Long-term results of the Italian Association of Pediatric Hematology and Oncology (AIEOP) acute lymphoblastic leukemia studies, 1982-1995

Secondary cytogenetic aberrations in childhood Philadelphia chromosome positive acute lymphoblastic leukemia are nonrandom and may be associated with outcome

Additional chromosomal aberrations occur frequently in Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) of childhood. The treatment outcome of these patients is heterogeneous. This study assessed whether such clinical heterogeneity could be partially explained by the presence and characteristics of additional chromosomal abnormalities. Cytogenetic descriptions were available for 249 of 326 children with Ph+ ALL, diagnosed and treated by 10 different study groups/large single institutions from 1986 to 1996. Secondary aberrations were present in 61% of the cases. Chromosomes 9, 22, 7, 14, and 8 were most frequently abnormal. Most (93%) karyotypes were unbalanced. Three main cytogenetic subgroups were identified: no secondary aberrations, gain of a second Ph and/or >50 chromosomes, or loss of chromosome 7, 7p, and/or 9p, while other secondary aberrations were grouped as combinations of gain and loss or others. Of the three main cytogenetic subgroups, the loss group had the worst event-free survival (P=0.124) and disease-free survival (P=0.013). However, statistical significance was not maintained when adjusted for other prognostic factors and treatment. Karyotypic analysis is valuable in subsets of patients identified by molecular screening, to assess the role of additional chromosomal abnormalities and their correlation with clinical heterogeneity, with possible therapeutic implications.

Prognosis in childhood and adult acute lymphoblastic leukaemia: a question of maturation?

Acute lymphoblastic leukaemia (ALL) is a disease diagnosed in children as well as adults. Progress in the treatment of ALL has led to better survival rates, however, children have benefited more from improved treatment modalities than adults. Recent evidence has underscored that the difference in characteristics and biology of adult versus childhood ALL might be the result of a different origin. According to the two-hit paradigm of Knudson, to develop cancer two genetic events are necessary. It has been suggested, that in childhood ALL the first genetic event happens in the more mature lymphoid committed progenitor cells, whereas in adult ALL the first hit occurs in multipotent stem cells. This review compares patient characteristics, the extent of the disease, leukaemic cell characteristics and treatment between childhood and adult ALL. This is discussed in relation to the hypothesis that the maturation stage of the cells, from which the leukaemia arises, is responsible for the differential behaviour of adult and childhood ALL.

Death during induction therapy and first remission of acute leukemia in childhood

BACKGROUND

Despite improvements in supportive care, death due to treatment toxicity remains a significant problem for children treated for acute leukemia.

METHODS

To determine the causes of and risk factors for death unrelated to refractory leukemia, to disease recurrence, or to second malignancy, the authors reviewed the records of 1011 patients with acute lymphoblastic leukemia (ALL) and 260 patients with acute myeloid leukemia (AML) treated between 1984 and 1999 and between 1983 and 2002, respectively, at St. Jude Children's Research Hospital (Memphis, TN). Data for patients who underwent stem cell transplantation were censored at the time of transplantation.

RESULTS

For patients with ALL, the estimated 10-year cumulative incidence of death was 2.9% +/- 5.3%. Age was the only predictor of death. Patients with ALL 1-9 years old had a significantly lower risk of death than did younger or older patients (P = 0.002). For patients with AML, the estimated 5-year cumulative incidence of death was 7.6% +/- 1.9%. Increasing age and increasing leukocyte count were significantly associated with increased risk of death. For patients with ALL and with AML, the incidence of death remained relatively constant during the time periods studied. Infection was the most common cause of death.

CONCLUSIONS

In the current study, the authors determined that children > or = 10 years of age are at increased risk of death during therapy for ALL and AML.

Outcome of children with high-risk acute lymphoblastic leukemia (HR-ALL): Nordic results on an intensive regimen with restricted central nervous system irradiation

BACKGROUND

Improvement in outcome of childhood high-risk (HR) ALL was sought with a very intensive Nordic protocol leaving most patients without CNS-RT.

METHODS

A total of 426 consecutive children entered the NOPHO-92 HR-ALL program. HR criteria included WBC > or =50 x 10(9)/L, CNS or testicular involvement, T-cell, lymphomatous features, t(9;22), t(4;11), or slow response. Of these, 152 children had very high risk (VHR) with special definitions. CNS consolidation was based on high-dose MTX (8 g/m2) and ARA-C (12 g/m2) alternating. VHR patients also received cranial RT.

RESULTS

The 9-year EFS was 61 +/- 3%, OS 74 +/- 2%, and EFS for T-ALL 62 +/- 4%. Cumulative incidence of isolated CNS relapse was 4.7 +/- 1%, and CNS relapse in total 9.9 +/- 2%. Poor prognostic factors were WBC > or =200 x 10(9)/L and a very slow response.

CONCLUSIONS

HR-ALL was successfully treated on the NOPHO-92 regimen, with a relatively low CNS relapse rate for non-irradiated children. WBC > or =200 x 10(9)/L and very slow response emerged as strong poor prognostic factors.

Childhood and adolescent lymphoid and myeloid leukemia

Remarkable progress has been made in the past decade in the treatment and in the understanding of the biology of childhood lymphoid and myeloid leukemias. With contemporary improved risk assessment, chemotherapy, hematopoietic stem cell transplantation and supportive care, approximately 80% of children with newly diagnosed acute lymphoblastic leukemia and 50% of those with myeloid neoplasm can be cured to date. Current emphasis is placed not only on increased cure rate but also on improved quality of life. In Section I, Dr. Ching-Hon Pui describes certain clinical and biologic features that still have prognostic and therapeutic relevance in the context of contemporary treatment programs. He emphasizes that treatment failure in some patients is not due to intrinsic drug resistance of leukemic cells but is rather caused by suboptimal drug dosing due to host compliance, pharmacodynamics, and pharmacogenetics. Hence, measurement of minimal residual disease, which accounts for both the genetic (primary and secondary) features of leukemic lymphoblasts and pharmacogenomic variables of the host, is the most reliable prognostic indicator. Finally, he contends that with optimal risk-directed systemic and intrathecal therapy, cranial irradiation may be omitted in all patients, regardless of the presenting features. In Section II, Dr. Martin Schrappe performs detailed analyses of the prognostic impact of presenting age, leukocyte count, sex, immunophenotype, genetic abnormality, early treatment response, and in vitro drug sensitivity/resistance in childhood acute lymphoblastic leukemia, based on the large database of the Berlin-Frankfurt-Münster consortium. He also succinctly summarizes the important treatment components resulting in the improved outcome of children and young adolescents with this disease. He describes the treatment approach that led to the improved outcome of adolescent patients, a finding that may be applied to young adults in the second and third decade of life. Finally, he believes that treatment reduction under well-controlled clinical trials is feasible in a subgroup of patients with excellent early treatment response as evidenced by minimal residual disease measurement during induction and consolidation therapy. In Section III, Dr. Raul Ribeiro describes distinct morphologic and genetic subtypes of acute myeloid leukemia. The finding of essentially identical gene expression profiling by DNA microarray in certain specific genetic subtypes of childhood and adult acute myeloid leukemia suggests a shared leukemogenesis. He then describes the principles of treatment as well as the efficacy and toxicity of various forms of postremission therapy, emphasizing the need of tailoring therapy to both the disease and the age of the patient. Early results suggest that minimal residual disease measurement can also improve the risk assessment in acute myeloid leukemia, and that cranial irradiation can be omitted even in those with central-nervous-system leukemia at diagnosis. In Section IV, Dr. Charlotte Niemeyer describes a new classification of myelodysplastic and myeloproliferative diseases in childhood, which has greatly facilitated the diagnosis of myelodysplastic syndromes and juvenile myelomonocytic leukemia. The recent discovery of somatic mutations in PTPN11 has improved the understanding of the pathobiology and the diagnosis of juvenile myelomonocytic leukemia. Together with the findings of mutations in RAS and NF1 in the other patients, she suggests that pathological activation of RAS-dependent pathways plays a central role in the leukemogenesis of this disease. She then describes the various treatment approaches for both juvenile myelomonocytic leukemia and myelodysplastic syndromes in the US and Europe, emphasizing the differences between childhood and adult cases for the latter group of diseases. She also raises some controversial issues regarding treatment that will require well-controlled international clinical trials to address.

International Collaboration on Childhood Leukemia

The current cure rate of childhood acute lymphoblastic leukemia has reached 80% in many industrialized countries, but in developing countries the rate is often less than 10%. To advance the cure rate, investigators have formed several parallel initiatives in both industrialized and developing countries through international collaboration and partnership. Among industrialized countries, investigators have combined data to conduct in-depth studies of the biology and heterogeneity of high-risk or drug-resistant subgroups of leukemia to identify optimal or novel treatments. Alliances have been established among government, local nongovernmental organizations, health care providers, and international groups to improve the survival rate of childhood leukemia in developing countries. "Twinning" partnerships between a well-established individual institution or study group and a pediatric cancer unit in a developing country has proved to be the most successful strategy to date.

Patient stratification based on prednisolone-vincristine-asparaginase resistance profiles in children with acute lymphoblastic leukemia

PURPOSE

To confirm the prognostic value of a drug resistance profile combining prednisolone, vincristine, and l-asparaginase (PVA) cytotoxicity in an independent group of children with acute lymphoblastic leukemia (ALL) treated with a different protocol and analyzed at longer follow-up compared with our previous study of patients treated according to the Dutch Childhood Leukemia Study Group (DCLSG) ALL VII/VIII protocol.

PATIENTS AND METHODS

Drug resistance profiles were determined in 202 children (aged 1 to 18 years) with newly diagnosed ALL who were treated according to the German Cooperative Study Group for Childhood Acute Lymphoblastic Leukemia (COALL)-92 protocol.

RESULTS

At a median follow-up of 6.2 years (range, 4.1 to 9.3 years), the 5-year disease-free survival probability (pDFS) rate +/- SE was 69% +/- 7.0%, 83% +/- 4.4%, and 84% +/- 6.8% for patients with resistant (PVA score 7 to 9), intermediate-sensitive (PVA score 5 to 6), and sensitive (SPVA score 3 to 4) profiles, respectively (sensitive and intermediate-sensitive v resistant, P </=.05). Resistant patients were at increased risk of an early event (nonresponse or relapse within 2.5 years of diagnosis) compared with sensitive and intermediate-sensitive patients (P =.03). The profile did not identify patients at higher risk of late relapse, which was also observed for DCLSG ALL-VII/VIII patients now analyzed at a median of 7.5 years of follow-up (range, 4.4 to 10.8 years). Despite being nondiscriminative for late relapses, the resistant profile was still the strongest prognostic factor for COALL-92 patients in a multivariate analysis including known risk factors (P =.07).

CONCLUSION

Drug resistance profiles identify patients at higher risk of early treatment failures and may, therefore, be used to improve risk-group stratification of children with ALL.

Clonality profile in relapsed precursor-B-ALL children by GeneScan and sequencing analyses. Consequences on minimal residual disease monitoring

Detection of minimal residual disease (MRD), using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements as clone-specific targets, represents the most recent development in diagnosis and treatment of acute lymphoblastic leukaemia (ALL). Nevertheless, risk of false-negative results, due to secondary or ongoing rearrangements of Ig/TCR genes during the disease course, might hamper MRD detection. Therefore, to gain extensive information on clonal stability, we performed PCR-GeneScan analysis of Ig/TCR gene rearrangements at diagnosis and subsequent relapse in bone marrow samples from 53 childhood precursor-B-ALL patients. In addition, sequencing analysis of junctional regions at diagnosis and relapse provided a detailed insight in the stability and changes of Ig/TCR gene rearrangements during the disease course. At least one stable clonal Ig/TCR target was found in 94% of patients. In three patients complete differences in Ig/TCR rearrangements between diagnosis and relapse were observed, suggesting relapse with a new clone. At relapse, 71% of diagnostic clonal PCR targets was conserved. Since the comparison of Ig/TCR gene rearrangements at diagnosis and relapse in our precursor-B-ALL patients did not show significant difference in the stability of different clonal PCR targets (IGH, 70%; IGK, 71%; TCRD, 67%; TCRG, 75%), we conclude that there is no 'preferential' clone-specific target for MRD monitoring.

Population-based survival after childhood lymphoblastic leukaemia in time periods corresponding to specific clinical trials from 1979 to 1998--a report from the Childhood Cancer Registry of Piedmont (Italy)

This study evaluated the outcome after childhood acute lymphoblastic leukaemia (ALL) in a population aged 0-14 years served by the Childhood Cancer Registry of Piedmont (CCRP) during the accrual periods to nationwide clinical studies run by the Italian Association for Paediatric Haematology and Oncology (AIEOP). In the time period considered (March 1979-December 1998) the CCRP recorded 498 incident cases of ALL. The living status on 31 December 2000 was known for 497 cases. Overall survival at 5 years was 74.1% standard error (S.E.) 2.0%). It increased from 58.6% (S.E. 4.9%) for cases diagnosed in March 1979-July 1982 to 87.3 (S.E. 3.6) in May 1995-December 1998. Results observed from data in our population-based study in Piedmont were similar to those presented in the nationwide clinical trials. Survival was better (statistically significant) for children aged 1-4 years, with a white blood cell (WBC) count lower than 10 000 x 10(3) cells/litre and for B-precursor ALL. Differences by immunophenotype were statistically significant only in the univariate analyses. Girls showed a non-statistically significant survival advantage over boys. Results of the present study show the impact on the population of recent clinical trials and emphasise the role of population-based cancer registries in evaluating childhood cancer care delivery in a given population.

Improvement over time in outcome for children with acute lymphoblastic leukemia in second remission given hematopoietic stem cell transplantation from unrelated donors

Aims of this study were to verify whether reduction in transplant-related mortality (TRM) of children with acute lymphoblastic leukemia (ALL) in second complete remission (CR) given allogeneic hematopoietic stem cell transplantation (HSCT) from unrelated volunteers has occurred over time and to investigate the role of other variables on the probabilities of relapse, TRM and event-free survival (EFS). We compared results obtained in 26 children given HSCT before January 1998 with those of 37 patients transplanted beyond that date. In all donor-recipient pairs, histocompatibility was determined by serology for HLA-A and -B antigens and by high-resolution DNA typing for DRB1 antigen. High-resolution molecular typing of HLA class I antigens was employed in 20 of the 37 children transplanted more recently. Probability of both acute and chronic GVHD was comparable in the two groups of patients. In multivariate analysis, children transplanted before January 1998, those with T-lineage ALL and those experiencing grade II-IV acute GVHD had a higher relative risk of TRM at 6 months after transplantation. Relapse rate was unfavorably affected by a time interval between diagnosis and relapse <30 months. The 2-year probability of EFS for children transplanted before and after 1 January 1998 was 27% (10-44) and 58% (42-75), respectively (P = 0.02), this difference remaining significant in multivariate analysis. EFS of unrelated donor HSCT in children with ALL in second CR has improved in the last few years, mainly due to a decreased TRM. This information is of value for counseling of patients with relapsed ALL.

Treatment of childhood acute lymphoblastic leukemia at a regional non-academic center in Belarus

The outlook for children with cancer is improving in the less privileged nations of the world. This report from Belarus is representative of results that can be achieved.

A single high dose of idarubicin combined with high-dose ARA-C for treatment of first relapse in childhood 'high-risk' acute lymphoblastic leukaemia: a study of the AIEOP group

The outcome of children with acute lymphoblastic leukaemia (ALL) and early relapse remains unsatisfactory. In January 1995, the AIEOP (Associazione Italiana di Oncologia ed Ematologia Pediatrica) group opened a trial for children with ALL in first isolated or combined bone marrow relapse defined at high risk according to the length of first remission and the immunophenotype. The treatment plan included the combination of a single high-dose idarubicin and high-dose cytarabine as induction therapy followed by an intensive consolidation and stem cell transplant (SCT). In total, 100 children from 16 Italian centres were enrolled; 80 out of the 99 evaluable patients (81%) achieved second complete remission; eight (8%) died during induction and 11 (11%) failed to respond. A total of 42 out of the 80 responders (52.5%) received a SCT: 19 from an identical sibling, 11 from a matched unrelated donor and 12 from umbilical cord blood cells. The estimated 4-year overall survival and event-free survival were 25% and 21% respectively. Disease-free survival at 4 years was 25.8% for the 80 responders. At 4 years, 39 out of 100 children remain alive, with 27 of them free of leukaemia. This induction therapy has shown antileukaemic efficacy with acceptable toxicity; moreover, all responders proved eligible for intensive consolidation.

Symptomatic hypoglycemia in children receiving oral purine analogues for treatment of childhood acute lymphoblastic leukemia

BACKGROUND

Antimetabolite-based continuation therapy is commonly used for childhood acute lymphoblastic leukemia (ALL) and hypoglycemia after prolonged fasting has been recently reported. We have found that spontaneous, symptomatic hypoglycemia (SH) may also occur in such patients.

PROCEDURE

Between 1995 and 1999, patients treated according to the AIEOP-ALL-95 study received BFM-type intensive chemotherapy; mercaptopurine (6-MP) was given (60 mg/m(2)/days, orally for 14 days) during the second part of induction and during consolidation therapy (25 mg/m(2)/day, orally for 8 weeks); thioguanine (6-TG) was given during reinduction therapy with protocol II (60 mg/m(2)/day, orally for 14 days); continuation therapy consisted of a combination of 6-MP (50 mg/m(2)/day orally) and methotrexate (MTX, 20 mg/m(2)/weekly, i.m.). We reviewed the charts of all patients treated for childhood ALL at our two centers. This was done to assess the incidence and the characteristics of all episodes of SH: sweating, pallor, nausea, abdominal pain with or without transient alterations of alertness, in the presence of blood glucose level of under 60 mg/dl.

RESULTS

Six of 86 patients (6.9%) developed 18 episodes of SH. Five were male, none was older than 5 years, and four were only 3 years old. SH episodes occurred during consolidation (n = 2), reinduction (n = 7), and continuation (n = 9) phases.

CONCLUSIONS

SH is a rare complication associated with administration of the purine analogues, mercaptopurine and thioguanine to children with reduced fat storage and young age.

Childhood acute lymphoblastic leukemia

As cure rates in childhood acute lymphoblastic leukemia reach 80%, emphasis is increasingly placed on the accurate identification of drug-resistant cases, the elucidation of the mechanisms involved in drug resistance and the development of new therapeutic strategies targeted toward the pivotal molecular lesions. Pharmacodynamic and pharmacogenomic studies have provided rational criteria for individualizing therapy to enhance efficacy and reduce acute toxicity and late sequelae. Currently, assessment of the early response to treatment by measurement of minimal residual disease (MRD) is the most powerful independent prognostic indicator. MRD is affected by both the drug sensitivity of leukemic cells and the pharmacodynamic and pharmacogenetic properties of the host cells. Rapid advances in biotechnology and bioinformatics should ultimately facilitate the development of molecular diagnostic assays that can be used to optimize antileukemic therapy and elucidate the mechanisms of leukemogenesis. In the interim, prospective clinical trials have provided valuable clues that are further increasing the cure rate of childhood acute lymphoblastic leukemia.

Treatment of acute leukemia in children: recent advances and future challenges

Recently advances have been made in the treatment of acute leukemia in children, it is now possible to cure more than 70% of children with acute lymphoblastic leukemia. With the introduction of more intensive chemotherapy regimens in patients at higher risk of relapse and the identification of cases that could be less intensely treated to diminish long-term toxicity, it could be possible to improve these excellent results. In contrast, pediatric acute myeloid leukaemia seems to be a more heterogeneous disease and its response to conventional chemotherapy is not as uniform. Introduction of new and more efficacious therapies is necessary to improve the poor outcome, especially among patients with high-risk features.

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.