Curing children of leukemia

L-Asparaginase from Erwinia carotovora: insights about its stability and activity

Enzymatic prospection indicated that L-asparaginase from Erwinia carotovora (ECAR-LANS) posses low glutaminase activity and much effort has been made to produce therapeutic ECAR-LANS. However, its low stability precludes its use in therapy. Herein, biochemical and biophysical assays provided data highlighting the influence of solubilization and storage into ECAR-LANS structure, stability, and activity. Moreover, innovations in recombinant expression and purification guaranteed the purification of functional tetramers. According to solubilization condition, the L-asparaginase activity and temperature of melting ranged up to 25-32%, respectively. CD spectra indicate the tendency of ECAR-LANS to instability and the influence of β-structures in activity. These results provide relevant information to guide formulations with prolonged action in the bloodstream.

Prevention of Brain Metastases

The incidence of brain metastases is projected to rise because survival rates of lung cancer, breast cancer, and melanoma continue to improve (1). The brain is being identified as a sanctuary site for harboring metastases despite excellent control of extracranial disease. This is thought to occur because the drug therapies that control extracranial disease have limited central nervous system (CNS) penetration. The development of brain metastases is a devastating diagnosis affecting both quality of life (QOL) and survival. Symptoms after diagnosis can include headache, nausea, vomiting, seizure, neurocognitive decline, and focal neurologic deficit. Some of these symptoms can be irreversible even after successful treatment of intracranial disease. Treatment of brain metastases often necessitates surgery and radiation. There have been some reports of systemic therapies offering an intracranial response however long-term data is lacking. These treatments for CNS metastases can also lead to neurocognitive sequelae impacting quality of life. Therefore, preventing disease from spreading to the brain is a topic that has generated much interest in oncology. Prophylactic cranial Irradiation (PCI) has been used in leukemia, small cell lung cancer (SCLC), and non-small cell lung cancer (NSCLC). While showing effectiveness in preventing intracranial disease development, its carries with it side effects of neurocognitive decline that can affect QOL. There are Clinical trials exploring novel delivery of PCI and concurrent neuroprotective drug therapy to try to mitigate these neurocognitive sequelae. These will be important trials to complete, as PCI has shown promise in controlling disease and prolonging survival in select patient populations. There are also drug therapies that have shown efficacy in preventing CNS metastases development. This review will explore the current therapies available to prevent CNS metastases.

Radiation therapy in the prevention of brain metastases

Over 150,000 cancer patients will be diagnosed with brain metastases this year alone. Survival for those diagnosed with brain metastases remains poor despite multimodality management with surgery, chemotherapy, and radiation. Preventative strategies to mitigate brain metastases have met with mixed results. In leukemia and small cell lung cancer there are defined roles for preventative radiation to be delivered, which can result in improved local control and survival. There is a less defined role for preventative radiation in locally advanced non-small cell lung cancer and budding interest for radiation prevention in breast cancer. The potential impact preventative cranial irradiation may have on neurocognitive function and quality of life needs to be considered prior to its administration.

Adult acute lymphocytic leukemia study testing chemotherapy and autologous and allogeneic transplantation. A follow-up report of the French protocol LALA 87

The French protocol LALA 87 was designed to compare three different postinduction strategies in adult acute lymphocytic leukemia (ALL): chemotherapy, autologous transplantation, and allogeneic transplantation. This trial demonstrated a significant superiority of allogeneic bone marrow transplantation (BMT) in high-risk ALL patients. Similarly, there was a trend in favor of autologous BMT over chemotherapy in those same patients. Allogeneic BMT was not superior to autologous BMT or chemotherapy in less aggressive leukemia (standard-risk ALL). Further improvements are warranted in the treatment of adult ALL. The authors' current ongoing study is stratifying patients to allocate them to regimens with risk-adapted treatment intensity.

Adult acute lymphocytic leukemia. Introduction and questions related to current programs

Significant progress has been made during the past 30 years in understanding the biology of adult acute lymphocytic leukemia and in treating the disease. This article lists some of the questions related to the current treatment programs for ALL and notes the remaining articles in this issue that address those questions.

Pilot studies of species-specific chemotherapy of childhood acute lymphoblastic leukemia using genotype and immunophenotype

Genotype and immunophenotype can be used to define biological species of acute lymphoblastic leukemia (ALL). The purpose of these two pilot studies, conducted between 1986 and 1994, was to explore the feasibility and acceptability of classifying ALL in this manner for selection of treatment rather than using conventional risk for failure factors such as age and initial white blood cell count. The possibility that conventional risk factors would be overcome and survival improved by this approach was also considered. Flow cytometry and chromosome analysis were used to classify the ALL of 150 children into one of five biologic categories as defined by cell surface antigens, DNA index and chromosome number and arrangement. Chemotherapy regimens depended on the assigned category. There was no provision for cranial irradiation and use of alkylating agents, anthracyclines and epipodophyllotoxins was restricted in order to reduce risk of late adverse sequelae. All patients are included in the analysis regardless of presenting condition or adherence to protocol. The majority of patients were Mexican-American or African-American. Eight-year event-free survival (EFS) is 60.7% (+/-4%) and 8-year overall survival (OAS) 72.6% (+/-3.7%). EFS and OAS varied significantly among the biologic categories despite differences in chemotherapy regimens. When the patients with B-precursor ALL were retrospectively classified by current Pediatric Oncology Group (POG) criteria, 8-year EFS was 82% (+/-7.3%) for the good risk group, 68.9% (+/-5.9%) for the standard risk and 48.8% (+/-7.6%) for the poor risk, all significant differences. However, when retrospectively classified according to the Rome/NCI prognostic criteria the 8-year EFS for standard risk patients was 69.1% (+/-5.1%) and for high risk 58.8% (+/-6.9%), not a statistically significant difference. Numbers of T cell and B cell patients are too few for comparison. Gender and ethnicity influenced survival as in treatment based on prognostic factors. Initial central nervous system (CNS) relapse occurred in five patients (3%) and combined CNS and hematological relapse in six (3%). Factors significantly associated with CNS and combined relapse were leukemic pleocytosis in the initial CSF sample, pro-B immunophenotype and DNA index <1.16, but not initial white blood cell count. Only three survivors appear to have serious late adverse sequelae, the only neurologic the result of asparaginase-induced cortical vein thrombosis. The results suggest that use of biologic species as defined by immunophenotype and genotype to select therapy of ALL is feasible and acceptable but under the conditions of these studies offered no apparent therapeutic advantage over conventional risk grouping. However, the introduction of molecular genotyping and novel gene targeted therapeutic agents justify further exploration of this approach.

Results of treatment with hyper-CVAD, a dose-intensive regimen, in adult acute lymphocytic leukemia

PURPOSE

To evaluate the efficacy and toxicity of Hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone), a dose-intensive regimen, in adult acute lymphocytic leukemia (ALL).

PATIENTS AND METHODS

Adults with newly diagnosed ALL referred since 1992 were entered onto the study; treatment was initiated in 204 patients between 1992 and January 1998. No exclusions were made because of older age, poor performance status, organ dysfunction, or active infection. Median age was 39.5 years; 37% were at least 50 years old. Mature B-cell disease (Burkitt type) was present in 9%, T-cell disease in 17%. Leukocytosis of more than 30 x 10(9)/L was found in 26%, Philadelphia chromosome-positive disease in 16% (20% of patients with assessable metaphases), CNS leukemia at the time of diagnosis in 7%, and a mediastinal mass in 7%. Treatment consisted of four cycles of Hyper-CVAD alternating with four cycles of high-dose methotrexate (MTX) and cytarabine therapy, together with intrathecal CNS prophylaxis and supportive care with antibiotic prophylaxis and granulocyte colony-stimulating factor therapy. Maintenance in patients with nonmature B-cell ALL included 2 years of treatment with mercaptopurine, MTX, vincristine, and prednisone (POMP).

RESULTS

Overall, 185 patients (91%) achieved complete remission (CR) and 12 (6%) died during induction therapy. Estimated 5-year survival and 5-year CR rates were 39% and 38%, respectively. The incidence of CNS relapse was low (4%). Compared with 222 patients treated with vincristine, doxorubicin, and dexamethasone (VAD) regimens, our patients had a better CR rate (91% v 75%, P <.01) and CR rate after one course (74% v 55%, P <.01) and better survival (P <.01), and a smaller percentage had more than 5% day 14 blasts (34% v 48%, P =.01). Previous prognostic models remained predictive for outcome with Hyper-CVAD therapy.

CONCLUSION

Hyper-CVAD therapy is superior to our previous regimens and should be compared with established regimens in adult ALL.

Accumulation of methotrexate polyglutamates, ploidy and trisomies of both chromosomes 4 and 10 in lymphoblasts from children with B-progenitor cell acute lymphoblastic leukemia: a Pediatric Oncology Group Study

Levels of accumulation of methotrexate polyglutamates were measured in vitro in lymphoblasts obtained at diagnosis from children with B-progenitor cell acute lymphoblastic leukemia (pro-B ALL). They were compared to numerical and structural chromosomal abnormalities present in these leukemic cells. In a series of 95 patients, the percent with high lymphoblast methotrexate polyglutamate levels increased with the increase in modal number of total chromosomes (p<0.001). Thus, lymphoblast methotrexate polyglutamate accumulation appeared to be closely linked to the extent of hyperdiploidy in childhood pro-B ALL. Lymphoblasts from 35 (88%) of the 40 children with hyperdiploid (>50 chromosomes) and 23 (88%) of 26 with hyperdiploid (DNA Index >1.16) pro-B ALL accumulated high levels of methotrexate polyglutamate, suggesting that they were more sensitive to methotrexate cytotoxicity. While children with hyperdiploid (DNA Index >1.16) pro-B ALL have a good prognosis, those with trisomies of both chromosomes 4 and 10, almost all of whom are hyperdiploid, have an even better outcome. There was no significant difference in methotrexate polyglutamate levels in lymphoblasts from 19 children with and 21 without trisomies of both chromosomes 4 and 10 (p = 0.25). The improved response to multi-agent chemotherapy conferred by the presence of trisomies of both chromosomes 4 and 10 in such patients may be due to increased sensitivity of their lymphoblasts to one or more anti-leukemic agents in addition to methotrexate.

Diagnostic and prognostic significance of chromosome abnormalities in childhood acute lymphoblastic leukemia

Current intensive chemotherapies cure about 70% of the children with ALL. On the other hand a significant number of the children are not cured despite intensive treatment. At the same time some highly curable patients are treated too intensively and suffer from unnecessary side effects of the chemo- and radiotherapy applied. In order to further improve the therapeutic results in this disease, we have to distinguish between the cases with a better and a worse prognosis. The initial karyotype (both numerical and structural chromosome abnormalities) proved to be one of the most reliable prognostic parameters, leading to the suggestion of developing genotype-specific therapies. Although the prognosis in patients with pseudodiploid karyotype is usually unfavorable, a significantly better prognosis can be observed in those with more than 50 chromosomes. Because the latter patients can achieve remission on a metabolite-based therapy, the toxic effects of more aggressive chemotherapy with anthracyclines and genotoxic agents can be avoided; thus, the reliable and accurate identification of patients with > 50 chromosomes is of particular importance. For this purpose three methods: chromosome analysis, DNA flow cytometry, and fluorescence in situ hybridization can be used. In 1993 it was decided to develop a comprehensive nationwide project in order to perform the initial genetic analysis of all ALL children diagnosed in the hematological/oncological centers of Hungary. Here the data obtained on 187 ALL patients diagnosed in the period from 1993 to 1995 are presented. In about 75% of patients (in 140 of 187) chromosome analysis was performed, in 78 cases (55.7%) successfully. The proportion of patients with abnormal karyotype was 36 of 78 (46.1%), and hyperdiploidy with more than 50 chromosomes was detected in 13 of 78 (16.6%) children. The lower ratio of hyperdiploid cases in our patients as compared to the data in the literature may be due to technical difficulties and the small number of patients studied, but it may reflect real geographic characteristics. Using flow cytometry, seven of 31 patients investigated (22.5%) proved to be hyperdiploid with a DNA index above 1.16. A higher ratio of hyperdiploid patients in this study calls attention to the significance of simultaneous application of the two methods. Taken together, 16 of 80 (20.0%) successfully studied patients proved to be hyperdiploid (> 50 chromosomes and/or DNA index above 1.16). The pattern of chromosome involvement in our study determined by chromosome analysis and/or FISH technique proved also to be different from the data of large international series. In addition to trisomies of chromosomes 4, 6, 10, 14, 17, 18, 21, and X, which are known to be the most frequently involved chromosomes, trisomies of chromosomes 3, 8, 11, and 13 were also observed with a high frequency. Comparison of survival curves of various cytogenetic subgroups showed a significant difference between diploid-pseudodiploid and diploid-hyperdiploid A (with 47-50 chromosomes) subgroups. No favorable prognosis of hyperdiploid patients (> 50 chromosomes) could be proved. Because of the small number of patients studied, prognostic differences of cytogenetic subgroups need further confirmation. The clinical and genetic differences observed, however, call attention to the necessity for further genetic studies of ALL patients in Hungary, because these differences may reflect real geographic characteristics and may be related to different environmental mutagen/carcinogen effects of the given geographic area. It is essential to determine whether or not these differences really exist and if they do to reveal the causes leading to these differences. In our view this is one of the routes by which the therapeutic results in childhood ALL can be further improved simultaneously with the avoidance of early and late toxicity of chemotherapy.

Testicular morphological changes in children with acute lymphoblastic leukemia following chemotherapy

Morphological changes in the testis induced by chemotherapy given according to the Tokyo Children's Cancer Study Group (TCCSG) regimens were studied in children with acute lymphoblastic leukemia (ALL). After informed consent, testicular biopsies were performed 14 times in 12 patients at the end of treatment. The testicular morphology in all cases had sustained a degree of damage. The tubular fertility index (TFI), calculated as the percentage of seminiferous tubules containing identifiable spermatogonia, was from 0 to 42.8% (mean 33.4%) below the normal value. Infiltration of leukemic cells was the most significant factor contributing to the decrease in TFI. There were no differences in the TFI among the TCCSG protocols. Formation of sperm was recognized in six cases, whose ages were 7, 8, 9, 10, 15 and 19 years. In two children, testicular biopsy was performed twice. In the second biopsy, TFI was elevated and sperm formation with the maturation of Leydig cells was observed. A number of other pathological changes were observed: modification of spermatogonia, Sertoli cells and inclusion bodies in spermatogonia, abnormal maturation of Leydig cells, evidence of interstitial fibrosis and thickening of the basement membrane. These results suggest that recent strong chemotherapy for the treatment of ALL might cause severe but not fatal damage to children's testicular tissue. As chemotherapy escalates, more investigation of testicular function will be necessary.

Drug combination testing in acute lymphoblastic leukemia using the MTT assay

Drug resistance assays may be useful to identify drug interactions. For this purpose, we studied three drug combinations, each at 8-12 concentrations, with the MTT assay in acute lymphoblastic leukemia (ALL) samples from 34 children obtained at initial diagnosis. This resulted in a total of 518 comparisons between expected and observed leukemic cell survivals. The combinations prednisolone (PRD) with vincristine (VCR), PRD with mafosfamide (MAF), and PRD with daunorubicin (DNR) were tested without technical difficulties, and without an increased assay variation as compared to single drugs. We observed a marked heterogeneity in drug interactions between patients, between combinations, and between different concentrations within one specific combination. Between PRD+VCR, synergism was found in 46%, antagonism in 18%, and additivity in 36% of the 228 observations. Between PRD+MAF, synergism was found in 51%, antagonism in 20%, and additivity in 29% of the 140 observations. Between PRD+DNR, synergism was found in 35%, antagonism in 31%, and additivity in 34% of the 150 observations. PRD+VCR and PRD+MAF showed more often synergism than PRD+DNR, while antagonism was observed more frequently between PRD+DNR (p < 0.05). However, the magnitude of antagonism was not much different between the three drug combinations, nor was there a significant antagonistic interaction in any of the drug combinations tested, if all samples were considered together. We conclude that the MTT assay can be used to study drug interactions in vitro in ALL samples. The type of interaction was different between patients, and depends on the drug combination and concentrations. The combinations PRD+VCR and PRD+MAF generally showed additive and even synergistic interactions. The cytotoxicity of PRD+DNR was generally not markedly higher than that of the most active single drug.

Concurrent RhGM-CSF does not offset myelosuppression from intensive chemotherapy: randomized placebo-controlled study in childhood acute lymphoblastic leukemia

To determine whether recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) can offset the myelosuppressive effects of intensive chemotherapy, we carried out a double-blind placebo-controlled trial in which 40 patients with acute lymphoblastic leukemia (ALL) were randomized into two groups of 20 each. One group received rhGM-CSF (5.5 micrograms/kg SC) coadministered with chemotherapy and the other, placebo coadministered with chemotherapy from day 5 to day 11 and from day 19 to day 25 of the 28-day intensification phase of our institutional high-risk protocol for childhood ALL. The results indicate that, at the dose and schedule used, rhGM-CSF did not prevent neutropenia or shorten the number of days required to complete this phase of therapy. In addition, the treated and placebo groups showed no significant difference in absolute neutrophil counts, number of days with neutropenia, number of days with fever, number of days spent in hospital, or number of days on antibiotics during the 28-day study period. There was also no difference between the two groups in the number, type, or severity of infectious episodes. Two of 20 patients in the treatment group have relapsed, whereas none of the patients in the placebo group has yet relapsed (follow-up: 3-37 months), but these events were not statistically significant. We conclude that treatment with rhGM-CSF at the dose and schedule employed is not clinically beneficial.

Lethality and mutagenesis of B lymphocyte progenitor cells following exposure to alpha-particles and X-rays

B lymphocyte precursor cells are the target cells for the major subtype of paediatric cancer, acute lymphoblastic leukaemia. Using a murine IL-7-dependent clonogenic assay for normal B cell precursors as a model, we have investigated the sensitivity of these cells versus other normal and leukaemic haemopoietic cells to alpha-particle radiation. We find that B cell precursors are remarkably susceptible to the lethal effects of alpha-particles and have a very low probability of surviving a single alpha-track. B cell precursors are also very sensitive to the lethal effects of low LET X-rays. The mutation frequency in a marker gene (HPRT) does not, however, appear to be greater in B cell precursors that survive X-radiation than in other haemopoietic cells.

Four-agent induction/consolidation therapy for childhood acute lymphoblastic leukemia: an Indian experience

During 1984-1986, a total of 128 children with acute lymphoblastic leukemia (ALL) were treated with an induction-consolidation regimen consisting of doxorubicin, vincristine, cytosine-arabinoside, and prednisolone. One hundred two (80%) patients belonged to high-risk group. The complete remission rate for all the patients was 91%. The event-free survival at 5 years was 32.0% +/- 23%. On multivariate analysis the event-free survival and disease-free survival was not altered by age, sex, WBC count, platelet count, LDH level, and surface phenotype. Infection due to prolonged marrow aplasia was a common complication, leading to mortality of 8 patients during induction and 33 patients during first remission. The relapse rate has been 36% (42 patients). The predominance of high-risk ALL in the Indian population underscores the need for intensive therapy. Improved supportive care during induction and remission seems essential to decrease therapy-related mortality, leading to improved survival.

Lessons from 20 years of curative therapy of childhood acute leukaemia

The past 20 years of curative therapeutics of childhood acute leukaemia has been largely a period of consolidation of gains, refinement of techniques and dissemination of expertise and technology. However, certain lessons have been learned. First, cure can be permanent but the complexity and cost of curative treatment currently restricts its accessibility; prevention or simple curative treatment is needed. Secondly, cure of the child demands that the risk of adverse sequelae of treatments be carefully balanced with known therapeutic benefits. Thirdly, preventive meningeal irradiation is no longer required. Fourth, treatment intensification is self-limiting. Adverse reactions can cancel out or exceed therapeutic benefits, resulting in a lower cure rate or a similar cure rate with lower quality of cure. Finally, morphology, immunophenotype and genotype of acute leukaemia are important criteria for selecting and scheduling drug therapy. Genotype may be the most important since leukaemia is a genetic disorder for which morphology and immunophenotype are mere reflections. However, none of these features, individually or together, are sufficient to explain all the difference in outcome among children on a given treatment plan or to completely fulfill the need of criteria for selection of treatment. Acute leukaemia remains an unsolved problem demanding considerably more basic and clinical research to meet the need for prevention and simple dependable curative treatment.

Minimal requirements for the diagnosis, classification, and evaluation of the treatment of childhood acute lymphoblastic leukemia (ALL) in the "BFM Family" Cooperative Group

Minimal requirements and their rationale for the diagnosis and the response to treatment in childhood acute lymphoblastic leukemia (ALL) were defined in the recently instituted "BFM-Family"-Group, in which the German, Austrian, Dutch, Italian, Belgian, French and Hungarian childhood leukemia study groups cooperate. ALL is defined as > or = 25% lymphoblasts in the bone marrow; for confirmation of the diagnosis and classification the criteria of the French-American-British (FAB) criteria are retained. For determination of the extent of the disease at diagnosis or relapse the criteria by the Rome Workshop [1986] are recommended: An obligatory panel of monoclonal antibodies for immunophenotyping was defined, as well as criteria for precursor B-ALL and T-ALL. Cytogenetic studies may support the diagnosis and subtyping, and are essential to identify certain patients with a high risk of treatment failure (f.i. t(9;22), t(4;11)). The role of molecular genetics for the diagnosis and the characterization of leukemia and the value of its clinical application needs further elucidation. Relapse was defined as recurrence of evident leukemia in the blood, bone marrow (> or = 25% lymphoblasts) or at any other site (to be confirmed by histological examination). Bone marrow involvement combined with extramedullary relapse was defined as > or = 5% lymphoblasts in the bone marrow.

Determination of the maximum tolerated dose of idarubicin when used in a combination chemotherapy program of reinduction of childhood ALL at first marrow relapse and a preliminary assessment of toxicity compared to that of daunorubicin: a report from the Childrens Cancer Study Group

An escalating-dose trial of idarubicin, used weekly for 3 doses in combination with vincristine, prednisone, and L-asparaginase (VPLI), to reinduce remission of childhood ALL at first bone marrow relapse was conducted by the Childrens Cancer Study Group (CCSG). The maximum tolerated dose (MTD) of idarubicin, used in the manner, was determined to be 12.5 mg/m2/dose. Twelve of 16 (75%) evaluable patients in first marrow relapse of ALL treated at a dose of 10 or 12.5 mg/m2 entered a second complete remission, compared to 41 of 69 evaluable patients (59%) treated in a comparable way with daunorubicin (30 mg/m2) (VPLD). Prolonged myelosuppression was observed in both groups, but the frequency of documented bacterial sepsis and the duration of required hospitalization were greater among patients treated with idarubicin. No additional toxicity, specifically attributable to idarubicin, was observed at these doses.

Maintenance chemotherapy and cure of childhood acute lymphoblastic leukaemia

Maintenance chemotherapy with 6-mercaptopurine and methotrexate, widely believed an essential contribution to the high cure rates achieved in children with acute lymphoblastic leukaemia (ALL), is thought to work by killing the leukaemia cells that remain after intensive chemotherapy. We suggest instead that ALL commonly arises in precursor B cells normally programmed to die, and that maintenance chemotherapy does not kill these cells but controls growth of the leukaemia clone so that programmed death can occur. A similar approach may apply to other cancers in which programmed death is intrinsic to the normal counterparts of the neoplastic cells.

Second neoplasms after acute lymphoblastic leukemia in childhood

BACKGROUND

Effective forms of treatment for acute lymphoblastic leukemia (ALL) in childhood now result in survival rates above 70 percent at five years, but the treatments are potentially carcinogenic. To determine the magnitude of this risk and identify possible risk factors for the development of second neoplasms, we studied a large cohort of children treated for ALL. METHODS AND RESULTS. We undertook a retrospective cohort study of 9720 children who had been given a diagnosis of ALL between June 1972 and August 1988 and had been treated according to the therapeutic protocols of the Children's Cancer Study Group. The median follow-up was 4.7 years (range, 2 months to 16 years). We found that 43 second neoplasms occurred among the children in the cohort, including 24 neoplasms of the central nervous system, 10 new leukemias and lymphomas, and 9 other neoplasms. This represented a 7-fold excess of all cancers and a 22-fold excess of neoplasms of the central nervous system. The estimated cumulative proportion of children in whom a second neoplasm developed was 2.53 percent 15 years after diagnosis (95 percent confidence limits, 1.74 percent and 3.38 percent). An even higher risk, particularly of central nervous system tumors, was evident in children five years of age or less at the time of the diagnosis of ALL (P = 0.012). All central nervous system neoplasms developed in children who had previously undergone irradiation. There was no association with exposure to cyclophosphamide or anthracyclines.

CONCLUSIONS

There is a substantial excess of second neoplasms, especially of the central nervous system, among children treated for ALL. Children five years old or younger and those receiving radiation are at higher risk, especially for second tumors arising in the central nervous system.

Descriptive epidemiology of childhood leukaemia

Internationally there is a 4-fold variation in age-adjusted incidence rates for childhood leukaemia (all types combined), with only slightly greater worldwide differences specifically for acute lymphocytic leukaemia (ALL) and for acute nonlymphocytic leukaemia (ANLL). Total leukaemia rates are highest among Hispanic populations in Costa Rica and Los Angeles (males), due primarily to elevated ALL incidence, while low rates occur among US blacks, Kuwaitis, Israeli non-Jews, and Bombay Indians. In most populations the patterns for ALL are similar to those for total leukaema, with peak incidence at ages 1-4 and a decline thereafter. Lower and more uniform rates are generally observed at all ages for ANLL. Age-adjusted rates for ANLL appear to vary substantially among some populations with uniform ALL incidence rates (e.g., among Asians) and yet appear to be similar in other populations with variation in ALL rates (e.g., whites and blacks in the US). Possible variation among registries in completeness of childhood leukaemia ascertainment and accuracy of diagnosis by cell type should be assessed, while case-control investigations among populations with very high and very low rates may provide useful information about the cell-type specific determinants of childhood leukaemia.

Curing acute leukemias in the 1990s

Recent advances have raised hope that all acute leukemias may be curable by the end of this decade. More specific and thus more effective and less toxic chemotherapy is now possible, and bone marrow transplantation has resulted in long-term survival of many patients. The authors discuss current management of acute leukemias and explain the implications of the latest research.

Idarubicin and high-dose cytarabine in the treatment of refractory and relapsed acute lymphoblastic leukemia

Between August 1985 and April 1989, 88 patients (31 children and 57 adults) with refractory of relapsed acute lymphoblastic leukemia (ALL) were treated in a cooperative Italian trial by an induction schedule of high-dose Cytarabine (HDAra-C) plus Idarubicin (IDA). Complete remission (CR) was achieved in 52 of the 88 patients (59%); 23 patients (26%) did not respond to treatment and 13 (15%) died during induction. The CR rate was significantly affected by the WBC count at the beginning of treatment and by the duration of first CR of the patients treated at first relapse. All of the patients experienced profound myelosuppression; the median time to recovery to neutrophils greater than 0.5 x 10(9)/l was 15 days (range 4-40), and 14 days (range 3-50) to platelets greater than 50 x 10(9)/l. The most common non-hematologic side effects observed were nausea and vomiting (51%), mucositis (40%) and diarrhea (23%). Twenty-one of the 52 patients who achieved CR underwent bone marrow transplantation (BMT), 16 autologous and 5 allogeneic. Eleven patients relapsed at a median of 4 months (range 1-31) after the transplantation, and three patients died while in CR. Seven patients have been in continuous CR (CCR) for a median of 36 months (range 26-42 months). Thirty-one patients were not entered in the BMT program: for two adults it was too early, three adults died in CR and 25 patients relapsed at a median of four months (range 1-25). Only one adult is still in CCR at 33 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment intensity and outcome for children with acute lymphocytic leukemia of standard risk. A Pediatric Oncology Group Study

Four hundred thirty-four children, with good-risk acute lymphocytic leukemia (ALL), were assigned randomly to receive intensive or less intensive maintenance therapy with 6-mercaptopurine and methotrexate, plus vincristine and prednisone pulses in such a way that patients on treatment 1 had their leukocyte counts maintained between 1500 and 3000/mm3. Patients on treatment 2 had leukocyte counts maintained between 3000 and 4500/mm3. Absolute granulocyte counts were maintained above 500/mm3 on both groups. All children received induction treatment with vincristine, prednisone and L-asparaginase and had central nervous system (CNS) prophylaxis with cranial irradiation and intrathecal methotrexate. The overall remission rate was 94%. Event-free survival at 8 years was 44% (SE, 5.6%). There was no significant difference in outcome between treatments 1 and 2 (P = 0.83). The incidence of infection was similar overall and not significantly different between treatment arms.

Species-specific therapy of acute lymphoid leukemia

In the past 10 years immunophenotyping of ALL has been demonstrated to be useful for selecting and scheduling chemotherapy. Different drug regimens are now used for T-cell and B-cell ALL than for non-T non-B ALL with the result that survival and cure of T-cell and B-cell ALL have been considerably improved. The use of different drug regimens for different immunophenotypic varieties of non-T non-B ALL is being tested. "Prognostic factors" of ALL are artifacts of data analysis and treatment and should no longer be used for guiding treatment. The administration of all-inclusive multiple-drug therapy to all patients with ALL regardless of species should also be abandoned. Minimally effective drugs can interfere with dosage and continuity of more effective drugs, and can result in side effects and sequelae that increase the mortality and morbidity of treatment. Since acute leukemias are genetic disorders of hematopoiesis the future direction of leukemic therapy is toward genetic targeting.

Intraocular penetration of cytosine arabinoside following subconjunctival administration in primates

Cytosine arabinoside was administered subconjunctivally to three monkeys. Blood, aqueous, and vitreous specimens were collected after 30 minutes, 1 hour, 2 hours, and 3 hours. Intraocular drug concentrations appeared stable or increasing over this time period while intravenous levels were relatively low. The results of this study suggest that therapeutic intraocular concentrations of cytosine arabinoside are obtained following subconjunctival administration in primates with lower, nontoxic intravenous levels during this time.

Epidemiology of the childhood acute leukemias

Epidemiologic studies of the childhood leukemias have provided information relevant to several aspects of the care and follow-up of these children. The observations made regarding in utero radiation and ALL risk have certainly curtailed the use of routine obstetric diagnostic radiographs; observations regarding the association between birth weight, fetal loss, and other gestational events provide added enthusiasm for further research into basic biologic events occurring during fetal development; and the genetic patterns of disease supply critical information for genetic counseling and follow-up of affected patients and families. Additionally, the continued epidemiologic surveillance of children with cancer serves to form the foundation from which we will assess any future changes in childhood cancer incidence or pattern. Although not discussed here, the epidemiology of late effects, including second malignancies, reproductive function, and neuropsychologic functioning will assume a more prominent role as more children survive ALL and move into adulthood. While analytic studies have yet to yield an association as strong as the lung cancer/cigarette association in adults, future research designed to isolate biologically homogeneous disease populations for study may lead us to new and important associations. The continued cooperation of large pediatric oncology groups and private physicians is crucial as these future investigations are undertaken.

T-cell acute childhood lymphoblastic leukemia with chromosome 14 q 11 anomaly: a morphologic, immunologic, and cytogenetic analysis of 10 patients

Ten patients with T-cell acute lymphoblastic leukemia (ALL) and a chromosome anomaly involving band 14 q 11 are described. Mitotic index of bone marrow blasts was high in all patients (average 3.0%). Lymphoid morphology of the leukemic blasts, however, varied somewhat among the patients. The leukemic cells of 5 patients showed an immunophenotypic profile corresponding to early or common thymic differentiation stages whereas 5 children showed strong expression of CD 3 suggesting a more mature thymic phenotype. Leukemic karyotypes revealed a modal chromosome number of 46 in 9 cases, 92 in one case. A chromosome translocation t(11; 14) (p 13; q 11) was found in 5 cases, a t(1; 14) (p 32; q 11) in 2 cases, a t(10; 14) (q 24; q 11) in one case, a (hitherto undescribed) t(12; 14) (q 22; q 11) in one case, and an inv (14) (q 11 q 32) in one patient. Additional abnormalities were t(3; 10), t(7; 9), dup(7 q), del(6 q), del(10 q), and del(1 q). Of 32 cases with T-cell ALL successfully karyotyped in our laboratory 15 (= 47%) had structural aberrations involving chromosomes 1, 3, 6, 7, 9, 10, 12, 14. Ten of these 15 patients (= 67%) had a chromosome 14 q 11 anomaly. It is concluded that chromosome band 14 q 11, the gene locus of the T-cell receptor alpha-chain, is the most common site for structural chromosome aberrations in T-cell ALL.