Response of children with high-risk acute lymphoblastic leukemia treated with and without cranial irradiation: a report from the Children's Cancer Group

Risk classification at the time of diagnosis differentially affects the level of residual disease in children with B-precursor acute lymphoblastic leukemia after completion of therapy

We have previously reported that children with B-precursor acute lymphoblastic leukemia (ALL) who remained in remission after successfully completing therapy had leukemia cells detectable by polymerase chain reaction (PCR) (N Engl J Med 1997;336(5):317-23). These patients were treated by an institutional protocol (P89-04) that lacked the post-remission intensification features of the contemporary Berlin-Frankfurt-Münster (BFM) based ALL protocols. In this report, we compared residual leukemia levels for patients on the P89-04 (n=15) and BFM-based Children's Cancer Group (CCG) studies (n=23) and for patients stratified according to risk group. Our goal was to establish which risk factors correlated with level of residual disease. Patients enrolled on the CCG protocols had lower levels of residual disease after completion of therapy than the P89-04 patients (P<0.019). Patients with high-risk disease also had lower levels of residual disease than patients with low risk disease (P<0.0001). Three-way analysis including time off treatment, risk group determined by features at presentation, and treatment protocol showed that risk group was the only significant independent variable (P<0.001).

CNS-directed therapy for childhood acute lymphoblastic leukemia: Childhood ALL Collaborative Group overview of 43 randomized trials

PURPOSE

A collaborative meta-analysis was performed to clarify the relative effects on relapse and survival of different types of therapies directed at the CNS in childhood acute lymphoblastic leukemia.

MATERIALS AND METHODS

Data were sought for each individual patient in all trials started in or before 1993 that included unconfounded randomized comparisons of such treatments. Log-rank survival analyses were performed for each trial, and overall results for groups of trials addressing similar questions were obtained from the totals of the observed minus expected number of events and their variances.

RESULTS

Radiotherapy and long-term intrathecal therapy gave similar outcomes, with no significant difference in event-free survival despite random assignment of treatment to 2,848 patients, 1,001 of whom suffered relapse or death. Intravenous methotrexate reduced non-CNS rather than CNS relapses, and hence, the addition of intravenous methotrexate to a treatment regimen including radiotherapy or long-term intrathecal therapy improved event-free survival, with a 17% reduction in the event rate (95% confidence interval, 6% to 27%; P =.003). The event-free survival at 10 years in these trials was 61.9% without intravenous methotrexate and 68.1% with intravenous methotrexate. There was no significant difference in survival (14% death rate reduction; P =.09). There were insufficient randomly assigned patients to adequately address other questions, such as effect of different doses. No evidence was found of differences, between trials or between subgroups of different types of patients, in the relative effects of treatment.

CONCLUSION

Radiotherapy can be replaced by long-term intrathecal therapy. Intravenous methotrexate gives some additional benefit by reducing non-CNS relapses.

Racial and ethnic differences in survival of children with acute lymphoblastic leukemia

Black children with acute lymphoblastic leukemia (ALL) have poor outcomes, but limited information is available for children from other racial and ethnic backgrounds, such as Hispanic and Asian. We undertook a retrospective cohort study of children with ALL treated on Children's Cancer Group therapeutic protocols to determine outcomes by racial and ethnic backgrounds of patients treated with contemporary risk-based therapy. In total, 8447 children (white, n = 6703; Hispanic, n = 1071; black, n = 506; and Asian, n = 167) with newly diagnosed ALL between 1983 and 1995 were observed for a median of 6.5 years. Analysis of disease outcome was measured as overall survival (OS) and event-free survival (EFS) and was adjusted for known predictors of outcome including clinical features, disease biology, socioeconomic status, and treatment era (1983-1989 vs 1989-1995). There was a statistically significant difference in survival by ethnicity (P <.001). Five-year EFS rates were: Asian, 75.1% +/- 3.5%; white, 72.8% +/- 0.6%; Hispanic, 65.9% +/- 1.5%; and black, 61.5% +/- 2.2%. Multivariate analysis revealed that when compared with white children, black and Hispanic children had worse outcomes and Asian children had better outcomes after adjusting for known risk factors. The poorer outcomes among black children were most apparent among patients with standard-risk features (relative risk [RR], 2.0; 95% confidence interval [CI], 1.6-2.5), whereas poorer outcomes in Hispanic children (RR, 1.4; 95% CI, 1.2-1.6) were most evident among patients with high-risk features. Asian children had better outcomes than all racial and ethnic groups among high-risk patients, particularly in the recent era (5-year EFS, 90.9% +/- 6.1%). Racial and ethnic differences in OS and EFS persist among children with ALL who receive contemporary risk-based therapy. Future studies should focus on reasons-perhaps compliance or pharmacogenetics-for those differences.

Glutathione S-transferase genotypes, genetic susceptibility, and outcome of therapy in childhood acute lymphoblastic leukemia

The glutathione S-transferase (GST) genes are involved in the metabolism of environmental carcinogens and of some classes of chemotherapy drugs. GSTM1 and GSTT1 genotypes are polymorphic in humans, and the phenotypic absence of enzyme activity is caused by a homozygous inherited deletion of the gene. Previous, smaller studies of childhood acute lymphoblastic leukemia (ALL) provided contrasting data on the role of the GST genotype in susceptibility and treatment outcomes. We analyzed GST genotypes in 710 children with ALL treated by the Children's Cancer Group. Frequencies were compared with those of normal controls, and outcomes were analyzed according to genotype. Comparisons of gene frequencies in ALL case and control patients showed similar frequencies (54% vs 53% GSTM1 null in whites, P =.9; 40% versus 32% in blacks, P =.45; 16% versus 15% GSTT1 null in whites, P =.8; 17% versus 28% in blacks, P =.3). ALL was not associated with the GSTM1-null genotype or the double-null genotype in blacks or whites, in contrast to previous reports. Stratification of cases by age at diagnosis, sex, white blood cell count at diagnosis, B or T lineage, or cytogenetics revealed no differences in genotype frequencies. Analysis of treatment outcomes showed no differences in outcome according to GST genotype; in particular, there were no differences in frequencies of relapse at any site. These data, representing a larger series than any reported previously, suggest that GST genotype does not affect etiology or outcome of childhood ALL.

Low incidence of second neoplasms among children diagnosed with acute lymphoblastic leukemia after 1983

Second malignant neoplasms are a serious complication after successful treatment of childhood acute lymphoblastic leukemia (ALL). With improvement in survival, it is important to assess the impact of contemporary risk-based therapies on second neoplasms in ALL survivors. A cohort of 8831 children diagnosed with ALL and enrolled on Children's Cancer Group therapeutic protocols between 1983 and 1995 were observed to determine the incidence of second neoplasms and associated risk factors. The median age at diagnosis of ALL was 4.7 years. The cohort had accrued 54 883 person-years of follow-up. Sixty-three patients developed second neoplasms, including solid, nonhematopoietic tumors (n = 39: brain tumors n = 19, other solid tumors n = 20), myeloid leukemia or myelodysplasia (n = 16), and lymphoma (n = 8). The cumulative incidence of any second neoplasm was 1.18% at 10 years (95% confidence interval, 0.8%-1.5%), representing a 7.2-fold increased risk compared with the general population. The risk was increased significantly for acute myeloid leukemia (standardized incidence ratio [SIR] 52.3), non-Hodgkin lymphoma (SIR 8.3), parotid gland tumors (SIR 33.4), thyroid cancer (SIR 13.3), brain tumors (SIR 10.1), and soft tissue sarcoma (SIR 9.1). Multivariate analysis revealed female sex (relative risk [RR] 1.8), radiation to the craniospinal axis (RR 1.6), and relapse of primary disease (RR 3.5) to be independently associated with increased risk of all second neoplasms. Risk of second neoplasms increased with radiation dose (1800 cGy RR 1.5; 2400 cGy RR 3.9). Actuarial survival at 10 years from diagnosis of second neoplasms was 39%. Follow-up of this large cohort that was treated with contemporary risk-based therapy showed that the incidence of second neoplasms remains low after diagnosis of childhood ALL.

Recent approaches in acute lymphoblastic leukemia in adults

In the last decades outcome of adult acute lymphoblastic leukemia (ALL) has improved considerably. In large multicenter studies remission rates range from 75% to 89%, and long-term leukemia-free survival (LFS) from 28% to 39%. Major progress has also been made regarding better characterization of subtypes of ALL. Complete diagnostic procedures are essential to identify these subtypes which have significant differences in clinical and laboratory features and prognosis. LFS of > 50% can be expected in favorable subtypes such as T-ALL or mature B-ALL, while LFS of < 20% is expected in Ph/BCR-ABL positive ALL. Prognostic factors can be used for risk stratification and selection of treatment strategies can be adapted to the subtype and relapse risk. This includes measurement of minimal residual disease (MRD) to evaluate individualized treatment strategies adapted to the molecular response. Several new approaches for improvement in chemotherapy and stem cell transplantation (SCT) are under investigation. They include the use of intensified anthracyclines, asparaginase, cyclophosphamide or high-dose cytarabine during induction and intensive rotational chemotherapy during consolidation. Also SCT - mainly from sibling donors - is now part of standard treatment of de novo ALL, although it remains open whether indications should be based on prognostic factors or whether SCT should be offered to all patients with sibling donor. However, substantial progress can only be achieved by new, experimental strategies. These include new approaches for SCT, such as nonmyeloablative SCT, measurement of MRD, causal treatment with molecular targeting, e.g. with kinase inhibitors, and antibody therapy.

A randomized comparison of native Escherichia coli asparaginase and polyethylene glycol conjugated asparaginase for treatment of children with newly diagnosed standard-risk acute lymphoblastic leukemia: a Children's Cancer Group study

For this study, 118 children with standard-risk acute lymphoblastic leukemia (ALL) were given randomized assignments to receive native or pegylated Escherichia coli asparaginase as part of induction and 2 delayed intensification phases. Patients treated with pegaspargase had more rapid clearance of lymphoblasts from day 7 and day 14 bone marrow aspirates and more prolonged asparaginase activity than those treated with native asparaginase. In the first delayed intensification phase, 26% of native asparaginase patients had high-titer antibodies, whereas 2% of pegaspargase patients had those levels. High-titer antibodies were associated with low asparaginase activity in the native arm, but not in the pegaspargase arm. Adverse events, infections, and hospitalization were similar between arms. Event-free survival at 3 years was 82%. A population pharmacodynamic model using the nonlinear mixed effects model (NONMEM) program was developed that closely fit the measured enzyme activity and asparagine concentrations. Half-lives of asparaginase were 5.5 days and 26 hours for pegaspargase and native asparaginase, respectively. There was correlation between asparaginase enzymatic activity and depletion of asparagine or glutamine in serum. In cerebrospinal fluid asparagine, depletion was similar with both enzyme preparations. Intensive pegaspargase for newly diagnosed ALL should be tested further in a larger population.

Cure model analysis in cancer: an application to data from the Children's Cancer Group

The most commonly used statistical methods for evaluating treatment or prognostic effects on cancer outcome--the logrank test and Cox regression analysis--rely on the proportional hazards (PH) assumption in that they have maximal power in this circumstance. Implicitly, these methods emphasize covariate effects on failure times rather than their effects on the proportion of long-term survivors ('cures'), which may be of equal or primary interest. In paediatric cancer, treatment has progressed dramatically in recent decades, and in many diagnoses cures are obtained in a large fraction of patients. A primary focus of clinical research is therefore the achievement of cure. Parametric cure model (PCM) analysis, introduced 50 years ago, is arguably better suited to the analytic requirements of clinical research in paediatric and other cancers where cure is achieved. In this paper two classes of PCMs are described and used to analyse examples from the Children's Cancer Group. These are compared to analyses using Cox regression analysis. Results from PCM analyses are similar or identical to Cox regression analysis when the PH assumption is appropriate. When it is not, PCMs can provide a coherent way to investigate and report covariate effects on the proportion cured separately from their effect on time to failure. Despite their reliance on explicit parametric forms, PCMs often provide a good description of cancer outcome, and are insensitive to lack of fit provided that follow-up is sufficient.

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.

Delay of the diagnostic lumbar puncture and intrathecal chemotherapy in children with acute lymphoblastic leukemia who undergo routine corticosteroid testing: Tokyo Children's Cancer Study Group study L89-12

PURPOSE

To determine the effects of eliminating initial lumbar punctures in 418 consecutively treated children with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Patients were enrolled onto a trial conducted in central Japan between 1989 and 1992. Treatment consisted of standard four-drug induction therapy followed by a risk-based intensification phase, reinduction therapy, late intensification, and remission maintenance therapy (total of 104 weeks). The initial lumbar puncture, with an intrathecal injection of chemotherapy, was performed after 1 week of prednisolone sensitivity testing (day 8). End points included response to prednisolone, CNS status at the time of the day 8 lumbar puncture, subsequent adverse events in CNS and bone marrow, and event-free survival (EFS).

RESULTS

The remission induction rate was 93.1% with a 6-year EFS rate (+/- SE) of 68.7% +/- 2.4%, which is similar to historical results for patients who received their diagnostic lumbar puncture and first instillation of intrathecal chemotherapy on day 0. Overall, 84.5% of the patients had good responses to prednisolone, whereas 15.5% had poor responses. Clinical outcome was strikingly better for the good responders (6-year EFS, 74.1% +/- 2.5% compared with 40.1% +/- 6.4% for patients with poor responses), suggesting that omission of intrathecal chemotherapy did not alter the predictive value of drug sensitivity testing. Eighteen patients experienced CNS relapse as their first adverse event (cumulative risk, 5.1%; 95% confidence interval, 2.7% to 7.4%), coincident with reports from groups using conventional strategies of CNS clinical management. Bleeding into the CSF at the time of the day 8 lumbar puncture was apparent in 29 cases (8.1%), but leukemic blasts were identified in only two.

CONCLUSION

Delay of the initial lumbar puncture and intrathecal injection of chemotherapy seems to be feasible in children with ALL. Further controlled evaluations are needed to establish the validity of this conclusion.

Duration of hospitalization as a measure of cost on Children's Cancer Group acute lymphoblastic leukemia studies

PURPOSE

We used duration of hospitalization as a surrogate for cost and event-free survival as a measure of effectiveness to estimate the cost-effectiveness ratios of various treatment regimens on Children's Cancer Group trials for acute lymphoblastic leukemia.

PATIENTS AND METHODS

The analyses included 4,986 children (2 to 21 years of age) with newly diagnosed acute lymphoblastic leukemia enrolled onto risk-adjusted protocols between 1988 and 1995. Analyses were based on a model of 100 patients. The marginal cost-effectiveness ratio (hospital days per additional patient surviving event-free) was the difference in total duration of hospitalization divided by the difference in number of event-free survivors at 5 years for two regimens. Relapse-adjusted marginal cost of frontline therapy was the difference in total duration of hospitalization for frontline therapy plus relapse therapy divided by the difference in number of event-free survivors at 5 years on the frontline therapy for two regimens.

RESULTS

One or two delayed intensification (DI) phases, augmented therapy, and dexamethasone all improved outcome. Marginal cost-effectiveness of these regimens compared with the control regimens was 133 days per patient for DI, 117 days per patient for double DI, and 41 days per patient for augmented therapy. Dexamethasone resulted in 17 fewer days per patient. Relapse-adjusted marginal costs were 68 days per patient for DI and 52 days for double DI. Augmented therapy and dexamethasone-based therapy resulted in 16 and 82 fewer hospital days, respectively. The estimated cost-effectiveness for treating any first relapse was 250 days per patient.

CONCLUSION

DI, double DI, augmented therapy, and dexamethasone-based therapy are cost-effective strategies compared with current treatment of first relapse.

Bone marrow leukemic progenitor cell content in pediatric T-lineage acute lymphoblastic leukemia patients with an isolated extramedullary first relapse

Isolated extramedullary relapse in childhood acute lymphoblastic leukemia (ALL) is associated frequently with the T-lineage immunophenotype and may be accompanied by occult bone marrow disease. We employed highly sensitive multiparameter flow cytometry and blast colony assays to quantify the leukemic progenitor cell (LPC) burden in the pretreatment bone marrows of 15 pediatric T-lineage ALL patients with an isolated extramedullary first relapse. Sites of extramedullary relapse were CNS (11 patients), testes (3 patients), and both CNS and testes (1 patient). Bone marrow LPC were detectable in 8 patients (53%) and undetectable in 7 patients (47%) at day 0 of post-relapse induction therapy, with LPC counts ranging from 0/10(6) mononuclear cells (MNC) to 518/10(6) MNC (mean +/- SEM, 50+/-34/10(6) MNC). Five of 9 patients with an early relapse (< 18 months after achieving a first complete remission [CR1]) and 3 of 6 patients with a late relapse (> or = 18 months from CR1) had detectable bone marrow LPC at day 0. Five of 8 patients with NCI-defined poor risk ALL and 3 of 7 patients with NCI-defined standard risk ALL had detectable LPC at day 0. Following post-relapse induction chemotherapy. LPC counts were detectable in bone marrows of 4 of 6 evaluated patients. Thus, approximately half of the extramedullary relapse T-lineage ALL patients studied had substantial occult involvement of the bone marrow. These findings may partly explain the previously observed poor prognosis of T-lineage patients following a CNS relapse.

Children's Cancer Group trials in childhood acute lymphoblastic leukemia: 1983-1995

Since 1968, the Children's Cancer Group (CCG) has treated more than 16,000 children with acute lymphoblastic leukemia (ALL). Herein, we report improvements obtained in CCG trials during two successive series of studies (1983-1988 and 1989-1995). Overall, 10-year EFS was 62% +/- 10% for the 1983-1988 series and 72% +/- 1% for the 1988-1995 series (P< 0.0001). Five-year cumulative rates of isolated CNS relapses were 5.9% and 4.4%. Therapy based on the Berlin-Frankfurt-Münster 76/79 study improved outcomes for intermediate and higher risk patients in the first series. For intermediate risk patients, delayed intensification (DI) was most crucial for improved outcome and cranial irradiation was safely replaced with maintenance intrathecal methotrexate, providing patients received intensified systemic therapy. In the second series, randomized trials showed better outcome with one vs no DI phase for lower risk patients, with two vs one DI phase for intermediate risk patients, and with the CCG 'augmented regimen' for higher risk patients with a slow day 7 marrow response. Cranial irradiation was safely replaced with additional intrathecal methotrexate for higher risk patients with a rapid day 7 marrow response. In a subsequent study, substitution of dexamethasone in place of prednisone in induction and maintenance improved outcome for standard risk patients. All patients received dexamethasone in DI. These successful treatment strategies form the basis for our current ALL trials.

Abnormalities of chromosome bands 13q12 to 13q14 in childhood acute lymphoblastic leukemia

PURPOSE

Little is known about nonrandom deletions of chromosome bands 13q12 to 13q14 (13q12-14) in acute lymphoblastic leukemia (ALL). We determined the prognostic significance of cytogenetically identified breakpoints in 13q12-14 in children with newly diagnosed ALL treated on Children's Cancer Group protocols from 1988 to 1995.

PATIENTS AND METHODS

Breakpoints in 13q12-14 were identified in 36 (2%) of the 1,946 cases with accepted cytogenetic data. Outcome analysis used standard life-table methods.

RESULTS

Seventeen patients (47%) with an abnormal 13q12-14 were classified, according to the National Cancer Institute (NCI), as poor risk, and 15 patients (42%) were standard risk; four (11%) were infants less than 12 months of age. Eight cases had balanced rearrangements of 13q12-14, 27 patients had a partial loss of 13q, and one had both a partial gain and a partial loss. The most frequent additional abnormalities among these patients were an abnormal 12p, a del(6q), a del(9p), a 14q11 breakpoint, and an 11q23 breakpoint. Nineteen patients were pseudodiploid, 10 were hyperdiploid, and seven were hypodiploid. Patients with an abnormal 13q12-14 had significantly worse event-free survival than patients lacking such an abnormality, with estimates at 6 years of 61% (SD = 14%) and 74% (SD = 1%), respectively (P =.04; relative risk = 1.74). Overall survival, however, was similar for the two groups (P =.25). The prognostic effect of an abnormal 13q was attenuated in a multivariate analysis adjusted for NCI risk status and ploidy (P =.72).

CONCLUSION

Aberrations of 13q12-14 may contribute to leukemogenesis of childhood ALL and confer increased risk of treatment failure but are associated with other poor-risk features.

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.

Prognostic impact of trisomies of chromosomes 10, 17, and 5 among children with acute lymphoblastic leukemia and high hyperdiploidy (> 50 chromosomes)

PURPOSE

Children with acute lymphoblastic leukemia (ALL) and high hyperdiploidy (> 50 chromosomes) have improved outcome compared with other ALL patients. We sought to identify cytogenetic features that would predict differences in outcome within this low-risk subset of ALL patients.

MATERIALS AND METHODS

High-hyperdiploid ALL patients (N = 480) were enrolled between 1988 and 1995 on Children's Cancer Group (CCG) trials. Karyotypes were determined by conventional banding. Treatment outcome was analyzed by life-table methods.

RESULTS

Patients with 54 to 58 chromosomes had better outcome than patients with 51 to 53 or 59 to 68 chromosomes (P = .0002). Patients with a trisomy of chromosome 10 (P<.0001), chromosome 17 (P = .0002), or chromosome 18 (P = .004) had significantly improved outcome compared with their counterparts who lacked the given trisomy. Patients with a trisomy of chromosome 5 had worse outcome than patients lacking this trisomy (P = .02). Patients with trisomies of both chromosomes 10 and 17 had better outcome than those with a trisomy of chromosome 10 (P = .09), a trisomy of chromosome 17 (P =.01), or neither trisomy (P<.0001). Multivariate analysis indicated that trisomy of chromosome 10 (P = .001) was the most significant prognostic factor for high-hyperdiploid patients, yet trisomy of chromosome 17 (P =.02) or chromosome 5 (P = .01) and modal chromosome number (P = .02) also had significant multivariate effects.

CONCLUSION

Trisomy of chromosomes 10 and 17 as well as modal chromosome number 54 to 58 identify subgroups of patients with high-hyperdiploid ALL who have a better outcome than high-hyperdiploid patients who lack these cytogenetic features. Trisomy of chromosome 5 confers poorer outcome among high-hyperdiploid patients.

Six months of maintenance chemotherapy after intensified treatment for acute lymphoblastic leukemia of childhood

PURPOSE

We postulated that intensification of chemotherapy immediately after remission induction might reduce the leukemic cell burden sufficiently to allow an abbreviated period of antimetabolite therapy.

PATIENTS AND METHODS

Three hundred forty-seven children (ages 1 to 15 years) with previously untreated acute lymphoblastic leukemia (ALL) were enrolled onto the Tokyo L92-13 study, which excluded patients with mature B-cell ALL and patients less than 1 year old. One hundred twenty-four patients were classified as standard risk, 122 as high risk, and 101 as extremely high risk, according to age, peripheral-blood leukocyte count, selected genetic abnormalities, and immunophenotype. All subjects received four drugs for remission induction, followed by a risk-directed multidrug intensification phase and therapy for presymptomatic leukemia in the CNS. Maintenance chemotherapy with oral mercaptopurine and methotrexate was administered for 6 months, with all treatment stopped by 1 year after diagnosis.

RESULTS

The mean (+/- SD) event-free survival (EFS) and overall survival rates for all patients were 59.5% +/- 3.4% and 81.5% +/- 2.2%, respectively, at 5. 5 years after diagnosis. EFS rates by risk category were similar (60. 2% +/- 6.0% for standard risk, 57.7% +/- 5.6% for high risk, and 62. 5% +/- 5.7% for extremely high risk), whereas overall survival rates differed significantly (91.2% +/- 2.7%, 80.0% +/- 4.1%, and 72.1% +/- 4.5%, respectively, P <.0001 by the log-rank test). There were 107 relapses. Eighty-five (79.4%) of these 107 patients achieved second complete remissions, with subsequent EFS rates of 61.5% +/- 7. 9% (standard risk), 42.6% +/- 8.1% (high risk), and 9.6% +/- 6.4% (extremely high risk). Of the five risk factors analyzed, only the response to prednisolone monotherapy among extremely high-risk patients proved important.

CONCLUSION

Early treatment intensification did not compensate for a truncated phase of maintenance chemotherapy in children with standard- or high-risk ALL. However, 6 months of antimetabolite treatment seemed adequate for extremely high-risk patients who were good responders to prednisolone and received intensified chemotherapy that included high-dose cytarabine early in the clinical course.

Effects of cranial radiation in children with high risk T cell acute lymphoblastic leukemia: a Pediatric Oncology Group report

Contemporary chemotherapy has significantly improved event-free survival among patients with T cell-lineage acute lymphoblastic leukemia (T-ALL). Unlike B-precursor ALL, most investigators are still using cranial radiation (CRT) and are hesitant to rely solely on intrathecal therapy for T-ALL. In this study we assessed the effects of CRT upon event-free survival and central nervous system (CNS) relapses in a cohort of children with high risk features of T cell leukemia. In a series of six consecutive studies (1987-1995) patients were non-randomly assigned their CNS prophylaxis per individual protocol. These protocols were based on POG 8704 which relied on rotating drug combinations (cytarabine/cyclophosphamide, teniposide/Ara-C, and vincristine/doxorubicin/6-MP/prednisone) postinduction. Modifications such as high-dose cytarabine, intermediate-dose methotrexate, and the addition of G-CSF, were designed to give higher CNS drug levels (decreasing the need for CRT), to eliminate epidophyllotoxin (decreasing the risk of secondary leukemia), and to reduce therapy-related neutropenia (pilot studies POG 9086, 9295, 9296, 9297, 9398). All patients included in this analysis qualified for POG high risk criteria, WBC >50000/mm3 and/or CNS leukemia. Patients without CNS involvement received 16 doses of age-adjusted triple intra-thecal therapy (TIT = hydrocortisone, MTX, and cytarabine) whereas patients with CNS disease received three more doses of TIT during induction and consolidation. Patients who received CRT were treated with 2400 cGy (POG 8704) or 1800 cGy (POG 9086 and 9295). CNS therapy included CRT in 144 patients while the remaining 78 patients received no radiation by original protocol design. There were 155 males and 57 females with a median age of 8.2 years. The median WBC for the CRT+ and CRT- patients were 186000/mm3 and 200000/mm3, respectively. CNS involvement at diagnosis was seen in 16% of the CRT+ and 23% of the CRT- groups. The complete continuous remission rate (CCR) was not significantly different for the irradiated vs. non-irradiated groups (P = 0.46). The 3-year event-free survival was 65% (s.e. 6%) and 63% (s.e. 4%) for the non-irradiated vs. the radiated group. However, the 3-year CNS relapse rate was significantly higher amongst patients who did not receive CRT; 18% (s.e. 5%) vs. 7% (s.e. 3%) in the irradiated group (P = 0.012). Our analysis in a non-randomized setting, suggests that CRT did not significantly correlate with event-free survival but omitting it had an adverse effect on the CNS involvement at the time of relapse.

Pediatric Acute Lymphoblastic Leukemia: Challenges and Controversies in 2000

This article discusses ways in which pediatric patients with acute lymphoblastic leukemia (ALL) can be stratified to receive intensive and less intensive therapies in order to decrease morbidity and mortality. Specifically, the focus may shift away from current intensive therapies for ultra low-risk patients and away from transplantation for certain patients at relapse. In contrast, infants with ALL comprise an ultra high-risk population in need of specialized approaches.

In Section I Dr. Lange describes the need to identify ultra low-risk children. Groups around the world have improved the outcome of children with ALL by identifying the basic “total therapy” model of the 1970s and stratifying treatment according to risk of relapse. Current first-line treatment cures about 85% of children with standard-risk ALL and 70% of children with high-risk disease. However, all children receive anthracyclines, alkylating agents, or moderate- to high-dose antimetabolite infusions. While randomized clinical trials prove that these intensifications reduce relapses, they also show that half of all children with ALL can be cured with the modest therapy of the 1970s and early 1980s. The patients curable with lesser therapy may be considered an ultra low-risk group. Attempts to use age, gender, white count, morphology, and karyotype to identify the ultra low-risk group of patients with a 90-95% cure rate with minimal therapy have failed. An expanded repertoire of tools such as pharmacogenetic profiling, PCR measurement of minimal residual disease and microarray technology may make this goal achievable in this decade.

In section II Dr. Chessells addresses the management of children with relapsed ALL. The chance of successful re-treatment with conventional chemotherapy for relapse depends on the duration of first remission and the site of relapse. Bone marrow transplantation from a histocompatible sibling or other suitable donor, which is widely accepted as the treatment of choice for children with a first remission of &lt; 24 months, is associated with a high risk of relapse. Bone marrow transplantation for later bone marrow relapse improves leukemia-free survival but has significant short-term and long-term toxicities. The challenges are to develop more effective treatment for early relapse and to identify those children with relapsed ALL who are curable with chemotherapy or, failing this, those children who would be candidates for bone marrow transplantation in third remission.

In Section III Dr. Felix addresses the problem of infant ALL. ALL of infancy is clinically aggressive, and infants continue to have the worst prognosis of all pediatric patients with ALL. High white blood cell count, younger age, bulky extramedullary disease, and CNS disease at diagnosis are unfavorable characteristics. These features occur with MLL gene translocations. The probability of an MLL gene translocation and the probability of poor outcome both are greatest in younger infants. Specialized intensive chemotherapy approaches and bone marrow transplantation in first remission for this disease may lead to improved survival.

Refined recognition of pediatric patients with ALL who need more and less intensive therapies is necessary to increase survival and decrease toxicities.

Effective preventive central nervous system therapy with extended triple intrathecal therapy and the modified ALL-BFM 86 chemotherapy program in an enlarged non-high risk group of children and adolescents with non-B-cell acute lymphoblastic leukemia: the Israel National Study report

BACKGROUND

Preventive cranial radiotherapy (CRT) in childhood acute lymphoblastic leukemia (ALL), although effective, may be associated with neurologic sequelae and second malignancies. Attempts to replace CRT with intensified intrathecal therapy (IT) have shown promise in lower risk subgroups. In the Israel National Study (INS) 89 trial, the efficacy of extended triple IT (TIT) alone for cranial prophylaxis in an enlarged non-high risk group (Non-HRG) was assessed in the context of a modified ALL-Berlin-Frankfurt-Munster (BFM) systemic chemotherapy program.

METHODS

Non-HRG patients included the standard-risk group (SRG) and the risk group (RG), as defined in ALL-BFM 86. In the INS 89 protocol, all Non-HRG patients were treated with extended TIT x 18 times and systemic therapy based on the BFM 86 protocol, with the addition of etoposide x 4 times. The HRG patients, classified according to BFM 86 criteria, were treated with the BFM 90 HRG protocol including CRT.

RESULTS

A total of 250 patients were enrolled. At a median follow-up of 58 months (range, 2-8.5 years), the overall 5-year event free survival (EFS) was 73.5% +/- 3% (standard error ¿SE), and the cumulative central nervous system (CNS) recurrence rate was 4.3% +/- 1.4% (SE) (isolated, 2.3%; combined, 2%). Of the 220 eligible children, 189 (86%) were in the Non-HRG group, and their 5-year EFS was 77.8% +/- 3% (SE). The cumulative CNS recurrence rate for patients without CNS disease at presentation was 3.1% +/- 1% (SE) (isolated, 1.7%; combined, 1.4%). Within the risk subsets defined by the BFM 86 of the Non-HRG, the 5-year EFS rates of the RG (148 patients) and the SRG (41 patients) were 74.8% +/- 4% (SE) and 89.5% +/- 5% (SE), respectively, and the rates of CNS recurrence (isolated and combined) were 4% and 0%, respectively. For the HRG (31 patients), the 5-year EFS and CNS recurrence rates were 47.9% +/- 9% (SE) and 8. 5% +/- 6% (SE), respectively.

CONCLUSIONS

Early extended TIT therapy in the context of modified BFM 86 systemic chemotherapy was found to provide adequate CNS protection and systemic leukemia control in patients with non-high risk ALL. However, no benefit for etoposide could be proven in this study.

Pediatric Acute Lymphoblastic Leukemia: Challenges and Controversies in 2000

This article discusses ways in which pediatric patients with acute lymphoblastic leukemia (ALL) can be stratified to receive intensive and less intensive therapies in order to decrease morbidity and mortality. Specifically, the focus may shift away from current intensive therapies for ultra low-risk patients and away from transplantation for certain patients at relapse. In contrast, infants with ALL comprise an ultra high-risk population in need of specialized approaches.

In Section I Dr. Lange describes the need to identify ultra low-risk children. Groups around the world have improved the outcome of children with ALL by identifying the basic “total therapy” model of the 1970s and stratifying treatment according to risk of relapse. Current first-line treatment cures about 85% of children with standard-risk ALL and 70% of children with high-risk disease. However, all children receive anthracyclines, alkylating agents, or moderate- to high-dose antimetabolite infusions. While randomized clinical trials prove that these intensifications reduce relapses, they also show that half of all children with ALL can be cured with the modest therapy of the 1970s and early 1980s. The patients curable with lesser therapy may be considered an ultra low-risk group. Attempts to use age, gender, white count, morphology, and karyotype to identify the ultra low-risk group of patients with a 90-95% cure rate with minimal therapy have failed. An expanded repertoire of tools such as pharmacogenetic profiling, PCR measurement of minimal residual disease and microarray technology may make this goal achievable in this decade.

In section II Dr. Chessells addresses the management of children with relapsed ALL. The chance of successful re-treatment with conventional chemotherapy for relapse depends on the duration of first remission and the site of relapse. Bone marrow transplantation from a histocompatible sibling or other suitable donor, which is widely accepted as the treatment of choice for children with a first remission of < 24 months, is associated with a high risk of relapse. Bone marrow transplantation for later bone marrow relapse improves leukemia-free survival but has significant short-term and long-term toxicities. The challenges are to develop more effective treatment for early relapse and to identify those children with relapsed ALL who are curable with chemotherapy or, failing this, those children who would be candidates for bone marrow transplantation in third remission.

In Section III Dr. Felix addresses the problem of infant ALL. ALL of infancy is clinically aggressive, and infants continue to have the worst prognosis of all pediatric patients with ALL. High white blood cell count, younger age, bulky extramedullary disease, and CNS disease at diagnosis are unfavorable characteristics. These features occur with MLL gene translocations. The probability of an MLL gene translocation and the probability of poor outcome both are greatest in younger infants. Specialized intensive chemotherapy approaches and bone marrow transplantation in first remission for this disease may lead to improved survival.

Refined recognition of pediatric patients with ALL who need more and less intensive therapies is necessary to increase survival and decrease toxicities.

Acute lymphoblastic leukemia in children

As the overall long-term event-free survival rate in children with acute lymphoblastic leukemia approaches 80%, emphasis is being placed on risk-directed therapy so that patients are neither overtreated nor undertreated. It has become apparent that a risk assignment system based on primary genetic abnormalities is inadequate by itself. For example, leukemias with the MLL-AF4 or BCR-ABL fusion gene are, in fact, heterogeneous diseases. Many require allogeneic hematopoietic stem-cell transplantation; some, if the patient is of favorable age and has a low presenting leukocyte count, can be cured with chemotherapy alone. Measurement of early responses to therapy and extent of minimal residual disease can greatly improve the accuracy of risk assessment. Consideration of the variable effects of therapy on the prognostic significance of specific genetic abnormalities is also important. Therefore, TEL-AML1 fusion confers a favorable prognosis in some protocols of chemotherapy but not in others. Studies to identify genetic polymorphisms with pharmacokinetic and pharmacodynamic significance promise to guide further refinement of treatment strategies. This will allow maximization of anticancer effects without induction of unacceptable toxicity in individual patients.

Early Intensification of Intrathecal Chemotherapy Virtually Eliminates Central Nervous System Relapse in Children With Acute Lymphoblastic Leukemia

Central nervous system (CNS) relapse has been an obstacle to uniformly successful treatment of childhood acute lymphoblastic leukemia (ALL) for many years. We therefore intensified intrathecal chemotherapy (simultaneously administered methotrexate, hydrocortisone, and cytarabine) for 165 consecutive children with newly diagnosed ALL enrolled in Total Therapy Study XIIIA from December 1991 to August 1994. The 64 patients (39%) who had 1 or more blast cells in cytocentrifuged preparations of cerebrospinal fluid at diagnosis, with or without associated higher-risk features, received additional doses of intrathecal chemotherapy during remission induction and the first year of continuation treatment. Patients with higher-risk leukemia, regardless of cerebrospinal fluid findings, also received additional doses of intrathecal chemotherapy during the first year of continuation treatment. Cranial irradiation was reserved for patients with higher-risk leukemia (22% of the total). The 5-year cumulative risk of an isolated CNS relapse among all 165 patients was 1.2% (95% confidence interval, 0% to 2.9%), whereas that of any CNS relapse was 3.2% (0.4% to 6.0%). The probability of surviving for 5 years without an adverse event of any type was 80.2% ± 9.2% (SE). Our results suggest that early intensification of intrathecal chemotherapy will reduce the risk of CNS relapse to a very low level in children with ALL, securing a higher event-free survival rate overall.

Early Intensification of Intrathecal Chemotherapy Virtually Eliminates Central Nervous System Relapse in Children With Acute Lymphoblastic Leukemia

Central nervous system (CNS) relapse has been an obstacle to uniformly successful treatment of childhood acute lymphoblastic leukemia (ALL) for many years. We therefore intensified intrathecal chemotherapy (simultaneously administered methotrexate, hydrocortisone, and cytarabine) for 165 consecutive children with newly diagnosed ALL enrolled in Total Therapy Study XIIIA from December 1991 to August 1994. The 64 patients (39%) who had 1 or more blast cells in cytocentrifuged preparations of cerebrospinal fluid at diagnosis, with or without associated higher-risk features, received additional doses of intrathecal chemotherapy during remission induction and the first year of continuation treatment. Patients with higher-risk leukemia, regardless of cerebrospinal fluid findings, also received additional doses of intrathecal chemotherapy during the first year of continuation treatment. Cranial irradiation was reserved for patients with higher-risk leukemia (22% of the total). The 5-year cumulative risk of an isolated CNS relapse among all 165 patients was 1.2% (95% confidence interval, 0% to 2.9%), whereas that of any CNS relapse was 3.2% (0.4% to 6.0%). The probability of surviving for 5 years without an adverse event of any type was 80.2% ± 9.2% (SE). Our results suggest that early intensification of intrathecal chemotherapy will reduce the risk of CNS relapse to a very low level in children with ALL, securing a higher event-free survival rate overall.