Time Of Central Nervous System Relapse Research Articles

Obesity as a Prognostic Factor of Central Nervous System Relapse in Children with Acute Lymphoblastic Leukemia: A Single-Centre Study and Literature Review.

Relapse as the commonest treatment failure through chemotherapy of child presented with acute lymphoblastic leukemia (ALL) is usually within 3 years of remission. Central nervous system (CNS) is expected as a site of extramedullary relapse in 3–8% of child leukemia, often leading to a poor prognosis. A few patients may have headache and vomiting and can be diagnosed without difficulty. However, most patients present with asymptomatic conditions. Obesity has become one of the greatest reported complications of children ALL survivors. Rarely, obesity presentation can be the first manifestation of CNS leukemia. Here, we present three unusual cases with B-ALL presentation of obesity as the first symptom at the time of CNS relapse after achieving remission. This highly localized presentation is unusual and would hopefully inform clinicians to have a high index of suspicion for relapse in children with ALL.

RARE-22. CHALLENGES IN MANAGEMENT OF CNS INVOLVEMENT OF CUTANEOUS T-CELL LYMPHOMA

Abstract BACKGROUND Cutaneous T-cell lymphoma (CTCL) is a group of T-cell lymphomas occurring primarily in the skin, without evidence of disease elsewhere. Central nervous system (CNS) involvement of CTCL is extremely rare, with a reported incidence of 5–9%. Due to its infrequency and radiographic appearance which mimics other CNS processes, CNS CTCL may be misdiagnosed. Here, we describe 8 cases of CNS CTCL at a single institution. METHODS The electronic medical records at our institution were queried for cases of CNS involvement by CTCL, between 2004–19. Clinical data, imaging and surgical pathology were reviewed. RESULTS Eight patients were diagnosed with CNS CTCL with median age of 68 and median time to development of CNS disease of 17 months. 1 patient had synchronous presentation of cutaneous and CNS disease identified at autopsy. Seven out of eight patients presented neurologically with behavioral and mental status changes and 1 patient had concurrent intraocular disease. Imaging showed bilateral non-enhancing T2/FLAIR signal changes in three patients; multifocal enhancement was noted in the others. Malignancy, inflammatory processes and infections including progressive multifocal leukoencephalopathy (PML) were often included in the radiographic differential diagnosis. Prior systemic therapies were variable, including palliative radiation, phototherapy, myeloablative chemotherapy followed by allogeneic stem cell transplant and oral methotrexate. 5 of 8 patients had active cutaneous disease at the time of CNS relapse. Six patients received initial treatment for CNS disease with high-dose methotrexate (HD-MTX). Comprehensive genomic analysis revealed recurrent alterations in genes associated with regulatory T-cell differentiation (SOCS1, NOTCH1), tumor suppressors (CDKN2A, PTEN, TP53); one case was hypermutated. CONCLUSIONS CNS involvement of CTCL is rare, occurring more than a year after initial cutaneous disease. Clinical and radiographic findings may be variable, necessitating high clinical suspicion. Most patients respond to HD-MTX. Further molecular analysis is ongoing.

Clinical presentation, treatment, and outcomes of patients with central nervous system involvement in extranodal natural killer/T-cell lymphoma

Extranodal natural killer (NK)/T-cell lymphoma (ENKTCL) is a rare type of Non-Hodgkin’s lymphoma which rarely metastasizes to the central nervous system (CNS). Ten of 60 patients (16.7%) with ENKTCL followed at Memorial Sloan Kettering Cancer Center (MSKCC) were diagnosed with CNS involvement between 1995 and 2016. Eight patients had systemic disease at the time of CNS diagnosis; one patient never developed systemic disease and another was in remission at the time of CNS relapse. Median overall survival was 3.8 months; at time of this report 9 patients have died and one who underwent autologous stem cell transplant (ASCT) is alive 27 months after CNS diagnosis. Five patients achieved a complete response in the CNS; one is still alive, one died of systemic disease, and three died of infection. CNS ENKTCL portends a grim prognosis, with no standard treatment. Prospective study on ASCT and immunotherapy in CNS ENKTCL is warranted.

Stearoyl-CoA Desaturase (SCD) Enhances Central Nervous System Leukemia

Background: Central nervous system (CNS) involvement by acute lymphoblastic leukemia (ALL) is a major clinical concern. Leukemic cells can be found in the CNS at diagnosis (1-2%) or, more frequently, at relapse (30%). Very little is known about the pathogenesis and therefore there are no targeted therapies. Prophylactic CNS-directed conventional intrathecal chemotherapy or irradiation are required for relapse-free survival. However, they are associated with substantial rates of short and long term toxicity. Therefore, elucidation of molecular mechanisms and pathways mediating leukemia-cell entry and survival in the CNS is needed to develop alternative CNS-directed treatment strategies. Previous studies showed an increased expression of Stearoyl-CoA desaturase (SCD), a key enzyme of the de novo fatty acid synthesis pathway, in B cell precursor (BCP) ALL cells isolated from cerebrospinal fluid (CSF) of patients at the time of CNS relapse. A small SCD positive population was detected in the bone marrow (BM) at leukemia diagnosis in patients who later developed isolated CNS relapse, defining a potential biomarker for CNS relapse. It is unknown, however, if SCD has a functional role in CNS leukemia.Aim: To examine the hypothesis that increased expression of SCD enhances trafficking and survival of human B-ALL cells in the CNSMethods: We analyzed leukemia-cell entry into the CNS using xenografts of human BCP-ALL cell lines. Microarray profile of cells isolated from CNS and BM of transplanted mice was performed. Cell lines were transduced to overexpress human SCD and evaluated in vitro for proliferation kinetics and metabolic SCD activity. In vivo, SCD overexpressing cells were transplanted in NSG mice,sacrificed upon the first symptoms of CNS involvement, e.g. hind limb paralysis. BM, spleen and meninges were collected and analyzed to check human engraftment by FACS. The tumor load was expressed as total amount of leukemic cells in each organ. Competition assays were performed by transplanting SCD overexpressing and WT cells in the same mouse in a 1:1 ratio.Results: BCP-ALL cells transplanted into NSG mice faithfully recapitulated pathological features of meningeal infiltration seen in patients with ALL. Gene expression analysis of cells collected from BM and meninges of leukemic mice revealed up-regulation of the genes belonging to the signaling pathway of sterol regulatory element binding proteins (SREBPs) in ALL cells isolated from the CNS. SCD, whose transcription is controlled by the SREBP family, was significantly upregulated. SCD overexpression did not alter proliferation in vitro. Since SCD introduces a double bond in Stearoyl-CoA, its activity was measured as the ratio of unsaturated/saturated fatty acids in the cells. That ratio was increased in SCD overexpressing cells in vitro, confirming the functionality of the enzyme. In vivo, mice transplanted with SCD overexpressing cells led to a faster onset of CNS disease manifested by a clinical phenotype of earlier hind limb paralysis compared to control and significant increased number of leukemic cells in the CNS (Figure 1A).SCD overexpression also induced CNS engraftment of another B-ALL cell line, REH, which is not naturally prone to invade the central nervous system. Mice transplanted with SCD overexpressing REH cells showed the same phenotype of earlier hind limb paralysis and accumulation of leukemic cells in the CNS as the CNS-prone 018z cells, while WT REH did not show any CNS engraftment but comparable tumor load in BM and spleen (Figure1B). To reproduce the clonal heterogeneity in SCD expression observed previously in patients' BM, we performed a competition assay transplanting SCD overexpressing cells and control cells, expressing different fluorochromes, in the same mouse in a 1:1 ratio. In the CNS, the ratio between SCD overexpressing and WT cells ranged from 2 to 20 fold. This effect was unique to the CNS and not reproducible in the other hematopoietic organs where the 1:1 ratio was maintained (Figure 1C). Moreover, SCD overexpression sensitized leukemic cells to mTOR inhibitors, suggesting a potential therapeutic optionConclusion: SCD has a role in homing and survival of leukemic cells in the CNS and may be used as early predictor of CNS relapse. This study reveals a role for SCD and fatty acid metabolism in the pathogenesis of CNS leukemia suggesting that this pathway maybe targeted for specific therapy of this devastating disease. [Display omitted] DisclosuresHalsey:Jazz Pharmaceuticals: Honoraria, Other: Support for conference attendance.

Incidence and Outcomes of Central Nervous System Hemophagocytic Lymphohistiocytosis Relapse after Reduced-Intensity Conditioning Hematopoietic Stem Cell Transplantation

Hemophagocytic lymphohistiocytosis (HLH) is an immune regulatory disorder that commonly presents with central nervous system (CNS) involvement. The only cure for genetic HLH is hematopoietic stem cell transplantation (HSCT), typically treated with reduced-intensity conditioning (RIC) regimens. We sought to estimate the incidence of CNS relapse after RIC HSCT, determine risk factors, and evaluate outcomes. We performed a retrospective chart review of 94 consecutive children and young adults with primary HLH who received RIC HSCT. CNS relapse within 1 year after transplantation was diagnosed by review of clinical symptoms, cerebral spinal fluid (CSF), and radiologic findings. Four (4.25%) patients developed symptoms of possible CNS HLH after HSCT and 3 patients were diagnosed. Eight patients underwent screening lumbar puncture because of history of active CNS disease at the onset of the conditioning regimen and 4 had evidence of continued disease. The overall incidence of CNS relapse and continued CNS disease after RIC HSCT was 8%. All patients with CNS disease after HSCT responded to CNS-directed therapy. Whole blood donor chimerism at the time of CNS relapse was low at 1% to 34%, but it remained high at 88% to 100% for patients with continued CNS disease. Overall survival for patients with CNS relapse was 50%, compared with 75% for patients without CNS disease (P = .079). Our data suggest that a low level of donor chimerism or active CNS disease at the time of transplantation increase the risk of CNS HLH after HSCT. Surveillance CSF evaluation after allogeneic RIC HSCT should be considered in patients with risk factors and CNS-directed treatment should be initiated if appropriate.

P4-17-01: Trastuzumab Does Not Increase the Incidence of Central Nervous System (CNS) Relapses in HER2−Positive Early Breast Cancer: The HERA Trial Experience.

Abstract Background: Retrospective studies of HER2−positive metastatic breast cancer (BC) showed an incidence of CNS metastases of 21% to 34%. We investigated the incidence and clinical aspects of CNS relapse (CNS-R) in patients (pts) enrolled in the HERA trial, a prospectively randomized adjuvant trial in node + or high-risk node - HER2−positive early BC pts. Methods: 3401 pts were randomized into the 1-year trastuzumab (1yT) or the observation (obs) arms of HERA (Piccart-Gebhart et al, 2005, Gianni et al, 2011). The cumulative incidences of first disease-free survival (DFS) events in the CNS vs other sites were estimated using competing risk analysis. The database of the main study had a clinical cut-off date of 9th June 2008. To obtain additional information regarding CNS-R (including occurrence of CNS-R after first DFS event), a specific CNS-directed questionnaire was sent to investigators of pts who were deceased as of July 2009. Information collected included the date of CNS-R, whether it was symptomatic, the type of CNS-R (brain metastases (BM) or meningeal carcinomatosis (MC)), methods of diagnosis, and treatments at the time of CNS-R. Results: 1yT significantly reduced the risk of other DFS events (p=0.000017, Gray's test), but not of CNS-R (p=0.55) as first event (see table). During the first year of follow up, CNS-R accounted for 15 (14.9%) of the 101 first DFS events in the 1yT arm and 15 (7.7%) of the 194 first DFS events in the obs arm. The analysis of baseline patient and tumor characteristics associated with CNS-R as first event confirmed known risk factors such as young age (<35y), T3 tumor, ≥ 4 + LN, ER neg, and G3. 413 of the 481 questionnaires (85.9%) were returned. 217 of the 413 deceased pts had a CNS-R diagnosed prior to death (52.5%), with more events occurring in the 1yT arm (see table). By contrast, the incidence of CNS-R as first DFS event was balanced across the arms. Based on the survey data, CNS-R was symptomatic in 189 pts (87.1%) with no differences between arms. BM were present in 211 pts (97.2%), absent in 5 (2.3%), and missing information in 1 (0.5%). MC was diagnosed in 25 pts (11.5%), absent in 187 (86.2%), missing information in 5 (2.3%). Frequencies for BM and MC were very similar in both arms. Conclusion: This retrospective analysis of a prospective large study shows more than 50% incidence of clinically diagnosed CNS-R in HER2−positive BC pts who have died. CNS-R was symptomatic in most pts. CNS-R at any time was less frequent in the 1yT arm (88 vs 129). There is no evidence that adjuvant trastuzumab increases the incidence of CNS-R. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-17-01.

High Prevalence of FLT3 - ITD Mutations in Patients (pts) with Acute Myeloid Leukemia (AML) Who Present with Central Nervous System (CNS) Relapse.

Abstract 1020Poster Board I-42Despite achievement of complete remission (CR) rates of 70% with modern chemotherapeutic regimens, most pts with AML eventually relapse. CNS extramedullary relapses have become uncommon with the use of high-dose cytarabine (HDAC; > 1.0 g/m2) containing regimens. The clinical and molecular features associated with a higher risk of CNS relapse are not defined. We analyzed adults who presented with AML and CNS relapses from 2005 until 2009. CNS leukemia was diagnosed by the presence of leukemic blasts in a cytocentrifuge preparation of cerebrospinal fluid (CSF). Patients with blasts in the CSF together with high numbers of red blood cells (> 5) were not considered to have CNS disease if the blasts were high in the peripheral blood ( 5 × 109/L). All pts with evidence of CNS disease underwent a marrow examination. There were 10 pts with a diagnosis of AML and CNS relapse observed during the above mentioned time period. Median age was 38 years (range 23-56) and 80% were female. At time of first diagnosis the median WBC was 61×109/L and 50% had M4/M5 phenotype by FAB. Six pts had received induction chemotherapy containing standard doses of cytarabine; five of them received HDAC as consolidation courses afterwards. Four pts received induction regimens containing HDAC. The CR rate was 80% (8 of 10 pts). The median CR duration was 6 months (range 3-7). CNS involvement was detected at a median of 8 months after diagnosis (range 5-29). No pt had isolated CNS relapse. CNS disease was detected in the setting of refractory AML (N=2), 1st systemic relapse (N=4) or 2nd and subsequent relapses (N=4). Eight pts had neurologic symptoms at time of CNS relapse, including headache (N=3), involvement of cranial nerves (N=2), visual impairment (N=1), seizures (N=1), confusion (N=1) and feet neuropathy (N=1) (one pt had more than one symptom). CNS imaging was done in 8 pts, and three pts had abnormal findings by MRI suggestive of CNS disease. The median cell count on CSF was 305 (range 0-880) and median blast percentage was 89%. Two pts had zero cells with blasts detected on cytocentrifuge preparation only. None of the 2 pts had circulating blasts and both had abnormal findings on brain MRI suggestive of CNS relapse. Cytogenetic information was available at initial diagnosis for 9 pts, being diploid in 6 pts. The pt without cytogenetic information was diploid at time of relapse. FLT3 mutation status was unknown at time of diagnosis in six pts, being positive for the ITD mutation in 4 pts. At time of 1st relapse, FLT3 mutation status was positive in 8 pts (80%; all cases were FLT3-ITD). Treatment for CNS disease consisted of intrathecal chemotherapy (methotrexate alternating with cytarabine) in all pts and whole brain radiation therapy in one (24 Gy in 12 fractions). Therapy was successful in clearing all signs of CNS disease in 9 pts. One pt persisted with disease after 4 intrathecal injections and expired 6 weeks afterwards. Five pts had additional CNS relapses at a median of 3 months (range 2-15) after being first diagnosed with CNS disease. Stem cell transplantation (SCT) was done in 3 pts, 2 with active disease and one in CR. All three relapsed with CNS disease after SCT. Only one pat currently remains alive and with active disease. Median survival after CNS relapse was 3 months (range 1-28). In conclusion, CNS relapse is a rare occurrence in AML and is associated with a poor prognosis. A high prevalence of FLT3-ITD mutations was observed in these pts; FLT3 mutations are associated with elevated WBC counts, which are traditionally considered a risk factor for CNS relapse. Analysis of merged data from larger databases may help to better discern the association between FLT3-ITD mutations and CNS relapse. If confirmed, prophylactic measures might be considered for such pts. Disclosures:Jabbour:Novartis: Speakers Bureau; Bristol Myers Squibb : Speakers Bureau.

Liposomal Cytarabine (DepoCyte) for Treatment of Myeloid CNS Relapse in CML Occurring during Therapy with Imatinib.

Central nervous system (CNS) relapse in chronic myeloid leukemia (CML) is rare and if recorded is usually found to occur in patients with lymphoblastic transformation or in those with a generalized myeloid relapse. The BCR/ABL tyrosine kinase (TK) inhibitor imatinib is highly effective in patients with CML, but hardly crosses the blood-brain-barrier. We report on two CML patients who developed a myeloid CNS relapse during treatment with imatinib. One patient was in major cytogenetic response at the time of CNS relapse. In both cases, the myeloid origin of neoplastic cells in the cerebrospinal fluid (CSF) was demonstrable by immunophenotyping, and their leukemic origin by detection of the BCR/ABL oncoprotein. No BCR/ABL kinase domain mutations could be detected. Both patients received intrathecal liposomal cytarabine (DepoCyte®) (50 mg each cycle; 6 cycles). In one patient, additional CNS radiation was performed, whereas in the other patient, consecutive treatment with dasatinib (70 mg per os twice daily) was started. In response to therapy, the clinical symptoms resolved and the leukemic cells in the CSF disappeared in both patients. After four months of observation, both patients are in complete cytogenetic and major molecular response, without evidence for a systemic or a CNS relapse. In conclusion, ‘anatomic' resistance against imatinib in the CNS can lead to an (isolated) myeloid CNS relapse. Liposomal cytarabine with or without radiation is effective as local therapy in these patients. For treatment of patients with a systemic relapse involving the CNS and for prophylaxis, second-generation BCR/ABL TK inhibitors crossing the blood-brain-barrier such as dasatinib should be considered.

Liposomal cytarabine for treatment of myeloid central nervous system relapse in chronic myeloid leukaemia occurring during imatinib therapy

Central nervous system (CNS) relapse in chronic myeloid leukaemia (CML) is rare and if recorded is usually found to occur in patients with lymphoblastic transformation. The BCR/ABL tyrosine kinase inhibitor imatinib is highly effective in patients with CML, but hardly crosses the blood-brain barrier. We report on two CML patients who developed a myeloid CNS relapse during treatment with imatinib. One patient was in major cytogenetic response at the time of CNS relapse. In both cases, the myeloid origin of neoplastic cells in the cerebrospinal fluid (CSF) was demonstrable by immunophenotyping, and their leukaemic origin by detection of the BCR/ABL oncoprotein. No BCR/ABL kinase domain mutations were found. Both patients received intrathecal liposomal cytarabine (50 mg each cycle; 6 cycles). In one patient, additional CNS radiation was performed, whereas in the other, consecutive treatment with dasatinib (70 mg per os twice daily) was started. In response to therapy, the clinical symptoms resolved, and the leukaemic cells in the CSF disappeared in both cases. After three months of observation, both patients are in complete cytogenetic and major molecular response, without evidence for a systemic or a CNS relapse. 'Anatomic' resistance against imatinib in the CNS can lead to a myeloid CNS relapse. Liposomal cytarabine with or without radiation is effective as local therapy in these patients. For systemic treatment and prophylaxis, BCR/ABL kinase inhibitors crossing the blood-brain barrier such as dasatinib should be considered in patients with CNS relapse.

Survival Outcome after the First Central Nervous System Relapse in Children with Acute Lymphoblastic Leukemia: A Retrospective Analysis of 79 Patients in a Joint Program Involving the Experience of Three Japanese Study Groups

In a retrospective review of the survival outcome of children with isolated central nervous system (CNS) relapse of acute lymphoblastic leukemia (ALL), we identified 79 patients with CNS relapse among the eligible patients enrolled in ALL trials of 3 Japanese pediatric oncology study groups (Japanese Children's Cancer and Leukemia Study Group [JCCLSG], Tokyo Children's Cancer Study Group [TCCSG], and Japan Association of Childhood Leukemia Study [JACLS]) between 1989 and 1999. CNS relapses were diagnosed as the first adverse event between 1991 and 1999. The median age at the time of CNS relapse was 5.0 years (range, 0.7-15.1 years). The duration of the first remission ranged from 1.4 to 54 months (median, 12.4 months), and the observation period after CNS relapse ranged from 1 to 131 months (median, 27 months). Overall, 75 of the 79 patients achieved a second complete remission, 44 of whom had second relapses in the following sites: CNS, 18 patients; bone marrow, 15 patients; combined sites, 8 patients; and testis, 2 patients. Rates of overall survival and event-free survival at 4 years were 43.7% +/- 5.8% (mean +/- SE) and 32.9% +/- 5.5%, respectively. The probability of remaining in second remission was significantly correlated with the leukocyte count (P= .005) and age (P= .02) at the initial diagnosis.

High-Dose Methotrexate for Isolated Central Nervous System Relapse in Patients with Testicular Non-Hodgkin's Lymphoma

Four consecutive patients with testicular non-Hodgkin's lymphoma who initially achieved a complete response to treatment with standard combination therapy later developed isolated central nervous system (CNS) relapses. At the time of CNS relapse, staging evaluations were negative for lymphoma outside the nervous system in all 4 patients. These patients were treated with high-dose intravenous methotrexate alone, and a complete remission was achieved in all 4 patients.

Leukoencephalopathy in Childhood Acute Lymphoblastic Leukemia with T(1; 19)

To clarify the incidence of leukoencephalopathy in patients with t(1;19) and their clinical characteristics, we studied 239 acute lymphoblastic leukemia (ALL) cases. The 1;19 translocation was found in 20 (8.5%) of the 239 children with ALL. Leukoencephalopathy occurred in 2 (10%) patients with t(1;19) during the early first remission and in one case with t(l;19) at the time of central nervous system (CNS) relapse. Leukoencephalopathy was not found during the early first remission in patients lacking t(1;19), but did develop in 4 patients lacking t(1;19) at the time of CNS relapse. There were no differences in age, sex, leukocyte count, platelet count or serum lactate dehydrogenase level between t(1;19) patients with and without leukoencephalopathy. Our results suggest the incidence of leukoencephalopathy in patients with t(1;19) during the early first remission to be 10%, but we can not predict which patients will develop leukoencephalopathy.

Cerebral metastases from ovarian carcinoma

Apart from choriocarcinoma, involvement of the central nervous system (CNS) by gynecologic malignancy is rare. A 10-year retrospective review at the University of Washington Medical Center (Seattle, WA) and Swedish Hospital and Medical Center Tumor Registry (Seattle, WA) identified 14 patients with cerebral metastases from ovarian carcinoma. Median age at diagnosis of cerebral metastases was 52.5 years. Median interval from the diagnosis of ovarian carcinoma to the diagnosis of CNS metastases was 14.5 months. Seven patients had received cisplatin therapy before CNS relapse. Seven patients underwent second-look procedures before developing CNS metastases; in three, results were negative. Eight patients had evidence of extraperitoneal spread to other sites at the time of CNS relapse. Clinical manifestations included motor weakness, seizures, headache, confusion, and speech disturbance. All lesions were contrast enhancing on computed tomography (CT) scans and were located in the cerebral hemispheres. Nine patients had single lesions, five of whom underwent surgical resection of the lesion with histologic confirmation of metastases from the primary site. Median survival was 2 months in patients receiving radiation therapy alone and 17 months in patients who received surgery and radiation. Median survival of the entire series was 3 months. The presence of multiple cerebral metastases or evidence of extraperitoneal spread elsewhere in the body was adversely associated with survival. The prognosis of patients with cerebral metastases from ovarian carcinoma appears poor. However, early diagnosis by routine CT scanning followed by surgical resection and radiation may improve overall survival in a select group of patients.

The significance of an isolated central nervous system relapse, occurring as first relapse in children with acute lymphoblastic leukemia.

In a retrospective study, which comprised the whole Dutch childhood population of approximately 3 million children, the authors assessed the influence of an isolated meningeal relapse, occurring as first relapse, together with some patient and treatment characteristics on prognosis in 142 children with acute lymphoblastic leukemia (ALL). Until their first relapse, patients were initially treated according to standard protocols, whereas the treatment for relapse was heterogeneous. Concerning the probability of achieving a second complete remission (CR) it appears that the duration of the first CR is the single most important prognostic factor. The duration of the first CR is also the most important factor with regard to the duration of the second CR, upon which also age and sex have a significant influence. Concerning the survival from the time of central nervous system (CNS) relapse, again the duration of the first CR appears to be the most important prognostic factor, followed by age and the institution of systemic reinduction treatment. Other factors, such as initial leukocyte count, attainment of first CR within 48 days, type of reinduction treatment, and the cerebral spinal fluid (CSF) blast count at the time of relapse, have a less important, but nevertheless significant influence on survival. The median survival from the time of CNS relapse is 25 months, the 5-year survival is 25%, whereas the ultimate survival will be less than 20%. From 90 patients who developed second or subsequent relapses, 75% experienced a bone marrow relapse during the follow-up period. From this study the authors conclude that CNS relapse in children with ALL carries a grave prognosis, which requires the institution of intensive retreatment programs.