Intrathecal arabinosyl cytosine in meningeal leukemia

Nucleobase and Nucleoside Analogues: Resistance and Re-Sensitisation at the Level of Pharmacokinetics, Pharmacodynamics and Metabolism

Antimetabolites, in particular nucleobase and nucleoside analogues, are cytotoxic drugs that, starting from the small field of paediatric oncology, in combination with other chemotherapeutics, have revolutionised clinical oncology and transformed cancer into a curable disease. However, even though combination chemotherapy, together with radiation, surgery and immunotherapy, can nowadays cure almost all types of cancer, we still fail to achieve this for a substantial proportion of patients. The understanding of differences in metabolism, pharmacokinetics, pharmacodynamics, and tumour biology between patients that can be cured and patients that cannot, builds the scientific basis for rational therapy improvements. Here, we summarise current knowledge of how tumour-specific and patient-specific factors can dictate resistance to nucleobase/nucleoside analogues, and which strategies of re-sensitisation exist. We revisit well-established hurdles to treatment efficacy, like the blood-brain barrier and reduced deoxycytidine kinase activity, but will also discuss the role of novel resistance factors, such as SAMHD1. A comprehensive appreciation of the complex mechanisms that underpin the failure of chemotherapy will hopefully inform future strategies of personalised medicine.

Relationship between Protein Binding and Extravascular drug Concentrations of a Water-soluble Drug, Cytosine Arabinoside

The degree of binding of a drug to plasma proteins has a marked effect on its distribution, elimination, and pharmacological effect. Since only the unbound fraction is available for distribution into extravascular space, the ratio of drug in cerebrospinal fluid (CSF) or saliva to that in plasma is often regarded as a physiological measure of the free fraction of a drug. CSF: plasma and saliva: plasma ratios of cytosine arabinoside (araC) have been measured in patients with acute leukaemia and found to be 0.1–0.28, implying a binding of 72–90%.

The protein binding of araC was measured by equilibrium dialysis in the plasma of patients with acute leukaemia at presentation. The mean binding ratio was 2.3 ± 6.8, implying that there was little or no protein binding. There was no correlation between alpha — 1 acid glycoprotein (AAG) levels and protein binding.

The low CSF and saliva: plasma araC ratios found, suggest that drugs such as araC which have low lipid solubility do not pass freely into extravascular space. Thus the CSF or saliva: plasma ratio cannot be considered a good physiological measure of protein binding for drugs with poor lipid solubility.

Aseptic meningitis in a child after systemic treatment with high dose cytarabine

Cytarabine was temporally associated with aseptic meningitis syndrome in an 8-year-old Hispanic girl being treated for acute lymphoblastic leukemia.

Drug-induced aseptic meningitis: diagnosis and management

Drug-induced aseptic meningitis (DIAM) has been reported as an uncommon adverse reaction with numerous agents. It is a diagnosis of exclusion, and clinical signs and CSF findings vary greatly. The body of evidence regarding DIAM is largely in the form of anecdotal case reports and must be interpreted carefully bearing this in mind. The major categories of causative agents are nonsteroidal anti-inflammatory drugs, antimicrobials, intravenous immunoglobulin, intrathecal agents, vaccines and a number of other less frequently reported agents. There appears to be an association between DIAM and connective tissue disease, particularly systemic lupus erythematosus, and ibuprofen. There are 2 major proposed mechanisms for DIAM. The first involves direct irritation of the meninges by intrathecal administration of the drug, and the second involves immunological hypersensitivity to the drug, most likely type III and type IV hypersensitivity. Recognition and diagnosis of DIAM is important, as it is treatable by withdrawal of the drug and recurrence is prevented. The outcome of DIAM is generally good, usually without long term sequelae. This article describes the case reports of DIAM in the current literature and discusses the diagnosis and management of this rare complication.

Drug- and chemical-induced aseptic meningitis: a review of the literature

OBJECTIVE

The primary objective of this article is to provide readers with case reports of drug- or chemical-induced aseptic meningitis (DCAM) described in the medical literature. Background information regarding the classification of DCAM, incidence, proposed mechanisms, associated risk factors, clinical management, and sequelae is presented.

DATA SOURCES

A MEDLINE search was used to identify pertinent background literature and case reports of DCAM.

DATA EXTRACTION

All case reports of DCAM involve anecdotal information. A critical analysis of a causal relationship to the implicated drug or chemical and the appearance of meningeal involvement is presented. Animal data are included when pertinent.

DATA SYNTHESIS

DCAM is a rare adverse event associated with numerous agents. Patients present with a variety of clinical signs and symptoms and laboratory findings of cerebral spinal fluid, when obtained, vary greatly. Most patients fully recover without sequelae.

CONCLUSIONS

Numerous drugs and chemicals have been implicated in the medical literature as producing DCAM. Two proposed mechanisms of DCAM have been theorized: a delayed hypersensitivity-type reaction and direct meningeal irritation. The nonsteroidal antiinflammatory drugs, certain antibiotics, radiographic agents, and muromonab-CD3 have been most frequently implicated. There appears to be an association between the occurrence of the hypersensitivity-type reactions and underlying collagen vascular or rheumatologic disease.

Carcinomatous meningitis: antibody-guided therapy with I-131 HMFG1

Seven patients with carcinomatous meningitis were administered intrathecal I-131 labelled monoclonal antibody HMFG1. Clinical responses were seen in two patients, with a long term survivor at 32 months. Aseptic meningitis occurred in 4/7 patients, but more serious toxicity was observed in the form of seizures (2/7 patients) and myelosuppression (3/7 patients). Partial obliteration of the subarachnoid space was identified as a potential problem in patients with advanced disease.

Plasma and cerebrospinal fluid pharmacokinetics of cytosine arabinoside in dogs

Cytosine arabinoside (ara-C) is a component of many protocols for the treatment of CNS (central nervous system) leukemia and lymphoma in humans and dogs. It is also used for the prophylaxis of CNS metastasis in acute lymphoblastic leukemia. Although ara-C enters the cerebrospinal fluid (CSF) of human cancer patients after i.v. administration, it is unclear whether a similar CNS distribution occurs in humans whose blood-brain barrier has not been compromised by invasive disease. No information on the penetration of ara-C into the CSF in dogs is available. We studied the plasma and CSF pharmacokinetics of 600 mg/m2 ara-C in ten healthy male dogs after its administration as a rapid i.v. bolus (six dogs) or as a 12-h i.v. infusion (four dogs). Ara-C concentration in blood and CSF samples was determined by high-performance liquid chromatography (HPLC). After an i.v. bolus of ara-C, the mean plasma distribution half-life was 7.1 +/- 4.5 min and the mean elimination half-life was 69 +/- 28 min. The mean plasma clearance was 227 +/- 125 ml min-1 m-2. The peak concentration of ara-C in the CSF was 29 +/- 11 microM, which occurred at 57 +/- 13 min after the ara-C bolus. The CSF elimination half-life was 113 +/- 26 min. During a 12-h infusion of ara-C (50 mg m-2 h-1), the plasma steady-state concentration was 14.1 +/- 4.2 microM, the CSF steady-state concentration was 8.3 +/- 1.1 microM, and the CSF: plasma ratio was 0.62 +/- 0.14. The plasma elimination half-life was 64 +/- 19 min and the plasma clearance was 214 +/- 69 ml min-1 m-2. The CSF elimination half-life was 165 +/- 28 min. No clinically significant toxicity was observed over a 21-day period following drug administration in either of the treatment groups. Our data indicate that ara-C crosses the blood-brain barrier in normal dogs and that i.v. administration of this drug has potential as a treatment modality for neoplasia involving the CNS.

Treatment-related central nervous system toxicity: MR imaging evaluation with CT and clinical correlation

Thirteen patients with abnormal brain MR scans attributable to treatment-induced injury were retrospectively reviewed. All patients were treated with radiation therapy and 62% received chemotherapy. Five patients were graded as having severe white matter (WM) changes, four had moderate WM changes, and four had mild WM changes. CT was generally equivalent to MR in evaluation of severe and moderate WM abnormalities, whereas MR was superior to CT in detection of mild WM abnormalities. In general, the severity of changes depicted by MR/CT correlated with the extent of neurologic dysfunction. The most severe changes were seen in those patients treated with combination irradiation and chemotherapy.

Phase I/II study of intraventricular and intrathecal ACNU for leptomeningeal neoplasia

A total of 27 patients with leptomeningeal neoplasia were treated with the water-soluble nitrosourea ACNU given intraventricularly or intrathecally in a phase I/II study. Patients were entered in the study if they showed evidence of either a positive CSF cytology or neurodiagnostic evidence of leptomeningeal disease, or both. Patients were evaluated for toxicity and efficacy; additionally, in 13 patients ACNU pharmacokinetic studies were carried out. A variety of tumor types were represented in the study group, including primary and metastatic CNS tumors. Toxicity was mild and included pain at the injection site (four patients), transient radicular symptoms at a short distance from the injection site (three patients), and nausea and vomiting (one patient). No myelotoxicity was seen. Of 21 patients who presented with positive cytology, 8 (38%) had a conversion from positive to negative cytology, with a range of response durations from 1 to 20+ months. Of the remaining six patients with negative cytology but other neurodiagnostic evidence of leptomeningeal disease, one patient showed an improvement seen on the myelogram and one underwent a brief reduction in CSF protein. ACNU elimination from the ventricular system is rapid, with a beta slope of 0.028 min-1 and a computed elimination constant, Ko of 13 min. The mean clearance was 3.8 ml/min (range, 1.0-6.2 ml/min). Peak ACNU levels varied between 108 and 620 micrograms/ml, with the AUC being 1.4-14.7 mg.min/ml. The total dose of ACNU given was between 9 and 104 mg, and the single dose range was 4-16.5 mg. We conclude that ACNU can be given safely with minimal toxicity as intra-CSF therapy, that it demonstrates efficacy in some patients with leptomeningeal disease, and that further studies are warranted to evaluate more fully alternative dosing and drug delivery approaches.

Exchange of cerebrospinal fluid in accidental intrathecal overdose of cytarabine

Intrathecal cytarabine (cytosine arabinoside) is included in many protocols for the treatment of acute lymphoblastic leukaemia of childhood. We report here the accidental administration of 200mg cytarabine intrathecally to a 4-year-old boy with CNS relapse. After the overdose the patient had dilated pupils during the first hour. One month later an unsteady gait and mild intention tremor in the hands were noted. By the exchange of cerebrospinal fluid with isotonic saline started 1 hour after overdose through a lumbar needle, about 27% of the administered dose was recovered. The estimated recovery in view of the time elapsed between overdose and start/end of the exchange procedure was 36%. This indicates that this procedure is of value in managing patients with heavy overdose of intrathecal cytarabine in hospitals without neurosurgical facilities.

Pyrimidine pathways enzymes in human tumors of brain and associated tissues: potentialities for the therapeutic use of N-(phosphonacetyl-L-aspartate and 1-beta-D-arabinofuranosylcytosine

The activities of aspartate transcarbamylase (de novo pyrimidine biosynthesis pathway) and of deoxycytidine kinase as well as deoxycytidine deaminase (salvage pyrimidine biosynthesis pathway) were determined in extracts prepared from 40 brain tumors of different types in comparison with extracts from normal nervous tissues. Aspartate transcarbamylase, which is undetectable in normal brain tissue, is present in all tumor samples and in some cases rises to very high activities. Deoxycytidine kinase activity is present in all tissues but its level is generally higher in tumors. Deoxycytidine deaminase is present in all the tissues which were analyzed, although its activity is lower in some of the tumor samples. 1-beta-D-Arabinofuranosylcytosine is a substrate for both deoxycytidine kinase and deaminase in all the samples used except one. These results suggest some potential for the utilization of 1-beta-D-arabinofuranosylcytosine and N-(phosphonacetyl)-L-aspartate in the treatment of brain tumors.

Treatment-related white matter changes in cancer patients

Forty cancer patients with bilateral diffuse cerebral white matter hypodensities on computerized tomography (CT) scan were reviewed. Brain irradiation and/or chemotherapy were considered responsible for the CT abnormalities in all patients but one, whose changes were presumably due to demyelination related to the aging process. Among these 39 patients, 7 had clinical symptoms of leukoencephalopathy. Two patients had acute transient leukoencephalopathy, and one of them experienced permanent neurologic changes after continuing treatment. Six additional patients had delayed leukoencephalopathy. The interval between whole-brain irradiation (WBXRT) alone and the CT detection of white matter hypodensities was almost always longer than 1 year. This interval was shortened to less than 1 year in a significant number of patients when WBXRT was followed by various chemotherapeutic protocols. More importantly, there was an increased incidence of clinical leukoencephalopathy. A higher incidence of clinical leukoencephalopathy in patients receiving intracarotid chemotherapy in the treatment of brain tumors and in patients receiving combination chemotherapy for central nervous system relapse of adult leukemia suggests a need for further investigation.

Non-Hodgkin's lymphoma involving the central nervous system

In 44 out of 758 patients (5.8%) with non-Hodgkin's lymphoma presenting between 1971 and 1982, the central nervous system (CNS) was involved. Patients with a diffuse histology had a 7.6% (34/449) incidence of CNS involvement compared to 3.9% (10/257) for patients with nodular lymphoma. In 63% of patients there was evidence of progressive systemic lymphoma at the time of diagnosis of CNS disease and in 23% CNS relapse occurred in clinical remission. Bone marrow was involved in 34% of patients at diagnosis and in 52% at some time prior to the onset of CNS complications. Cerebrospinal fluid cytology was positive in 63% and an elevated protein level was found in 95% of patients. The median length of survival of the 44 patients was only 3.2 months, but patients who responded to treatment of CNS lymphoma survived significantly longer than those who showed no response or progressed on therapy. Complete response to CNS treatment was achieved in five patients, of whom none relapsed in the CNS and two are long-term disease-free survivors. CNS prophylaxis appears justified for patients with lymphoblastic lymphoma, Burkitt's tumour, and diffuse undifferentiated lymphoma, who are at high risk of developing CNS complications. Patients with diffuse histiocytic, and diffuse poorly differentiated lymphocytic, lymphoma who have bone marrow involvement may also benefit from CNS prophylaxis.

Diagnosis and treatment of leptomeningeal metastases from solid tumors: experience with 90 patients

The clinical findings and response to treatment of leptomeningeal metastases from solid tumors are analyzed in 90 patients treated at Memorial Sloan-Kettering Cancer Center during the period from January 1975 to February 1980. Patients included those who had either typical clinical findings of leptomeningeal tumor or conclusive laboratory evidence supporting the diagnosis. Carcinoma of the breast (46 patients), lung (23 patients) and melanoma (11 patients) were the common primary tumors. Symptoms of leptomeningeal metastasis occurred as the presenting sign in five patients and as late as ten years after the primary tumor was diagnosed in four other patients. Most patients had active systemic disease outside the nervous system. Signs and symptoms could be classified as involving either the brain, cranial nerves, or spinal nerves. Most patients had either symptoms or signs in more than one area at the time the diagnosis was established. The initial spinal fluid examination was abnormal in all but three patients, but only 49 had cytologic evidence of leptomeningeal metastases. Repeated spinal fluid assay yielded a positive cytology in 82 patients. Measurement of biochemical markers, including beta-glucuronidase, carcinoembryonic antigen and lactic dehydrogenase, assisted in the diagnosis. Approximately half of the patients treated by intraventricular methotrexate experienced improvement or stabilization of neurological symptoms for more than a month; median survival was 5.8 months after diagnosis, with a range of 1--29 months. In 18 patients disease was limited to the nervous system, and median survival was eight months, with four patients surviving one year and two patients for two years. Side effects of therapy were, for the most part, minor. We conclude that vigorous treatment of leptomeningeal metastases with intrathecal chemotherapeutic agents improves symptomatology in some patients, and at times prolongs survival.

Central nervous system toxicity of high-dose systemic cytosine arabinoside

Forty-nine adult patients with acute leukemia in relapse, refractory to conventional therapy, were studied. Increasing quantities of i.v. bolus high-dose cytosine arabinoside (cytarabine) were administered using the following schedules: 3 g/m2 every 12 hrs for 4-16 consecutive doses, or 4.5 g/m2 every 12 hrs for 12 consecutive doses. Patients ages ranged 16-76 year (median: 38). Thirty-seven patients had previously received either induction or maintainance therapy with conventional doses of cytarabine. Cerebral or cerebellar dysfunction attributable to cytarabine was observed in eight patients and appeared 6-8 days (mean: 6.6) after the first dose and lasted 3-7 days (mean: 4.7). None of 12 patients receiving up to 24 g/m2 total dose of 48 g/m2 developed reversible neurologic dysfunction. Four of six patients receiving 54 g/m2 developed CNS toxicity (irreversible in two cases), a significantly greater incidence compared to toxicity in patients receiving less than or equal to 48 g/m2 total dose (P less than 0.01). CNS toxicity was dose-related since patients treated for 12 consecutive doses of 4.5 g/m2 had significantly greater CNS toxicity than 12 consecutive doses at 3 g/m2 (P less than 0.04). Systemic cytarabine doses less than 54 g/m2 can be administered with minimal CNS side-effects.

Central nervous system involvement at presentation in acute granulocytic leukemia. A prospective cytocentrifuge study

We have undertaken a perspective study of the prevelance of the central nervous disease in acute granulocytic leukemia (AGL). Thirty-nine newly diagnosed patients with AGL underwent cytocentrifuge examination of cerebral spinal fluid. Seven of the 39 patients had blast cells in their cerebral spinal fluid. All seven of these patients had acute myelomonocytic leukemia (AMML). No patients with other variants of AGL demonstrated blast cells in their cerebral spinal fluid. Other high risk factors associated with meningeal infiltration were elevated serum lysozyme levels, high peripheral white blood cell count, low age, splemomegaly and the presence of infiltration in other organs. The admission rates for patients with meningeal leukemia were lower and the survival time was shorter than in both the 32 noninvolved patients and the noninvolved patients with AMML. We believe that a lumbar puncture is indicated in all patients with newly diagnosed AMML.

Paraplegia following intrathecal cytosine arabinoside

Paraplegia following prophylactic intrathecal cytosine arabinoside (Ara-C) is described in a patient with acute myelogenous leukemia in remission who received doses of 100 mg/m2/d for 5 consecutive days. Cerebrospinal fluid examination prior to the last dosage of cytosine arabinoside revealed a mononuclear pleocytosis and increased protein. The neurological manifestations developed within one week after the last dose of Ara-C and persisted for over 8 weeks. Administration of intrathecal Ara-C in the same dose over longer intervals within 3-5 days between consecutive doses resulted in mild, transient neurological symptoms (paresthesias) in only one of 30 patients so treated.

Central nervous system involvement at presentation in the chronic phase of chronic myelogenous leukemia in childhood

With the advent of more effective chemotherapy an increasing incidence of central nervous system involvement in acute lymphocyte (ALL) and myelocytic leukemias (AML) and chronic myelocytic leukemia (CML) in blast crisis has become evident. Meningeal involvement in the chronic phase of CML is rare. We report two children whose initial presentation of Ph1 CML was in the central nervous system as documented by cytocentrifugation. Aggressive combination chemotherapy and cranial irradiation has resulted in prolonged survival without blastic transformation or further meningeal disease. An approach to children with CML is suggested.

Seizures following intrathecal cytosine arabinoside in young children with acute lymphoblastic leukemia

Two young children (3 1/2 years and 19 months) developed seizures within 24 hours of receiving intrathecal cytosine arabinoside. Both had previously received intrathecal cytosine and methotrexate as well as cranial irradiation without untoward effect. Possible mechanisms of causation are discussed and caution is stressed for use of intrathecal cytosine arabinoside in young children.

The management of adult acute lymphoblastic leukaemia

The important advances made in recent years in the therapy of adult ALL have been reviewed. The definition of bad-prognosis patients has been improved and includes those with T-ALL, ABLL, and Ph1+ALL, in addition to those presenting with evidence of extensive disease. In contrast to childhood ALL, induction chemotherapy should include another drug (or drugs) in addition to VCR and prednisolone, and one of the anthracycline drugs (ADR or DNR) has been employed most frequently in this context. Such therapy should result in a CR rate of 70 to 75%. Similar to the experience in childhood ALL, the improvement in haematological response rate has led to an apparent increase in CNS leukaemia, and the need for adequate CNS prophylaxis is stressed. Despite these improvements, the outlook for adults with ALL is not yet as good as it is for childhood ALL. Controlled studies involving large numbers of patients are urgently needed to provide answers to a number of questions. In induction therapy, the use of higher drug dosage, the use of more and other drugs, and the use of an individual patient's risk factors to determine drug dosage, must be assessed. The benefits of consolidation therapy and the optimal duration and intensity of maintenance therapy have yet to be established. Methods of CNS prophylaxis other than cranial irradiation and IT MTX must be carefully studied. These important questions require that adult patients with ALL should be concentrated in centres capable of providing optimal overall care and, at the same time, able to conduct the necessary clinical trials.

Paraparesis following intrathecal cytosine arabinoside: a case report with neuropathologic findings

A 65-year-old white male with acute myelogenous leukemia received whole brain irradiation (2550 rads) and intrathecal cytosine arabinoside for CNS prophylaxis. Bone marrow remission had been previously achieved with systemic chemotherapy (vincristine, Adriamycin, prednisone, and cytosine arabinoside). Two weeks following the last intrathecal cytosine arabinoside treatment, the patient developed a spastic paraparesis requiring the use of a walker. A gas myelogram was normal and CSF examination revealed a protein of 50 mg/100 ml but was otherwise unremarkable. Five months later, the patient had improved in that he could stand on his own. A relapse of his leukemia subsequently occurred and the patient died the following month. Striking degenerative changes were found in the spinal cord at postmortem examination. These included microvacuolization, axonal swellings, and loss of myelin with scattered macrophages laden with fat.

Radiation therapy in Burkitt's lymphoma of the central nervous system

Involvement of the central nervous system in patients with with Burkitt's lymphoma was treated by superfractionated irradiation. The primary effect in 20 patients is reported. In 3 of 5 patients with paraplegia, complete regression was achieved. Only one patient of 6 with cranial neuropathy and irradiated to the brain improved. In 8 patients with either cranial neuropathy or other neurologic symptoms of signs, the brain and spinal cord were irradiated. Three of these patients, with recurrences after previous intrathecal chemotherapy, responded with complete regression.

Neurotoxicity due to CNS therapy for leukemia

CNS symptoms ranging from mild to lethal have occurred following CNS radiotherapy and intrathecal chemotherapy. Cranial radiotherapy often produces signs of mild encephalopathy, with predominance of somnolence. In rare cases, it appears that CNS radiotherapy may be followed by progressive encephalopathy. Intrathecal methotrexate frequently causes symptoms of meningeal irritation. Occasionally cases of weakness and paralysis, and rare instances of severe encephalopathy, may occur. However, in leukemic children treated with intensive chemotherapy and CNS radiotherapy who develop neurological complications, it is often difficult to determine which of many possible factors may be causing the CNS symptoms. The pathogenesis of the various forms of methotrexate neurotoxicity is poorly understood. The best-established cause for these symptoms is high concentrations of methotrexate in the CSF or porlonged exposure of the brain to low CSF concentrations of methotrexate. These elevated concentrations of the drug may in turn be due to impaired elimination of the drug from the cerebrospinal fluid (usually due to overt CNS leukemia) or to increased dosage in relation to cerebrospinal fluid volume (due to adolescent age). Leukoencephalopathy is occasionally found at autopsy in children given intensive therapy with CNS radiotherapy and intrathecal methotrexate, together with intensive systemic chemotherapy. It was proposed that alteration of the blood-brain barrier by cranial radiotherapy allows systemically administered anti-leukemic drugs to enter the brain and to cause necrotic changes in the CNS white matter. Leukoencephalopathy also occurs following intraventricular administration of methotrexate. CNS-toxicity due to intrathecal cytosine arabinoside is clinically similar to the symptoms seen following intrathecal methotrexate.

Recurrent childhood lymphocytic leukemia following cessation of therapy: treatment and response

A unique population of patients--children who developed recurrent acute lymphocytic leukemia (ALL) following cessation of initial prolonged therapy--was studied. During a 2-year period, 17 such children were admitted to a planned combination chemotherapy program. Complete bone-marrow remissions were achieved in 16 patients, and the median duration of second hematologic remissions was 216 days. These responses were significantly better than those obtained in seven patients who relapsed during the administration of continuation chemotherapy. Although the rate and duration of induced remissions were notably high, 9 of the 17 patients who relapsed off therapy have again developed recurrent leukemia. This result, together with the moderate toxicity encountered during treatment, indicates that more therapy is needed. The equal proportion of bone marrow and meningeal relapses was interpreted to mean that a secon course of preventive central nervous system therapy early in remission may be especially useful.

Meningeal leukemia in the blastic phase of chronic granulocytic leukemia

One hundred one patients were treated for Ph' positive chronic granulocytic leukemia (CGL) in the blastic phase. In seven of these (6.9 per cent), meningeal leukemia developed. Of the 99 patients who died of their disease, a complete remission was achieved in 12 with a median survival of 12 months (three to 28 months). Incomplete responders had a median survival of only 2.5 months (one to 14 months). In five of the 12 complete responders (42 per cent), but in only two of the incomplete responders (2.3 per cent), meningeal leukemia developed. The principal neurologic signs were cranial nerve palsies and papilledema. All patients had pleocytosis with myeloblasts in the cerebrospinal fluid. As in patients with acute leukemia and diffuse histiocytic lymphoma, increased survival of patients in whom hematologic remission from the blastic phase of CGL is achieved may allow sufficient time for the development of meningeal leukemia. Intrathecal methotrexate is extremely successful in treating this complication. Cerebrospinal fluid pleocytosis was eradicated in all seven of our patients, and neurologic symptoms and signs were completely eliminated in five patients. No evidence of meningeal leukemia was found in three of the five patients in whom an autopsy was performed.

Proliferative kinetics of central nervous system (CNS) leukemia

The proliferative kinetics of the leukemic cells in the cerebrospinal fluid (CSF) were studied in three adults with CNS leukemia after 18 and 8 months while receiving an intensive treatment regimen. One (J.L.) had acute myeloblastic leukemia and developed CNS disease after 5 years' treatment with arabinosylcytosine and 6-thioguanine. All were in marrow remission at the time of study. G.H. had had no therapy for CNS disease, A.K. had had intrathecal methotrexate 2 months previously, and J.L. had recently completed radiotherapy (1900 R) to the head. An Ommaya reservoir was placed in a lateral ventricle and 3H-thymidine was injected into the resrvoir every 12 hours for 10 days; samples of cells were obtained by lumbar puncture periodically for autoradiography. In all patients the flash 3H-thymidine labeling index (LI) of the leukemic cells was less than 2% (determined in vitro) and the mitotic index less than 0.1%. After 10 days of 3H-thymidine injections in vivo, the LIs of the leukemic cells were 55%, 36%, and 21% in G.H., A.K., and J.L., respectively. These findings indicate that leukemic cells may proliferate very slowly in the CNS, and stress the difficulty of eradicating CNS leukemia with chemotherapeutic agents which are only active against proliferating cells.

Management of CNS leukemia in childhood. An outline of current concepts

Progress in prolonging the lives of children with leukemia has resulted in a great increase in neurological complications. Exact diagnosis and intensive therapy are needed. Prophylactic CNS therapy offers bright new hope for prolonged survival or cure.

Intrathecal chemotherapy in Burkitt's lymphoma

Meningeal involvement with Burkitt lymphoma cells constitutes the most challenging therapeutic problem in the management of Burkitt's tumour. The results of intrathecal chemotherapy with methotrexate or cytosine arabinoside in 55 episodes of malignant pleocytosis in 38 patients with Burkitt's tumour are described. The response was complete in nearly all patients after the administration of either agent. Cerebrospinal fluid (C.S.F.) remissions were more prolonged in patients receiving intrathecal methotrexate or cytosine arabinoside daily for four days as opposed to a 10-day schedule. A controlled randomized trial of "prophylactic" intrathecal chemotherapy in patients without malignant cells in the C.S.F. on admission showed no protective effect against the subsequent development of malignant pleocytosis. Future therapeutic approaches are considered in the light of these results.