Long-term follow-up of Dutch Childhood Leukemia Study Group (DCLSG) protocols for children with acute lymphoblastic leukemia, 1984-1991

Increased risk of subsequent neoplasm after hematopoietic stem cell transplantation in 5-year survivors of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) survivors are at risk for developing subsequent neoplasms, but there is limited information on long-term risks and risk factors for both subsequent malignant neoplasms (SMNs) and subsequent non-malignant neoplasms (SNMNs). We analyzed long-term risk and risk factors for SMNs and SNMNs among 3291 5-year ALL survivors from the Dutch Childhood Cancer Survivor Study-LATER cohort (1963-2014). We calculated standardized incidence ratios (SIRs) and cumulative incidences and used multivariable Cox proportional hazard regression analyses for analyzing risk factors. A total of 97 survivors developed SMNs and 266 SNMNs. The 30-year cumulative incidence was 4.1% (95%CI: 3.5-5.3) for SMNs and 10.4%(95%CI: 8.9-12.1) for SNMNs. Risk of SMNs was elevated compared to the general population (SIR: 2.6, 95%CI: 2.1-3.1). Survivors treated with hematopoietic stem cell transplantation (HSCT) with total body irradiation (TBI) (HR:4.2, 95%CI: 2.3-7.9), and without TBI (HR:4.0,95%CI: 1.2-13.7) showed increased SMN risk versus non-transplanted survivors. Cranial radiotherapy (CRT) was also a risk factor for SMNs (HR:2.1, 95%CI: 1.4-4.0). In conclusion, childhood ALL survivors have an increased SMN risk, especially after HSCT and CRT. A key finding is that even HSCT-treated survivors without TBI treatment showed an increased SMN risk, possibly due to accompanied chemotherapy treatment. This emphasizes the need for careful follow-up of HSCT and/or CRT-treated survivors.

Reduced Dose Intensity of Daunorubicin During Remission Induction for Low-Risk Patients With Acute Lymphoblastic Leukemia: A Retrospective Cohort Study of the Chinese Children’s Cancer Group

It is urgently necessary to reduce the adverse effects of chemotherapy while maintaining their cure high rates for children with acute lymphoblastic leukemia (ALL). The present study aimed to determine whether the dose intensity of daunorubicin during the remission-induction phase could be reduced for low-risk patients with ALL. A total of 2396 eligible patients, who participated in CCCG-ALL-2015 study and were provisionally assigned to the low-risk group, were included and divided into single-dose group and double-dose group according to the dosage of daunorubicin during the remission-induction phase. For patients with ETV6-RUNX1 positive ALL or hyperdiploidy ALL, there were no significant differences in outcomes between the two groups. For other patients, the 5-year event-free survival rate was significantly better and the 5-year cumulative risk of any relapse was significantly lower in the double-dose group compared with the single-dose group. Both the 5-year overall survival rate and the risk of early deaths were not significantly different between the two groups. Our results suggested that only B-lineage ALL patients with ETV6-RUNX1 positivity or hyperdiploidy who achieved an early negative minimal residual disease status were suitable candidates for dosage reduction of daunorubicin during the remission-induction phase.

Female reproductive function after treatment of childhood acute lymphoblastic leukemia

BACKGROUND

The aim was to evaluate self-reported reproductive characteristics and markers of ovarian function in a nationwide cohort of female survivors of childhood acute lymphoblastic leukemia (ALL), because prior investigations have produced conflicting data.

PROCEDURE

Self-reported reproductive characteristics were assessed by questionnaire among 357 adult 5-year survivors, treated between 1964 and 2002, and 836 controls. Ovarian function was assessed by serum levels of anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), and inhibin B and by antral follicle count (AFC). Differences between controls and (subgroups of) survivors (total group, chemotherapy [CT]-only group, CT and radiotherapy [RT] group) were analyzed.

RESULTS

Survivors treated with CT only do not differ from controls regarding timing of menarche, virginity status, desire for children, or pregnancy rates. Compared to controls, the CT+RT group was at significantly increased risk of a younger age at menarche (P < .01), virginity, an absent desire for children, and lower pregnancy rates (odds ratio [OR] [95% CI]: 0.3 [CI 0.1-0.6], 0.5 [0.3-0.9], and 0.4 [0.2-0.9], respectively). Survivors in the CT-only group were significantly younger at the birth of their first child. Pregnancy outcomes were not significantly different between any (sub)groups. Survivors treated with total body irradiation (TBI) or hematopoietic stem cell transplantation (HSCT) are at increased risk of abnormal markers of ovarian function.

CONCLUSION

Reproductive function of ALL survivors treated with CT only does not differ from controls. However, survivors additionally treated with RT seem to be at an increased risk of certain adverse reproductive outcomes. Providing personalized counseling about (future) reproductive health risks in this group is imperative.

Predicting the neurobehavioral side effects of dexamethasone in pediatric acute lymphoblastic leukemia

Although dexamethasone is an effective treatment for acute lymphoblastic leukemia (ALL), it can induce a variety of serious neurobehavioral side effects. We hypothesized that these side effects are influenced by glucocorticoid sensitivity at the tissue level. We therefore prospectively studied whether we could predict the occurrence of these side effects using the very low-dose dexamethasone suppression test (DST) or by measuring trough levels of dexamethasone. Fifty pediatric patients (3-16 years of age) with acute lymphoblastic leukemia (ALL) were initially included during the maintenance phase (with dexamethasone) of the Dutch ALL treatment protocol. As a marker of glucocorticoid sensitivity, the salivary very low-dose DST was used. A post-dexamethasone cortisol level <2.0nmol/L was considered a hypersensitive response. The neurobehavioral endpoints consisted of questionnaires regarding psychosocial and sleeping problems administered before and during the course of dexamethasone (6mg/m(2)), and dexamethasone trough levels were measured during dexamethasone treatment. Patients with a hypersensitive response to dexamethasone had more behavioral problems (N=11), sleeping problems, and/or somnolence (N=12) (P<0.05 for all three endpoints). The positive predictive values of the DST for psychosocial problems and sleeping problems were 50% and 30%, respectively. Dexamethasone levels were not associated with neurobehavioral side effects. We conclude that neither the very low-dose DST nor measuring dexamethasone trough levels can accurately predict dexamethasone-induced neurobehavioral side effects. However, patients with glucocorticoid hypersensitivity experienced significantly more symptoms associated with dexamethasone-induced depression. Future studies should elucidate further the mechanisms by which neurobehavioral side effects are influenced by glucocorticoid sensitivity.

Hydrocortisone as an Intervention for Dexamethasone-Induced Adverse Effects in Pediatric Patients With Acute Lymphoblastic Leukemia: Results of a Double-Blind, Randomized Controlled Trial

PURPOSE

Dexamethasone is a key component in the treatment of pediatric acute lymphoblastic leukemia (ALL), but can induce serious adverse effects. Recent studies have led to the hypothesis that neuropsychological adverse effects may be a result of cortisol depletion of the cerebral mineralocorticoid receptors. We examined whether including a physiologic dose of hydrocortisone in dexamethasone treatment can reduce neuropsychologic and metabolic adverse effects in children with ALL.

PATIENTS AND METHODS

We performed a multicenter, double-blind, randomized controlled trial with a crossover design. Of 116 potentially eligible patients (age 3 to 16 years), 50 were enrolled and were treated with two consecutive courses of dexamethasone in accordance with Dutch Childhood Oncology Group ALL protocols. Patients were randomly assigned to receive either hydrocortisone or placebo in a circadian rhythm (10 mg/m(2)/d) during both dexamethasone courses. Primary outcome measure was parent-reported Strength and Difficulties Questionnaire in Dutch, which assesses psychosocial problems. Other end points included questionnaires, neuropsychological tests, and metabolic parameters.

RESULTS

Of 48 patients who completed both courses, hydrocortisone had no significant effect on outcome; however, a more detailed analysis revealed that in 16 patients who developed clinically relevant psychosocial adverse effects, addition of hydrocortisone substantially reduced their Strength and Difficulties Questionnaire in Dutch scores in the following domains: total difficulties, emotional symptoms, conduct problems, and impact of difficulties. Moreover, in nine patients who developed clinically relevant, sleep-related difficulties, addition of hydrocortisone reduced total sleeping problems and disorders of initiating and maintaining sleep. In contrast, hydrocortisone had no effect on metabolic parameters.

CONCLUSION

Our results suggest that adding a physiologic dose of hydrocortisone to dexamethasone treatment can reduce the occurrence of serious neuropsychological adverse effects and sleep-related difficulties in pediatric patients with ALL.

Early Response to Dexamethasone as Prognostic Factor: Result from Indonesian Childhood WK-ALL Protocol in Yogyakarta

Early response to treatment has been shown to be an important prognostic factor of childhood acute lymphoblastic leukemia (ALL) patients in Western studies. We studied this factor in the setting of a low-income province in 165 patients treated on Indonesian WK-ALL-2000 protocol between 1999 and 2006. Poor early response, defined as a peripheral lymphoblasts count of ≥1000/μL after 7 days of oral dexamethasone plus one intrathecal methotrexate (MTX), occurred in 19.4% of the patients. Poor responders showed a higher probability of induction failures compared to good responders (53.1% versus 23.3%, P < 0.01), higher probability of resistant disease (15.6% versus 4.5%, P = 0.02), shorter disease-free survival (P = 0.034; 5-year DFS: 24.9% ± 12.1% versus 48.6% ± 5.7%), and shorter event-free survival (P = 0.002; 5-year EFS: 9.7% ± 5.3% versus 26.3% ± 3.8%). We observed that the percentage of poor responders in our setting was higher than reported for Western countries with prednisone or prednisolone as the steroids. The study did not demonstrate a significant additive prognostic value of early response over other known risk factors (age and white blood cell count) for DFS and only a moderately added value for EFS.

Long-term results of Dutch Childhood Oncology Group studies for children with acute lymphoblastic leukemia from 1984 to 2004

The Dutch Childhood Oncology Group (DCOG) has used two treatment strategies for children with acute lymphoblastic leukemia (ALL) based on Pinkel's St Jude Total Therapy or the Berlin-Frankfurt-Münster (BFM) backbone. In four successive protocols, 1734 children were treated. Studies ALL-6 and ALL-9 followed the Total Therapy approach; cranial irradiation was replaced by medium-dose methotrexate infusions and prolonged triple intrathecal therapy; dexamethasone was used instead of prednisone. Studies ALL-7 and ALL-8 had a BFM backbone, including more intensive remission induction, early reinduction and maintenance therapy without vincristine and prednisone pulses. The 5-year event-free survival and overall survival increased from 65.4 to 80.6% (P<0.001) and from 78.7 to 86.4% (P=0.07) in ALL-7 and ALL-9, respectively. In ALL-7 and ALL-8 National Cancer Institute (NCI) high-risk criteria, male gender, T-lineage ALL and high white blood cells (WBCs) predict poor outcome. In ALL-9 NCI criteria, gender, WBC >100 x 109/l, and T-lineage ALL have prognostic impact. We conclude that the chemotherapy-only approach in children with ALL in Total Therapy-based strategies and BFM-backbone treatment does not jeopardize survival and preserves cognitive functioning. This experience is implemented in the current DCOG-ALL-10 study using a BFM backbone and minimal residual disease-based stratification.

Acute leukemia as a secondary malignancy in children and adolescents: current findings and issues

Secondary acute leukemia is a devastating complication in children and adolescents who have been treated for cancer. Secondary acute lymphoblastic leukemia (s-ALL) was rarely reported previously but can be distinguished today from recurrent primary ALL by comparison of immunoglobulin and T-cell receptor rearrangement. Secondary acute myeloid leukemia (s-AML) is much more common, and some cases actually may be second primary cancers. Treatment-related and host-related characteristics and their interactions have been identified as risk factors for s-AML. The most widely recognized treatment-related risk factors are alkylating agents and topoisomerase II inhibitors (epipodophyllotoxins and anthracyclines). The magnitude of the risk associated with these factors depends on several variables, including the administration schedule, concomitant medications, and host factors. A high cumulative dose of alkylating agents is well known to predispose to s-AML. The prevalence of alkylator-associated s-AML has diminished among pediatric oncology patients with the reduction of cumulative alkylator dose and limited use of the more leukemogenic alkylators. The best-documented topoisomerase II inhibitor-associated s-AML is s-AML associated with epipodophyllotoxins. The risk of s-AML in these cases is influenced by the schedule of drug administration and by interaction with other antineoplastic agents but is not consistently found to be related to cumulative dose. The unpredictable risk of s-AML after epipodophyllotoxin therapy may discourage the use of these agents, even in patients at a high risk of disease recurrence, although the benefit of recurrence prevention may outweigh the risk of s-AML. Studies in survivors of adult cancers suggest that, contrary to previous beliefs, the outcome of s-AML is not necessarily worse than that of de novo AML when adjusted for cytogenetic features. More studies are needed to confirm this finding in the pediatric patient population.

Monitoring treatment response of childhood precursor B-cell acute lymphoblastic leukemia in the AIEOP-BFM-ALL 2000 protocol with multiparameter flow cytometry: predictive impact of early blast reduction on the remission status after induction

Treatment response is a strong outcome predictor for childhood acute lymphoblastic leukemia (ALL). Here, we evaluated the predictive impact of flow cytometric blast quantification assays (absolute blast count, BC, and blast reduction rate, BRR) in peripheral blood (pB) and/or bone marrow (BM) at early time points of induction therapy (days 0, 8 and 15) on the remission status in the AIEOP-BFM-ALL 2000 protocol. At the single parameter level (905 patients), the strongest predictive parameter for the remission status as a dichotomous minimal residual disease (MRD) parameter (positive/negative) has been provided by the BC at day 15 in BM (cutoff: 17 blasts/microl; 50 vs 15%; odds ratio: 5.6; 95% confidence interval: 4.1-7.6, P<0.001), followed by the BRR at day 15 in BM and by the BC at day 8 in pB (odds ratios: 3.8 and 2.6, respectively). In the multiple regression analysis (440 patients), BC in pB (d0 and d8) and in BM (d15) as well as BRR at day 8 in pB provided significantly contributing variables with an overall correct prediction rate of 74.8%. These data show that the quantitative assessment of early response parameters, especially absolute BCs at day 15 in BM, has a predictive impact on the remission status after induction therapy.

Early postinduction intensification therapy is essential in childhood acute lymphoblastic leukemia

Postinduction intensification therapy (PII) has been key to success in the treatment of many types of childhood cancer and has led to an increase in cure rates during the past 3 decades. This Practice Point commentary discusses the recent findings of the Children's Cancer Group CCG-1961 study, which enrolled 2,078 children and adolescents with acute lymphoblastic leukemia. Patients with rapid marrow response to induction therapy were randomly allocated in a 2 x 2 factorial trial to receive either longer or increased intensity PII. A clear advantage--9% improved event-free survival and 6% improved overall survival at 5 years--was shown for more-intensive but not for longer PII; however, a high incidence of osteonecrosis and an increased rate of infections were observed in rapid early responders. This commentary emphasizes the need to balance the beneficial effects of PII in terms of disease control against the possibility of potentially debilitating late adverse sequelae.

The comparison of outcome and cost of three protocols for childhood non-high risk acute lymphoblastic leukemia in China

OBJECTIVE

To compare the outcome and treatment cost of three protocols for childhood non-high risk acute lymphoblastic leukemia (ALL), and evaluate the feasibility of less intensive treatment protocol for low income families.

METHODS

Two hundred forty-three children were newly diagnosed ALL in a university hospital from May 1999 to August 2006. Three protocols were offered to the patients: China-98 protocol, or modified ALLIC BFM2002 protocol, or an in-house Reduced Intensity Protocol (or also known as Economic Protocol).

RESULTS

Among 243 patients, 19 abandoned treatment, 3 transferred to other hospitals, 48 were high-risk and were treated with the high risk protocol, and 4 had mature B-ALL. A total of 169 cases were enrolled on non-high risk protocols: 46 treated on China-98 protocol, 73 on modified ALLIC BFM2002 and 50 from low income families on Economic Protocol. The event-free survival (EFS) at 4 years was 80.4% (95%CI, 68.8-92.2%), 83.5% (95%CI, 73.5-93.5%), and 72.8% (95%CI, 59.3-86.3%) for China-98 protocol, modified ALLIC BFM2002, and Economic Protocol respectively. The hospitalization costs (range and median) were significantly different between protocols: US$ 8,700-25,500 (12,500), US$ 6,900-16,400 (9,900), US$ 3,100-6,800 (4,300) for China-98 protocol, modified ALLIC BFM2002, and Economic Protocol respectively.

CONCLUSION

This report from China has systematically reviewed the outcome and costs of protocols for ALL having different dose intensity. The reduced intensity protocol appears to achieve reasonable EFS (72.8% at 4 years) for non-high risk ALL at a much lower cost. This is especially important for low income families in developing countries.

Neuropsychological Outcome in Chemotherapy-Only–Treated Children With Acute Lymphoblastic Leukemia

Purpose

To evaluate neuropsychological functioning over time in children treated for acute lymphoblastic leukemia (ALL) with chemotherapy only.

Patients and Methods

Forty-nine consecutive patients (median age at first assessment, 6.8 years; range, 4.0 to 11.8 years) treated with intrathecal and systemic chemotherapy were included in a nationwide, prospective-longitudinal, sibling-controlled study. Patients and siblings completed three extensive neuropsychological assessments: at diagnosis, 3 to 6 months after completion of (2-year) treatment and 4.5 years after diagnosis. Assessments included measures of learning, memory, attention, speed, executive functioning, visual-constructive functioning, and fine-motor functioning. Multilevel analyses were applied to evaluate patients' performances over time and to compare patients to 29 siblings (median age of siblings at first assessment, 8.2 years; range, 4.5 to 12.6 years) and to normative data.

Results

No major differences were found in neuropsychological performance between patients and siblings, with both groups performing mainly in the normal range. The patient group as a whole, however, scored significantly lower than the siblings on complex fine-motor functioning at the last evaluation. Large practice effects were found for both patients and siblings in four of 11 tasks. Patients who uttered physical complaints (ie, pain and/or tiredness) at the first pretreatment assessment scored significantly lower than siblings on attention and speed at the last two evaluations.

Conclusion

Despite intensive and potentially neurotoxic treatment, no evident negative, neuropsychological late effects were found 4.5 years after diagnosis, except for effects on complex fine-motor functioning. Both the large practice effects observed and the poorer performances on sustained attention for patients with physical complaints should be reckoned with in prospective, longitudinal neuropsychological research in children.

Circumvention of glucocorticoid resistance in childhood leukemia

In this study, we determined if in vitro resistance to prednisolone and dexamethasone could be circumvented by cortivazol or methylprednisolone, or reversed by meta-iodobenzylguanidine in pediatric lymphoblastic and myeloid leukemia. As there were strong correlations between the LC50 values (drug concentration inducing 50% leukemic cell kill, LCK) of the different glucocorticoids and median prednisolone/methylprednisolone, prednisolone/dexamethasone and prednisolone/cortivazol LC50 ratios did not differ between the leukemia subtypes, we conclude that none of the glucocorticoids had preferential anti-leukemic activity. Meta-iodobenzylguanidine however, partially reversed glucocorticoid resistance in 19% of the lymphoblastic leukemia samples.

Risk-adjusted therapy of acute lymphoblastic leukemia can decrease treatment burden and improve survival: treatment results of 2169 unselected pediatric and adolescent patients enrolled in the trial ALL-BFM 95

The trial ALL-BFM 95 for treatment of childhood acute lymphoblastic leukemia was designed to reduce acute and long-term toxicity in selected patient groups with favorable prognosis and to improve outcome in poor-risk groups by treatment intensification. These aims were pursued through a stratification strategy using white blood cell count, age, immunophenotype, treatment response, and unfavorable genetic aberrations providing an excellent discrimination of risk groups. Estimated 6-year event-free survival (6y-pEFS) for all 2169 patients was 79.6% (+/- 0.9%). The large standard-risk (SR) group (35% of patients) achieved an excellent 6y-EFS of 89.5% (+/- 1.1%) despite significant reduction of anthracyclines. In the medium-risk (MR) group (53% of patients), 6y-pEFS was 79.7% (+/- 1.2%); no improvement was accomplished by the randomized use of additional intermediate-dose cytarabine after consolidation. Omission of preventive cranial irradiation in non-T-ALL MR patients was possible without significant reduction of EFS, although the incidence of central nervous system relapses increased. In the high-risk (HR) group (12% of patients), intensification of consolidation/reinduction treatment led to considerable improvement over the previous ALL-BFM trials yielding a 6y-pEFS of 49.2% (+/- 3.2%). Compared without previous trial ALL-BFM 90, consistently favorable results in non-HR patients were achieved with significant treatment reduction in the majority of these patients.

Minimal residual disease-directed risk stratification using real-time quantitative PCR analysis of immunoglobulin and T-cell receptor gene rearrangements in the international multicenter trial AIEOP-BFM ALL 2000 for childhood acute lymphoblastic leukemia

Detection of minimal residual disease (MRD) is the most sensitive method to evaluate treatment response and one of the strongest predictors of outcome in childhood acute lymphoblastic leukemia (ALL). The 10-year update on the I-BFM-SG MRD study 91 demonstrates stable results (event-free survival), that is, standard risk group (MRD-SR) 93%, intermediate risk group (MRD-IR) 74%, and high risk group (MRD-HR) 16%. In multicenter trial AIEOP-BFM ALL 2000, patients were stratified by MRD detection using quantitative PCR after induction (TP1) and consolidation treatment (TP2). From 1 July 2000 to 31 October 2004, PCR target identification was performed in 3341 patients: 2365 (71%) patients had two or more sensitive targets (< or =10(-4)), 671 (20%) patients revealed only one sensitive target, 217 (6%) patients had targets with lower sensitivity, and 88 (3%) patients had no targets. MRD-based risk group assignment was feasible in 2594 (78%) patients: 40% were classified as MRD-SR (two sensitive targets, MRD negativity at both time points), 8% as MRD-HR (MRD > or =10(-3) at TP2), and 52% as MRD-IR. The remaining 823 patients were stratified according to clinical risk features: HR (n=108) and IR (n=715). In conclusion, MRD-PCR-based stratification using stringent criteria is feasible in almost 80% of patients in an international multicenter trial.

Biology and treatment of acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL), the most common type of cancer in children, is a heterogeneous disease in which many genetic lesions result in the development of multiple biologic subtypes. Today, with intensive multiagent chemotherapy, most children who have ALL are cured. The many national or institutional ALL therapy protocols in use tend to stratify patients in a multitude of different ways to tailor treatment to the rate of relapse. This article discusses the factors used in risk stratification and the treatment of pediatric ALL.

Post-treatment intellectual functioning in children treated for acute lymphoblastic leukaemia (ALL) with chemotherapy-only: A prospective, sibling-controlled study

Intellectual functioning (verbal, performance and full-scale IQ) in 43 children treated for acute lymphoblastic leukaemia (ALL) with chemotherapy-only was evaluated in a nationwide, prospective, sibling-controlled study. Intellectual assessment was performed at diagnosis and repeated shortly after cessation of 2 years treatment, including intrathecal and systemic chemotherapy. Using hierarchical regression analysis, patients' and siblings' (n=27) scores were longitudinally analysed and compared to assess possible changes and differences over time. At both assessments, before and after treatment, the patients showed average scores on intelligence tests compared to population norms. Longitudinal analysis and cross-sectional comparisons revealed no significant differences between patients and controls. Young patients showed a small relative decline, albeit not significant, on performance-IQ compared to healthy siblings. Despite intensive and potentially neurotoxic treatment, no evident negative effects on intelligence were found. However, it cannot be precluded that younger patients are at risk for a small decline in PIQ.

Changes in hypercoagulability by asparaginase: a randomized study between two asparaginases

Alterations in hemostasis have frequently been observed in children with acute lymphoblastic leukemia. Thrombotic events are well documented in patients receiving L-asparaginase as a single agent or in combination with other chemotherapeutic drugs. The present prospective, randomized study evaluated the effect of two different L-asparaginase preparations, native Escherichia coli L-asparaginase (Crasnitin; Bayer AG, Leverkusen, Germany; n = 10) and L-asparaginase derived from Erwinia chrysanthemi (Erwinase; Porton Pruducts, London, UK; n = 10) on the changes in parameters concerning hypercoagulability. Patients were randomized to receive a total of eight doses of 10,000 IU/m2 L-asparaginase intravenously with intervals of 3 days during induction therapy. Before starting L-asparaginase treatment all patients had already demonstrated an increased thrombin generation shown by the elevated levels of prothrombin fragment 1+2 and thrombin antithrombin III, presumably due to therapy with prednisone, daunorubicin and vincristine. A significant decrease in alpha2-antiplasmin and plasminogen levels was measured in the E. coli L-asparaginase but not in Erwinase-treated patients. Increased thrombin generation combined with a decrease in alpha2-antiplasmin and plasminogen levels may lead to a state of increased risk for thrombosis due to a delay in fibrin elimination in E. coli L-asparaginase-treated patients only.

[Twenty years of treating childhood acute lymphoblastic leukemia]

BACKGROUND

Conventional prognostic factors for relapse in patients with acute lymphoblastic leukemia (ALL) are the main basis of risk-stratified treatments.

OBJECTIVES

To analyze conventional risk factors for relapse and design a predictive model for relapse in our series, after 20 years of experience in treating ALL.

PATIENTS AND METHOD

We performed a multivariate analysis of conventional prognostic factors in the treatment of ALL in our unit and compared them with the risk groups in the Berlin-Frankfurt-Münster (BFM-ALL) treatment protocols.

RESULTS

Between 1984 and 2004, 232 children were diagnosed with ALL and treated according to the different versions of the BFM protocols (BFM83, BFM86, BFM90 and BFM95) at the Hospital Niño Jesús, Madrid, Spain. The event-free survival for all patients was 79.4 % (95 % CI: 72.7-85.4). Overall survival among patients who relapsed was 10.72 % (95 % CI: 6-27.3). The only significant prognostic factor for relapse identified by multivariate analysis was leukocyte [white blood cell (WBC)] count higher than 80,000/ml at diagnosis (hazard ratio [HR]: 4.63; 95 % CI: 1.61-13.3; p 5 0,004). The sensitivity and specificity of WBC in predicting relapses were 31.4 % and 87.5 %, respectively. The sensitivity and specificity of BFM risk group stratification in predicting relapses were 25 and 85.9 respectively.

CONCLUSIONS

A leukocyte count at diagnosis higher than 80,000/ml and BFM risk-stratified treatment have insufficient sensitivity and specificity to identify relapses.

Leukaemia incidence and survival in children and adolescents in Europe during 1978–1997. Report from the Automated Childhood Cancer Information System project

Leukaemias constitute approximately one-third of cancers in children (age 0-14 years) and 10% in adolescents (age 15-19 years). Geographical patterns (1988-1997) and time trends (1978-1997) of incidence and survival from leukaemias in children (n=29,239) and adolescents (n=1929) were derived from the ACCIS database, including data from 62 cancer registries in 19 countries across Europe. The overall incidence rate of leukaemia in children was 44 per million person-years during 1988-1997. Lymphoid leukaemia (LL) accounted for 81%, acute non-lymphocytic leukaemia (ANLL) for 15%, chronic myeloid leukaemia (CML) for 1.5% and unspecified leukaemia for 1.3% of cases. Adjusted for sex and age, incidence of childhood LL was significantly lower in the East and higher in the North than in the British Isles. The overall incidence among adolescents was 22.6 per million person-years. The incidence of LL was rising in children (0.6% per year) and adolescents (1.9% per year). During 1988-1997 5-year survival of children with leukaemias was 73% (95% CI 72-74) and approximately 44% for infants and adolescents. Similar differences in survival between children and adolescents were observed for LL, much less so for ANLL. Survival differed between regions; prognosis was better in the North and West than the East. Remarkable improvements in survival occurred in most of the subgroups of patients defined by diagnostic subgroup, age, sex and geographic categories during the period 1978-1997. For children with ANLL most improvements in survival were observed in the 1990s.

Long-term results of a randomized trial on extended use of high dose L-asparaginase for standard risk childhood acute lymphoblastic leukemia

PURPOSE

Between September 1991 and May 1997, within the International Berlin-Frankfurt-Muenster Study Group (I-BFM-SG), a randomized study was performed aimed at assessing the efficacy of prolonged use of high-dose l-asparaginase (HD-l-ASP) during continuation therapy in children with standard risk (SR) acute lymphoblastic leukemia (ALL), treated with a reduced BFM-type chemotherapy.

PATIENTS AND METHODS

The Italian, Dutch, and Hungarian groups participated in this study denominated IDH-ALL-91, and 494 children were enrolled. Treatment consisted of a BFM-type modified backbone with omission of the IB part in induction and elimination of two doses of anthracyclines during reinduction in both arms at the beginning of continuation therapy. Patients were randomly assigned to receive (YES-ASP) or not (NO-ASP) 20 weekly HD-l-ASP (25,000 IU/m2).

RESULTS

The event-free-survival and overall survival probabilities at 10 years for the entire group were 82.5% (1.8) and 90.3% (1.3), respectively. Of the 490 patients eligible for random assignment, 355 (72.4%) were randomly assigned (178 YES-ASP and 177 NO-ASP). After a median follow-up of 9 years, the probability of disease-free survival at 10 years was 87.5% (SE, 2.5) for YES-ASP arm versus 78.7% (SE, 3.3) for NO-ASP arm (P = .03). In multivariate analysis, NO-ASP arm (P = .03), male sex (P = .004), and age older than 10 years (P = .0003) had a significantly adverse impact on outcome.

CONCLUSION

In this subset of patients, selected with criteria not including monitoring of minimal residual disease, application of extended HD-l-ASP may improve prognosis, compensating reduced leukemia control that results from adoption of a reduced-intensity BFM-backbone for treatment of children with SR ALL.

Treatment strategy and results in children treated on three Dutch Childhood Oncology Group acute myeloid leukemia trials

This report describes the long-term follow-up data of three consecutive Dutch Childhood Oncology Group acute myeloid leukemia (AML) protocols. A total of 303 children were diagnosed with AML, of whom 209 were eligible for this report. The first study was the AML-82 protocol. Results were inferior (5-year probability of overall survival (pOS) 31%) to other available regimes. Study AML-87 was based on the BFM-87 protocol, with prophylactic cranial irradiation in high-risk patients only, and without maintenance therapy. This led to a higher cumulative incidence of relapse than that reported by the Berlin-Frankfurt-Münster (BFM), but survival was similar (5-year pOS 47%), suggesting successful retrieval at relapse. The subsequent study AML-92/94 consisted of a modified BFM-93 protocol, that is, without maintenance therapy and prophylactic cranial irradiation. However, all patients were to be transplanted (auto- or allogeneic), although compliance was poor. Antileukemic efficacy was offset by an increase in the cumulative incidence of nonrelapse mortality, especially in remission patients, and survival did not improve (5-year pOS 44%). Our results demonstrate that outcome in childhood AML is still unsatisfactory, and that further intensification of therapy carries the risk of enhanced toxicity. Our patients are currently included in the MRC AML studies, based on the results of their AML 10 trial.

Clinical characteristics, biologic features and outcome for young adult patients with acute lymphoblastic leukaemia

Young adult patients with acute lymphoblastic leukaemia (ALL) represent a unique epidemiologic subgroup in that therapy may be provided by either adult or paediatric oncologists. There seem to be no differences in presenting clinical features, immunophenotypic characteristics, or cytogenetic abnormalities for young adult ALL patients treated on paediatric or adult protocols with the exception of median age (16-paediatric trials versus 19-adult trials). There is no evidence to suggest that age within the 16-21 year old subgroup has any prognostic significance. Compared with patients 1-9 years, young adult ALL patients have a lower incidence of favourable cytogenetics t(12; 21) hyperdiploidy, a slightly increased incidence of the t(9;22), and an increased frequency of T cell immunophenotype. Compared with patients >30 years, young adult ALL patients have a significantly lower incidence of the t(9; 22). In multiple studies, there is a consistent, large event-free survival and survival advantage for young adult patients treated on paediatric versus adult protocols.

Life-threatening hypercalcemia complicated by pancreatitis in a child with acute lymphoblastic leukemia

The authors describe a 9-year-old girl with precursor-B acute lymphoblastic leukemia (ALL) who presented with dehydration and severe hypercalcemia. She had received oral vitamin D and calcium supplementation for 4 days, the last dose 48 hours prior to admission, and required pediatric intensive care unit (PICU) hospitalization for management of the hypercalcemia and safe initiation of induction chemotherapy. Her clinical course was complicated by pancreatitis, disseminated intravascular coagulation, pleural effusion, and focal seizures. Although the exact mechanism of hypercalcemia was not elucidated, it was likely related to the underlying ALL, without dismissing the prior vitamin D and calcium supplementation as a possible contributing factor. The hypercalcemia resolved with specific antileukemic therapy along with supportive care and administration of calcitonin. Hypercalcemia is an uncommon metabolic abnormality in children with ALL, but it can be life-threatening. Children with ALL should be referred to tertiary-care institutions with PICU and subspecialty support because serious metabolic and other complications can occur before or after the administration of chemotherapy.

Feasibility of neuropsychological assessment in leukaemia patients shortly after diagnosis: directions for future prospective research

AIMS

To study neuropsychological functioning of newly diagnosed children with acute lymphoblastic leukaemia (ALL) within two weeks after diagnosis in order to determine the feasibility of a sibling controlled prospective study design.

METHODS

Fifty consecutive patients (median age at testing 6.6 years, range 4-12) were included in a prospective, longitudinal, nationwide study. Treatment would include intrathecal and systemic chemotherapy according to the DCLSG ALL-9 protocol. Children were evaluated with an extensive neuropsychological battery including measures of intelligence, memory, attention, language, visual-constructive function, and fine-motor abilities within two weeks after start of the chemotherapy. The control group consisted of 29 healthy siblings (median age at testing 8.2 years, range 4-12), who were tested <4 weeks after the patients' assessment.

RESULTS

Mean scores on Wechsler Intelligence Scales did not differ significantly between patients and siblings; mean IQ scores for both the patients and the controls were high average. To examine specific neuropsychological functions, norm scores based on the exact age were acquired by fitting procedures, but no significant differences were found.

CONCLUSIONS

Neuropsychological assessment of patients during early hospitalisation is feasible. The results indicate no adverse effect of illness and psychological factors on IQ and neuropsychological functioning of patients with recently diagnosed ALL. The prospective design of this study of cognitive late effects of chemotherapy will allow discrimination between adverse sequelae of disease and treatment.

Second induction in pediatric patients with recurrent acute lymphoid leukemia using DFCI-ALL protocols

Between 15% and 30% of children with acute lymphoblastic leukemia (ALL) experience disease recurrence. With the possible exception of patients presenting with late isolated extramedullary relapse, induction of second complete remission (CR) is employed as a stepping stone to allogeneic hematopoietic stem cell transplantation (HSCT). The authors report their institutional experience in the management of children with recurrent ALL using the Dana Farber Cancer Institute (DFCI) ALL protocol in patients treated initially with that same protocol. Successful reinduction was followed by allogeneic HSCT when possible. Between April 1986 and May 2003, 34 patients with recurrent ALL, treated at initial diagnosis with DFCI-ALL protocol therapy, were given the same protocol as repeat induction chemotherapy. The median age was 4.6 years at diagnosis and 7.1 years at recurrence. Median duration of CR1 was 30.3 months. Second CR was obtained in 29 (85%) patients. Twenty went on to allogeneic HSCT; 10 of them currently remain in CR. Two additional patients treated with chemotherapy without HSCT are also in continuous CR2. Overall, 13 (38%) of the 34 patients are alive with a median follow-up of 105 months. There were no toxic deaths due to the reinduction therapy. One child died of cardiac failure after autologous HSCT. The treatment of children with recurrent ALL using the DFCI-ALL protocol induction regimen after initial use of the same protocol is associated with a high rate of second CR with no excess toxicity. However, the overall prognosis in these patients remains unsatisfactory and needs to be improved.

Cytogenetics in acute leukemia

Cytogenetic analyses in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) have revealed a great number of non-random chromosome abnormalities. In many instances, molecular studies of these abnormalities identified specific genes implicated in the process of leukemogenesis. The more common chromosome aberrations have been associated with specific laboratory and clinical characteristics, and are now being used as diagnostic and prognostic markers guiding the clinician in selecting the most effective therapies. Specific chromosome aberrations and their molecular counterparts have been included in the World Health Organization classification of hematologic malignancies, and together with morphology, immunophenotype and clinical features are used to define distinct disease entities. However, the prognostic importance of less frequent recurrent aberrations in AML and ALL, both primary and secondary, is still to be determined. This review summarizes current views on clinical relevance of major cytogenetic findings in adult AML and ALL.

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.

Acute lymphoblastic leukemia followed by a clonally-unrelated EBV-positive non-Hodgkin lymphoma and a clonally-related myelomonocytic leukemia cutis

BACKGROUND

Complicating malignant hematopoietic proliferations might severely hamper the course of acute lymphoblastic leukemia (ALL) in patients with an otherwise good prognosis. It is important to distinguish whether such neoplastic proliferations represent ALL relapses or secondary treatment-related malignancies.

PROCEDURE

We present an 11-year-old girl with precursor-B-ALL in whom maintenance treatment was complicated by an isolated ALL relapse in the brain, nodular lymphoproliferations in the liver, and an isolated myelo-monocytic leukemia cutis. All these hemato-oncologic malignancies occurred in the background of a secondary immunodeficiency, most likely caused by cytotoxic treatment.

RESULTS AND CONCLUSIONS

Using a stepwise molecular approach, we were able to demonstrate that the liver infiltrates were Epstein-Barr virus (EBV)-positive, contained monoclonal mature B-cells with immunoglobulin heavy chain gene (IGH) gene rearrangements unrelated to the primary ALL, and thus represented a true secondary non-Hodgkin lymphoma (NHL). In contrast, the skin infiltrates consisted of myelo-monocytic cells with clonal IGH and T-cell receptor gamma gene rearrangements, identical to the precursor-B-ALL blasts at diagnosis. Thus, the disease course of the precursor-B-ALL patient was complicated by two different isolated extramedullary relapses (brain and skin) and a secondary EBV(+) B-NHL.

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.

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.

Recent advances in pediatric acute lymphoblastic and myeloid leukemia

Acute leukemia is the most common form of childhood cancer and is the primary cause of cancer-related mortality in children. In the United approximately 3250 cases are diagnosed annually in children and adolescents younger than 20 years, of whom 2400 have acute lymphoblastic leukemia (ALL). Treatment results in childhood ALL continue to improve, and the expected current cure rates approach 75 to 80% of all children with ALL, including T-ALL and mature B-cell ALL, the two variants that, not too long ago, had a considerably poorer prognosis compared with the common form of BpALL. The most significant new development in the past 2 years has been the development of further evidence for fetal origin of childhood leukemias, and additional evidence to support the notion that postnatal events modulating the events of immune-mediated elimination of these leukemic clones play a major role in the eventual development of clinical disease. Other epidemiologic developments include (1) increased appreciation of the role of drug-metabolizing enzymes, both in determining the predisposition to leukemia and response to therapy; and (2) both clinical observations and gene expression studies seeming to identify a new approach to the evaluation and treatment of children with MLL (11q23) rearrangements. A most remarkable new development in the induction therapy of childhood leukemia and lymphoma in the United States is the use of urate oxidase for prevention of tumor lysis syndrome and the associated uric acid nephropathy. Drug resistance, determined either on leukemic blast cells in vitro or by studies of MRD, is being looked at critically in an effort to improve the treatment results further. Consolidation with HDMTX has gained wider popularity with the realization that effective CNS prophylaxis can be achieved with intrathecal therapy plus HDMTX for consolidation. In contrast to ALL, the progress in the therapy of acute myeloid leukemia (AML) lags behind, with cure rates of approximately 40 to 50%. There is no convincing evidence for substitution of daunorubicin with other anthracyclines, nor evidence for using high-dose cytarabine during induction in childhood AML. Rather, a 3 + 10 regimen with total daunorubicin 180 mg/m2 and cytarabine 100 to 200 mg/2 for 10 days appears to yield the best results. The most important component of the postremission chemotherapy continues to be several courses of high-dose cytarabine. The results from the MRC 10, LAME 89/91 studies and the recent BFM 93 trial with high-dose cytarabine and mitoxantrone suggest that there may be some benefit to including this combination in the postremission phase of AML. Despite these improvements in chemotherapy, allogeneic BMT from a matched family donor remains the best option for most patients (excluding Down syndrome, APL, and possibly those with inv16). Newer prognostic markers of interest include FLT3/ITD and minimal residual disease at the end of induction therapy.

Minimal residual disease levels in bone marrow and peripheral blood are comparable in children with T cell acute lymphoblastic leukemia (ALL), but not in precursor-B-ALL

Sensitive and quantitative detection of minimal residual disease (MRD) in bone marrow (BM) samples of children with acute lymphoblastic leukemia (ALL) is essential for evaluation of early treatment response. In this study, we evaluated whether the traumatic BM samplings can be replaced by peripheral blood (PB) samplings. MRD levels were analyzed in follow-up samples of 62 children with precursor-B-ALL (532 paired BM-PB samples) and 22 children with T-ALL (149 paired BM-PB samples) using real-time quantitative PCR (RQ-PCR) analysis of immunoglobulin and T cell receptor gene rearrangements with sensitivities of 10(-3) to 10(-5) (one ALL cell in 10(3) to 10(5) normal cells). In 14 of the 22 T-ALL patients, detectable MRD levels were found in 67 paired BM-PB samples: in 47 pairs MRD was detected both in BM and PB, whereas in the remaining pairs very low MRD levels were detected in BM (n = 11) or PB (n = 9) only. The MRD levels in the paired BM-PB samples were very comparable and strongly correlated (r(s) = 0.849). Comparable results were obtained earlier by immunophenotyping in 26 T-ALL patients (321 paired BM-PB samples), which also showed a strong correlation between MRD levels in paired BM and PB samples (r(s) = 0.822). In 39 of the 62 precursor-B-ALL patients, MRD was detected in 107 BM-PB pairs: in 48 pairs MRD was detected in both BM and PB, in 47 pairs MRD was solely detected in BM (at variable levels), and in 12 pairs only the PB sample was MRD-positive at very low levels (</=10(-4)). Furthermore, in the 48 double-positive pairs, MRD levels in BM and PB varied enormously with MRD levels in BM being up to 1000 times higher than in the corresponding PB samples. Consequently, BM samples cannot easily be replaced by PB sampling for MRD analysis in childhood precursor-B-ALL, in line with their BM origin. In T-ALL, which are of thymic origin, BM sampling might be replaced by PB sampling, because the dissemination of T-ALL cells to BM and PB appears to be comparable.

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.

BFM-oriented treatment for children with acute lymphoblastic leukemia without cranial irradiation and treatment reduction for standard risk patients: results of DCLSG protocol ALL-8 (1991-1996)

Modern treatment strategies, consisting of intensive chemotherapy and cranial irradiation, have remarkably improved the prognosis for children with acute lymphoblastic leukemia. However, patients with a potential for cure are at risk of severe acute and late adverse effects of treatment. Furthermore, in 25-30% of patients treatment still fails. The objectives of the DCLSG study ALL 8 were to decrease the toxicity and to increase the effectivity of BFM-oriented treatment. Decrease of toxicity was aimed at by confirmation of the results of the previous DCLSG study ALL-7, showing that the majority (94%) of children with ALL can successfully be treated with BFM-oriented therapy without cranial irradiation, and by reduction of treatment for standard risk (SRG) patients. To increase the cure rate in medium risk (MRG) patients the efficacy of high doses of intravenous 6-mercaptopurine (HD-6MP) during protocol M and in SRG patients the efficacy of high doses of L-asparaginase (HD-L-ASP) during maintenance treatment was studied in randomized studies. Patient stratification and treatment were identical to protocol ALL-BFM90, with the following differences: no prophylactic cranial irradiation, SRG patients received only phase 1 of protocol I. Four hundred and sixty-seven patients entered the protocol: 170 SRG, 241 MRG and 56 HRG patients. The 5 years event-free survival rate for all patients was 73% (s.e. 2%); for SRG, MRG and HRG patients 85% (s.e. 3%), 73% (s.e. 3%) and 39% (s.e. 7%), respectively. In patients >1 year of age at diagnosis unfavorable prognostic factors were male sex, >25% blasts in the bone marrow at day 15 and initial white blood cell count (WBC) >50 x 10(9)/l. The cumulative risk of CNS relapse rate was 5% (s.e. 1%) at 5 years. These results confirm that the omission of cranial irradiation in BFM-oriented treatment does not jeopardize the overall good treatment results, nor does early reduction of chemotherapy in SRG patients. No benefit was observed from treatment intensification with HD-L-ASP in SRG patients, nor from HD-6MP in MRG patients.

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.

Variation in survival of European children with acute lymphoblastic leukaemia, diagnosed in 1978--1992: the EUROCARE study

The aim of this study was to provide a comparative description of geographical variations and time trends in the population-based survival of European children with acute lymphoblastic leukaemia (ALL). Data on 13344 newly diagnosed children (0--14 years) with ALL were included in the EUROCARE study and were collected were collected by 34 population-based cancer registries (four comprising only childhood malignancies), operating in 17 countries (four in Scandinavia, two in Southern Europe, three in Eastern Europe, six in Continental Europe and two in the UK). Age-specific crude survival rates were estimated for boys and girls according to country for the period 1985--1989 and in adjusted form to attain comparability. Overall pooled and weighted rates were estimated as European standards. Children dead at diagnosis or diagnosed only through a death certificate were excluded. Geographical variation was also estimated by calculating the relative death rate with respect to the pooled overall European rate. After adjustment for age, gender and country, a Cox regression analysis was used to estimate time trends in survival. Survival was compared with that in the USA, Japan, Canada and Australia. During 1985--1989, the 1-year survival rate varied from 99 to 79%, the 5-year survival rate from over 80 to 56% (with the exception of Estonia; 34%; 95% confidence interval (CI) 20--52) among the various countries; the European weighted means were 90 (95% CI 87--93) and 72% (95% CI 69--75), respectively. Survival was particularly favourable in (south) Sweden, Finland, Germany and The Netherlands and rather unfavourable in Estonia and (surprisingly) France, where only 4% of its population was covered by the participating registries. Compared with the period 1978--1981, the hazard ratio for the period 1986--1989 decreased to 0.59 (95% CI 0.54--0.64) and -- in a smaller set of registries -- to 0.49 (0.45--0.55) for 1990-1992, an annual decrease in this rate of approximately 3.5%. During 1985--1989, the 5-year survival rates for European children were largely similar to those found in the USA, Canada and Australia, but markedly better than those in Japan. Higher survival rates were found for countries with 'good' access to centrally organised diagnostic and treatment facilities which stimulated 'aggressive' treatments according to a protocol. However, a subdivision according to risk profiles, e.g. according to the initial white blood cell count at diagnosis, could not be made and this might have explained partially the geographical differences in survival, because a positive association appeared between incidence at age 1--4 years and 5-year survival in most countries.