Prognosis of Down's syndrome with acute leukaemia

Down syndrome and leukemia: An insight into the disease biology and current treatment options

Children with Down syndrome (DS) have a 10- to 20-fold greater predisposition to develop acute leukemia compared to the general population, with a skew towards myeloid leukemia (ML-DS). While ML-DS is known to be a subtype with good outcome, patients who relapse face a dismal prognosis. Acute lymphocytic leukemia in DS (DS-ALL) is considered to have poor prognosis. The relapse rate is high in DS-ALL compared to their non-DS counterparts. We have a better understanding about the mutational spectrum of DS leukemia. Studies using animal, embryonic stem cell- and induced pluripotent stem cell-based models have shed light on the mechanism by which these mutations contribute to disease initiation and progression. In this review, we list the currently available treatment strategies for DS-leukemias along with their outcome with emphasis on challenges with chemotherapy-related toxicities in children with DS. We focus on the mechanisms of initiation and progression of leukemia in children with DS and highlight the novel molecular targets with greater success in preclinical trials that have the potential to progress to the clinic.

Comprehensively evaluating cancer survival in children with birth defects: a population-based assessment

PURPOSE

Congenital malformations are strong risk factors for childhood cancer. Our objective was to determine whether cancer survival differs by birth defect status among Oklahoma children.

METHODS

We used accelerated failure time models to estimate survival time ratios (SRs) and 95% confidence intervals (CIs), adjusted for maternal race/ethnicity and census tract-level poverty, among children diagnosed with cancer and born in Oklahoma from 1997 to 2012 (n = 971), by linking records from birth certificates, birth defects, and cancer registries.

RESULTS

We observed decreased, though imprecise, survival time among survivors with any birth defect (SR: 0.82, 95% CI: 0.29, 2.31) or chromosomal defects (n = 24) (SR: 0.43, 95% CI: 0.06, 3.30) compared to those without birth defects. We observed no difference in survival time among children with non-chromosomal defects (SR: 0.98, 95% CI: 0.31, 3.12) compared to children with no birth defects.

CONCLUSION

Our study did not identify significant differences in cancer survival for children with and without birth defects. Future studies should consider pooling data from multiple states to allow in-depth study of specific birth defects and cancer types and confirm whether survival differs by type and number of birth defects.

Excellent long-term survival of children with Down syndrome and standard-risk ALL: a report from the Children's Oncology Group

The Children's Cancer Group 1991 study was a clinical trial for children with National Cancer Institute standard-risk acute lymphoblastic leukemia (ALL). This trial demonstrated that 5 doses of vincristine and escalating IV methotrexate (MTX) without leucovorin rescue in the interim maintenance (IM) phases resulted in superior event-free survival (EFS) when compared with 2 doses of vincristine, oral (PO) MTX, PO mercaptopurine, and dexamethasone. This report describes a favorable outcome of this regimen in patients with Down syndrome (DS). Forty-four patients with DS were randomized to the arms containing PO MTX during IM, and 31 to those containing IV MTX. Ten-year EFS rates for patients with DS randomized to IV MTX vs PO MTX were 94.4% ± 5.4% vs 81.5% ± 6.6%, respectively. IV methotrexate with strict escalation parameters, as given in this study, was well tolerated, although the mean total tolerated dose received was lower in patients with DS than in those without DS. There was no increase in hepatic toxicity, systemic infections, or treatment-related deaths in patients with DS during IM on either the IV or PO MTX arms, as compared with those without DS. The incidence of mucositis was increased in patients with DS as compared with patients without DS, particularly among patients who received IV MTX. This trial was registered at www.clinicaltrials.gov as #NCT00005945.

Epigenetic Therapy in a Patient With Down Syndrome and Refractory Acute Myeloid Leukemia

Acute myeloid leukemia (AML) associated with Down syndrome (DS-AML) is a unique entity of AML with superior treatment response and overall survival compared with children with non-DS-AML. Despite good outcomes in DS-AML, those who relapse or have refractory disease have poor survival. Successful treatment of these patients is challenged by increased incidence of treatment-related toxicities often encountered with high-dose chemotherapy. Here we report the experience of epigenetic modifying agents (decitabine and vorinostat) followed by fludarabine, cytarabine, and granulocyte colony stimulating growth factor for a child with refractory DS-AML. This combination was well tolerated and resulted in a brief clinical response.

Characteristics and survival of children with acute leukemia with Down syndrome or other birth defects in New York State

BACKGROUND

Acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) among DS children have been studied extensively using data from clinical trials or institutional reports. The purpose of this study was to link population-based cancer and birth defects data to evaluate characteristics and survival of children with acute leukemia according to the presence of DS or other birth defects.

METHODS

ALL and AML cases diagnosed between 1983 and 2012 among children aged 0-14 years were obtained from the New York State Cancer Registry. Birth defect status (DS, other birth defects, or no birth defects) was determined by linking with birth defects data. Associations between birth defect status and demographic characteristics were evaluated using contingency table analysis. Ten-year survival was calculated by birth defect status and other potential prognostic factors. Cox proportional hazards regression analysis was also performed.

RESULTS

Among 2941 ALL children, 1.6% had DS, 3.8% had other birth defects, and 94.5% had no birth defects. Birth defect status was significantly associated with age at ALL diagnosis. Survivals were similar among three groups. Among 563 AML children, 11.0% had DS, 6.0% had other birth defects, and 83.0% had no birth defects. Children with DS were more likely to be diagnosed with AML at a younger age and showed the best survival.

CONCLUSION

Age at leukemia diagnosis was significantly associated with the birth defect status. Comparable survival was observed for ALL children. However, AML children with DS demonstrated superior survival compared to children with other birth defects or no birth defects.

Childhood cancer research in Oxford II: The Childhood Cancer Research Group

BACKGROUND

We summarise the work of the Childhood Cancer Research Group, particularly in relation to the UK National Registry of Childhood Tumours (NRCT).

METHODS

The Group was responsible for setting up and maintaining the NRCT. This registry was based on notifications from regional cancer registries, specialist children's tumour registries, paediatric oncologists and clinical trials organisers. For a large sample of cases, data on controls matched by date and place of birth were also collected.

RESULTS

Significant achievements of the Group include: studies of aetiology and of genetic epidemiology; proposals for, and participation in, international comparative studies of these diseases and on a classification system specifically for childhood cancer; the initial development of, and major contributions to, follow-up studies of the health of long-term survivors; the enhancement of cancer registration records by the addition of clinical data and of birth records. The Group made substantial contributions to the UK government's Committee on Medical Aspects of Radiation in the Environment.

CONCLUSION

An important part of the ethos of the Group was to work in collaboration with many other organisations and individuals, both nationally and internationally: many of the Group's achievements described here were the result of such collaborations.

Long-term sequelae in survivors of childhood leukemia with Down syndrome: A childhood cancer survivor study report

BACKGROUND

Children with Down syndrome (DS) are at increased risk of developing acute leukemia and are more prone to acute toxicities. We studied the incidence and severity of chronic health conditions among survivors of childhood leukemia with DS compared with those without DS.

METHODS

Chronic health conditions reported by questionnaire were compared between 154 pediatric leukemia survivors with DS and 581 without DS, matched by leukemia, age at diagnosis, race/ethnicity, sex, radiation location and chemotherapy exposure using Cox models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Subjects were selected from 7139 5-year survivors of leukemia in the Childhood Cancer Survivor Study.

RESULTS

Risk of at least 1 late onset chronic health condition (grade 1-5) was similar in the DS population compared with the non-DS group (HR, 1.1; 95% CI, 0.7-1.5). Serious chronic health conditions (grade 3-5) were more common in DS survivors (HR, 1.7; 95% CI, 1.1-2.6), as were ≥ 3 chronic health conditions (grades 1-5) (HR, 1.7; 95% CI, 1.2-2.4). The 25-year cumulative incidence of any condition (grades 1-5) was 83% for DS survivors and 69% for non-DS survivors.

CONCLUSION

Leukemia survivors with DS have therapy-related chronic health conditions comparable to those of similarly treated survivors without DS, with a few notable exceptions: 1) an increased risk of cataracts, hearing loss, and thyroid dysfunction compared with survivors without DS (though these are known risks in the DS population), 2) decreased risk of second cancers, and 3) increased risk of severe or multiple conditions. Practitioners should be aware of these risks during and after therapy. Cancer 2018;124:617-25. © 2017 American Cancer Society.

Supportive care utilization and treatment toxicity in children with Down syndrome and acute lymphoid leukaemia at free-standing paediatric hospitals in the United States

Although inferior outcomes of children with Down syndrome (DS) and acute lymphoid leukaemia (ALL) are established, national supportive care patterns for these patients are unknown. A validated retrospective cohort of paediatric patients diagnosed with ALL from 1999 to 2011 was assembled from the US Pediatric Health Information System (PHIS) database to examine organ toxicity, sepsis, and resource utilization in children with and without DS. Among 10699 ALL patients, 298 had DS-ALL (2·8%). In a multivariate model, DS was associated with increased risk of cardiovascular (odds ratio [OR] 2·0, 95% confidence interval [CI] 1·6-2·7), respiratory (OR 2·1, 95% CI: 1·6-2·9), neurologic (OR 3·4, 95% CI 1·9-6·2), and hepatic (OR 1·4, 95% CI 1·0-1·9) dysfunction and sepsis (OR 1·8, 95% CI: 1·4-2·4). Children with DS-ALL used significantly more respiratory support, insulin, and anti-infectives, including broad-spectrum Gram-positive agents, quinolones, and azoles. They used significantly fewer analgesics and antiemetics compared to non-DS-ALL children. Ultimately, this study confirms the increased risk of infectious and end-organ toxicity in children with DS-ALL and quantifies important differences in resource utilization between children with DS and non-DS ALL. These findings highlight the importance of investigating the impact of these care variations and developing specific supportive care guidelines for this population.

Anthracycline-Related Cardiotoxicity in Patients with Acute Myeloid Leukemia and Down Syndrome: A Literature Review

Pediatric patients with Down syndrome (DS) are at an increased risk of developing certain cancers. Specifically, patients with DS have a reported 10-20-fold increased risk of developing acute myeloid leukemia (AML). Anthracycline-based treatment regimens achieve good results in patients with DS and AML. It has been proposed that DS status constitutes a risk factor for the cardiotoxicity associated with the use of anthracyclines in the pediatric setting. However, published evidence pointing toward an increased risk of cardiotoxicity in patients with DS is relatively scarce and conflictive. This concise review compiles literature relating to the incidence of anthracycline-related cardiotoxicity in pediatric patients with DS. In general, reports from trials using anthracyclines at the maximum recommended dose showed increases in the incidence of anthracycline-related cardiotoxicity in patients with DS in comparison with trials that used anthracyclines at reduced doses. Evidence from the literature suggests that patients with DS can achieve favorable therapeutic outcomes after receiving treatment with reduced doses of anthracyclines to minimize the potential for cardiotoxicity. Further prospective trials, along with the available evidence, would assist the design of treatment protocols for patients with pediatric leukemias and DS.

Recruitment of childhood leukaemia patients to clinical trials in Great Britain during 1980-2007: variation by birth weight, congenital malformation, socioeconomic status and ethnicity

OBJECTIVE

To assess recruitment of children to national clinical trials for acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML) in Great Britain during 1980-2007 and describe variation by some factors that might influence trial entry.

DESIGN AND SETTING

Records of leukaemia patients aged 0-14 years at diagnosis were identified in the National Registry of Childhood Tumours and linked to birth registrations, Children's Cancer and Leukaemia Group records, Hospital Episode Statistics and Medical Research Council clinical trial registers. Trial entry rates were compared between categories of birth weight, congenital malformation, socioeconomic status and ethnicity.

RESULTS

9147 ALL and 1466 AML patients were eligible for national clinical trials during 1980-2007. Overall recruitment rates were 81% and 60% respectively. For ALL, rates varied significantly with congenital malformation (Down syndrome 61%, other malformations 80%, none 82%; p<0.001) and ethnicity (South Asian 78%, other minority groups 80%, white 85%; p<0.001). For AML, rates varied with birth weight (< 2500 g 48%, 2500-4000 g 69%, >4000 g 67%; p=0.001) and congenital malformation (Down syndrome 28%, other malformations 56%, none 63%; p<0.001).

CONCLUSIONS

Although recruitment rates to clinical trials for childhood leukaemia are high, future trials should monitor possible variation by birth weight, ethnicity and presence of congenital malformations.

Clinical and genetic features of pediatric acute lymphoblastic leukemia in Down syndrome in the Nordic countries

Background

Children with Down syndrome (DS) have an increased risk for acute lymphoblastic leukemia (ALL). Although previous studies have shown that DS-ALL differs clinically and genetically from non-DS-ALL, much remains to be elucidated as regards genetic and prognostic factors in DS-ALL.

Methods

To address clinical and genetic differences between DS-ALL and non-DS-ALL and to identify prognostic factors in DS-ALL, we ascertained and reviewed all 128 pediatric DS-ALL diagnosed in the Nordic countries between 1981 and 2010. Their clinical and genetic features were compared with those of the 4,647 B-cell precursor (BCP) ALL cases diagnosed during the same time period.

Results

All 128 DS-ALL were BCP ALL, comprising 2.7% of all such cases. The 5-year event-free survival (EFS) and overall survival (OS) were significantly (P = 0.026 and P = 0.003, respectively) worse for DS-ALL patients with white blood cell counts ≥50 × 10⁹/l. The age distributions varied between the DS and non-DS cases, with age peaks at 2 and 3 years, respectively; none of the DS patients had infant ALL (P = 0.029). The platelet counts were lower in the DS-ALL group (P = 0.005). Abnormal karyotypes were more common in non-DS-ALL (P < 0.0001), and there was a significant difference in the modal number distribution, with only 2% high hyperdiploid DS-ALL cases (P < 0.0001). The 5-year EFS and 5-year OS were significantly worse for DS-ALL (0.574 and 0.691, respectively) compared with non-DS-ALL (0.783 and 0.894, respectively) in the NOPHO ALL-1992/2000 protocols (P < 0.001).

Conclusions

The present study adds further support for genetic and clinical differences between DS-ALL and non-DS-ALL.

Myelopathy mimicking subacute combined degeneration in a Down syndrome patient with methotrexate treatment for B lymphoblastic leukemia: report of an autopsy case

We report clinicopathological features of a 23-year-old woman with Down syndrome (DS) presenting with subacute myelopathy treated with chemotherapy, including intravenous and intrathecal administration of methotrexate (MTX), and with allogenic bone-marrow transplantation for B lymphoblastic leukemia. Autopsy revealed severe demyelinating vacuolar myelopathy in the posterior and lateral columns of the spinal cord, associated with macrophage infiltration, marked axonal loss and some swollen axons. Pathological changes of posterior and lateral columns were observed from the medulla oblongata to lumbar cord. Proximal anterior and posterior roots were preserved. Cerebral white matter was relatively well preserved. There were no vascular lesions or meningeal dissemination of leukemia. Longitudinal extension of cord lesions was extensive, unlike typical cases of subacute combined degeneration (SACD), but distribution of lesions and histological findings were similar to that of SACD. DS patients show heightened sensitivity to MTX because of their genetic background. Risk factors for toxic myelopathy of DS are discussed, including delayed clearance of MTX despite normal renal function, alterations in MTX polyglutamation and enhanced folic acid depletion due to gene dosage effects of chromosome 21. Alteration of folate metabolism and/or vitamin B12 levels through intravenous or intrathecal administration of MTX might exist, although vitamin B12 and other essential nutrients were managed using intravenous hyperalimentation. To the best of our knowledge, this is the first report of an autopsy case that shows myelopathy mimicking SACD in a DS patient accompanied by B lymphoblastic leukemia. The case suggests a pathophysiological mechanism of MTX-related myelopathy in DS patients with B lymphoblastic leukemia mimicking SACD.

Physicians compliance during maintenance therapy in children with Down syndrome and acute lymphoblastic leukemia

Children with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) have an inferior prognosis compared with non-DS ALL patients. We reviewed methotrexate (MTX)/mercaptopurine (6MP) maintenance therapy data for children with DS treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL92 or the NOPHO ALL2000 protocols between 1992 and 2007. The 5-year event-free survival probability (pEFS(5 yr)) for the 66 DS patients was inferior to the 2602 non-DS patients (0.50 ± 0.07 vs 0.77 ± 0.01 (P<0.001)). The 48 DS patients in first remission at the beginning of maintenance therapy had pEFS(10 yr) below that of the 522 non-DS control patients (pEFS(10 yr): 0.58 (95% confidence interval (CI) 0.43-0.77) vs 0.83 (95% CI 0.80-0.86), respectively (P<0.0001)). The DS patients received lower median doses of MTX (median: 11.8 vs 15.4 (P<0.0001)) and 6MP (median: 43.6 vs 59.4 (P<0.0001)). In Cox regression analysis, male gender, presence of DS and high median maintenance therapy white blood cell levels (mWBC) were associated with increased risk for relapse. DS-ALL patients with mWBC above or below 3.5 × 10(9)/l (protocol target) had pEFS(10 yr) of 0.31 and 0.72 (P=0.02), and the mWBC hazard ratio for DS-ALL patients was 2.0 (P<0.0005). We conclude that insufficient treatment intensity during maintenance therapy of DS-ALL patients may contribute to their poor prognosis.

High frequency of BTG1 deletions in acute lymphoblastic leukemia in children with down syndrome

Previous cytogenetic studies of myeloid and acute lymphoblastic leukemias in children with Down syndrome (ML-DS and DS-ALL) have revealed significant differences in abnormality patterns between such cases and acute leukemias in general. Also, certain molecular genetic aberrations characterize DS-related leukemias, such as GATA1 mutations in ML-DS and deregulation of the CRLF2 gene in DS-ALL. Whether microdeletions/microduplications also vary between DS and non-DS cases is presently unclear. To address this issue, we performed single nucleotide polymorphism array analyses of eight pediatric ML-DS and 17 B-cell precursor DS-ALL. In the ML-DS cases, a total of 29 imbalances (20 gains and nine losses) and two partial uniparental isodisomies (pUPDs) were detected. None of the 11 small (defined as <10 Mb) imbalances were recurrent, nor were the pUPDs, whereas of the 18 large aberrations, three were recurrent-dup(1q), +8 and +21. In contrast, several frequent changes were identified in the DS-ALL cases, which harbored 82 imbalances (30 gains and 52 losses) and four pUPDs. Of the 40 large changes, 28 were gains and 12 losses, with +X, dup(Xq), dup(1q), del(7p), dup(8q), del(9p), dup(9p), del(12p), dup(17q), and +21 being recurrent. Of the 40 microdeletions identified, several targeted specific genes, with the following being repeatedly deleted: BTG1 and CDKN2A/B (29% of cases), ETV6, IKZF1, PAX5 and SERP2 (18%), and BTLA, INPP4B, P2RY8, and RB1 (12%). Loss of the SERP2 and INPP4B genes, encoding the stress-associated endoplasmic reticulum protein family member 2 and the inositol polyphosphate 4-phosphatase-II, respectively, has previously never been implicated in leukemia. Although deletions of the other genes have been associated with ALL, the high frequency of BTG1 loss is a novel finding. Such deletions may characterize a clinical subgroup of DS-ALL, comprising mainly boys with a high median age. In conclusion, ML-DS and DS-ALL are genetically distinct, with mainly gains in ML-DS and deletions in DS-ALL. Furthermore, DS-ALL is characterized by several recurrent gene deletions, with BTG1 loss being particularly frequent.

Intracranial yolk sac tumor in a patient with Down syndrome

The authors report a rare case of intracranial yolk sac tumor in a 13-year-old boy with Down syndrome who presented with left hemiparesis. Admission MR imaging revealed a tumor in the right basal ganglia. Serum α-fetoprotein was markedly elevated. Yolk sac tumor was diagnosed radiologically and serologically. The standard therapy for intracranial yolk sac tumor is platinum-based chemotherapy with concomitant radiotherapy. However, the authors used reduced-dose chemotherapy and asynchronized radiotherapy because of the well-known low tolerance of patients with Down syndrome to chemotherapy. This treatment was successful with no complications. Blood cancers are frequently associated with Down syndrome, whereas solid tumors occur less frequently in these patients, and the risk of chemoradiotherapy is unclear. The results indicate that dose-reduction therapy can be effective for treatment of a brain tumor in a patient with Down syndrome.

Myeloid leukaemia in children with Down syndrome: report of the registry-based French experience between 1990 and 2003

AIM

To determine the epidemiology of myeloid leukaemia (ML) in children with Down syndrome (DS) and the efficacy of two approaches, low-dose cytarabine-based regimen (LDC) and standard-dose intensive chemotherapy (SD).

PROCEDURE

All children with Down syndrome aged from 2 months to 15 years with ML/myelodysplasia registered in the French registry between January 1990 and December 2003 were included.

RESULTS

Forty-four patients were included. The median age was 1.75 years. The French-America-British subtypes were as follows: M7: 24, M0: 6, M2: 5, M6: 2. Forty-three patients were treated with curative prospect, 20 patients with LDC regimen and 22 according to SD protocols, 1 was given the LDC regimen plus autologous stem-cell transplantation. The event-free survival (EFS) and overall survival (OS) at 5 years were 64.4% and 76.8%. At 5 years, OS in LDC and SD groups were 65% and 85.9% (P = 0.08). EFS were 45% and 80.3% respectively (P < 0.01).

CONCLUSION

Children with DS can adequately tolerate SD chemotherapy with a significant superiority of EFS relative to LDC. We suggest that higher levels of cure can be obtained in DS-ML with SD chemotherapy including cytarabine and anthracyclines.

Down syndrome childhood acute lymphoblastic leukemia has a unique spectrum of sentinel cytogenetic lesions that influences treatment outcome: a report from the Children's Oncology Group

Children with Down syndrome (DS) have an increased risk of acute lymphoblastic leukemia (ALL) and an inferior outcome. We reviewed data from 2811 children with ALL enrolled in Children's Oncology Group P9900, which included prospective testing for the major cytogenetic lesions in childhood ALL: ETV6-RUNX1, TCF3-PBX1, BCR-ABL1, and MLL translocations and trisomies of chromosomes 4 and 10. Eighty (3%) B-precursor ALL patients had DS. Age, sex, white blood cell count, and risk group were similar between DS-ALL and non-DS-ALL but significantly more patients with DS-ALL were white (91.2% vs 76.4%, P = .001). Children with DS-ALL had lower rates of the favorable cytogenetic lesions ETV6-RUNX1 (2.5% vs 24%, P < .001) and trisomies 4 and 10 (7.7% vs 24%, P < .001). Five-year event-free (EFS) and overall survival (OS) were inferior in children with DS-ALL: 69.9% +/- 8.6% versus 78.1% +/- 1.2% (P = .078), and 85.8% +/- 6.5% versus 90.0% +/- 0.9% (P = .033). However, when children with MLL translocations, BCR-ABL1, ETV6-RUNX1, and trisomies 4 and 10 were excluded, the EFS and OS were similar for children with and without DS (EFS 68.0 %+/- 9.3% vs 70.5% +/- 1.9%, P = .817; and OS 86.7% +/- 6.7% vs 85.4% +/- 1.5%; P = .852), both overall and adjusted for race. DS-ALL displays a unique spectrum of biologic subtypes with different frequencies of sentinel cytogenetic lesions having a large influence on outcome.

Outcome and toxicity of chemotherapy for acute lymphoblastic leukemia in children with Down syndrome

BACKGROUND

Acute lymphoblastic leukemia (ALL) in children with Down syndrome (DS) presents with an increased incidence, higher frequency of adverse effects and inferior probability of survival. Attempts at improving outcomes face the dilemma posed by the need to avoid excessive toxicity while maintaining the efficacy of treatment. Dose reductions and avoidance of infusions of intermediate and high-dose methotrexate are common in this group.

PROCEDURE

In a matched pair analysis we compared adverse effects and survival after ALL chemotherapy using intermediate and high doses of methotrexate in children with and without Down syndrome.

RESULTS

Following intermediate and high doses of methotrexate to treat primary ALL, children with DS did not require opiate analgesia and parenteral nutrition for severe mucositis more often than children without DS. Children with DS spent more days in hospital and missed more doses of maintenance chemotherapy. Chemotherapy dose reductions were common and in this study had no detectable adverse impact. Event-free and overall survival (OS) of children with ALL was lower in the DS than the non-Down syndrome (NDS) control group. The difference, however, was no longer significant during the recent treatment era.

CONCLUSIONS

The feasibility of all treatment elements that are efficacious in pediatric ALL needs to be carefully considered in children with DS. In addition to survival data, the prospective collection of data on both adverse events and treatment modifications is essential to strike a balance between the avoidance of adverse effects and the need for intensive therapy that will safely improve ALL outcomes in this group.

Acute lymphoblastic leukemia and Down syndrome: presenting features and treatment outcome in the experience of the Italian Association of Pediatric Hematology and Oncology (AIEOP)

BACKGROUND

The presenting features and treatment outcome of 120 patients with Down syndrome (DS) and childhood acute lymphoblastic leukemia (ALL) were compared with 6237 non-DS patients treated in the same years.

METHODS

We reviewed the database of 6 consecutive Italian Association of Pediatric Hematology and Oncology (AIEOP)-ALL trials conducted between 1982 and 2004. Features of DS patients were compared with those of non-DS patients.

RESULTS

The 120 DS patients (1.9%) were more often girls (P = .027), aged > or = 10 years (P = .014), and high risk according to National Cancer Institute (NCI) criteria (P = .045). The distribution of white blood cell count did not differ (P = .32). DS patients belonged less frequently to the current high-risk group (P = .017). In all but 1 case they demonstrated B-cell precursor (BCP) immunophenotype (P < or = .001). TEL/AML1 molecular fusion transcript was found in only 1 of 44 (2.2%) tested patients. Induction death occurred more often in DS patients (4.2%, P = .009), but not failure to achieve remission. Leukemia relapse occurred in 31.6% of DS patients (vs 23.5%; P = .003), usually in the marrow. Remission death was more frequent in DS patients (4.2%, P = .03). Ten-year event-free survival and survival were significantly worse compared with non-DS patients (P < 0.001). DS patients diagnosed since 1995 had a better outcome (P = .06) than those diagnosed in previous years, but still had worse outcomes than non-DS patients (P = .04). Event-free survival of DS patients at NCI standard risk was lower than that of non-DS patients (P = .006).

CONCLUSIONS

Presenting features of childhood ALL in DS differ from those in non-DS patients. They are almost invariably characterized by BCP phenotype, and are often TEL/AML1 negative. Treatment results, although not as good as for non-DS patients, improved progressively, with modern therapy and support allowing 75% to survive.

Acute megakaryoblastic leukaemia (AMKL) in children: a comparison of AMKL with and without Down syndrome

To characterize childhood acute megakaryoblastic leukaemia (AMKL), we reviewed 45 children with AMKL diagnosed between 1986 and 2005 at Nagoya University Hospital and Japanese Red Cross Nagoya First Hospital. Twenty-four patients (53%) had AMKL associated with Down syndrome (DS-AMKL) and 21 (47%) had non-DS-AMKL. The median age of the DS-AMKL patients was 21 months (range, 8-38 months) and that of non-DS-AMKL patients was 15 months (range, 2-185 months). The morphology of blast cells was categorized into three groups according to the stage of megakaryocyte maturation. The blast cells were more immature in DS-AMKL than in non-DS-AMKL in terms of morphology and immunophenotyping. Cytogenetic abnormalities of leukaemic cells were classified into seven categories: normal karyotype including constitutional trisomy 21 in DS-AMKL; numerical abnormalities only; t(1;22)(p13;q13); 3q21q26 abnormalities; t(16;21)(p11;q22); -5/del(5q) and/or -7/del(7q); and other structural changes. The outcome of children with either DS-AMKL or non-DS-AMKL is excellent. The 10-year overall survival estimate was 79% [95% confidence interval (CI): 54-90] for DS-AMKL and 76% (95% CI: 58-91) for non-DS-AMKL (P = 0.81) with a median follow-up of 78 months (range, 20-243 months). Our study shows the diverse heterogeneity of childhood AMKL and the need for subclassification according to cytogenetic and morphological features.

Hematopoietic disorders in Down syndrome

Patients with Down syndrome have an increased risk of developing various hematological disorders. In this article, the clinical characteristics and differential diagnosis of the hematological disorders associated with Down syndrome are reviewed, and the underlying molecular mechanisms discussed.

Relapse, not regimen-related toxicity, was the major cause of treatment failure in 11 children with Down syndrome undergoing haematopoietic stem cell transplantation for acute leukaemia

We report a retrospective analysis of 11 children with Down syndrome (DS) treated by SCT in eight German/Austrian SCT centres. Indications for transplantation were acute lymphoblastic leukaemia (N=8) and acute myeloid leukaemia (N=3). A reduced intensity conditioning (RIC) containing 2 Gy TBI was given to two patients, another five received a myeloablative regimen with 12 Gy TBI. Treosulphan or busulphan was used in the remaining four children. Four of eleven (36%) patients are alive. All of them were treated with a myeloablative regimen. One of the four surviving children relapsed 9 months after SCT and is currently receiving palliative outpatient treatment. The main cause of death was relapse (5/11). Two children died of regimen-related toxicity (RRT), one from severe exfoliative dermatitis and multiorgan failure after a treosulphan-containing regimen, the other from GvHD-related infections after RIC. Acute GvHD of the skin was observed in 10 of 10 evaluable patients, and chronic GvHD in 4 of 8. Our data show that DS patients can tolerate commonly used, fully myeloablative preparative regimens. The major cause of death is relapse rather than RRT resulting in an event-free survival of 18% and over all survival of 36%.

Down syndrome and acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia in children with Down syndrome (ALL-DS) is characterised by unique clinical and biological features. Notable among these are an absence of ALL in DS patients <1 year of age; a lower incidence of favourable and unfavourable chromosomal translocations; heightened sensitivity to methotrexate; and an increased propensity to infections. Although children with ALL-DS have historically fared less well than their non-DS counterparts (ALL-NDS), recent data indicate that outcomes in ALL-DS are now comparable with ALL-NDS with risk-adapted therapies, after adjusting for biological differences between the ALL-DS and ALL-NDS populations. Given the increased risk of ALL-DS patients for treatment-related toxicities, further intensification of therapy may not yield continued improvements in survival. Future investigations in the ALL-DS population should focus on maintaining excellent outcomes while reducing treatment-related complications through novel treatment strategies, such as the integration of targeted noncytotoxic agents.

Treatment for myeloid leukaemia of Down syndrome: population-based experience in the UK and results from the Medical Research Council AML 10 and AML 12 trials

Down syndrome (DS) children are at an increased risk of developing myelodysplasia and acute myeloid leukaemia (AML). We retrospectively analysed the population-based data on 81 children with myeloid leukaemia of Down syndrome (ML-DS) from the UK National Registry of Childhood Tumours and experience in the Medical Research Council (MRC) AML 10 and AML 12 trials, which enrolled 46 children with ML-DS from 1988 to 2002. Eight per cent of UK children with AML had DS, but DS children comprised only 5% of children registered in MRC trials. The unique clinical characteristics of ML-DS were confirmed. Overall survival (OS) of ML-DS at 5 years increased from 47% in UK children diagnosed from 1988 to 1995 to 75% in children diagnosed from 1996 to 2002. OS for DS children registered in AML 10 and AML 12 was 74% in 5 years and improved from AML 10 to AML 12 (56% vs. 83%) There was no significant difference in OS between DS and non-DS children (OS: 74% vs. 62%, P = 0.4) in the trials, but this result masked a significant increase in early death amongst DS children, with a significant reduction in mortality later on. Relapse was significantly reduced (3% vs. 39%, P = 0.0003), leading to the improved disease-free survival (83% vs. 56%, P = 0.02). Given the increased number of early treatment-related deaths, future treatment protocols should aim to reduce chemotherapy dosage or intensity whilst maintaining low rates of resistant and recurrent disease.

Optimizing therapy for myeloid disorders of Down syndrome

Children with Down syndrome (DS) are at increased risk of leukaemia. Myeloid disorders include transient abnormal myelopoiesis (TAM), myelodysplasia (MDS) and acute myeloid leukaemia (AML). Mutations in the GATA-1 gene, which encodes for a transcription factor central to the normal development of the erythroid and megakaryocytic lineages, are found in cases of TAM, MDS and AML in DS children. DS children with MDS/AML mostly present between the ages of 1 and 4 years, and have a large predominance of megakaryoblastic disease (French-American-British type M7). The MDS and AML are part of a single disease entity (myeloid leukaemia of Down syndrome) that is extremely sensitive to chemotherapy. Resistant disease and relapse are rare, but treatment-related toxicity is high, and deaths in remission have exceeded those due to disease in most series. Accordingly, controlled dosage reduction is the focus of contemporary treatment studies.

Hematological disorders in Down syndrome: ten-year experience at a Tertiary Care Centre in North India

A total of 239 cases of Down syndrome (DS) were seen in the genetic clinic between 1992 and 2003, of which of 15 had hematological manifestations at presentation. These comprised 4 cases of transient myeloproliferative disorder (TMD), 3 cases of TMD/acute leukemia, 4 cases of acute leukemia (AL), 2 of dual deficiency anemia, and 1 case each of myelofibrosis and idiopathic thrombocytopenia. This study emphasizes the fact that an abnormal hemogram in a DS patient does not necessarily indicate AL/TMD, as a considerable number of the cases in this study had other hematological abnormalities. TMD can be differentiated from acute leukemia only on follow-up.

Acute leukaemia in children with Down syndrome: a population-based Nordic study

To determine the epidemiology and outcome of children with Down syndrome (DS) diagnosed with acute leukaemia in the Nordic countries, data registered in the Nordic Society of Paediatric Haematology and Oncology (NOPHO) population-based leukaemia registry were analysed. Of 3494 children with acute leukaemia diagnosed between July 1984 and December 2001, 136 patients (3.9%) with DS were identified. 2.1% of the children with acute lymphoid leukaemia (ALL) and 14.0% of the children with acute myeloid leukaemia (AML) had DS. In ALL, DS patients had similar age and sex distribution and no major differences in blood counts compared with non-DS children. None of the DS patients had T cell leukaemia. Outcome was inferior to that of non-DS children and treatment results did not improve over time. In AML, DS patients showed a significant female predominance and all but one were <5 years old. DS patients with AML had significantly lower platelet and white blood cell counts and two-thirds were type M7 as according to the French-American-British classification. None of the patients <5 years of age had typical AML cytogenetic aberrations. Outcome was far better in the DS group. DS patients treated for AML after 1992 had an excellent outcome (probability of event-free survival, 83 +/- 6%). The high proportion of female DS patients with AML is unexplained. The differing treatment results in AML versus ALL need further evaluation and represent a challenge for the coming years.

Lymphoblast biology and outcome among children with Down syndrome and ALL treated on CCG-1952

BACKGROUND

Patients with Down syndrome (DS) and standard risk (SR) acute lymphoblastic leukemia (ALL-DS) are reported to have inferior event free (EFS) and overall survival (OS) compared to patients without DS (ALL-NDS).

PROCEDURE

We compared the prevalence of favorable and unfavorable clinical and biologic features, toxicity and outcome within the ALL-DS and ALL-NDS cohorts of 2,174 eligible patients with SR-ALL enrolled on CCG-1952.

RESULTS

Fifty-nine patients (3%) had ALL-DS. DS patients were less likely to have either favorable (hyperdiploidy, triple trisomy of chromosomes 4, 10, and 17, TEL-AML1 rearrangement) or unfavorable (T-cell ALL, hypodiploidy, adverse translocations) biologic features. Toxicity occurred significantly more often and number of days hospitalized was significantly greater in ALL-DS than in ALL-NDS. ALL-DS patients had an inferior 4-year EFS compared to the NDS cohort. However, EFS was equivalent when the comparison excluded ALL-NDS with favorable biologic features. OS was significantly inferior for ALL-DS.

CONCLUSIONS

The absence of favorable biologic features within ALL-DS contributes to the difference in EFS previously observed between DS and NDS SR-ALL cohorts.

Down syndrome, drug metabolism and chromosome 21

It has been recognized that chromosomal abnormalities in childhood leukemia, are linked to both leukemogenesis and segregate patients into prognostic treatment groups. This is best exemplified in cases of children with Down syndrome (DS), who have significantly higher risks of developing leukemia compared to non-DS children and distinctive treatment outcomes, particularly in cases of acute myeloid leukemia (AML). The high event-free survival (EFS) rates of DS AML patients and in particular, patients with megakaryocytic leukemia (AMkL), at least in part reflects an increased sensitivity to cytosine arabinoside (ara-C) secondary to increased expression of the chromosome 21-localized gene, cystathionine-beta-synthase, and potentially global mechanisms which increase the susceptibility of cells to undergo apoptosis. Somatic mutations of the X-linked transcription factor gene, GATA1, have been detected uniformly and exclusively in DS AMkL cases, which may lead to altered expression of GATA1 target genes and alter the metabolism of drugs including ara-C. Hyperdiploid acute lymphoblastic leukemia (ALL) cells with extra copies of chromosome 21, generate higher levels of the active methotrexate (MTX) metabolite, MTX polyglutamates. This is on account of increased intracellular transport of MTX via the reduced folate carrier (RFC) whose gene is localized to chromosome 21 and may also account for the increased MTX-associated toxicity of DS ALL patients. Microarray technology should lead to the identification of additional gene targets linked to the treatment response of specific cytogenetic leukemia subgroups.

Acute myeloid leukemia and Down syndrome evolution of modern therapy--state of the art review

Over the past decade, a series of clinical reports have described the experience of Down syndrome (DS) children treated for acute myeloid leukemia (AML). Whereas prior to the first reports in the early 1980's it was felt that DS children with AML had poor outcomes, these clinical trials concluded that DS had a better outcome than non-DS (NDS) children with AML. With these recent reports, it is clear that DS children have a better outcome utilizing less intensive chemotherapy regimens. They also tolerate the more intensive regimens less well than the NDS children. This review focuses upon the six multi-institutional reports that described the DS and AML experience in order to better ascertain the chemotherapy combinations that may be useful in the future for these children. Regimens of varying intensity have all had similar outcomes. In general, the remission rates are approximately 90% with event-free survival (EFS) approximating 70-80%. Most recently, the clinical trials have been large enough to explore prognostic factors specifically in the DS children. This has identified that the younger DS children fair significantly better than the older children. AML in DS is unique and these differences in comparison to NDS children are highlighted. The significantly better outcomes for DS children likely represents a combination of the unique AML seen in DS children and the heightened sensitivity to cytarabine that DS AML cells have. Future trials should focus on age-stratified approaches that exploit the greater sensitivity of DS AML to cytarabine.

Increased age at diagnosis has a significantly negative effect on outcome in children with Down syndrome and acute myeloid leukemia: a report from the Children's Cancer Group Study 2891

PURPOSE

To determine the outcome of children with Down syndrome (DS) and acute myeloid leukemia (AML) receiving standard timing chemotherapy without bone marrow transplantation (BMT), with determination of prognostic factors.

PATIENTS AND METHODS

Children with DS and newly diagnosed AML or myelodysplasia were prospectively enrolled on Children's Cancer Group study 2891 (N = 161) and treated uniformly with four standard timing induction courses of dexamethasone, cytarabine arabinoside, 6-thioguanine, etoposide, daunorubicin (DCTER) followed by intensively timed high-dose cytarabine.

RESULTS

Children with DS were significantly younger at diagnosis than those without (median age, 1.8 v 7.5 years, respectively; P <.001), with more megakaryocytic leukemia (70% v 6%; P <.001). Higher complete remission rates (91%) were achieved in children with DS than among those without DS (75%; P <.001). Equivalent grade 3 to 4 toxicity (29% v 30%; P =.84) was seen, though children with DS had greater pulmonary toxicity (P <.01) during induction and mucositis during intensification (P =.12). Children with DS had significantly better 8-year event-free survival (EFS; 77% v 21% standard and 40% intensive induction; P <.0001). Multivariate analysis in children with DS revealed that only age at diagnosis of 2 years or older was a risk factor for greater relapse risk (odds ratio, 4.9; P =.006) and worse survival. Children between ages 0 to 2 years (n = 94) had a 6-year EFS of 86%; those from 2 to 4 years (n = 58), 70%; and those older than 4 years (n = 9), 28%. Remission failures were the primary reason for worse 6-year EFSs (1% in those 0 to 2 years v 14% if >2 years; P =.002).

CONCLUSION

Outcome for children with DS and AML is excellent with standard induction therapy, but declines with increasing age.

Down's syndrome and acute lymphoblastic leukaemia: clinical features and response to treatment

AIMS

To examine the clinical and biological features of acute lymphoblastic leukaemia in children with Down's syndrome (DS), to compare their survival with other children, and to determine if entry to trials and survival has improved.

METHODS

Examination of presenting features and response to treatment in patients treated in two consecutive national trials, MRC UKALL X and XI.

RESULTS

The proportion of children with DS was significantly higher in UKALL XI (1.9%) than UKALL X (0.9%). Children with DS tended to be under 10 years and to have the common ALL subtype. Cytogenetic analysis showed that favourable features, such as high hyperdiploidy and t(12;21) were less frequent but also that there was a lack of translocations associated with a poor prognosis. Children with DS showed no increase in risk of relapse at any site but their survival and event free survival were inferior to other children. These results were caused by an increased number of infective deaths during remission (11% compared to 2%). At five years overall survival was 73% in DS children compared with 82% in other children; event free survival was 53% compared to 63% in non-DS children.

CONCLUSIONS

Entry of children with DS to national trials has increased and survival has improved. However they remain at risk of relapse and also of treatment related mortality. These findings emphasise the need for both intensive chemotherapy and optimal supportive care.

Incidence of leukemia and other cancers in Down syndrome subjects in Israel

Epidemiologic data have confirmed the high susceptibility of persons with Down syndrome (DS) to leukemia. The question of proneness to other kinds of cancer is still open. In this study we reassessed the incidence rates of leukemia and other malignancies in Israeli DS subjects, based on the total population. The target population consisted of all DS subjects in Israel in the period of 1948--1995. Due to incompleteness of data, the target population was not fully achieved, thus the study population was divided into 2 subgroups: subjects born in Israel between 1979 and 1995 (registry group) and currently or past-institutionalized subjects born before 1979 (institution group). The cohort was linked with the Cancer Registry, and cancer cases that had been diagnosed through December 1995 were subsequently identified. Observed incidence rates were compared with expected rates in the general population. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were computed for each disease category. Analyses were performed separately for each subgroup of the study population. In the registry group, 7 cancer cases were observed, compared with 1.5 expected (SIR = 4.67, 95% CI 1.9--9.6), all leukemia cases. For the institution group a total of 17 cancer cases were observed, compared with 12.8 expected. These included 4 cases of leukemia (SIR = 6.90, 95% CI 1.90--17.70). An excess of gastric cancer in male subjects (SIR = 11.9, 95% CI 1.3--42.9) was also observed. Significant excess of leukemia in DS population in Israel is in accordance with previously published data. An excess of gastric cancer in DS male subjects born before 1979, which has not been reported before, should be further explored.

Childhood leukemia: Understanding the significance of chromosomal abnormalities

The survival for children with acute lymphoblastic leukemia (ALL) has increased from 3% to greater than 70% in the last 30 years, with some patients achieving 95% survival. These advances have been made not only because therapy has improved, but also because there is a much greater understanding of the diversity of ALL. The identification of clinical and biological prognostic factors associated with ALL has resulted in the formation of subsets of patients classified into risk groups. Although age, initial white blood cell count, and central nervous system or testicular disease are all important prognostic factors, cytogenetic abnormalities have now emerged as the single most important prognostic factor for children with ALL. There are specific cytogenetic findings in the leukemic blast cells of these children that influence their prognosis. Some of these findings are positive factors and some adverse. Treatment protocols for ALL today are now determined by these specific chromosomal abnormalities.

Progressive reduction in treatment-related deaths in Medical Research Council childhood lymphoblastic leukaemia trials from 1980 to 1997 (UKALL VIII, X and XI)

In the last 20 years, the survival rate for children with acute lymphoblastic leukaemia (ALL) has markedly improved, largely owing to a decrease in relapses. However, children still die from complications of treatment and these are potentially preventable. We have analysed data from three large consecutive national protocols for ALL from 1980 to 1997 [Medical Research Council United Kingdom ALL (MRC UKALL) trials VIII, X and XI] to compare the incidence and causes of treatment-related deaths (TRD). The percentage of TRD has fallen from 9% to 2% (UKALL VIII to XI), largely as a result of a decrease in fatal infections. Deaths during induction have fallen from 3% to 1%, the main causes of death being bacterial, followed by fungal infection, while other causes, chiefly haemorrhage, have not declined. Remission deaths also decreased from 6% to 1%, particularly those deaths due to measles and pneumocystis carinii. More guidelines for surveillance and treatment of infections have been included within progressively more intensive protocols. Risk factor analysis showed increased TRD in patients with Down's syndrome, high leucocyte count and older age in UKALL XI. In contrast, the introduction of blocks of intensification was not associated with an increased death rate. While improved supportive care has reduced the incidence of TRD, there is still scope for further reduction by prompt treatment of suspected infection. Maintenance of herd immunity remains of vital importance in avoiding deaths from measles.

Patterns of care and survival for children with acute lymphoblastic leukaemia diagnosed between 1980 and 1994

AIMS

To document survival rates after acute lymphoblastic leukaemia (ALL) during the era of modern chemotherapy, to assess effects of prognostic factors at presentation, and to investigate the relation of survival to patterns of organisation of care.

PATIENTS

From a population based series of 5078 children diagnosed in the UK during 1980-94, 4988 remained for analysis after exclusion of nine children ascertained from death certificates alone and 81 who received no antileukaemia treatment.

MAIN OUTCOME MEASURES

Actuarial survival rates.

RESULTS

Between 1980-84 and 1990-94, the proportion of children treated at paediatric oncology centres rose from 77% to 89%, and the proportion entered into national trials rose from 59% to 82%. Each of age, sex, white blood count, immunophenotype, and Down's syndrome status had a highly significant effect on survival. Five year survival improved from 67% in 1980-84 to 81% in 1990-94, a 42% reduction in the risk of death within five years of diagnosis. Survival did not differ significantly between hospitals with different numbers of new patients per year or between paediatric oncology centres and other hospitals. Children who were entered into national trials had higher survival and this difference became greater in recent years; five year survival rates for children diagnosed during 1980-84 were 70% and 64% for trial and non-trial patients, respectively; in 1990-94 the rates were 84% and 68% for trial and non-trial patients, respectively.

CONCLUSIONS

Survival after ALL continues to improve. Nearly 50 children/year diagnosed during 1990-94 survived who would have died a decade before. Survival does not vary systematically with place of treatment but is higher for children entered into national trials.

Improved outcome of acute myeloid leukaemia in Down's syndrome

OBJECTIVE

To review the clinical features, treatment, and outcome of children in the UK with Down's syndrome and acute myeloid leukaemia (AML).

DESIGN

A retrospective study of 59 children with Down's syndrome and AML presenting between 1987 and 1995. Data were obtained from hospital case notes, trial records, and by questionnaire.

RESULTS

The patients were unusually young (median age, 23 months) with a predominance of megakaryoblastic AML. Two of the seven infants who presented with abnormal myelopoesis aged 2 months or younger achieved complete spontaneous remission. Most of the older children with AML (32 of 52) were treated on recognised intensive protocols but 13 received individualised treatment and seven symptomatic treatment alone. Only four received a bone marrow transplant (BMT) in first remission. For the 45 older children who received chemotherapy the overall survival was 55% (median follow up 4.5 years). Patients on individualised protocols had a similar overall survival and toxic death rate but marginally higher relapse rate than those on standard (intensive) protocols. Children with Down's syndrome treated on the national AML 10 trial had a similar overall survival (70% v 59%) at five years to children of comparable age without Down's syndrome: their improved relapse risk (12% v 38%) offset the slight increase in deaths as a result of treatment toxicity (19% v 11%).

CONCLUSION

Neonates with Down's syndrome and abnormal myelopoesis may achieve spontaneous remission, and older children with Down's syndrome and AML can be treated successfully with intensive chemotherapy, without BMT.

Down syndrome, transient myeloproliferative disorder, and infantile liver fibrosis

BACKGROUND

In neonates, Down syndrome is rarely accompanied by the leukemoid reaction called transient myeloproliferative disorder.

PROCEDURES AND RESULTS

We present clinical and histopathologic data of another Down syndrome neonate with transient myeloproliferative disorder and severe infantile liver fibrosis. These findings in our patients are compared in detail with the 20 cases published previously. Similar clinical and laboratory findings were present in all 21.

CONCLUSIONS

Knowing the cellular mechanism of hepatic fibrosis and its modulation by growth factors (e.g, platelet-derived growth factor), a pathogenetic link between transient myeloproliferative disorder and the development of liver fibrosis in Down syndrome neonates seems probable. An association of this triad of findings no longer appears to be accidental.

Acute myelogenous leukemia in Down's syndrome: report of a single pediatric institution using a BFM treatment strategy

Between July 1990 and December 1995, 111 new consecutive pediatric patients with acute myelogenous leukemia (AML) have been treated in our institution. Eleven of them (9.9%) had Down's syndrome (DS), 6 boys and 5 girls. The median age was 22.5 (range 10-40) months. FAB subtypes were the following: M7: 6, M4: 3, and M0: 2. Five of them had previously had myelodysplasia and in 3, all FAB M7, myelofibrosis was detected. This population was treated with two consecutive protocols. Nine patients were included in the AML-HPG-90 protocol and 2 patients in the AML-HPG-95 study, respectively. However, all DS patients in this series received the same treatment. Eight patients achieved complete remission: two patients received two cycles of intensification with high dose (HD) ara-C, and 1 patient, only one cycle; the other 5 were prevented from receiving such therapy because of unacceptable toxicity or death. At 45 months, event-free survival and overall survival estimates were 0.30, S.E. 0.16. Mortality was remarkably high. All deaths (7) were associated with sepsis (5) or pulmonary infection (2). Three deaths occurred before achieving complete remission, 3 patients died during the consolidation phase and 1 died whilst off treatment. No one presented leukemic relapse. We conclude that this AML-BFM treatment strategy is highly toxic to children with DS and AML in our setting. Efforts will be made to improve clinical support and to administer less intensive therapy to this particular pediatric AML subgroup, which, in fact, has a better prognosis than the same non-trisomic population.

Malignancies in Down syndrome

Down Syndrome (DS) is associated with an increased incidence of malignancies, especially leukaemias. We came across 8 DS children presenting with malignancies and having trisomy 21 as the sole cytogenetic abnormality. Of these 8 DS cases, 4 presented with acute lymphocytic leukaemia, 2 with acute myeloid leukaemia and one case each with Hodgkin's disease and Wilms' tumour. There are contradictory reports regarding the distribution of myeloid versus lymphoid malignancies in DS children and their response to therapy. The exact mechanism by which patients with DS are predisposed to develop malignancies is unclear. However, presence of the extra chromosome no. 21 is presumed to disrupt the genetic balance which increases generalized susceptibility to genetic and environmental trauma. Furthermore, an increased methotrexate toxicity observed in these patients should also be taken into consideration in designing treatment for DS children with malignancies.