stem cell transplant. A reference cohort of all nononcology pediatric admissions using the same intensive care resources in the same time period (n = 242,192 admissions) was also studied.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-third of pediatric patients with acute myeloid leukemia (553 of 1,673) required intensive care during a hospitalization within 9 months of diagnosis. Among intensive care admissions, mortality was higher in the acute myeloid leukemia cohort compared with the nononcology cohort (18.6% vs 6.5%; odds ratio, 3.23; 95% CI, 2.64-3.94). However, when sepsis was present, mortality was not significantly different between cohorts (21.9% vs 19.5%; odds ratio, 1.17; 95% CI, 0.89-1.53). Mortality was consistently higher for each type of organ failure in the acute myeloid leukemia cohort versus the nononcology cohort; however, mortality did not exceed 40% unless there were four or more organ failures in the admission. Mortality for admissions requiring intensive care decreased over time for both cohorts (23.7% in 1999-2003 vs 16.4% in 2004-2010 in the acute myeloid leukemia cohort, p = 0.0367; and 7.5% in 1999-2003 vs 6.5% in 2004-2010 in the nononcology cohort, p < 0.0001).

CONCLUSIONS

Pediatric patients with acute myeloid leukemia frequently required intensive care resources, with mortality rates substantially lower than previously reported. Mortality also decreased over the time studied. Pediatric acute myeloid leukemia patients with sepsis who required intensive care had a mortality comparable to children without oncologic diagnoses; however, overall mortality and mortality for each category of organ failure studied was higher for the acute myeloid leukemia cohort compared with the nononcology cohort.

The adolescent and young adult with cancer: state of the art-- acute leukemias

Despite survival gains over the past several decades, adolescent and young adult (AYA) patients with both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) demonstrate a consistent survival disadvantage. The AYA population exhibits unique disease and host characteristics, and further study is needed to improve their outcomes. This review will highlight distinctive aspects of disease biology in this population, as well as salient treatment-related toxicities including osteonecrosis, pancreatitis, thromboembolism, hyperglycemia, and infections. The impact of obesity and differences in drug metabolism and chemotherapy resistance will also be discussed, as well as optimal treatment considerations for the AYA population.

Outcome of adolescents and young adults with acute myeloid leukemia treated on COG trials compared to CALGB and SWOG trials

BACKGROUND

A retrospective meta-analysis of adolescents and young adults (AYAs) with acute myeloid leukemia (AML) was performed to determine if differences in outcome exist following treatment on pediatric versus adult oncology treatment regimens.

METHODS

Outcomes were compared of 517 AYAs with AML aged 16 to 21 years who were treated on Children's Oncology Group (COG), Cancer and Leukemia Group B (CALGB), and Southwest Oncology Group (SWOG) frontline AML trials from 1986 to 2008.

RESULTS

There was a significant age difference between AYA cohorts in the COG, CALGB, and SWOG trials (median, 17.2 versus 20.1 versus 19.8 years, P < .001). The 10-year event-free survival of the COG cohort was superior to the combined adult cohorts (38% ± 6% versus 23% ± 6%, log-rank P = .006) as was overall survival (45% ± 6% versus 34% ± 7%), with a 10-year estimate comparison of P = .026. However, the younger age of the COG cohort is confounding, with all patients aged 16 to 18 years doing better than those aged 19 to 21 years. Although the 10-year relapse rate was lower for the COG patients (29% ± 6% versus 57% ± 8%, Gray's P < .001), this was offset by a higher postremission treatment-related mortality of 26% ± 6% versus 12% ± 6% (Gray's P < .001). Significant improvements in 10-year event-free survival and overall survival were observed for the entire cohort in later studies.

CONCLUSIONS

Patients treated on pediatric trials had better outcomes than those treated on adult trials, but age is a major confounding variable, making it difficult to compare outcomes by cooperative group.

Therapeutic approaches to haematological malignancies in adolescents and young adults

Tremendous strides have been made in improving the outcomes of haematological malignancies (HM) over the last three decades, but adolescents and young adult (AYA) patients have not benefitted equally compared to younger and older patients. Excellent outcomes in Hodgkin lymphoma have allowed tailoring of highly effective regimens that limit the incidence of late effects. Early successes in paediatric acute lymphoblastic leukaemia set the stage for a series of studies in young adults utilizing a paediatric-type treatment strategy. These studies have determined that AYAs benefit from paediatric-type chemotherapy regimens. Despite the increased incidence of acute myeloid leukaemia and non-Hodgkin lymphoma in the AYA age group, optimal strategies for these patients have not been systematically pursued. There is renewed interest in improving HM outcomes in AYA patients and this will rely on the development of clinical trials that specifically target these patients. Understanding and addressing the unique psychosocial challenges of this population will be critical in supporting this endeavor.

Development and validation of a single-cell network profiling assay-based classifier to predict response to induction therapy in paediatric patients with de novo acute myeloid leukaemia: a report from the Children's Oncology Group

Single cell network profiling (SCNP) is a multi-parameter flow cytometry technique for simultaneous interrogation of intracellular signalling pathways. Diagnostic paediatric acute myeloid leukaemia (AML) bone marrow samples were used to develop a classifier for response to induction therapy in 53 samples and validated in an independent set of 68 samples. The area under the curve of a receiver operating characteristic curve (AUC(ROC)) was calculated to be 0·85 in the training set and after exclusion of induction deaths, the AUC(ROC) of the classifier was 0·70 (P = 0·02) and 0·67 (P = 0·04) in the validation set when induction deaths (intent to treat) were included. The highest predictive accuracy was noted in the cytogenetic intermediate risk patients (AUC(ROC) 0·88, P = 0·002), a subgroup that lacks prognostic/predictive biomarkers for induction response. Only white blood cell count and cytogenetic risk were associated with response to induction therapy in the validation set. After controlling for these variables, the SCNP classifier score was associated with complete remission (P = 0·017), indicating that the classifier provides information independent of other clinical variables that were jointly associated with response. This is the first validation of an SCNP classifier to predict response to induction chemotherapy. Herein we demonstrate the usefulness of quantitative SCNP under modulated conditions to provide independent information on AML disease biology and induction response.

Cytogenetic abnormalities and monosomal karyotypes in children and adolescents with acute myeloid leukemia: correlations with clinical characteristics and outcome

The whole spectrum of chromosomal abnormalities and their prognostic significance in children and adolescents with acute myeloid leukemia (AML) has not been fully elucidated yet, although a considerable amount of knowledge has been gained recently. Moreover, the incidence and prognostic impact of monosomal karyotypes (MKs), which are new cytogenetic categories reported recently in adults with AML, are currently unknown for childhood and adolescent AML. In this study, we investigated the cytogenetic and clinical characteristics of 140 children and adolescents (≤21 y) with AML, and correlated their cytogenetic features with both the clinical characteristics and outcomes of our patient cohort. The most frequent cytogenetic abnormality found in our study was the t(15;17), followed by the t(8;21). Striking differences in the genetic abnormalities and French-American-British subtypes were found among infants, children, and adolescents. Of 124 cases, 15 (12.1%) met the criteria of the MK definition, and 12 of the 15 MKs (80%) were complex karyotypes. Of 124 cases, 27 (21.8%) had cytogenetic abnormalities sufficient to be diagnosed as AML with myelodyspastic sydrome-related features. As expected, patients with the t(15;17) had the most favorable outcomes, whereas patients with 11q23 rearrangements and monosomy 7 had the worst outcomes. These data expand our knowledge by providing novel insights into the cytogenetic features and their correlations with clinical characteristics and outcomes in childhood and adolescent AML.

Treatment outcome in older patients with childhood acute myeloid leukemia

BACKGROUND

Older age has historically been an adverse prognostic factor in pediatric acute myeloid leukemia (AML). To the authors' knowledge, the impact of age relative to that of other prognostic factors on the outcome of patients treated in recent trials is unknown.

METHODS

Clinical outcome and causes of treatment failure of 351 patients enrolled on 3 consecutive protocols for childhood AML between 1991 and 2008 were analyzed according to age and protocol.

RESULTS

The more recent protocol (AML02) produced improved outcomes for patients aged 10 years to 21 years compared with 2 earlier studies (AML91 and AML97), with 3-year rates of event-free survival (EFS), overall survival (OS), and cumulative incidence of refractory leukemia or recurrence (CIR) for this group being similar to those of patients aged birth to 9 years: EFS: 58.3% ± 5.4% versus 66.6% ± 4.9% (P = .20); OS: 68.9% ± 5.1% versus 75.1% ± 4.5% (P = .36); and CIR: 21.9% ± 4.4% versus 25.3% ± 4.2% (P = .59). The EFS and OS estimates for patients aged 10 to 15 years overlapped those for patients aged 16 to 21 years. However, the cumulative incidence of toxic death was significantly higher for patients aged 10 to 21 years compared with younger patients (13.2% ± 3.6% vs 4.5% ± 2.0%; P = .028).

CONCLUSIONS

The survival rate for older children with AML has improved on the results of a recent trial and is now similar to that of younger patients. However, deaths from toxicity remain a significant problem for patients in the older age group. Future trials should focus on improving supportive care while striving to develop more effective antileukemic therapy.

Age as prognostic factor in patients with osteosarcoma

Age at diagnosis is a well known prognostic factor in many different malignancies; its significance for patients with osteosarcoma is however controversial. To gain more insight in the prognostic role of age, we performed a retrospective study at our institute. We included 102 patients with de-novo osteosarcoma and formed three age groups to evaluate age specific survival rates: ≤ 14 years, 15-19 years and 20-40 years. Differences in outcome between patients aged 15-19 years treated at either the pediatric department or the adult department of oncology were evaluated. The 5-year overall survival rate (OSR) of the whole population was 53.5%±1.5%. OSR of 70.6%±0.8% was seen in patients ≤ 14 years old, 52.5%±1.1% in patients 15-19 years old and 33.3%±0.9% in the patients aged 20-40 years (p=0.01). Significant differences were observed with regard to stage at presentation (higher in older age groups), size of the tumor (larger in younger age groups) and histological response (more good responders in younger age groups). No significant difference was seen between outcomes of patients aged 15-19 years treated at the pediatric or adult oncology department. In conclusion, younger patients have a significantly better outcome than older patients.

Malignant hematologic diseases in adolescents and young adults

Adolescents and young adults (AYA) with cancer have been designated as a vulnerable population by the National Cancer Institute. This group, defined by the ages of 16-39 years, has not enjoyed the same survival improvements over the past several decades as older and younger cohorts. Several barriers prevent the optimal delivery of oncologic care in this subpopulation. This review will describe these challenges in the context of the major hematologic malignancies affecting this population (acute lymphoblastic leukemia [ALL], acute myeloid leukemia [AML], Hodgkin lymphoma [HL], and non-Hodgkin lymphoma [NHL]). For example, historical differences in care delivery between pediatric and adult health care systems have created confusion about optimal treatment planning for AYAs, a population that spans the pediatric-adult divide. In the case of ALL, retrospective studies have demonstrated significantly better outcomes when AYAs are treated according to pediatric and not adult protocols. Additional challenges more specific to AYAs include increased treatment-related toxicity relative to younger patients; less access to care and, specifically, access to clinical trials; lower adherence to medications and treatment plans; and psychosocial stressors relevant to individuals at this stage of life. Recognizing and responding to these challenges in AYAs may create opportunities to improve the cancer outcomes of this group.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Minimal residual disease-directed therapy for childhood acute myeloid leukaemia: results of the AML02 multicentre trial

BACKGROUND

We sought to improve outcome in patients with childhood acute myeloid leukaemia (AML) by applying risk-directed therapy that was based on genetic abnormalities of the leukaemic cells and measurements of minimal residual disease (MRD) done by flow cytometry during treatment.

METHODS

From Oct 13, 2002, to June 19, 2008, 232 patients with de-novo AML (n=206), therapy-related or myelodysplasia-related AML (n=12), or mixed-lineage leukaemia (n=14) were enrolled at eight centres. 230 patients were assigned by block, non-blinded randomisation, stratified by cytogenetic or morphological subtype, to high-dose (18 g/m(2), n=113) or low-dose (2 g/m(2), n=117) cytarabine given with daunorubicin and etoposide (ADE; induction 1). The primary aim of the study was to compare the incidence of MRD positivity of the high-dose group and the low-dose group at day 22 of induction 1. Induction 2 consisted of ADE with or without gemtuzumab ozogamicin (GO anti-CD33 monoclonal antibody); consolidation therapy included three additional courses of chemotherapy or haematopoietic stem-cell transplantation (HSCT). Levels of MRD were used to allocate GO and to determine the timing of induction 2. Both MRD and genetic abnormalities at diagnosis were used to determine the final risk classification. Low-risk patients (n=68) received five courses of chemotherapy, whereas high-risk patients (n=79), and standard-risk patients (n=69) with matched sibling donors, were eligible for HSCT (done for 48 high-risk and eight standard-risk patients). All 230 randomised patients were analysed for the primary endpoint. Other analyses were limited to the 216 patients with AML, excluding those with mixed-lineage leukaemia. This trial is closed to accrual and is registered with ClinicalTrials.gov, number NCT00136084.

FINDINGS

Complete remission was achieved in 80% (173 of 216 patients) after induction 1 and 94% (203 of 216) after induction 2. Induction failures included two deaths from toxic effects and ten cases of resistant leukaemia. The introduction of high-dose versus low-dose cytarabine did not significantly lower the rate of MRD-positivity after induction 1 (34%vs 42%, p=0.17). The 6-month cumulative incidence of grade 3 or higher infection was 79.3% (SE 4.0) for patients in the high-dose group and 75.5% (4.2) for the low-dose group. 3-year event-free survival and overall survival were 63.0% (SE 4.1) and 71.1% (3.8), respectively. 80% (155 of 193) of patients achieved MRD of less than 0.1% after induction 2, and the cumulative incidence of relapse for this group was 17% (SE 3). MRD of 1% or higher after induction 1 was the only significant independent adverse prognostic factor for both event-free (hazard ratio 2.41, 95% CI 1.36-4.26; p=0.003) and overall survival (2.11, 1.09-4.11; p=0.028).

INTERPRETATION

Our findings suggest that the use of targeted chemotherapy and HSCT, in the context of a comprehensive risk-stratification strategy based on genetic features and MRD findings, can improve outcome in patients with childhood AML.

FUNDING

National Institutes of Health and American Lebanese Syrian Associated Charities (ALSAC).

Genetic changes including gene copy number alterations and their relation to prognosis in childhood acute myeloid leukemia

We studied a series of 68 subjects diagnosed with childhood acute myeloid leukemia (AML) using conventional cytogenetics and fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) to analyze mutations in FLT3 and NPM1 genes, and/or array comparative genomic hybridization (CGH). Cytogenetic/FISH abnormalities were observed in 71% of subjects, FLT3-ITD mutations in 15%, and NPM1 mutations in 13%. The array CGH alterations (average 3.6 per case) were observed in 96% of the tested subjects. The most frequent alterations were gains of 8q24.3 and 11p15.5-p15.4 in 16% of the samples. Six genes (AKT1, RUNX1, LTB, SDC1, RUNX1T1, and JAK2) from the imbalanced regions have been reported to be involved in AML, whereas other 30 cancer genes, not previously reported in an AML context, were identified as imbalanced. They probably correspond to non passenger alterations that cooperate with the recurrent translocations. The clinical data and genetic changes were tested to find out the possible association with prognosis. Genomic instability (four or more genomic imbalances) was correlated with poor patient outcome (p = 0.029).

Hematopoietic stem cell transplantation for leukemia

Leukemia represents the most common pediatric malignancy, accounting for approximately 30% of all cancers in children less than 20 years of age. Most children diagnosed with leukemia are cured without hematopoietic stem cell transplantation (HSCT), but for some high-risk subgroups, allogeneic HSCT plays an important role in their therapeutic approach. The characteristics of these high-risk subgroups and the role of HSCT in childhood leukemias are discussed.

Prognostic significance of myeloperoxidase expression in childhood acute myeloid leukemia

BACKGROUND

The percentage of myeloperoxidase (MPO)-positive blast cells is associated with prognosis in adult acute myeloid leukemia (AML), but this association is unsubstantiated in pediatric AML.

PROCEDURE

We retrospectively compared cytochemical MPO results with outcome in 154 patients younger than 21 years treated on three consecutive institutional protocols for newly diagnosed AML (1987-2001). Patients with FAB M0 and M7 AML (no MPO expression) or M3 AML (100% MPO expression) and Down's syndrome were excluded.

RESULTS

Median MPO expression was higher in FAB M2 subtype than in other subtypes (P < 0.0001) and differed significantly across cytogenetic risk groups (P = 0.002) with highest MPO expression among those with favorable karyotypes. The percentage of MPO-positive blasts was not significantly associated with the probability of complete remission (P = 0.97), event-free survival (P = 0.72), or survival (P = 0.76) in multivariate analyses that accounted for age, FAB subtype, presenting WBC count, cytogenetic and protocol treatment risk group. In analysis limited to patients with intermediate-risk cytogenetics, higher MPO expression appeared to be associated with improved EFS (P = 0.06) but was not associated with remission induction rate (P = 0.16) or overall survival (P = 0.38).

CONCLUSIONS

The percentage of MPO-positive blast cells is related to FAB subtype in pediatric AML but has limited prognostic relevance.

Absolute lymphocyte count is a novel prognostic indicator in ALL and AML: implications for risk stratification and future studies

BACKGROUND

Leukemia is the leading cause of disease-related death in children, despite significant improvement in survival and modern risk stratification. The prognostic significance of absolute lymphocyte counts (ALC) was evaluated in young patients with acute myeloblastic leukemia (AML) and acute lymphoblastic leukemia (ALL).

METHODS

In all, 171 consecutive de novo cases of AML and ALL, age <or=21 years, were analyzed. Age, initial white blood cell count, cytogenetics, and bone marrow response were compared with lymphocyte, neutrophil, and platelet counts at weekly intervals during induction chemotherapy.

RESULTS

ALC is a significant independent predictor of relapse and survival. For example, in patients with AML an ALC on Day 28 of induction (ALC-28) <350 cells/microL predicts very poor survival, with a 5-year relapse-free survival (RFS) of only 10% (hazard ratio [HR] 3.7, P= .003). In contrast, an ALC-15 >350 cells/microL carries an excellent prognosis, with a 5-year overall survival (OS) of 85% (HR 0.2, P= .012). Similarly in ALL, an ALC-15 <350 cells/microL predicts poor survival, with a 6-year RFS of 43% (HR 4.5, P= .002), whereas an ALC-15 >350 cells/microL predicts excellent outcome, with a 6-year OS of 87% (HR 0.2, P= .018). Importantly, ALC remains a strong predictor in multivariate analysis with known prognostic factors.

CONCLUSIONS

ALC is a simple, statistically powerful measurement for patients with de novo AML and ALL. The results, when combined with previous studies, demonstrate that ALC is a powerful new prognostic factor for a range of malignancies. These findings suggest a need for further exploration of postchemotherapy immune status and immune-modulating cancer therapies.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Establishment of a novel childhood acute myeloid leukaemia cell line, KOPM-88, containing partial tandem duplication of the MLL gene and an in vivo model for childhood acute myeloid leukaemia using NOD/SCID mice

MLL gene rearrangement is common in both adult and childhood acute myeloid leukaemia (AML), and its role in oncogenesis has been investigated. While over 50 translocated-partner genes have been identified so far, few studies have detailed the molecular mechanism of partial tandem duplication (PTD) of the MLL gene. The prognostic impact and contribution to leukaemogenesis of MLL-PTD, especially in childhood cases, remain unknown. We have established a novel cell line containing MLL-PTD derived from an 11-year-old patient with AML and designated as KOPM-88. KOPM-88 cells exhibited certain characteristics associated with the myeloid lineage including abundant primary granules in the cytoplasm and the expression of myeloperoxidase. The cell growth of KOPM-88 was cytokine independent but was accelerated by granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. MLL-PTD of exon 2 to exon 6 and exon 2 to exon 8 was revealed using Southern blotting, fluorescence in situ hybridisation, and reverse transcription polymerase chain reaction/DNA sequencing. Furthermore, non-obese diabetic/severe combined immunodeficient mice inoculated with KOPM-88 cells exhibited leukaemic infiltrations in the bone marrow and hemiparalysis because of compression myelopathy. This is the first report of an in vivo animal model exhibiting the systemic involvement of childhood AML containing MLL-PTD. KOPM-88 cells and our murine model may be useful for investigating the pathogenesis of childhood AML associated with MLL gene rearrangement.