The utility of performing the initial lumbar puncture on day 8 in remission induction therapy for childhood acute lymphoblastic leukemia: TCCSG L99-15 study

Central nervous system involvement in childhood acute lymphoblastic leukemia: challenges and solutions

Delivery of effective anti-leukemic agents to the central nervous system (CNS) is considered essential for cure of childhood acute lymphoblastic leukemia. Current CNS-directed therapy comprises systemic therapy with good CNS-penetration accompanied by repeated intrathecal treatments up to 26 times over 2-3 years. This approach prevents most CNS relapses, but is associated with significant short and long term neurotoxicity. Despite this burdensome therapy, there have been no new drugs licensed for CNS-leukemia since the 1960s, when very limited anti-leukemic agents were available and there was no mechanistic understanding of leukemia survival in the CNS. Another major barrier to improved treatment is that we cannot accurately identify children at risk of CNS relapse, or monitor response to treatment, due to a lack of sensitive biomarkers. A paradigm shift in treating the CNS is needed. The challenges are clear - we cannot measure CNS leukemic load, trials have been unable to establish the most effective CNS treatment regimens, and non-toxic approaches for relapsed, refractory, or intolerant patients are lacking. In this review we discuss these challenges and highlight research advances aiming to provide solutions. Unlocking the potential of risk-adapted non-toxic CNS-directed therapy requires; (1) discovery of robust diagnostic, prognostic and response biomarkers for CNS-leukemia, (2) identification of novel therapeutic targets combined with associated investment in drug development and early-phase trials and (3) engineering of immunotherapies to overcome the unique challenges of the CNS microenvironment. Fortunately, research into CNS-ALL is now making progress in addressing these unmet needs: biomarkers, such as CSF-flow cytometry, are now being tested in prospective trials, novel drugs are being tested in Phase I/II trials, and immunotherapies are increasingly available to patients with CNS relapses. The future is hopeful for improved management of the CNS over the next decade.

Asian population may have a lower incidence of hip osteonecrosis in childhood acute lymphoblastic leukemia

Osteonecrosis (ON), a long-term complication of acute lymphoblastic leukemia (ALL) treatment affects patients' quality of life. Although the incidence of any ON, including asymptomatic, was 21.7% among children with ALL in the U.S., the actual incidence and risk factors in Asia remain unknown. For over 11 years, we performed hip magnetic resonance imaging (MRI) screening to detect asymptomatic ON while initiating maintenance chemotherapy in newly diagnosed children with ALL. Overall, 164 of 175 patients underwent hip MRI screening. The incidence of symptomatic or any ON was 3.0% and 11.6%, respectively. Asymptomatic ON in patients < 10 and ≥ 10 years old was 4.0% and 35.9%, respectively (P < 0.001). In multivariate analysis, age ≥ 10 years was the only significant risk factor. Asymptomatic ON with necrosis of > 30% of the epiphyseal surface of the femoral head was detected in four patients (2.4%). All were ≥ 10 years. Three of them progressed to severe symptomatic ON. The incidence of any ON in Asia may be lower than that seen in the only screening study in the U.S. Future studies should clarify factors affecting such regional differences and develop an effective approach to avoid the progression of ON in children with ALL.

In-Hospital Management Might Reduce Induction Deaths in Pediatric Patients With Acute Lymphoblastic Leukemia: Results From a Japanese Cohort

Induction deaths (ID) remain a critical issue in the treatment of pediatric patients with acute lymphoblastic leukemia (ALL). The reported rate of ID in this population is 1% or higher. We speculate that this proportion might be lower in Japan because of mandatory hospitalization during induction therapy to manage complications. We retrospectively analyzed the incidence of ID among children with ALL enrolled in 4 Japanese study groups between 1994 and 2013. Among 5620 children, 41 (0.73%) cases of ID were noted. The median age was 6.5 years; 24 children were female, and 7 had T-cell ALL. Infection was the most common cause of ID (n=22), but the incidence (0.39%) was lower than that reported in western countries. Mortality within 48 hours from the onset of infection was low, comprising 25% of infection-related deaths. The incidence of infections caused by Bacillus species was low. Only 1 patient died because of Aspergillus infection. Fatal infections mostly occurred during the third week of induction therapy. Our findings suggest that close monitoring, stringent infection control, and immediate administration of appropriate antibiotics through hospitalization might be important strategies in reducing the rate of infection-related ID in pediatric patients with ALL.

Central Nervous System Involvement in Childhood Acute Lymphoblastic Leukemia: An Analysis of Day-One Versus Day-Eight Lumbar Punctures in Remission Induction Therapy

Introduction

Traumatic lumbar puncture (TLP+) can lead to the iatrogenic infiltration of the central nervous system (CNS) by circulating leukemic blast cells in childhood acute lymphoblastic leukemia (ALL). The risk of TLP+ is increased by a number of factors at the time of presentation of the disease, such as a high white cell count (WCC), T-ALL phenotype, and unstable clinical condition of the patient. For this reason, the first lumbar puncture (LP) was deferred until Day Eight of prednisolone prophase during remission induction therapy in one set of patients. The objective was to compare the historical cohort of Day-One LP with Day-Eight LP with respect to the incidence of TLP+ and de novo CNS leukemia.

Methods

A retrospective comparative data analysis of 1,185 childhood ALL patients aged 1-16 years was conducted based on the electronic medical records of the pediatric hematology-oncology department of The Indus Hospital (TIH), Karachi, from January 2010 to August 2018. A total of 600 patients whose LP was done on Day One (January 2010-May 2015) were placed in cohort A, whereas 585 patients whose LP was performed on Day Eight (June 2015-August 2018) were placed in cohort B. After the examination of the cerebrospinal fluid (CSF), the status of CNS infiltration was classified as CNS-1, CNS-2, CNS-3, and TLP+.

Results

A total of 1,185 patients were included in the study, of whom 600 patients were in cohort A and 585 patients in cohort B. The incidence of TLP+ was found to be lower in cohort B (1.7%) as compared with the incidence in cohort A (4.3%) (p-value=0.009). However, there was an increase in the incidence of CNS-3 cases in cohort B (8%) as compared to cohort A (3%) (p-value: <0.001). When the CNS status of both the cohorts was compared with that of the internationally published data, a low incidence of TLP+ cases was noted in patients with LP on Day Eight.

Conclusion

The modified approach of performing the first LP on Day Eight significantly reduced the incidence of TLP+ cases. However, an unusual finding of a significant increase in the CNS-3 leukemia was noted. More prospective studies are needed to investigate this significant increase in CNS-3 cases.

Prednisolone Prophase for a Week Versus Upfront Multiagent Chemotherapy in Childhood Acute Lymphoblastic Leukemia: An Analysis With Reference to Induction Mortality in a Developing Country

In childhood acute lymphoblastic leukemia, high treatment-related mortality, especially in the induction phase of treatment, is a major challenge for developing countries. The reasons are multifactorial, including a late presentation with higher disease burden, malnourishment, and limited support services. These factors may aggravate the toxic effects of upfront multiagent chemotherapy in terms of severe neutropenic sepsis and tumor lysis. Therefore, instead of upfront chemotherapy, we offered prednisolone prophase for 1 week with the objective of balancing the antileukemic versus the toxic effect of treatment. The data of 538 patients who received induction with this approach (cohort B) are compared for induction mortality with previous records of 438 patients (cohort A) treated with upfront chemotherapy. In the presence of similar clinical characteristics including age, sex, risk group, and phenotype in both cohorts, a significant difference was found in overall induction mortality of 9% in cohort B versus 14% in cohort A (P<0.05). This difference was also significant in the high-risk and T-cell phenotype, which strengthens our hypothesis that patients with higher burden of disease may experience more fatal toxic effects with upfront intensive chemotherapy. Therefore, we suggest that the prednisolone prophase approach is beneficial to control the disease with less severe toxic effects in our settings.

Nationwide survey of pediatric hypodiploid acute lymphoblastic leukemia in Japan

BACKGROUND

Ploidy is a highly significant prognostic factor for pediatric acute lymphoblastic leukemia (ALL). Children with hypodiploid ALL have poor outcomes despite current intensive chemotherapy. Little has been investigated with regard to hypodiploid ALL in Japanese children.

METHODS

We retrospectively collected clinical data on hypodiploid ALL cases from the registries of prospective multicenter trials conducted by the four independent clinical study groups in Japan between 1997 and 2012.

RESULTS

A total of 117 ALL patients with hypodiploidy were analyzed in this study. There were 101, eight, and eight patients with 45, 44, and fewer than 44 chromosomes, respectively. The 5 year overall survival rates differed significantly: 86.0%, 87.5%, and 62.5% for patients with 45, 44, and fewer than 44 chromosomes, respectively (P = 0.037). Of the eight patients with 44 chromosomes, seven were alive, including five patients who maintained complete remission without undergoing hematopoietic stem cell transplantation (HSCT). Of the eight patients with fewer than 44 chromosomes, six were good responders to prednisolone and none had induction failure, but the relapse rate was high (5/8). No patients had central nervous system relapse. Four patients underwent HSCT after relapse, but only one survived.

CONCLUSIONS

Outcomes of Japanese ALL patients with fewer than 44 chromosomes were poor, as previously reported in other countries. Although the sample size was small, patients with 44 chromosomes had better prognoses than those previously reported. Further studies including international collaboration are needed to improve outcomes for pediatric ALL patients with fewer than 44 chromosomes.

Treatment outcome of children with acute lymphoblastic leukemia: the Tokyo Children's Cancer Study Group (TCCSG) Study L04-16

The survival rate of children with acute lymphoblastic leukemia (ALL) has increased to approximately 90% after substantial progress in risk-oriented treatment strategies. Between 2005 and 2013, the Tokyo Children's Cancer Study Group (TCCSG) conducted a risk-oriented, non-randomized study, L04-16. The principal aim of this study was to assemble background characteristics and treatment outcomes, and gather genetic information on leukemic cells under central diagnosis. This report outlines the background characteristics and treatment outcomes of 1033 children with ALL treated according to a TCCSG platform. The 5-year event-free and overall survival (OS) rates for all children were 78.1 ± 1.3 and 89.6 ± 1.0%, respectively. The OS rate was significantly higher in children with B-cell precursor (BCP)-ALL (91.9 ± 1.0%, n = 916) than in those with T-ALL (71.9 ± 4.3%, n = 117, p < 0.001). In univariate analysis for BCP-ALL, children aged 1-6 years (5y-OS: 94.2 ± 1.0%), with an initial white blood cell count of < 20,000/μL (94.0 ± 1.0%), high hyperdiploidy (95.4 ± 1.6%), ETV6-RUNX1 (97.4 ± 1.2%) or TCF3-PBX1 (96.9 ± 2.1%), and "Day8NoBlasts" (96.4 ± 1.1%) had the best outcomes. Genetic investigation revealed two novel fusion genes within this cohort: ETV6-ZNF385A and ZNF362-TCF4. Our study highlighted the clinical aspects of genomic features of ALL in Japanese children. We provide fundamental information for the further molecular investigation of this disease.

Use of platelet transfusions prior to lumbar punctures or epidural anaesthesia for the prevention of complications in people with thrombocytopenia

BACKGROUND

People with a low platelet count (thrombocytopenia) often require lumbar punctures or an epidural anaesthetic. Lumbar punctures can be diagnostic (haematological malignancies, subarachnoid haematoma, meningitis) or therapeutic (spinal anaesthetic, administration of chemotherapy). Epidural catheters are placed for administration of epidural anaesthetic. Current practice in many countries is to correct thrombocytopenia with platelet transfusions prior to lumbar punctures and epidural anaesthesia, in order to mitigate the risk of serious procedure-related bleeding. However, the platelet count threshold recommended prior to these procedures varies significantly from country to country. This indicates significant uncertainty among clinicians regarding the correct management of these patients. The risk of bleeding appears to be low, but if bleeding occurs it can be very serious (spinal haematoma). Consequently, people may be exposed to the risks of a platelet transfusion without any obvious clinical benefit.This is an update of a Cochrane Review first published in 2016.

OBJECTIVES

To assess the effects of different platelet transfusion thresholds prior to a lumbar puncture or epidural anaesthesia in people with thrombocytopenia (low platelet count).

SEARCH METHODS

We searched for randomised controlled trials (RCTs), non-randomised controlled trials (nRCTs), controlled before-after studies (CBAs), interrupted time series studies (ITSs), and cohort studies in CENTRAL (the Cochrane Library 2018, Issue 1), MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 13 February 2018.

SELECTION CRITERIA

We included RCTs, nRCTs, CBAs, ITSs, and cohort studies involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given to prevent bleeding in people of any age with thrombocytopenia requiring insertion of a lumbar puncture needle or epidural catheter.The original review only included RCTs.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane for including RCTs, nRCTs, CBAs, and ITSs. Two review authors independently assessed studies for eligibility and risk of bias and extracted data. Results were only expressed narratively.

MAIN RESULTS

We identified no completed or ongoing RCTs, nRCTs, CBAs, or ITSs. No studies included people undergoing an epidural procedure. No studies compared different platelet count thresholds prior to a procedure.In this update we identified three retrospective cohort studies that contained participants who did and did not receive platelet transfusions prior to lumbar puncture procedures. All three studies were carried out in people with cancer, most of whom had a haematological malignancy. Two studies were in children, and one was in adults.The number of participants receiving platelet transfusions prior to the lumbar puncture procedures was not reported in one study. We therefore only summarised in a narrative form the relevant outcomes from two studies (150 participants; 129 children and 21 adults), in which the number of participants who received the transfusion was given.We judged the overall risk of bias for all reported outcomes for both studies as 'serious' based on the ROBINS-I tool.No procedure-related major bleeding occurred in the two studies that reported this outcome (2 studies, 150 participants, no cases, very low-quality evidence).There was no evidence of a difference in the risk of minor bleeding (traumatic tap) in participants who received platelet transfusions before a lumbar puncture and those who did not receive a platelet transfusion before the procedure (2 studies, 150 participants, very low-quality evidence). One of the 14 adults who received a platelet transfusion experienced minor bleeding (traumatic tap; defined as at least 500 x 10⁶/L red blood cells in the cerebrospinal fluid); none of the seven adults who did not receive a platelet transfusion experienced this event. Ten children experienced minor bleeding (traumatic taps; defined as at least 100 x 10⁶/L red blood cells in the cerebrospinal fluid), six out of the 57 children who received a platelet transfusion and four out of the 72 children who did not receive a platelet transfusion.No serious adverse events occurred in the one study that reported this outcome (1 study, 21 participants, very low-quality evidence).We found no studies that evaluated all-cause mortality within 30 days from the lumbar puncture procedure, length of hospital stay, proportion of participants who received platelet transfusions, or quality of life.

AUTHORS' CONCLUSIONS

We found no evidence from RCTs or non-randomised studies on which to base an assessment of the correct platelet transfusion threshold prior to insertion of a lumbar puncture needle or epidural catheter. There are no ongoing registered RCTs assessing the effects of different platelet transfusion thresholds prior to the insertion of a lumbar puncture or epidural anaesthesia in people with thrombocytopenia. Any future study would need to be very large to detect a difference in the risk of bleeding. A study would need to be designed with at least 47,030 participants to be able to detect an increase in the number of people who had major procedure-related bleeding from 1 in 1000 to 2 in 1000. The use of a central data collection register or routinely collected electronic records (big data) is likely to be the only method to systematically gather data relevant to this population.

Treatment and biology of pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. In the past ALL was intractable but now the survival probability is as high as 80-90%. Improved supportive care, treatment stratification based on relapse risk, biological features of leukemic cells, and optimization of treatment regimens by nationwide and international collaboration have contributed to this dramatic improvement. While including traditional risk factors (e.g. age and leukocyte count at diagnosis), the treatment has been modified based on biological characteristics (aneuploidy and translocation) and treatment response (assessed by minimal residual disease). Treatment for pediatric ALL typically consists of induction therapy with steroids, vincristine, and asparaginase with or without anthracycline, followed by multi-agent consolidation including high-dose methotrexate and re-induction therapy. After consolidation, less intensive maintenance therapy is required for 1-2 years to maintain event-free survival. Recently, using advanced genomic analysis technology, novel sentinel genomic alterations that may provide more precise stratification or therapeutic targets, were identified. Moreover, in the last decade germline variations have been recognized as similarly important contributors to understanding the etiology and sensitivity of ALL to treatment. A more individualized approach based on genomic features (somatic and germline) and treatment response, the introduction of newly developed agents such as molecular targeted drugs or immunotherapy, and social support including long-term follow up are required for further improvement.

Prognostic factors and treatment of pediatric acute lymphoblastic leukemia

The event-free survival (EFS) for pediatric acute lymphoblastic leukemia (ALL) has shown remarkable improvement in the past several decades. In Korea also, a recent study showed 10-year EFS of 78.5%. Much of the improved outcome for pediatric ALL stems from the accurate identification of prognostic factors, the designation of risk group based on these factors, and treatment of appropriate duration and intensity according to risk group, done within the setting of cooperative clinical trials. The schema of first-line therapy for ALL remains mostly unchanged, although many groups have now reported on the elimination of cranial irradiation in all patients with low rates of central nervous system relapse. Specific high risk subgroups, such as Philadelphia chromosome-positive (Ph+) ALL and infant ALL continue to have significantly lower survival than other ALL patients. The introduction of tyrosine kinase inhibitors into therapy has led to enhanced outcome for Ph+ ALL patients. Infant ALL patients, particularly those with MLL rearrangements, continue to have poor outcome, despite treatment intensification including allogeneic hematopoietic cell transplantation. Relapsed ALL is a leading cause of mortality in pediatric cancer. Recent advances in immunotherapy targeting the CD19 of the ALL blast have shown remarkable efficacy in some of these relapsed and refractory patients. With improved survival, much of the current focus is on decreasing the long-term toxicities of treatment.

Immunophenotyping of the cerebrospinal fluid as a prognostic factor at diagnosis of acute lymphoblastic leukemia in children and adolescents

This study aimed at evaluating the use of immunophenotyping (IMP) in the identification of blast cells in the cerebrospinal fluid (CSF) of children and adolescents with acute lymphoblastic leukemia (ALL). Sixty-seven patients aged 18 years or younger were included. Fifty-five CSF samples were analyzed at initial diagnosis and 17 at the time of relapse. A cytological analysis (CA) was performed in all 72 samples, while IMP was done in 63. Blasts were identified in only three samples by CA, whereas all three samples were found negative by IMP, one of which had no isolation of nucleated cells after centrifugation. Among the samples analyzed by IMP, 11 showed a positive blast count, two of which had been inconclusive using CA. No equivalence was found between CA and IMP results (p = 0.55). CSF IMP positivity was not associated with other risk factors for ALL relapse. Among the 55 patients included at the time of diagnosis of ALL, eight relapsed during follow-up. Considering the cases of central nervous system (CNS) relapse, one of the patients belonged to the CSF IMP-positive group (11%) at diagnosis, and the other two cases, to the IMP-negative (5%) group. Detection of CSF blast cells using IMP was associated with a worse overall (p < 0.0001) and event-free survival (p < 0.0001). These results show that CSF IMP may be a useful additional method to conventional CA in the diagnosis of CNS involvement in ALL, and for the identification of high-risk subgroups that would benefit from an intensified therapy.

Treatment for childhood acute lymphoblastic leukemia in Taiwan: Taiwan Pediatric Oncology Group ALL-2002 study emphasizing optimal reinduction therapy and central nervous system preventive therapy without cranial radiation

BACKGROUND

Reinduction therapy has improved the outcomes in children with acute lymphoblastic leukemia (ALL). We sought to determine the optimal course(s) of reinduction therapy for standard-risk (SR, or "low-risk" in other groups) patients. Also, we evaluated outcomes using triple intrathecal therapy without cranial radiation (CrRT) for central nervous system (CNS) preventive therapy.

PROCEDURE

From 2002 to 2012, all newly diagnosed children with ALL in Taiwan were enrolled in Taiwan Pediatric Oncology Group ALL-2002 protocol. SR patients were randomized to receive single or double reinduction courses. The patients enrolled before 2009 received CrRT, while those enrolled later did not. The Kaplan-Meier method was used to estimate survival rates and the difference between two groups was compared by the two-sided log-rank test.

RESULTS

In 1,366 eligible patients, the 5-year overall survival (OS) was 81.6 ± 1.1% (standard error) and 5-year event-free survival (EFS) was 74.3 ± 1.2%. In SR patients, the 5-year OS for one and two reinduction courses was 91.6 ± 2.1% and 93.7 ± 1.8%, respectively, and the 5-year EFS was 85.2 ± 2.7% and 89.8 ± 2.3%, respectively. There were no significant differences in survival between these two groups. Patients with MLL or BCR-ABL1 had the worst outcomes: 5-year EFS was 23.4 and 31.8% and 5-year OS was 28.6 and 44.7%, respectively. There was no significant difference in CNS relapse or survival between the era with or without CrRT.

CONCLUSIONS

For SR patients, one-course reinduction was adequate. Triple intrathecal therapy alone successfully prevented CNS relapse.

Evaluation and Outcome of Central Nervous System Involvement in Pediatric Acute Lymphoblastic Leukemia in Dar es Salaam, Tanzania

BACKGROUND

Outcomes for acute lymphoblastic leukemia (ALL) in low-income countries lag far behind high-income countries (HIC). We explored the impact of central nervous system (CNS) involvement on outcome of pediatric patients with ALL in Tanzania.

PROCEDURE

Comprehensive chart review was performed to characterize CNS involvement, treatment, and outcomes of pediatric patients with ALL at Muhimbili National Hospital in Dar es Salaam, Tanzania between January 1, 2011 and December 31, 2013.

RESULTS

One hundred fifty-six patients with confirmed ALL had accessible data, and 128 initiated therapy. Sixteen percent of 156 patients had a documented cerebral spinal fluid analysis by cytospin. Seventy patients (45%) had a documented lumbar puncture with intrathecal (IT) therapy within 1 week of diagnosis. Thirteen patients presented with CNS involvement at diagnosis based on cytospin and/or unequivocal symptoms. Twenty-one patients (16%) experienced CNS relapse, three of whom had CNS disease at diagnosis. Median event-free survival (EFS) for all patients was 7.9 months and estimated EFS at 24 months was 31%. For the patients with CNS involvement at diagnosis, the estimated EFS at 24 months was 45%. Only three of 21 patients with CNS relapse were still alive with a median follow up of 3 months.

CONCLUSIONS

The rate of CNS disease in patients with ALL in Dar es Salaam at diagnosis and relapse was higher than that reported in HIC, and overall survival was lower. Improving outcomes will require further advances including consistent CNS prophylaxis and may include targeting high-risk patients with additional IT treatments.

Outcome of pediatric acute lymphoblastic leukemia with very late relapse: a retrospective analysis by the Tokyo Children's Cancer Study Group (TCCSG)

Relapse period is strongly associated with second relapse risk in relapsed acute lymphoblastic leukemia (ALL) in children. In this context, the treatment outcome of very late relapse should be better; however, data regarding very late relapse is limited. We retrospectively analyzed the outcomes of two consecutive Tokyo Children's Cancer Study Group (TCCSG) ALL trials (1995-2004) with a focus on late relapse, which was divided into two categories: late relapse (6-24 months from the end of therapy, n = 48) and very late relapse (>24 months from the end of therapy, n = 57). Forty-three patients (29 late relapse and 14 very late relapse) received allogeneic hematopoietic stem cell transplantation (HSCT) at second remission. The event-free survival (EFS) probabilities of late relapse and very late relapse were 54.5 ± 7.3 and 64.8 ± 6.8 % at 7 years, respectively (P = 0.36), and were not significantly different. However, the second relapse incidence of late relapse (34.7 ± 7.1 %) was higher than that of very late relapse (15.5 ± 5.1 %, P = 0.03). The second relapse risk was low for very late relapse ALL, which suggests that these patients should be treated without allogeneic HSCT.

Triple Intrathecal Therapy Alone With Omission of Cranial Radiation in Children With Acute Lymphoblastic Leukemia

Purpose

To eliminate the toxicities and sequelae of cranial irradiation (CrRT) and to minimize the adverse impact of traumatic lumbar puncture (TLP) with blasts, a prospective study of a modified CNS-directed therapy was conducted in children with acute lymphoblastic leukemia (ALL).

Patients and Methods

Since June 1999, children with newly diagnosed ALL have been treated with triple intrathecal therapy (TIT) alone without CrRT. The first TIT was delayed until the disappearance of blasts from peripheral blood (PB) for up to 10 days of multidrug induction, and CrRT was omitted in all patients. If PB blasts persisted on treatment day 10 (d10), the TIT was then performed.

Results

Of a total of 156 patients, 152 were eligible. Seventeen patients did not have PB blasts at diagnosis. Three fourths of the remaining patients achieved complete clearance of PB blasts by d10. Only hyperleukocytosis at diagnosis showed a significantly lower clearance rate. Six standard-risk patients were upgraded to high risk because of detectable PB blasts on d10. TLPs were encountered in four patients (2.6%), but none were contaminated with lymphoblasts. Neither CNS-2 (less than 5 WBCs/μL with blasts in a nontraumatic sample) nor CNS-3 (≥ 5 WBCs/μL with blasts in a nontraumatic sample or the presence of cranial nerve palsy) was present. The 5-year event-free survival and overall survival rates ± SE were 84.2% ± 3.0% and 90.6% ± 2.4%, respectively. No isolated CNS relapse occurred, but two patients experienced combined CNS relapses. The 7-year cumulative risk of any CNS relapse was 1.4% ± 1.0%.

Conclusion

Delaying first TIT until circulating blasts have cleared may improve CNS control in children with newly diagnosed ALL and preclude the need for CrRT.

Incidence and risk factors for central nervous system relapse in children and adolescents with acute lymphoblastic leukemia

BACKGROUND

Despite all the advances in the treatment of childhood acute lymphoblastic leukemia, central nervous system relapse remains an important obstacle to curing these patients. This study analyzed the incidence of central nervous system relapse and the risk factors for its occurrence in children and adolescents with acute lymphoblastic leukemia.

METHODS

This study has a retrospective cohort design. The studied population comprised 199 children and adolescents with a diagnosis of acute lymphoblastic leukemia followed up at Hospital das Clinicas, Universidade Federal de Minas Gerais (HC-UFMG) between March 2001 and August 2009 and submitted to the Grupo Brasileiro de Tratamento de Leucemia da Infância - acute lymphoblastic leukemia (GBTLI-LLA-99) treatment protocol.

RESULTS

The estimated probabilities of overall survival and event free survival at 5 years were 69.5% (± 3.6%) and 58.8% (± 4.0%), respectively. The cumulative incidence of central nervous system (isolated or combined) relapse was 11.0% at 8 years. The estimated rate of isolated central nervous system relapse at 8 years was 6.8%. In patients with a blood leukocyte count at diagnosis ≥ 50 x 10(9)/L, the estimated rate of isolated or combined central nervous system relapse was higher than in the group with a count < 50 x 10(9)/L (p-value = 0.0008). There was no difference in cumulative central nervous system relapse (isolated or combined) for the other analyzed variables: immunophenotype, traumatic lumbar puncture, interval between diagnosis and first lumbar puncture and place where the procedure was performed.

CONCLUSIONS

These results suggest that a leukocyte count > 50 x 10(9)/L at diagnosis seems to be a significant prognostic factor for a higher incidence of central nervous system relapse in childhood acute lymphoblastic leukemia.