Intensification of treatment and survival in all children with lymphoblastic leukaemia: results of UK Medical Research Council trial UKALL X. Medical Research Council Working Party on Childhood Leukaemia

Long-term follow-up of relapsed childhood acute lymphoblastic leukaemia

We have reviewed the outcome after relapse in a cohort of 505 children with acute lymphoblastic leukaemia (ALL) seen at a single institution. The majority of relapses (74%) occurred within 3 years from diagnosis, and most involved the bone marrow alone or with overt extramedullary relapse. Early relapse was more common in children with T-ALL and those with unfavourable cytogenetics. Factors influencing second remission included length of first remission and type of relapse. Children who had not received previous cranial irradiation had a superior survival. The German relapse score involving length of first remission, site of relapse and immunophenotype was highly predictive of outcome: event-free survival with 95% confidence intervals at 6 years for patients who received modern treatment [intensive chemotherapy or bone marrow transplantation (BMT)] was 78% (51-92%) for standard risk, 41% (33-49%) for intermediate risk and 19% (10-31%) for highest risk. Retrospective comparison of BMT with chemotherapy showed no difference in the intermediate-risk group but a possible advantage in the highest risk group. Follow-up of 235 patients who relapsed after chemotherapy and received a third course of treatment showed an extremely high early attrition rate, but a small number of patients survived in third remission. We conclude that new approaches are needed to individualize therapy in intermediate-risk patients and to improve the outcome for those in the highest risk group. Only a small number of children can be treated effectively in third remission.

Prognostic factors in childhood acute lymphoblastic leukemia

Approximately 80% of children and adolsecents with acute lymphoblastic leukemia (ALL) can be cured. To reduce the rate of relapses, but also to limit treatment toxicity, risk-adapted treatment has been attempted after identifying the most specific prognostic factors. In addition to clinical factors such as age and WBC, or factors of the leukemic cell such as the immunphenotype and the cytogenetics, the in vivo response to therapy has evolved as the most important predictor for relapse. The lack of specificity of most prognostic factors stimulated the search for more relevant parameters. Detection of residual disease at defined timepoints by cytomorphology can provide specific prognostic information, which allows to define new risk groups. Detection of minimal residual disease (MRD) by identifying clone-specific T-cell receptor- (TCR) or immunglobuline (Ig) gene rearrangements is currently being evaluated to extend this approach of testing the individual's sucsceptibility to therapy. The high sensitivity of the method when indicating fast clearance of leukemia might eventually spare some patients of inadequately toxic therapy. Persistent disease is an indication for treatment modification and intensification. If standardized tools are used for treatment response evaluation, logistics and quality controls are demanding but essential for the reliable conduct of such clinical studies.

Expression of heat-shock protein 90 in glucocorticoid-sensitive and -resistant childhood acute lymphoblastic leukaemia

Early reduction of leukaemic cells by chemotherapy is a strong predictor for treatment outcome in childhood acute lymphoblastic leukaemia (ALL). In ALL-(Berlin-Frankfurt-Münster) trials, early treatment response is assessed by the in vivo response to glucocorticoids (prednisone response, PR), the molecular background of which is unknown. The intracellular effects of glucocorticoids (GCs) are mediated by the glucocorticoid receptor (GR). In the absence of GC, the inactive GR resides within a multiprotein complex, consisting predominantly of the chaperone protein hsp90 (heat-shock protein 90). Until now, studies targeting GC resistance mainly focused on GR disorders and alterations of genes known to be associated with drug resistance. In addition, the GR multiprotein complex was associated with GC resistance in in vitro studies. We performed a case-control study for PR to investigate the association of in vivo GC resistance and hsp90 expression in childhood ALL. Hsp90 expression was assessed using a real-time PCR approach (Taqman technology) and Western blot technology. In this setting, we found no association of in vivo GC resistance and hsp90 expression. Therefore, we conclude that the expression of hsp90, the major component of the GR activating complex, is of minor importance for the in vivo GC resistance in childhood ALL.

Economic evaluation of recombinant human granulocyte colony-stimulating factor in very high-risk childhood acute lymphoblastic leukemia

PURPOSE

In a previous randomized study, the authors reported that granulocyte colony-stimulating factor (G-CSF) increased the chemotherapy dose-intensity delivered during the consolidation therapy of high-risk childhood acute lymphoblastic leukemia (ALL). The aim of the current study was to perform an economic evaluation in the same cohort.

METHODS

In this open-label multicenter randomized trial, prophylactic G-CSF was administered after consolidation therapy courses. Economic data were retrospectively quantified for each patient: hospital stays, drugs, and blood products.

RESULTS

Sixty-seven children were enrolled in the very high-risk branch of the FRALLE 93 protocol. Chemotherapy dose-intensity was significantly increased (105 +/- 5% in the G-CSF group vs. 91 +/- 4% in the non-G-CSF group, P < 0.001). The mean total costs per child were not statistically different: 32,309 dollars in the G-CSF group versus 31,569 dollars in the non-G-CSF group. Further analysis per child and per course (R3 or COPADM) demonstrated that the mean cost of hospitalization and the mean cost of intravenous antibiotics were significantly decreased in the G-CSF group after R3 courses (3,857 dollars vs. 4,993.80 dollars, P < 0.001; 171.40 dollars vs. 306.20 dollars, P = 0.029, respectively), but the cost of platelet transfusion was significantly increased (P = 0.03). Conversely, post-COPADM costs were similar. Finally, mean costs per course in the two randomized groups were not significantly different: 5,848.80 dollars versus 6,181 dollars and 7,388.10 dollars versus 6,475.70 dollars for R3 and COPADM, respectively. The 3-year probability of event-free survival between the two groups was not different.

CONCLUSIONS

G-CSF can increase chemotherapy dose-intensity in very high-risk ALL without raising costs, but event-free survival was not improved. The cost benefit of prophylactic treatment by G-CSF relies on the chemotherapeutic regimen given prior to G-CSF administration.

Randomized controlled trials in pediatric surgery: could we do better?

BACKGROUND/PURPOSE

Randomized controlled trials (RCTs) are accepted as the gold standard for assessing the effectiveness of clinical interventions but are rarely reported in pediatric surgery. Have RCTs submitted to the British Association of Paediatric Surgeons (BAPS) Annual Congress during the last 5 years been adequately designed and large enough to produce a valid result?

METHODS

Abstracts accepted by the Annual BAPS Congress meetings between 1996 and 2000 were examined in collaboration with a senior health services researcher. The quality of the design, methodology, statistical analysis and conclusions, and the adequacy of the sample size were assessed for all identifiable clinical RCTs.

RESULTS

From 760 accepted abstracts, there were only 9 RCTs (1%) of clinical interventions. In only 4 trials was the relevant primary end-point specified at the outset of the study, and none documented the method of randomization. Only one abstract mentioned blinding with respect to the intervention or outcome measure. Sample sizes were inadequate to detect even large clinical differences. To date, only one of these RCTs has been published in an English-language, peer-reviewed journal.

CONCLUSIONS

Clear guidelines exist for the conduct of RCTs, yet compliance with these standards was rarely documented in abstracts of pediatric surgical RCTs presented at BAPS. Sample sizes were inadequate. RCTs in pediatric surgery are difficult to perform, but the specialty would benefit from well-designed, carefully conducted, multicentre, clinical RCTs to advance evidence-based practice.

Prognostic factors and outcome for children after second central nervous system relapse of acute lymphoblastic leukaemia

The Medical Research Council acute lymphoblastic leukaemia trials (UKALL X and XI) recruited 3,702 children with ALL between January 1985 and March 1997. Seventy-nine children had central nervous system (CNS) involvement in their first two relapses. Fourteen children survived at a median follow-up of 22 months from second relapse; seven (9%) in third remission, two in later remissions and five with disease. Factors predictive of survival from second relapse were site (isolated CNS was better than combined CNS, P = 0.02) and time from diagnosis to second CNS relapse (longer time was better, P = 0.004). Prognosis after second CNS relapse is extremely poor, and palliative therapy is appropriate.

Pediatric acute lymphoblastic leukemia

The outcome for children with acute lymphoblastic leukemia (ALL) has improved dramatically with current therapy resulting in an event free survival exceeding 75% for most patients. However significant challenges remain including developing better methods to predict which patients can be cured with less toxic treatment and which ones will benefit from augmented therapy. In addition, 25% of patients fail therapy and novel treatments that are focused on undermining specifically the leukemic process are needed urgently. In Section I, Dr. Carroll reviews current approaches to risk classification and proposes a system that incorporates well-established clinical parameters, genetic lesions of the blast as well as early response parameters. He then provides an overview of emerging technologies in genomics and proteomics and how they might lead to more rational, biologically based classification systems. In Section II, Drs. Mary Relling and Stella Davies describe emerging findings that relate to host features that influence outcome, the role of inherited germline variation. They highlight technical breakthroughs in assessing germline differences among patients. Polymorphisms of drug metabolizing genes have been shown to influence toxicity and the best example is the gene thiopurine methyltransferase (TPMT) a key enzyme in the metabolism of 6-mercaptopurine. Polymorphisms are associated with decreased activity that is also associated with increased toxicity. The role of polymorphisms in other genes whose products play an important role in drug metabolism as well as cytokine genes are discussed. In Sections III and IV, Drs. James Downing and Cheryl Willman review their findings using gene expression profiling to classify ALL. Both authors outline challenges in applying this methodology to analysis of clinical samples. Dr. Willman describes her laboratory's examination of infant leukemia and precursor B-ALL where unsupervised approaches have led to the identification of inherent biologic groups not predicted by conventional morphologic, immunophenotypic and cytogenetic variables. Dr. Downing describes his results from a pediatric ALL expression database using over 327 diagnostic samples, with 80% of the dataset consisting of samples from patients treated on a single institutional protocol. Seven distinct leukemia subtypes were identified representing known leukemia subtypes including: BCR-ABL, E2A-PBX1, TEL-AML1, rearrangements in the MLL gene, hyperdiploid karyotype (i.e., > 50 chromosomes), and T-ALL as well as a new leukemia subtype. A subset of genes have been identified whose expression appears to be predictive of outcome but independent verification is needed before this type of analysis can be integrated into treatment assignment. Chemotherapeutic agents kill cancer cells by activating apoptosis, or programmed cell death. In Section V, Dr. John Reed describes major apoptotic pathways and the specific role of key proteins in this response. The expression level of some of these proteins, such as BCL2, BAX, and caspase 3, has been shown to be predictive of ultimate outcome in hematopoietic tumors. New therapeutic approaches that modulate the apoptotic pathway are now available and Dr. Reed highlights those that may be applicable to the treatment of childhood ALL.

New treatment strategies in childhood acute lymphoblastic leukaemia

Today, 80% of paediatric patients with acute lymphoblastic leukaemia (ALL) can be cured. To reduce the rate of relapses, but also to limit treatment morbidity, risk-adapted treatment has been attempted after identifying the most specific prognostic factors. In addition to clinical factors (e.g. age, WBC), the immunophenotype and cytogenetic results, the early in vivo treatment response as determined by cytology had evolved as the most important predictor for relapse. The lack of specificity of most prognostic factors stimulated the search for more relevant parameters. Detection of minimal residual disease (MRD) at defined time points by identifying clone-specific T-cell receptor- (TCR) or immunoglobulin (Ig) gene rearrangements can provide new, highly specific prognostic information which allows definition of new risk groups. The high sensitivity of the method is a prerequisite for applying treatment reduction in patients with fast clearance of leukaemia. Persistent disease is an indication for treatment modification and intensification. Logistics and quality control are demanding but are essential for the introduction of this new technology into clinical practice.

Prospective molecular monitoring of BCR/ABL transcript in children with Ph+ acute lymphoblastic leukaemia unravels differences in treatment response

Children with Philadelphia-chromosome-positive (Ph+) acute lymphoblastic leukaemia (ALL) represent a subgroup at very high risk for treatment failure, despite intensive chemotherapy. However, recent retrospective studies showed that Ph+ childhood ALL is a heterogeneous disease with regard to treatment response. We have prospectively monitored, by reverse transcription polymerase chain reaction (RT-PCR) during follow-up, the presence of the BCR/ABL fusion transcript in Ph+ ALL children diagnosed in the Italian multicentre Associazione Italiana Ematologia Oncologia Pediatrica ALL-AIEOP-95 therapy protocol. To our knowledge, this is the first report on the evaluation of minimal residual disease (MRD) in childhood Ph+ ALL prospectively enrolled in an intensive, Berlin-Frankfurt-Munster (BFM)-type treatment protocol. Twenty-seven of 36 (75.0%) Ph+ patients consecutively enrolled into the high-risk group of the AIEOP-ALL protocol between May 1995 and October 1999 were successfully analysed. Twenty were good responders to the pre-phase of prednisone/intrathecal methotrexate treatment (PGR) and seven were poor responders (PPR). Within the PPR group, the RT-PCR monitoring constantly showed positivity for the BCR/ABL fusion transcript and all the patients died of disease progression. In contrast, highly sensitive qualitative RT-PCR monitoring revealed heterogeneity within the PGR group of Ph+ childhood ALL patients. Three different subgroups could be defined, according to the clearance of Ph+ cells within the first 5 months of treatment. This provides useful information on the capability of chemotherapy to reduce the leukaemic clone, with prognostic implications.

Acute lymphoblastic leukemia: optimizing treatment strategies in children

After the substantial improvements in cure rates for childhood acute lymphoblastic leukemia (ALL) obtained with intensified treatment strategies in the 1970s and 1980s, the last decade has seen slower progress on several fronts. Long-term follow-up has revealed late treatment-related adverse effects and focused attention on risk-targeted therapy to minimize adverse effects in patients at standard risk. Advances in the understanding of the biological features of childhood ALL have provided a platform for the development of such risk-directed protocols. At the same time, salvage of patients who have relapsed has improved such that 5-year overall survival rates are approaching 85%. The United Kingdom Medical Research Council Childhood Leukaemia Working Party has conducted trials of childhood ALL therapy (UKALL protocols) since the late 1960s. Early studies (UKALL I, II, III and V) focused on randomized testing of various aspects of the St Judes' first total therapy protocol. Later studies have confirmed the benefit of intensified therapy (UKALL X and XI), and shown that standard risk patients do not need cranial radiotherapy to prevent central nervous system relapse. UKALL R1 and R2 documented the efficacy of salvage chemotherapy. Improvements in infant ALL outcome have been less impressive and 5-year event free survival is still a disappointing 40%. Future strategies will incorporate more specific risk-directed therapy and greater international collaboration.

Loss of heterozygosity of p16 correlates with minimal residual disease at the end of the induction therapy in non-high risk childhood B-cell precursor acute lymphoblastic leukemia

We evaluated the incidence of MTS1/p16 deletions by loss of heterozygosity (LOH) analysis in 36 non-high risk B-cell precursor childhood acute lymphoblastic leukemia (BCP-ALL) and correlated these results with clinical features and with the presence of minimal residual disease (MRD) at the end of induction therapy. LOH was analyzed using three microsatellite markers flanking the p16 gene. MRD was studied by the polymerase chain reaction (PCR) for IgH and TCRdelta genes. All patients were classified and treated according to the BFM-86 protocol. A slower response to the induction treatment (MRD) was associated with LOH of p16 and worse clinical outcome. Thus, LOH of p16 may be a marker of chemotherapy resistance among the children classified as non-high risk BCP-ALL.

Progress in the treatment of acute myeloid leukaemia in adults

There has been important progress in the treatment of Acute Myeloid Leukaemia (AML) in patients under 60 years. A remission rate of 80% can be achieved by several schedules, and 40-45% of patients diagnosed will survive. It may still be possible to improve remission induction treatment eg by intensifying the Ara-C dose although may this only be detectable in an improved disease free survival. The is to reduce relapse. The risk main challenge is pre-determined by a number of powerful risk factors. In the experience of the MRC age, cytogenetics and clearance of blasts from the bone marrow after course 1. Using the later two in combination good risk patients (FAB M3, t(8;21) t(15;17) inv(16)) have a relapse risk of 32%. Poor risk (blasts >15% after course 1 or abnormalities of Chs 5 or 7, 3q- and complex changes have a relapse risk of 82%. All other cases are standard risk and ve a relapse risk of 56%. FLT3 mutations have been detected in about 25% of cases and provide additional negative predictive value overall and within each risk group. The assessment of the most effective consolidation treatment must be made taking into account the heterogeneity of the relapse risk. The MRC investigated the role of allo and autoBMT in addition to intensive chemotherapy. The data was analysis on an intent-to-treat or donor vs no donor basis. Although both types of transplant were able to reduce relapse overall and in all risk groups, there was an overall survival advantage only in standard risk patients. Since chemotherapy has improved since this study, there remains uncertainty about the benefit of transplant in all risk groups. Overall this experience has demonstrated that relapse can be reduced with more therapy. It is probable that the limits of conventional chemotherapy have been reached. The new AML15 trial will assess the value of adding the immunoconjugate (Mylotarg) to induction and/or chemotherapy. Improvements in older patients have been less detectable. MRC trials over the last 20 years show an improvement in remission rate (now 65%) but persistent poor survival (12% at 5 years). In the MRC AML11 Trial three induction schedules were compared (DAT vs ADE vs MAC) with DAT being superior. A comparison of a total of 3 vs 6 courses of treatment or the addition of interferon maintenance did not improve results. Newer approaches currently being assessed include resistance modulation; addition of immunoconjugate and minigrafts. New targets for treatment are emerging of which the most interesting is FLT3 inhibitors.

Association of initial response to prednisone treatment in childhood acute lymphoblastic leukaemia and polymorphisms within the tumour necrosis factor and the interleukin-10 genes

Plasma levels of TNF and IL-10 have been associated with therapy outcome in haematological malignancies and are influenced by genetic variation due to germline polymorphisms within the TNF and IL-10 genes. Different TNF and IL-10 genetic polymorphisms might therefore also correlate with clinical outcome in childhood acute lymphoblastic leukaemia (ALL). We analysed the association of TNF and IL-10 polymorphisms with response to initial treatment and risk of relapse in 135 children with ALL, treated according to Berlin-Frankfurt-Münster (BFM) protocols. Our data showed a protective effect from prednisone poor response in patients with the IL-10 G/G genotype, whereas no association of the risk of relapse and IL-10 genotype was found. In the total study group, subjects expressing the TNF2 allele neither showed a statistically significant general association with prednisone response nor with risk of relapse compared to subjects homozygous for the TNF1 allele. Nevertheless, we did find a higher risk of relapse in poor prednisone responders expressing the TNF2 allele compared to poor prednisone responders not expressing the TNF2 allele. We conclude that IL-10 genotype might influence prednisone response in patients with childhood ALL, whereas TNF genotype seems to influence the risk of relapse in high risk ALL patients.

Failure of a new protocol to improve treatment results in paediatric lymphoblastic leukaemia: lessons from the UK Medical Research Council trials UKALL X and UKALL XI

The impact of various types of intensification therapy was examined in a cohort of 3617 children aged 1-14 years with acute lymphoblastic leukaemia (ALL) enrolled in the Medical Research Council (MRC) UKALL X (1985-90) and UKALL XI (1990-97) trials. UKALL XI was modified in 1992 to incorporate the "best arm" of UKALL X with two 5-d intensification blocks at 5 and 20 weeks, and an additional randomization in respect of a third intensification at 35 weeks but omission of two consecutive injections of daunorubicin during induction. All children were eligible for randomization irrespective of risk group. The impact of the various types of intensification therapy was examined in a stratified analysis. At a median follow up of 102 months, both trials had an identical event-free survival of 61% (95% CI 58-63%) at 8 years. Survival at 8 years in UKALL XI was significantly better in than in UKALL X, 81% (79-83%) compared with 74% (72-76%) (P = < 0.001), owing to improved management of relapse. There was a highly significant trend in reduction of the number of relapses and deaths with increased intensity of therapy both for children with initial leucocyte count < 50 x 10(9)/l (P = < 0.001) and > or = 50 x 10(9)/l (P = 0.002). Introduction of a third late intensification block compensated for omission of anthracyclines during induction but produced little additional benefit. These results show, in a large cohort of patients, that minor modifications of therapy may influence relapse rate and obviate the benefit of previous randomized trials. The failure to adapt treatment for higher risk children contributed to these disappointing results.

Nucleoside analogues and nucleobases in cancer treatment

Cytotoxic nucleoside analogues and nucleobases were among the first chemotherapeutic agents to be introduced for the medical treatment of cancer. This family of compounds has grown to include a variety of purine and pyrimidine nucleoside derivatives with activity in both solid tumours and malignant disorders of the blood. These agents behave as antimetabolites, compete with physiological nucleosides, and interact with a large number of intracellular targets to induce cytotoxicity. Progress has recently been made in the identification and characterisation of nucleoside transporters and the enzymes of nucleoside metabolism. In addition, there is now greater understanding of the molecular mechanisms of anticancer nucleoside activity, which provides opportunities for potentiating their antitumour effects. Strategies to optimise intracellular analogue accumulation and to enhance cancer-cell selectivity are proving beneficial in clinical trials.

Leucemia linfóide aguda: uma doença curável

RESUMO: Leucemia linfóide Aguda (LLA), é o tipo mais comum de câncer infantil, constituindo cerca de um terço de todas as neoplasias malignas da criança. A incidência de LLA em crianças nos Estados Unidos é aproximadamente de 3,4 casos por 100.000 crianças menores de 15 anos de idade. Até a metade do século passado, as leucemias eram consideras universalmene, uma doença fatal. O desenvolvimento de combinações terapêuticas, utilizando diversas drogas citotóxicas com ou sem transplante de medula óssea, tem aumentado o percentual de cura da criança portadora de Leucemia linfóide Aguda em mais de 80%. Anualmente cerca de 1.500 crianças com LLA, nos Estados Unidos, estão sendo curadas. Contudo, dos 75.000 novos casos de LLA, que são diagnosticados anualmente em todo o mundo, cerca de 60.000 (80%) não têm acesso a essas modernas formas de tratamento e são, portanto excluídos desse processo de cura. O desafio de tornar a LLA uma doença curável começa a ser vencido com o relato de taxas de sobrevida maior que 50% para crianças tratadas em países com recursos limitados. Em El salvador, Bonilla, conseguiu aumentar a taxa de sobrevida de crianças com LLA de 5% para 50%. No Recife, Pernambuco, Brasil, Pedrosa evoluiu de uma taxa de 29% nos anos 80, para 75% na era atual.

Gene expression signatures define novel oncogenic pathways in T cell acute lymphoblastic leukemia

Human T cell leukemias can arise from oncogenes activated by specific chromosomal translocations involving the T cell receptor genes. Here we show that five different T cell oncogenes (HOX11, TAL1, LYL1, LMO1, and LMO2) are often aberrantly expressed in the absence of chromosomal abnormalities. Using oligonucleotide microarrays, we identified several gene expression signatures that were indicative of leukemic arrest at specific stages of normal thymocyte development: LYL1+ signature (pro-T), HOX11+ (early cortical thymocyte), and TAL1+ (late cortical thymocyte). Hierarchical clustering analysis of gene expression signatures grouped samples according to their shared oncogenic pathways and identified HOX11L2 activation as a novel event in T cell leukemogenesis. These findings have clinical importance, since HOX11 activation is significantly associated with a favorable prognosis, while expression of TAL1, LYL1, or, surprisingly, HOX11L2 confers a much worse response to treatment. Our results illustrate the power of gene expression profiles to elucidate transformation pathways relevant to human leukemia.

A randomised study of prophylactic G-CSF following MRC UKALL XI intensification regimen in childhood ALL and T-NHL

BACKGROUND

Despite the current widespread use of prophylactic G-CSF in children with solid tumours and leukaemia, its effectiveness has not been clearly demonstrated. This randomised study evaluates the role of G-CSF given after a 5-day intensification block in children with acute lymphoblastic leukaemia (ALL).

PROCEDURE

Forty-six children with ALL or T-Cell non-Hodgkins lymphoma (NHL) treated on MRC ALL 97, UKALL XI or UKCCSG 9504 NHL protocols were randomised to receive granulocyte colony-stimulating factor following either the first or the second block of intensive chemotherapy in a cross-over study to determine if the prophylactic administration of G-CSF could reduce the rate of readmission to hospital for management of febrile neutropenia.

RESULTS

There was a statistically significant difference in the rate of hospital admission in the group receiving prophylaxis, with 34 of 46 being admitted, compared to 42 of 46 patients in the control arm (74 vs. 91%; P=0.0386). There were no differences found in duration of hospital admission, haematological toxicity, neutrophil recovery or duration of supportive care between the two groups. There was no demonstrable cost benefit derived from the prophylactic administration of G-CSF.

CONCLUSIONS

This study shows that the prophylactic administration of G-CSF following intensification chemotherapy for childhood ALL and T-NHL produces a significant reduction in the rate of readmission to hospital for the management of febrile neutropenia.

Acute lymphoblastic leukemia

Acute leukemia is the most common childhood malignancy, representing 30% of all cancer in American children under the age of 15 years and 12% of cancer cases in those ages 15 to 19 years old. In the United States, approximately 2500 new cases are diagnosed annually; 80% of these are acute lymphoblastic leukemia, 15% are acute myelogenous leukemia, and 5% belong to the chronic leukemia category.(1) The survival rates of children with acute leukemia have increased dramatically in the last 40 years.(2-5) The most success in outcome has occurred in acute lymphoblastic leukemia, although improvement is also being reported in acute myelogenous leukemia in the past few years. Progress comes from treatment strategy modifications on the basis of observations made in sequential large-scale therapeutic trials, an approach that serves as a paradigm for research in other malignant diseases.

Consolidation therapy for childhood acute lymphoblastic leukaemia: clinical and cellular pharmacology of cytosine arabinoside, epipodophyllotoxins and cyclophosphamide

The intensification of post-remission induction therapy has been shown to improve the relapse-free survival for childhood acute lymphoblastic leukaemia (ALL), and is now a standard component of the treatment of childhood acute lymphoblastic leukaemia. For cytosine arabinoside (ara-C), methotrexate, vincristine and corticosteroids, in-vitro studies indicate that the extracellular drug concentration and exposure time are important determinants of cytotoxicity for human leukaemia cell lines. For L-asparaginase, epipodopyllotoxins and cyclophosphamide, there have been few studies of the relationship between cellular pharmacology and cytotoxicity in relation to ALL. The clinical and cellular pharmacology of methotrexate and cytosine arabinoside have been studied in relation to childhood ALL in vivo. For these drugs, there is evidence to suggest that maintenance of plasma concentrations that are biochemically optimal is necessary to maximize anti-leukaemic effects. For cytosine arabinoside in particular, optimal extracellular fluid concentrations are not likely to be achieved or maintained by bolus or short-duration i.v. infusions. A potentially important example of this may be served by the success of antimetabolite-based intrathecal chemotherapy for CNS-directed treatment of childhood ALL. Intrathecal administration of both methotrexate and cytosine arabinoside results in prolonged leukaemic cell exposure to cytotoxic concentrations of the drug. For vincristine, anthracyclines and asparaginase, the actual dose intensity received by children during consolidation therapy may be important, and there is considerable interpatient variation in the pharmacokinetics of cyclophosphamide and teniposide in the therapy of childhood cancers. The importance of this relationship to childhood ALL is not known. The pharmacological and cellular pharmacological studies performed at St Jude Children's Research Hospital (Memphis, TN, USA) have allowed investigation of the relationships between the clinical and cellular pharmacology of methotrexate and prognosis, and have supported the individualization of consolidation therapy with this drug. Cytosine arabinoside has been less well studied in relation to childhood ALL, although evidence exists to suggest that the administration of conventional-dose bolus or infusion schedules may not be optimal in terms of the antileukaemic efficacy of this antimetabolite. For L-asparaginase, ongoing studies may allow the relationship between dose and schedule of administration to be related to pharmacodynamic measures such as asparagine depletion and prognosis. Therefore, through knowledge of clinical and cellular pharmacological properties, it may be possible to optimize the consolidation phase of therapy for childhood ALL, without disrupting the fundamental principles by which the overall treatment is administered. This may be particularly important for children with disease that has inherent or acquired resistance to therapy.

Low relapse rate in children with acute lymphoblastic leukemia after risk-directed therapy

PURPOSE

Even though acute lymphoblastic leukemia (ALL) responds well to chemotherapy, relapse remains the major problem. This study documents relapse and survival rates in 85 consecutive children (33 at good risk, 52 at high risk) with ALL diagnosed in 1991 to 1996.

PATIENTS AND METHODS

Until 1993, the New York II protocol for the high-risk group and a combination of UKALL XI (induction) and R blocks of ALL-REZ BFM-87 (intensification) regimens for patients at good risk were used. To reduce toxicity, the protocols were subsequently modified. Consolidation treatment was the same for both groups, consisting of a lower cytarabine dose and methotrexate removal, whereas intensification was changed only for the high-risk group using the BB block of the NHL-BFM-90 protocol. The bone marrow clearance of leukemia was assessed on day 22, and minimal residual disease was detected using polymerase chain reaction analysis of Ig heavy-chain gene rearrangements.

RESULTS

Seventy patients had common precursor B lineage ALL, six had pre-B-ALL, eight had T-ALL, and one had B-ALL. Two patients never achieved remission and died. Six patients died of consolidation-related complications. Four more patients died, two during induction and two during maintenance therapy. Two other children had relapse (2.3%), both of whom were treated with the earlier protocols and then underwent bone marrow transplantation. Four more children with morphologically complete remission showed minimal residual disease (which reached the levels of 1 leukemic cell among 10(2)-10(4) normal cells) with the use of clone-specific probes at several points of the study intervals, but never had relapse. The 5-year overall and event-free survival rates were 86% and 83%, respectively. The 5-year overall survival rates for good-risk and high-risk groups were 94% and 81%; the corresponding event-free rates were 91% and 78%. The 5-year event-free survival rate in the patients at high risk was significantly higher after the protocol change (90% vs. 65%, P = 0.04).

CONCLUSIONS

The modification proved to be effective in diminishing the therapeutic toxicity and improving the efficacy, mainly for the high-risk group.

Continuing therapy for childhood acute lymphoblastic leukaemia: clinical and cellular pharmacology of methotrexate, 6-mercaptopurine and 6-thioguanine

Across the world, therapy with 6-mercaptopurine (6-MP) and methotrexate (MTX) forms the basis of the continuing therapy of childhood acute lymphoblastic leukaemia (ALL). In this review, the pharmacological determinants of the sensitivity of human leukaemia cell lines and lymphoblasts derived from children with ALL will be discussed. In addition, clinical pharmacological studies of 6-MP and MTX in relation to the continuing therapy with childhood ALL will be reviewed. For 6-MP in vitro, prolonged exposure times to relatively high extracellular drug concentrations are necessary for cytotoxicity, and these concentrations are much higher than those achieved during continuing therapy for childhood ALL. For MTX, plasma concentrations are achieved during continuing therapy that would be cytotoxic to human leukaemia cells during prolonged exposures in vitro. For both MTX and 6-MP, wide inter- and intrapatient variation in plasma pharmacokinetic parameters has been described. For 6-MP and MTX, cellular pharmacological studies have been largely restricted to erythrocytes as a surrogate of the possible effects in leukaemic blasts. Although measures of the pharmacology of 6-MP and MTX in erythrocytes has been related to prognosis in many studies, 6-MP systemic exposure and the dose intensity of 6-MP and MTX actually received by children during this phase of therapy seems to be the most important determinant of efficacy. Further studies will be needed to determine the importance of pharmacokinetic variability during continuing therapy as a determinant of outcome for children with ALL. In this respect, minimal residual disease status during this phase of treatment may prove to be a useful pharmacodynamic endpoint.

Remission induction therapy for childhood acute lymphoblastic leukaemia: clinical and cellular pharmacology of vincristine, corticosteroids, L-asparaginase and anthracyclines

Remission induction therapy with vincristine, a corticosteroid, L-asparaginase and an anthracycline has been the mainstay of the initial phase of treatment for childhood acute lymphoblastic leukaemia (ALL) for the past 25 years. The speed and depth of the early response to remission induction therapy has become an important determinant of the intensity of subsequent therapy in many protocols worldwide. Moreover, the detection of significant levels of minimal residual disease at the end of remission induction may have an important bearing on subsequent outcome. Although these clinical observations may reflect, in part, the inherent sensitivity of lymphoblasts to remission induction therapy, the pharmacology of these agents in relation to childhood ALL may also play an important part in early response to therapy. In-vitro studies of human leukaemia cell lines indicate that both the extracellular fluid concentration and duration of exposure to vincristine and anthracyclines are important determinants of cytotoxicity. For L-asparaginase and corticosteroids, the cellular and molecular pharmacological determinants of chemosensitivity have been partially characterized, but further work is needed in this area. The clinical pharmacology of vincristine and L-asparaginase have been well characterized in relation to childhood ALL, and considerable interpatient pharmacokinetic variability exists for these drugs. For corticosteroids and anthracyclines, pharmacology studies are needed in order to fully characterize and understand the factors influencing interpatient pharmacokinetic variability for these agents in relation to childhood ALL. Whereas the relationship between the clinical pharmacology, and potentially important pharmacodynamic effects such as asparagine depletion, has been well characterized for therapy with L-asparaginase, similar studies have yet to be performed for the other drugs that form the mainstay of remission induction therapy for childhood ALL. Therefore, further studies are required to investigate the relative importance of the clinical and cellular pharmacology of vincristine, corticosteroids, L-asparaginase and anthracyclines in the speed and depth of response to remission induction therapy for childhood ALL. Where these have been studied, interindividual differences in the clinical and cellular pharmacology of anticancer agents have been shown to be important determinants of the long-term disease-free survival for children with ALL.

Initial bone marrow aspiration in childhood idiopathic thrombocytopenia: decision analysis

PURPOSE

Bone marrow aspiration (BMA) is routinely performed before starting steroid therapy in children with idiopathic thrombocytopenia, primarily to rule out leukemia.

METHODS

A decision tree for the initial management of a child older than age 6 months, presenting with idiopathic thrombocytopenia, without blasts on the peripheral smear was constructed. The three strategies are: 1) initial BMA in all patients; 2) initial BMA only in patients at high risk; and 3) empiric therapy for all patients without initial BMA. High-risk criteria include any of: platelet count >50 x 10(9)/L; hemoglobin <100 g/L (age younger than 12 months) or <110 g/L (age older than 12 months): white blood cell count <5 x 10(9)/L (younger than 6 years) or <4 x 10(9)/L (older than 6 years); or absolute neutrophil count <1.5 x 10(9)/L (younger than 6 years) or <2 x 10(9)/L (older than 6 years). The results are expressed as quality-adjusted life years (QALYs), a measure that estimates the overall life expectancy in years for patients receiving a particular treatment strategy, corrected for the patient's quality of life.

RESULTS

The base case results are: 1) BMA all = 69.649 QALYs; 2) high-risk BMA = 69.652 QALYs; and 3) empiric therapy = 69.644 QALYs. These results indicate a three-way toss-up because there is less than a 4-day quality-adjusted difference (0.01) between strategies.

CONCLUSION

This study indicates that the initial BMA does not significantly change the overall QALYs of a child presenting with thrombocytopenia and, consequently, is not mandatory in every patient before starting steroids.

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.

Early response to chemotherapy as a prognostic factor in childhood acute lymphoblastic leukaemia: a methodological review

Published studies of the prognostic value of the early response to induction treatment in childhood acute lymphoblastic leukaemia (ALL) were analysed. Three criteria were used to judge the early treatment response: persistence of peripheral blasts (PPB) or of bone marrow blasts (PBMB) during induction therapy and minimal residual disease (MRD) after completion of induction therapy. Studies with more than 50 patients, published between 1980 and 2000, were reviewed. Among 13 659 distinct articles published on ALL, we identified only 43 applicable studies. Within- and between-laboratory variations were evaluated in only one study. Treatment modalities differed among, and sometimes within, studies. The cut-off points used in the statistical analyses were never discussed, and in many studies appeared to be selected after multiple tests. The proportion of missing data was > 30% in almost all studies of MRD, as a result of technical difficulties and not missing samples. PPB and PBMB were associated with shorter survival in, respectively, 13 out of 14 and 15 out of 16 studies. Detection of MRD was associated with poor outcome in 12 of the 13 studies. Because none of the parameters used to measure the early response to induction therapy for childhood ALL have been properly assessed as prognostic factors, we conclude that they should be considered only as candidate prognostic indicators pending more thorough studies.

The success of paediatric oncological research

The current health service climate has focussed attention on the lack of a solid evidence base for much accepted practice in medicine. Paediatric oncology is more fortunate than most specialties in being able to draw on an evidence base for much of its practice. The speciality has benefitted from a history of robust randomized trials, which also serve as the basis for future improvements.

Adverse metabolic and cardiovascular risk following treatment of acute lymphoblastic leukaemia in childhood; two case reports and a literature review

We report two patients who survived childhood acute lymphoblastic leukaemia (ALL) following treatment with chemotherapy, total body irradiation (TBI) and bone marrow transplantation (BMT). The first case presented with an acute cerebral infarction at 23 years of age and was found to have non-ketotic diabetes and gross mixed hyperlipidaemia; the second presented with non-ketotic diabetes, hypertension, proteinuria and dyslipidaemia at age 16 years. The association of glucose intolerance with other vascular risk factors in young adult survivors of BMT was recently highlighted in a follow-up study of 23 survivors of BMT [1], but none presented with such gross mixed hyperlipidaemia. The improving survival rates of childhood malignancy over the last two decades will present adult physicians with patients who have accelerated vascular risk at a young age who will require early treatment to modify it.

Intensification of chemotherapy using block therapies as consolidation and reinduction therapies for acute lymphoblastic leukemia during childhood

Between April 1994 and March 1997, 143 children (age range, 1-15 years) with newly diagnosed acute lymphoblastic leukemia (ALL), except for those patients with t(9;22), were treated according to protocol-94 of the Osaka Childhood Leukemia Study Group. In this trial, the intensity of chemotherapy was enforced in the consolidation and reinduction phases by introducing AML-type block therapies consisting of concentrated administration of 4 to 6 drugs during 5 or 6 days. For patients in the higher risk groups, rotational combination chemotherapy was introduced following the early phase. A total of 124 children with B-cell precursor ALL (B-pre ALL) were classified into 3 groups, the ultrahigh-risk group (UHRG) (15 patients), the high-risk group (HRG) (61 patients), or the standard-risk group (SRG) (48 patients), based on age. leukocyte count, immunophenotype, central nervous system leukemia, response to treatment, and selected chromosomal abnormalities. The complete remission rate was 93%, and the 6-year event-free survival (EFS) rate was 79%+/-4%. EFS rates for the UHRG, HRG, and SRG groups were 67%+/-12%, 80%+/-6%, and 81%+/-6%, respectively. Nineteen patients with T-cell ALL were treated with the protocol for the UHRG. Thirteen patients (68%) attained complete remission, and the 6-year EFS rate was 55%+/-12%. Thus, intensification of chemotherapy improved the EFS rate and AML-type block therapies appeared to be effective as the consolidation and reinduction therapies for B-pre ALL.

No disadvantage in outcome of using matched unrelated donors as compared with matched sibling donors for bone marrow transplantation in children with acute lymphoblastic leukemia in second remission

PURPOSE

We evaluated the outcome of children with acute lymphoblastic leukemia (ALL) in second remission (2CR), comparing bone marrow transplantation (BMT) using either matched sibling donors or unrelated donors (URDs).

PATIENTS AND METHODS

A total of 65 patients, aged 2 months to 20 years at BMT, with ALL in 2CR underwent allogeneic BMT at seven Nordic centers during 1990 to 1997. Of the first relapses, 85% were in bone marrow; 46% occurred on therapy, and 54%, off therapy. The preparative regimens were cyclophosphamide plus total-body irradiation +/- antithymocyte/antilymphocyte globulin, busulfan plus cyclophosphamide +/- antithymocyte/antilymphocyte globulin, or cytarabine plus total-body irradiation. Of the allografts, 37 were from HLA-matched siblings and 28 were from URDs.

RESULTS

In the sibling versus URD graft recipient groups, the posttransplantation 5-year event-free survival was 39% versus 54% (P =.4), the estimated posttransplantation relapse rate was 76% versus 40% (P = not significant [NS]), and the toxic death rate was 19% versus 11% (P = NS). The incidence of significant (grade 2 to 4) acute graft-versus-host disease (GVHD) was 38% versus 64% (P <.05) and was 14% versus 32% (P <.10) for severe (grade 3 to 4) acute GVHD; the incidence of chronic GVHD was 26% versus 57% (P <.05) and was 13% versus 22% (P = NS) for extensive chronic GVHD in the sibling and URD groups.

CONCLUSION

BMT with matched URD allografts offers at least equal survival for children with ALL in 2CR, as compared with allografts from matched sibling donors. URD allografts were not associated with a higher toxic mortality rate, although both acute and chronic GVHD were more frequent with URD. Indications for using matched URD allografts in ALL 2CR can be considered the same as for using matched sibling donors.

Outcome of acute lymphoblastic leukemia in children with AL90 regimen: impact of response to treatment and sex difference on prognostic factors

BACKGROUND

In our previous studies, the outcome of high-risk ALL was still poor. In the present study, all children with ALL were classified into three groups and treated with a new regimen (AL90).

PATIENTS AND METHODS

Between 1990 and 1996, 220 children with ALL, treated with the AL90 regimen, were classified into three risk groups: low, intermediate, and high: LR, IR, and HR, respectively. The protocol consisted of three- to five-drug induction, consolidation with intermediate-dose methotrexate and/or cytarabine, mercaptopurine and cyclophosphamide, four-drug intensification, and sequential maintenance therapies. Only intrathecal chemotherapy was used for CNS prophylaxis in the LR group, whereas cranial irradiation was added for the IR and HR groups.

RESULTS

The number of eligible patients was 91: LR group, 71: IR group, and 58: HR group. Complete remission (CR) was obtained in > 98% of the LR and IR groups, while only 88% achieved CR in the HR group. The 5-year event-free survival (EFS) rate was 67.4% in all patients: 70.4% in the LR group, 71.7% in the IR group, and 57.5% in the HR group. With respect to the previous study, EFS in the HR group who showed positive residual leukemia at 14 days was improved, whereas EFS in boys versus girls was significantly lower (48.8% : 85.7%, P = 0.02).

CONCLUSIONS

In high-risk ALL, the rate of induction failure was high and boys had a worse outcome, calling for improvements in induction therapy and a specific approach for boys.

A comparison of early intensive methotrexate/mercaptopurine with early intensive alternating combination chemotherapy for high-risk B-precursor acute lymphoblastic leukemia: a Pediatric Oncology Group phase III randomized trial

A prospective, randomized multicenter study was performed to evaluate the relative efficacy of two different concepts for early intensive therapy in a randomized trial of children with B-precursor acute lymphoblastic leukemia (ALL) at high risk (HR) for relapse. Four hundred and ninety eligible children with HR-ALL were randomized on the Pediatric Oncology Group (POG) 9006 phase III trial between 7 January 1991 and 12 January 1994. After prednisone (PDN), vincristine (VCR), asparaginase (ASP) and daunorubicin (DNR) induction, 470 patients received either 12 intensive parenteral treatments of intermediate dose (1 g/m2 each) methotrexate (MTX) and mercaptopurine (MP) over 24 weeks (regimen A) or 12 intensive course of alternating myelosuppressive drug combinations given over 30 weeks (regimen B). These drug combinations included MTX/MP, teniposide (VM-26)/cytosine arabinoside (AC) and VCR/PDN/DNR/AC/ASP. Central nervous system (CNS) prophylaxis was age-adjusted triple intrathecal chemotherapy. Patients with CNS disease at diagnosis were treated with craniospinal irradiation after the intensive phase. Continuation was standard doses of MTX and MP for 2 years. This trial was closed early because of an apparent early difference favoring regimen B. Results show that 470 patients achieved remission (97%). Two hundred and thirty two were randomized to regimen A and 238 to regimen B. The estimated 4-year event-free survival (EFS) for patients treated with regimen A is 61.6 % (s.e. = 3.3%) and with regimen B is 69.4% (s.e. = 3.1%), P = 0.091. Toxicities were more frequent on regimen B. In conclusion, for children with B-precursor ALL at high risk to relapse, early intensification with myelosuppressive combination chemotherapy was more toxic but produced no significant difference in EFS when compared to those treated with parenteral methotrexate and mercaptopurine.

Determinants of outcome after intensified therapy of childhood lymphoblastic leukaemia: results from Medical Research Council United Kingdom acute lymphoblastic leukaemia XI protocol

The single most important prognostic determinant in childhood acute lymphoblastic leukaemia (ALL) is effective therapy and changes in therapy may influence the significance of other risk factors. The effect of intensified therapy on the importance of currently recognized phenotypic and genotypic determinants of outcome was assessed in 2090 children enrolled on the Medical Research Council United Kingdom acute lymphoblastic leukaemia XI (MRC UKALL XI) protocol. Treatment allocation was not determined by risk factors. Multivariate analysis confirmed the dominant influence on prognosis of age, sex and presenting white cell count (WCC). After allowing for these features, blast karyotype, d 8 marrow blast percentage and remission status at the end of induction therapy were the only remaining significant predictors of outcome. Organomegaly, haemoglobin concentration, French--American--British type, body mass index, presence of central nervous system disease at diagnosis, immunophenotype and presence of TEL/AML1 fusion gene (examined in a subset of 659 patients) either had no significant effect on outcome or were significant only in univariate analysis. Among karyotype abnormalities with an independent influence on prognosis, high hyperdiploidy (> 50 chromosomes) was shown to be favourable, whereas near haploidy (23--29 chromosomes), presence of the Philadelphia chromosome, t(4;11) and abnormalities affecting the short arm of chromosome 9 [abn (9p)] were adverse risk factors. Early responders to therapy, determined by residual marrow infiltration after 8 d of induction therapy, had a good outcome, while the small proportion of patients who did not achieve a complete remission by the end of induction therapy had a poor outcome. A third block of late intensification was shown to improve event-free survival by 8% at 5 years. The effect of these risk factors was not significantly different between those randomized to the third intensification block and those not randomized to a third block.

Long-term outcome of treatment with protocols AL841, AL851, and ALHR88 in children with acute lymphoblastic leukemia: results obtained by the Kyushu-Yamaguchi Children's Cancer Study Group

We analyzed the long-term outcome and late effects of treatment in 187 patients with childhood acute lymphoblastic leukemia (ALL) diagnosed between 1984 and 1990. Overall survival and event-free survival rates were 68.2% +/- 3.7% and 63.2% +/- 3.6% at 15 years, respectively. Of 55 patients who relapsed after achieving the first complete remission (CR), only 17.4% were rescued by salvage therapy. The advantage of stem cell transplantation over chemotherapy was observed only in those patients with bone marrow relapse during therapy. The SD for score height in patients maintaining the first CR significantly decreased at the time of final follow-up compared with that at diagnosis: 0.059 to -0.800 (P < .0001). The decrease was remarkable in patients younger than 5 years at diagnosis. Other late effects included mild liver dysfunction in 18% and hepatitis C virus infection in 9%. Congestive heart failure was observed in only 2.9% of patients despite the high cumulative dose of daunorubicin (450 mg/m2). Although the survival rates of patients on our protocols were comparable to those of other study groups, some modification, including reduction in dose of cranial irradiation and/or anticancer drugs, should be considered to reduce late adverse effects in survivors of childhood ALL.

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.

Topoisomerase II alpha and II beta expression in childhood acute lymphoblastic leukaemia: relation to prognostic factors and clinical outcome

BACKGROUND/AIMS

Many regimens used in the treatment of childhood acute lymphoblastic leukaemia (ALL) include Daunorubicin or Etoposide, which act as topoisomerase poisons. It has been suggested that there may be a relation between topoisomerase expression and response to topoisomerase poisons, based mainly on results from in vitro studies. Therefore, the aim of this study was to investigate this relation in a clinical setting and determine whether topoisomerase II alpha and II beta might be of predictive value in ALL.

METHODS

Cellular expression of topoisomerases II alpha and II beta was assessed in 177 cases of ALL by immunohistochemistry using monoclonal antibodies to the two enzymes. The percentages of cell nuclei showing positive staining for topoisomerase II alpha and II beta expression were assessed.

RESULTS

Taking the series as a whole, a clear separation of survival curves was seen with the established prognostic markers white blood cell (WBC) count, CD10 status, and sex. However, topoisomerase II alpha and II beta expression showed no relation to survival. No association was found between the topoisomerases and the prognostic markers CD10 and WBC count; however, topoisomerase II alpha expression was found to be related to sex, with expression being lower in girls (p = 0.002).

CONCLUSIONS

These results suggest that the response to topoisomerase poisons cannot be predicted by the assessment of topoisomerase II alpha and II beta expression as defined by immunohistochemistry.

Long-term results of four consecutive trials in childhood ALL performed by the ALL-BFM study group from 1981 to 1995. Berlin-Frankfurt-Münster

Four thousand, four hundred and forty eligible children of up to 18 years of age were treated in four consecutive trials between 1981 and 1995 with the treatment protocols of the Berlin-Frankfurt-Münster (BFM) study group for childhood acute lymphoblastic leukemia (ALL). The probability for event-free survival (pEFS) at 8 years improved from 65.8% in study ALL-BFM 81 to 75.9% in study ALL-BFM 90. The cumulative incidence of recurrences with CNS involvement was 10.1% and 9.3% in studies ALL-BFM 81 and 83, but was reduced to less than 5% in study ALL-BFM 90 (for isolated CNS relapses from 5.3% in study ALL-BFM 81 to 1.1% in study ALL-BFM 90). Four major findings were derived from this series of trials performed by 37 to 96 centers in Germany, Austria, and Switzerland: (1) Reintensification is a crucial part of treatment, even in low risk patients; (2) presymptomatic cranial radiotherapy can be safely reduced to 12 Gy, or even be eliminated if it is replaced by early intensive systemic and intrathecal methotrexate applied; (3) maintenance therapy given a total of 24 months from diagnosis provides a lower rate of systemic relapses than treatment for 18 months; (4) inadequate response to an initial 7-day prednisone window (combined with one intrathecal injection of methotrexate on day 1) defines about 10% of the patients with a very high risk of relapse. For patients with adequate early response (90% of all) an 8-year pEFS of 80% has been achieved in the most recent trial ALL-BFM 90. While it has proven so far to be impossible to improve the outcome for the small group of high risk patients, the number of recurrences could be effectively reduced for the large group of patients responding adequately to the prednisone in vivo sensitivity test. Apart from inadequate prednisone response, patients with hyperleukocytosis, age <1 year, or the presence of the Philadelphia-chromosome (Ph+ ALL) are at a particularly high risk of failure.

Prognostic study of continuous variables (white blood cell count, peripheral blast cell count, haemoglobin level, platelet count and age) in childhood acute lymphoblastic leukaemia. Analysis Of a population of 1545 children treated by the French Acute Lymphoblastic Leukaemia Group (FRALLE)

Many cutpoints have been proposed to categorize continuous variables in childhood acute lymphoblastic leukaemia (white blood cell count, peripheral blast cell count, haemoglobin level, platelet count and age), and have been used to define therapeutic subgroups. This variation in the choice of cutpoints leads to a bias called the 'Will Rogers phenomenon'. The aim of this study was to analyse variations in the relative risk of relapse or death as a function of continuous prognostic variables in childhood ALL and to discuss the choice of cutpoints. We studied a population of 1545 children with ALL enrolled in three consecutive protocols named FRALLE 83, FRALLE 87 and FRALLE 89. We estimated the risk of relapse or death associated with different values of each continuous prognostic variable by dividing the sample into quintiles of the distribution of the variables. As regards age, a category of children under 1 year of age was distinguished and the rest of the population was divided into quintiles. The floated variance method was used to calculate the confidence interval of each relative risk, including the reference category. The relation between the quantitative prognostic factors and the risk was monotonic for each variable, except for age. For the white blood cell count (WBC), the relation is log linear. The risk associated with WBC values in the upper quintile was 1.9 times higher than that in the lower quintile. The peripheral blast cell count correlated strongly with WBC (correlation coefficient: 0.99). The risk increased with the haemoglobin level, and the risk in the upper quintile was 1.3 times higher than that in the lower quintile. The risk decreased as the platelet count increased: the risk in the lower quintile was 1.2 times higher than that in the upper quintile. The risk increased gradually with increasing age above one year. The small subgroup of patients (2.5% of the population) under 1 year of age at diagnosis had a risk 2.6 times higher than the reference category of patients between 3 and 4.3 years of age. When the risk associated with a quantitative prognostic factor varies monotonously, the selection of a cutpoint is arbitrary and represents a loss of information. Despite this loss of information, such arbitrary categorization may be necessary to define therapeutic stratification. In that case, consensus cutpoints must be defined if one wants to avoid the Will Rogers phenomenon. The cutpoints proposed by the Rome workshop and the NCI are arbitrary, but may represent an acceptable convention.

Long-term follow-up of the United Kingdom Medical Research Council protocols for childhood acute lymphoblastic leukaemia, 1980-1997. Medical Research Council Childhood Leukaemia Working Party

Results of three consecutive completed UK trials (1980-1997) for childhood lymphoblastic leukaemia are presented. National accrual has progressively increased so that over 90% of all the country's ALL cases were treated on the latest trial reported, UKALLXI. From 1980 to 1990, event-free and overall survival progressively improved, following adoption of an American therapy template and use of two post-remission intensification modules. Since 1990 despite demonstration of the benefit of a third intensification module overall event-free survival (EFS) has not improved further. Survival remains high due to a good retrieval rate especially for those relapsing off treatment after receipt of two intensification pulses. Possible reasons for the plateau in event-free survival (including type and dose of induction steroid, dropping of induction anthracycline, type and dose of asparaginase, gaps early in therapy following intensification, and overall lack of compliance in maintenance) are being explored in the latest protocol ALL '97. Cranial irradiation had been successfully replaced by a long course of intrathecal methotrexate injections for the majority of patients. Age (<1 year >10 years) sex (male) and white count >50 x 10(9)/l plus slow initial bone marrow clearance were consistently the most important independent prognostic indicators during this time period. Rome/NCI criteria accurately predict standard and high-risk groups for B cell lineage, but not consistently for T cell disease. This international collaborative venture might help us to define those truly at highest risk, and how we can optimise therapy for specific subgroups including T-ALL and those with unfavourable cytogenetics.

Bone marrow transplantation versus chemotherapy in the treatment of very high–risk childhood acute lymphoblastic leukemia in first remission: results from Medical Research Council UKALL X and XI

The role of bone marrow transplantation (BMT) in first remission of children with high-risk acute lymphoblastic leukemia (ALL) remains unclear. There were 3676 patients (aged 1 to 15 years) entered into the United Kingdom (UK) Medical Research Council (MRC) trials UKALL X and XI from 1985 to 1997. Of these patients, 473 patients (13%) were classified as very high (VH) risk and were eligible for a transplantation from a matched histocompatible sibling donor (MSD). We tissue-typed 286 patients; 99 patients had a matched related donor, and 76 patients received transplantations. Additionally, 25 children received transplantations from a matched unrelated donor (MUD) despite trial guidelines for MSD transplantations only. The median time to transplantation was 5 months (range, 2 to 19 months), and the median follow-up was 8 years. The 10-year event-free survival (EFS) adjusted for the time to transplantation, diagnostic white blood cell (WBC) count, Ph chromosome status, and ploidy was 6.0% higher (95% confidence interval (CI), −10.5% to 22.5%) for 101 patients who received a first-remission transplantation (MSD and MUD) than for the 351 patients treated with chemotherapy (transplantation, 45.3%, vs chemotherapy, 39.3%). The transplantation group had fewer relapses (31%) compared to relapses in the chemotherapy group (55%); however, the transplantation group had more remission deaths (18%) compared to remission deaths in the chemotherapy group (3%). In contrast the adjusted 10-year EFS was 10.7% higher (95% CI, −2.6% to 24.0%) for patients without a human leukocyte antigen (HLA)–matched donor than for those patients with a donor (no donor, 50.4%, vs donor, 39.7%). In conclusion, for the majority of children with VH-risk ALL, the first-remission transplantation has not improved EFS.

Bone marrow transplantation versus chemotherapy in the treatment of very high–risk childhood acute lymphoblastic leukemia in first remission: results from Medical Research Council UKALL X and XI

The role of bone marrow transplantation (BMT) in first remission of children with high-risk acute lymphoblastic leukemia (ALL) remains unclear. There were 3676 patients (aged 1 to 15 years) entered into the United Kingdom (UK) Medical Research Council (MRC) trials UKALL X and XI from 1985 to 1997. Of these patients, 473 patients (13%) were classified as very high (VH) risk and were eligible for a transplantation from a matched histocompatible sibling donor (MSD). We tissue-typed 286 patients; 99 patients had a matched related donor, and 76 patients received transplantations. Additionally, 25 children received transplantations from a matched unrelated donor (MUD) despite trial guidelines for MSD transplantations only. The median time to transplantation was 5 months (range, 2 to 19 months), and the median follow-up was 8 years. The 10-year event-free survival (EFS) adjusted for the time to transplantation, diagnostic white blood cell (WBC) count, Ph chromosome status, and ploidy was 6.0% higher (95% confidence interval (CI), −10.5% to 22.5%) for 101 patients who received a first-remission transplantation (MSD and MUD) than for the 351 patients treated with chemotherapy (transplantation, 45.3%, vs chemotherapy, 39.3%). The transplantation group had fewer relapses (31%) compared to relapses in the chemotherapy group (55%); however, the transplantation group had more remission deaths (18%) compared to remission deaths in the chemotherapy group (3%). In contrast the adjusted 10-year EFS was 10.7% higher (95% CI, −2.6% to 24.0%) for patients without a human leukocyte antigen (HLA)–matched donor than for those patients with a donor (no donor, 50.4%, vs donor, 39.7%). In conclusion, for the majority of children with VH-risk ALL, the first-remission transplantation has not improved EFS.

Treatment of children with early pre-B and pre-B acute lymphocytic leukemia with antimetabolite-based intensification regimens: a Pediatric Oncology Group Study

Between May 1987 and January 1991, 1354 patients, 1-21 years old, with standard or poor prognosis B-lineage acute lymphocytic leukemia were treated on the Pediatric Oncology Group Study 8602. One thousand three hundred and twenty-three patients entered remission and 1051 patients were randomized on day 43 to an intensification regimen containing L-asparaginase and intermediate-dose methotrexate (regimen B) or cytarabine and intermediate dose methotrexate (regimen C). After completion of intensification at week 25, all patients received the same maintenance therapy until 3 years from diagnosis. Overall 5-year continuous complete remission (CCR) for regimen B was 72+/-2% (s.e.) and for regimen C, 73+/-2% (P = 0.72 by log-rank analysis). Significant differences between treatments for CCR, testicular, CNS relapses overall or with regard to phenotype (pre-B vs early pre-B), gender, or race were not detected. During intensification, regimen C had significantly more bacterial infections (P = 0.05) and days spent in the hospital (P < 0.001) compared with regimen B, while regimen B had significantly more allergic reactions (P < 0.0001). No significant differences in CCR were noted between patients with pre-B and early pre-B ALL (P = 0.22 stratified by risk group and treatment). This study was unable to detect statistical difference between asparaginase (regimen B) and cytarabine (regimen C) during the intensification phase of therapy in children with B-lineage acute lymphocytic leukemia.

Comparison of allogeneic transplant versus chemotherapy for relapsed childhood acute lymphoblastic leukaemia in the MRC UKALL R1 trial. MRC Childhood Leukaemia Working Party

BACKGROUND

Although reinduction rates are good for children with relapsed acute lymphoblastic leukaemia there is no consensus on whether bone marrow transplantation (BMT) is the most effective treatment to prolong second remission.

PATIENTS AND METHODS

Analyses comparing the outcome of related donor allogeneic BMT (related allograft) with chemotherapy are unreliable because of selection biases. To avoid these biases, the MRC UKALL R1 trial was analysed by HLA-matched donor availability.

RESULTS

No significant difference in outcome was found between the donor and no donor groups. The donor group had a non-significant eight-year event-free survival (EFS) advantage of 8%, (95% confidence interval -9%-24%) over the no donor group. Patients with a first remission less than two years appeared to benefit most from having a donor, although the effect was only marginally significantly different from patients with longer first remission. Analysis by treatment received gave similar results, with BMT patients having a 5% (P = 0.8) eight-year EFS advantage over patients who received chemotherapy.

CONCLUSIONS

Related allograft was not found to be significantly better than chemotherapy, but there was the possibility of a moderate EFS benefit with related allograft. especially in patients with a short first remission.

Recent advances in management of acute leukaemia

There have been significant improvements in the outlook for children with acute leukaemia but these advances are only available to a minority of the world's children. There is still room for improvements in conventional chemotherapy and these need evaluation in randomised trials. The role of bone marrow transplants in first remission is evolving as chemotherapy becomes more effective. New treatments are needed for relapsed patients. Molecular diagnosis has refined the assessment of prognosis but the extra value afforded by measurement of minimal residual disease is not clear. International collaboration is needed to evaluate treatment for rare subtypes of leukaemia.