Cognitive and academic functioning in survivors of pediatric bone marrow transplantation

Age differences in perceived social support by paediatric haematopoietic progenitor cell transplant patients: a longitudinal study

OBJECTIVES

To describe longitudinally different sources of perceived social support by children and adolescents who undergo haematopoietic progenitor cell transplant (HPCT).

METHODS

Thirty-six (20 males, 16 females) survivors of paediatric HPCT, aged 8-18 years (Mean = 11.73), were assessed pre-HPCT and 6 months, 1 year and 2 years post-HPCT. Survivors were compared with siblings (n = 22) during the last assessment. The Social Support Scale for Children (SSSC), a self-report measure, provided scores on perceived social support from parents, teachers, friends and classmates.

RESULTS

Throughout the 2 years post-HPCT, perceived social support from all sources was generally higher for survivors than for population norms. Over time, both children and adolescents reported higher social support from parents than the normative values. Over time, children perceived higher support from teachers than did adolescents, whereas adolescents' perceived social support from classmates increased but children's decreased. Survivors and siblings did not differ significantly in their perceived social support 2 years post-BMT.

CONCLUSIONS

This exploratory study suggests that perceived parental support is equally important for children and adolescents but classmate and teacher social support varies with age. These developmental differences have important clinical implications for the care of these patients.

Validity and consequence of informed consent in pediatric bone marrow transplantation: The parental experience

BACKGROUND

Conditions supporting a high quality of consent for pediatric bone marrow transplantation (BMT) are suboptimal given the complexity of the procedure, lack of options, and parent emotional duress. We studied if parents perceived choice when consenting to BMT, if they felt the consent provided was valid, and how the consent process affected them.

METHODS

Telephone or face-to-face interviews were recorded using a semi-structured interview outline. Interview transcripts were anonymized, and independently analyzed by three reviewers.

RESULTS

Twenty parents of twelve children participated, including five bereaved parents. There were no differences in patient transplant characteristics between the eligible and study groups. Divorced or separated parents were underrepresented in the participant group. Fifteen parents felt personally compelled to consent; most (18) denied feeling external medical pressure to do so. All parents felt their consent was valid and most reported adequate levels of freedom, capacity, and information. Expectations formulated during the consent process strongly influenced parents' experience post-BMT. Good communication during consent contributed to trust and therapeutic alliance with physicians following BMT. Late parental stress and anxiety were periodic, but very high in some families.

CONCLUSIONS

Parents feel consent for pediatric BMT is valid, despite feeling personally compelled to consent. Strategies aimed at nurturing hope and realistic expectations may assist in improving the consent process, while diminishing long-term stressors.

Using Q-methodology to understand perceived fatigue reported by adolescents with cancer

Although fatigue is an unpleasant symptom commonly experienced by pediatric oncology patients, it also tends to be under-recognized and under-treated. A conceptual understanding of how patients perceive fatigue is beneficial for better identification and treatment planning. The purpose of this study was to understand how adolescents with cancer perceive their fatigue and to explore potential factors influencing their perceptions by using Q-methodology. The sample included 15 patients (ages 12-18 years) from the Chicago metropolitan area who were receiving cancer treatment. All participants completed a 37-statement Q-sort task. Data were analyzed by using PQMethod computer software. Results identified three descriptors of perceived fatigues reported by adolescents: energy and related capacity for physical functioning, psychosocial effects, and anemia-specific concerns. Appropriate referral for patients with the latter two descriptors of fatigue was recommended.

A prospective cohort study of late sequelae of pediatric allogeneic hematopoietic stem cell transplantation

As survivors of pediatric allogeneic hematopoietic stem cell transplantations (HSCTs) increase in number, it is increasingly important to evaluate their well-being. We conducted this prospective cohort study to evaluate the cumulative incidence and risk factors for late sequelae of HSCT. Comprehensive surveillance tests were performed annually on every participant, regardless of signs and symptoms, to obtain accurate information on the time-of-onset of each late event to allow hazard function analyses. All participants included in this report had been followed for at least 3 years after HSCT. With a median follow-up of 9 years and a current age of 18.5 years, only 20 of the 155 participants (13%) had no late sequelae; 18 survivors (12%) had 1 chronic health condition, 71 (46%) had 2-4 conditions, and 46 (30%) had 5-9 conditions. Risk factors for increasing number of chronic conditions included young age at the time of HSCT, female sex, high radiation dose, and history of chronic graft-versus-host disease. The cumulative incidence at 10 years for common late events was as follows (ordered by the median time-of-onset): osteonecrosis 13.8%, chronic renal insufficiency 26.8%, hypothyroidism 45.1%, growth hormone deficiency 31.2%, female hypogonadism 57.4%, osteopenia 47.7%, cataracts 43.4%, pulmonary dysfunction 63.2%, and male hypogonadism 20.3%. Coexistence of multiple late sequelae was common in HSCT survivors. Our findings provide a basis for more effective patient counseling, optimal surveillance, and early intervention.

Health care utilization by adult long-term survivors of hematopoietic cell transplant: report from the Bone Marrow Transplant Survivor Study

The high intensity of therapy and prolonged immune suppression after hematopoietic cell transplantation (HCT) increase the risk of long-term complications and health care needs among survivors. The aim of this study was to evaluate the current status of health care utilization by long-term HCT survivors and to identify factors associated with lack of utilization. A total of 845 individuals who had undergone HCT between 1974 and 1998 at age 21 years or older and survived 2 or more years after HCT participated in the study. Health care utilization was assessed through a mailed questionnaire in three domains: general contact with health care system, general physical examination, and cancer/HCT-related visit. The median age at HCT was 38.2 years, and the median length of follow-up was 6.4 years. Overall, 98% of allogeneic and 94% of autologous HCT survivors reported medical contact 11+ years after HCT. Cancer/HCT-related visits decreased with increasing time from HCT (allogeneic HCT, 98-57%; autologous HCT, 94-63%). The prevalence of general physical examination increased with time (allogeneic HCT, 56-74%; autologous HCT, 72-81%). Primary care physicians provide health care for an increasing number of adult long-term survivors of HCT, emphasizing the need for increased awareness of the long-term follow-up needs of the HCT survivors by the health care providers.

Secondary malignancies and quality of life after stem cell transplantation

Malignant diseases (MD) occurring after stem cell transplantation (SCT) are of particular concern as increasing number of patients survive and remain free of their original disease. The cumulative incidence at 15 years is 10-12%. The B-cell proliferative disorders (BCLP) are the most common MD in the first year after SCT; the incidence probability is 1% in allogeneic transplants but is much higher (until 14%) after HLA-identical, T-cell-depleted SCT in which Campath 1G or ATG are given. BCLP develop because of reactivation of the EBV and a depressed cellular immunity. Prediction of risk of BCLP can be made by frequent monitoring of EBV load in patients with risk factors. The most effective therapies are the early administration of anti-CD20 monoclonal antibody and adoptive immunotherapy with in vitro generated EBV-specific cytotoxic T cells. Myelodysplasia and acute myeloid leukemia with very poor prognosis have been described in 4-18% of patients with non-Hodgkin lymphoma and Hodgkin disease, 12-24 months after autologous SCT. The risk of development of solid tumors increases over time and the cumulative incidence among children who underwent an SCT at less than 10 years of age is 6-11% at 15 years. There are few studies evaluating quality of life (QOL) in children and adolescents who had received an SCT. The findings of these studies can be summarized as follows: (a) The majority of long survivors enjoy good QOL and return successfully to school or work. (b) A minority (10-15%) complain of physical problems or present moderate cognitive or psychological dysfunctions. (c) The importance of family, other social support and psychological adjustments is generally recognized. More extensive, longitudinal and comparative studies with other alternative therapies are required.

Neuropsychological resiliency after treatment for advanced stage neuroblastoma

The purpose of this study was to describe the neuropsychological functioning of survivors of advanced stage neuroblastoma. In all, 16 survivors, diagnosed at a median of 2.8 years, who had received intensive chemotherapy and surgical treatments, were identified; 11 had received myeloablative consolidation therapy, eight with total body irradiation (TBI). All patients were evaluated with a neuropsychological assessment battery at a median age of 8.8 years. Analyses included comparison of the performances of the TBI group vs the no-TBI group; determination of whether the proportion of individuals with impaired or superior performance on each measure exceeded normative expectations; and performance indexes reflecting patterns of performance. Results indicate no significant deleterious impact of TBI and/or presence or absence of myeloablative therapy on neurocognitive and neurobehavioral functioning. For this cohort, resilience to neuropsychological vulnerability was observed, which included the emergence of a profile of full-scale IQ, verbal IQ, and mathematical achievement well above average expectations. We concluded that the results document a lack of neuropsychological morbidity among this cohort of survivors of advanced stage neuroblastoma, regardless of the inclusion of TBI. Moreover, a striking pattern of excellent neurocognitive functioning with intact neurobehavioral functioning was observed.

Psychosocial supportive care for children receiving stem cell transplantation: practice patterns across centers

Although pediatric stem cell transplantation is associated with elevated risks for quality-of-life (QOL) deficits, morbidity, and late effects, little is known about how supportive care needs are addressed across different pediatric centers. This study examined practice patterns among centers enrolled in the Pediatric Blood and Marrow Transplant Consortium. In all, 65 centers (response rate=82.2%) were surveyed regarding QOL screening, psychosocial intervention services, and long-term follow-up care. Approximately 80% of centers provided routine screening for psychological difficulties and pain. A smaller number screened for fatigue (69.2%), cognitive deficits (52.3%), sleep difficulties (60.0%) or spiritual concerns (38.5%). Screening was conducted predominantly via interview; little use was made of standardized measures. Community-based centers screened some deficits more frequently than did academic ones (all P's</=0.09). In all, 60% of centers provided support groups and 49.2% offered arts-in-medicine programs. Most centers provided extended follow-up care. In some, follow-up continued until age 21 (45.4%), while in others it was sustained indefinitely (40.6%). Findings suggest that QOL screening would be enhanced by greater attention to domains that currently receive limited scrutiny, and by increased use of validated measures to supplement interview information. The proportion of centers that provide extended follow-up is encouraging, and offers opportunities to study long-term outcomes.

Psychosocial Functioning in Pediatric Cancer

OBJECTIVE

To describe the emergence of pediatric psycho-oncology and to summarize research on psychosocial aspects of childhood cancer and survivorship.

METHODS

To review research into illness communication and informed consent, procedural pain, late effects, psychological distress, coping and adjustment, and special risk populations. Methodological challenges, appropriate methodology, and directions for future research are discussed.

RESULTS

The past 30 years have seen change from avoidance of communication about cancer to an emphasis on straightforward discussion of diagnosis and prognosis. Behavioral research has led to interventions to reduce procedural distress. Late effects have been observed in social functioning. Although average levels of distress in survivors of pediatric cancer are typical, subsets of more vulnerable patients and family members exist. Factors predicting positive and negative coping have been identified.

CONCLUSIONS

As the numbers of pediatric cancer survivors increase, psychosocial researchers will be better able to conduct longitudinal studies not only of adjustment and its predictors but also of the impact of the emerging medical treatments and interventions to ameliorate late effects of treatment. Additional funding, improving methodology, and multi-institutional cooperation will aid future pediatric psycho-oncology investigators.

Cancer Survivorship—Pediatric Issues

The last three decades have seen tremendous improvements in survival of children diagnosed with cancer, with the 5-year survival rate approaching 80%. This improvement in survival has resulted in a growing population of childhood cancer survivors. Use of cancer therapy at an early age can produce complications that may not become apparent until years later. Approximately two thirds of the survivors of childhood cancer will experience at least one late effect, and about one third will experience a late effect that is severe or life threatening. Long-term complications in childhood cancer survivors, such as impairment in growth and development, neurocognitive dysfunction, cardiopulmonary compromise, endocrine dysfunction, renal impairment, gastrointestinal dysfunction, musculoskeletal sequelae, and subsequent malignancies, are related not only to the specific therapy employed, but may also be determined by individual host characteristics. We review the known late effects of treatment in survivors of childhood cancer in order to suggest reasonable starting points for evaluation of specific long-term problems in this unique but growing population. The Children’s Oncology Group (COG) has developed risk-based, exposure-related guidelines for follow-up care that are available at www.surivorshipguidelines.org.

Anticancer agents are potent neurotoxins in vitro and in vivo

Neurotoxicity of anticancer agents complicates treatment of children with cancer. We investigated neurotoxic effects of common cytotoxic drugs in neuronal cultures and in the developing rat brain. When neurons were exposed to cisplatin (5-100 microM), cyclophosphamide (5-100 microM), methotrexate (5-100 microM), vinblastin (0.1-1 microM), or thiotepa (5-100 microM), a concentration-dependent neurotoxic effect was observed. Neurotoxicity was potentiated by nontoxic glutamate concentrations. The N-methyl-D-aspartate receptor antagonist MK 801 (10 microM), the AMPA receptor antagonists GYKI 52466 (10 microM) and NBQX (10 microM), and the pancaspase inhibitor Ac-DEVD-CHO (1 nM) ameliorated neurotoxicity of cytotoxic drugs. To investigate neurotoxicity in vivo, we administered to 7-day-old rats the following: cisplatin (5-15 mg/kg i.p.), cyclophosphamide (200-600 mg/kg i.p.), thiotepa (15-45 mg/kg), or ifosfamide (100-500 mg/kg) and their brains were analyzed at 4 to 24 hours. Cytotoxic drugs produced widespread lesions within cortex, thalamus, hippocampal dentate gyrus, and caudate nucleus in a dose-dependent fashion. Early histological analysis demonstrated dendritic swelling and relative preservation of axonal terminals, which are morphological features indicating excitotoxicity. After longer survival periods, degenerating neurons displayed morphological features consistent with active cell death. These results demonstrate that anticancer drugs are potent neurotoxins in vitro and in vivo; they activate excitotoxic mechanisms but also trigger active neuronal death.

Busulfan and cyclophosphamide as a conditioning regimen for pediatric acute lymphoblastic leukemia patients undergoing bone marrow transplantation

Bone marrow transplantation (BMT) has become the standard therapy for children with relapsed acute lymphoblastic leukemia. The authors report their experience with histocompatible BMT for 52 children with acute lymphoblastic leukemia conditioned with a non-total body irradiation (TBI) regimen using busulfan and cyclophosphamide (Bu/Cy). The efficacy and long-term toxicity of the Bu/Cy regimen were determined. Overall survival was 35%. One-year, 3-year, and 7-year event-free survival rates were 54%, 33%, and 23%, respectively. Of the 52 BMT recipients, 26 relapsed. Thirteen of the relapsed patients received a second BMT and three were surviving as of this writing. The most frequent cause of death was leukemia relapse. An initial remission duration of less than 18 months was a factor in decreasing the event-free survival. The Bu/Cy regimen was well tolerated, with minimal transplant-related mortality. Neurocognitive function was tested before BMT and 1 year after BMT. When 1-year posttransplant neurocognitive test scores were compared with pretransplant scores, there was no decrease. However, there was a significant decrease in the pretransplant neurocognitive test scores in BMT recipients compared with their normal siblings. The use of Bu/Cy as a conditioning regimen for BMT does not appear to affect posttransplant neurocognitive function. Other long-term side effects, such as endocrinopathies and secondary malignancies, were also minimal. These data show that the Bu/Cy regimen is well tolerated, but the overall survival rate remains low.

Randomized trial of busulfan vs total body irradiation containing conditioning regimens for children with acute lymphoblastic leukemia: a Pediatric Blood and Marrow Transplant Consortium study

Conditioning regimens for children with ALL have generally included total body irradiation (TBI), which may result in significant sequelae. The primary aim of this study was to evaluate the outcome for children with ALL undergoing allogeneic stem cell transplant (SCT) with either busulfan (Bu) or TBI regimens. Patients <21 years with ALL undergoing allogeneic SCT were eligible. Conditioning included either Bu or TBI, with etoposide 40 mg/kg and cyclophosphamide 120 mg/kg. Randomization was stratified based upon duration of remission, remission status, and prior cranial irradiation. A total of 43 patients were enrolled; 21 received Bu and 22 TBI. Median patient age was 8 years (0.5-20 years). Remission status included 12 patients in CR1, 25 in CR2, and six in CR3. At a median follow-up of 43 months, event-free survival (EFS) is 45% at 3 years, with 29% EFS in the Bu arm and 58% in the TBI arm (P=0.03). There was no significant difference between Bu and TBI for patients who received stem cells from related donors (36 vs 58%, P=0.3). However, for URD, EFS was 20% for Bu and 57% for TBI (P=0.04). Relapses were similar in both arms. This randomized prospective study suggests that Bu is inferior to TBI for pediatric patients with ALL undergoing allogeneic SCT.

Late effects among survivors of leukemia during childhood and adolescence

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, accounting for one-third of all cancers occurring in childhood and adolescents. Over the last 3 decades there has been a marked improvement in survival, with 5-year survival rates approaching 80%. With this improvement in survival, increasing attention is now being focused on issues relating to long-term morbidity and mortality associated with the treatments responsible for that increased survival. Because of the young age of these cancer survivors, and thus the potential longevity, the delayed consequences of therapy may have a significant impact on their lives. Long-term sequelae of treatment, such as impaired intellectual and psychomotor functioning, neuroendocrine abnormalities, impaired reproductive capacity, cardiotoxicity, and second malignant neoplasms, are now being reported with increasing frequency in this growing cohort of survivors and knowledge of the late -effects associated with cancer in children and adolescents continues to increase through ongoing research efforts. However, much of the available information relates to outcomes within the first decade following treatment, although information about the longer term outcomes that may occur later in adulthood is emerging as a result of well-conducted, large cohort studies. Through a multi-disciplinary approach to the diagnosis, treatment, and long-term follow-up of pediatric leukemia patients, we can achieve the goal of cure while minimizing the occurrence of long-term adverse outcomes. This review summarizes some of the well-described long-term consequences of therapy among children and adolescents treated for ALL.

Allogeneic bone marrow transplantation for children with histiocytic disorders: use of TBI and omission of etoposide in the conditioning regimen

The histiocytoses are rare disorders of antigen-processing phagocytic or antigen-presenting cells. Allogeneic bone marrow transplantation (BMT) can be curative of these disorders. We report a series of five children with Langerhans cell histiocytosis (n=2) or hemophagocytic lymphohistiocytosis (n=3), who received allogeneic BMT with a total body irradiation (TBI)-containing regimen (TBI, cytarabine, and cyclophosphamide) at our institution between 1995 and 2000. One of these patients received busulfan, cyclophosphamide, and etoposide for the first of two BMTs. All grafts except one (a matched sibling-donor graft) were T-cell-depleted grafts from unrelated donors. All received cyclosporine graft-versus-host disease (GvHD) prophylaxis; the recipient of the matched sibling graft also received methotrexate. Three patients engrafted at a median of 24 days after transplantation. The patient who did not receive TBI experienced primary graft failure and recurrent disease. After the TBI-containing conditioning regimen was given, a second transplant engrafted on day +17. One patient with concurrent myelodysplastic syndrome died of toxicity on day +33 without evidence of engraftment. No acute or chronic GvHD was observed. Four patients survive disease-free, a median of 63 months after transplantation, all with Lansky performance scores of 100. We conclude that a conditioning regimen containing TBI but not etoposide is effective in allogeneic BMT for children with histiocytic diseases.

Neuropsychological outcome in long-term survivors of a childhood extracranial solid tumor who have undergone autologous bone marrow transplantation

The purpose of this study was to evaluate neuropsychological and adaptive functioning of children who have undergone bone marrow transplantation (BMT) without previous cranial irradiation. In total, 76 children treated for an extracranial tumor with BMT without total body irradiation (TBI) were evaluated at least 5 years after the end of the treatment.Overall, their performance and skills were in the normal range and their professional and academic outcomes were satisfactory. Nevertheless, we observed a deleterious effect of deafness on verbal IQ associated with the previous administration of cisplatin during conventional chemotherapy. In addition, reading difficulties had arisen. This could be related to absence from kindergarten or primary school during hospitalization. Finally, in the younger subgroup, visual-perceptual skills were found to be more fragile.

Cognitive and psychosocial functioning of pediatric hematopoietic stem cell transplant patients: a prospective longitudinal study

A prospective longitudinal study of cognitive and psychosocial functioning in pediatric hematopoietic stem cell transplant (HSCT) patients was conducted on three occasions: pre-HSCT, 1 year post-HSCT, and 2 years post-HSCT. In contrast to the previous hypothesis that cognitive declines would occur as a result of HSCT treatment, it was hypothesized that (1) global cognitive functioning (IQ scores), as well as specific areas would remain stable over time; (2) pre-transplant functioning would be predictive of later functioning; and (3) age would be negatively related to cognitive functioning. Based on previous research it was further hypothesized: that (4) while declines in psychosocial functioning might be seen at 1 year, functioning would improve by 2 years. 153 children and adolescents were evaluated pre-HSCT and at 1 year, with 2 year data available for 74 children. Longitudinal analyses of Wechsler IQ data were completed on 100 children (longitudinal exact test) and 52 children (repeated measures analysis of variance. Results of cognitive assessment indicated (1) stability of IQ scores over time; and (2) that the strongest predictor was pre-HSCT cognitive functioning. Psychosocial assessment results indicated: (1) a low prevalence of behavioral and social problems; (2) stability in functioning over time; (3) pre-HSCT functioning strongly predictive of later functioning.

Cognitive, behavioral, and social outcome in survivors of childhood stem cell transplantation

PURPOSE

To evaluate prospectively the cognitive functioning and to obtain ratings of cognitive, behavioral, and social functioning for children receiving stem cell transplantation (SCT).

PATIENTS AND METHODS

Forty-seven children treated with SCT for malignant or nonmalignant disorders who had no previous cranial radiation therapy, no central nervous system tumors, and were aged birth to 16 years were administered the Bayley Scales of Infant Development or IQ test before SCT and an intelligence test 1 and 2 years after SCT. Children and parents rated behavior and social functioning, and parents reported on everyday cognitive abilities (including academic ability) 2 to 6 years after SCT.

RESULTS

There were no statistically significant differences in IQ over the course of time (before SCT to 2 years after SCT). Only parent ratings of academic ability were significantly lower than the normal standardization sample. Mean mental scale scores for children younger than 3 years were lower than mean IQ scores for children older than 3 years at the pre-SCT assessment. Mean test scores not only decreased for younger children but also were 16 points lower than mean scores for older children at 2 years after SCT.

CONCLUSIONS

The cognitive, behavioral, and social functioning of children 3 years and older is not detrimentally affected 2 years after SCT. Parents of older children report no cognitive ability problems but lower academic ability. Children younger than age 3 years may be at risk for decreased cognitive skills.

Cognitive and behavioral abnormalities in adenosine deaminase deficient severe combined immunodeficiency

OBJECTIVE

The objective was to evaluate the cognitive, behavioral, and neurodevelopmental function in patients with adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) and to compare the findings with those of a case control group of patients without ADA-SCID.

STUDY DESIGN

Case-matched pairs of patients with ADA-SCID (n = 11) and patients without ADA-SCID who had undergone bone marrow transplantation were recruited. Subjects were assessed by age-appropriate standard tests of intelligence, behavior, and neurodevelopment.

RESULTS

Cognitive ability was not significantly different between the 2 groups, but patients with ADA-SCID showed a significant inverse correlation between deoxyadenosinetrisphosphate levels at diagnosis and IQ (P =.048). Behavioral assessment showed that patients with ADA-SCID functioned in the pathologic range on all domains, whereas mean scores for the control group were within normal limits. Behavioral impairment in patients with ADA-SCID also showed a significant positive correlation with age (P =.026).

CONCLUSIONS

Cognitive function in ADA deficiency is adversely affected by the severity of metabolic derangement at the time of diagnosis. In addition, patients with ADA-SCID have significant behavioral abnormalities after transplantation. These defects are not due to the transplant procedure but reflect the systemic nature of ADA deficiency. These findings have important implications for future medical and nonmedical management strategies.

Allogeneic bone marrow transplantation for infants with acute leukemia or myelodysplastic syndrome

The objective of this study is to investigate the outcome of children 24 months of age or younger (infants) at the time of allogeneic bone marrow transplantation (BMT) for acute leukemia or myelodysplasia. We analyzed the survival rate, prognostic factors, incidences of late sequelae, and immune reconstitution in 22 infants who underwent allogeneic BMT. The 5-year event-free survival estimate was 45.5% (95% confidence interval (CI), 24.4% to 63.3%). Six patients died of transplant-related complications and six died of disease relapse. Remission status at the time of BMT was the most important prognostic factor (P = 0.005): no patient who received a transplant while their disease was not in remission survived, whereas the 5-year survival estimate for infants who underwent BMT during remission was 56% (95% CI, 31% to 75%). Long-term outcomes in the 10 infant survivors were compared with those of 10 older controls matched for diagnosis, disease status at the time of BMT, calendar year at the time of BMT, and source of stem cells. Immune function 1 year after transplantation and the incidences and spectra of late sequelae were similar for both groups during a median of 3.5 years (range, 1.5 to 7.2 years) of follow-up.

Acute myeloid leukaemia in children

Acute myeloid leukaemia (AML) is characterized by a block in differentiation and an unregulated proliferation of myeloid progenitor cells. While the cause of AML in children is unknown, risk factors that have been identified include exposure to toxins such as ethanol, pesticides and dietary topoisomerase II inhibitors, prior chemotherapy with alkylating agents or topoisomerase II inhibitors, constitutional disorders such as Down's syndrome and type I neurofibromatosis, and haematopoietic failure syndromes such as Fanconi anaemia and severe congenital neutropenia. With intensified chemotherapy including high-dose Ara-C, followed in many cases by bone marrow transplantation, and with improvements in supportive care, current survival rates approach 50%. Future advances in paediatric AML will include better risk stratification to determine optimal treatment and targeted cytotoxic therapy.