Central nervous system pharmacology of antileukemic drugs

The blood-brain barrier provides a pharmacologic sanctuary for leukemic cells within the central nervous system (CNS), protecting them from the cytotoxic effects of systemic antileukemic therapy. Attempts to overcome this problem have included specific CNS-directed treatment in the form of direct intrathecal drug injection, cranial irradiation, and alteration in the dose and schedule of systemic agents to enhance their CNS penetration. Use of these treatments and strategies has led to the effective prevention and control of meningeal leukemia. Intrathecal therapy, primarily with methotrexate or cytosine arabinoside, is a form of regional chemotherapy that can achieve very high drug concentrations at the target site [i.e., in the meninges and cerebrospinal fluid (CSF)] with a low total dose. Therefore, there is minimal systemic toxicity. The dose and schedules, clinical pharmacology, and toxicities of the commonly used intrathecal agents are discussed in detail in this article. Another approach to overcoming the limited penetration of antileukemic drugs into the CNS has been the use of high-dose systemic therapy. Methotrexate and cytosine arabinoside in high doses have produced favorable clinical responses in patients with overt meningeal disease, and pharmacokinetic studies have documented cytotoxic concentrations of these drugs within the cerebrospinal fluid. A clear understanding of the CNS pharmacology of the antileukemic drugs is required in order to use these agents in the safest and most efficacious manner for the treatment of meningeal leukemia.     

CSF lysosomal enzyme activities in children treated for acute leukaemia

Activities of the lysosomal enzymes, β-hexosaminidase, α-Mannosidase, acid phosphatase, α-fucosidase and β-glucuronidase in cerebrospinal fluid (CSF) were studied in controls, patients with central nervous system (CNS) damage, and patients with leukaemia. Activities were markedly increased in patients with acute CNS disease. Activity levels in patients with leukaemia were in the normal range whether during induction with intrathecal chemotherapy or cranial irradiation or off treatment. These results suggest that lysosomal enzyme activities in CSF may not provide a sensitive enough marker of CNS damage following induction therapy in leukaemia. Acute leukaemia, cerebrospinal fluid, lysosomal enzymes.     

Feasibility and toxicity of intrathecal liposomal cytarabine in 5 children and young adults with refractory neoplastic meningitis

Intrathecal (IT) treatment of neoplastic meningitis secondary to relapsed or refractory malignancies is a major challenge for clinicians. We studied feasibility and toxicity of IT administered liposomal cytarabine on a compassionate basis in 5 patients (male, n=4; female, n=1; age at diagnosis 5 to 18 y) with recurrent acute lymphoblastic leukemia (n=3), primary refractory acute myeloid leukemia (n=1), or relapsed medulloblastoma (n=1). All of them had evidence of meningeal involvement as shown by presence of leukemic blasts or solid tumor cells on cytologic examination of cerebrospinal fluid and were refractory to standard central nervous system (CNS) therapy. A total of 33 doses were given. Leukemic blasts or solid tumor cells were cleared from cerebrospinal fluid in all patients. IT liposomal cytarabine was well tolerated in 2 patients, but may have contributed to neurologic side effects in 2 other patients with 1 patient who received high-dose methotrexate 96 hours before IT liposomal cytarabine developing transient encephalopathy. Another patient experienced seizures after 6 well-tolerated doses of IT liposomal cytarabine. In the fifth patient, treatment with IT liposomal cytarabine was not continued after a single dose because of toxic cauda equina syndrome, resulting from previous intensive CNS therapy. If administered simultaneously to other neurotoxic drugs, IT liposomal cytarabine may contribute to neurologic side effects in patients who had received prior intensive CNS-directed therapy. IT liposomal cytarabine should, therefore, be used cautiously, if a patient receives other potentially neurotoxic drugs simultaneously.     

Central nervous system complications in childhood leukemia. Correlation between clinical and computed tomographic findings

We used cranial computed tomography (CT) to evaluate 51 leukemic patients with or without central nervous system (CNS) symptoms. Among 17 symptomatic patients, nine had gross abnormalities on CT scans; leukemic infiltrations, infections (CNS aspergillosis), hemorrhages, and therapy-related complications were all evident. One with a leukemic infiltration showed a periventricular low density on the CT scans. The differential diagnosis of CT findings and the correlation between clinical and CT findings is described. The significance of a low-density area observed in an asymptomatic patient on long-term intrathecal methotrexate therapy for CNS leukemia is also discussed.     

Primary intraspinal soft-tissue sarcoma in childhood: Report of two cases with a review of the literature

Two young children who presented with lower spinal cord dysfunction manifested by bilateral leg weakness and urinary retention were diagnosed with intraspinal soft-tissue sarcoma. Neither patient had a significant extradural mass. Both tumors had histochemical features of rhabdomyosarcoma. Temporary responses were noted after combination chemotherapy either with vincristine, actinomycin D, and cyclophosphamide or with ifosfamide/mesna and etoposide. However, both patients developed uncontrollable cerebrospinal fluid (CSF) dissemination of tumor and died within 6 months of diagnosis, despite intrathecal chemotherapy and irradiation for one and very high-dose intravenous methotrexate (33 g/m²) for the other. This rare tumor can respond to parenteral antisarcoma chemotherapy, but better strategies are needed to prevent CSF spread and ultimate demise. Early institution of intrathecal cytostatic agents may retard or prevent CSF dissemination and prolong survival. © 1994 Wiley-Liss, Inc.     

Treatment of a primary intracranial germ cell tumor with systemic chemotherapy

Primary germ cell neoplasms of the central nervous system (CNS) are rare tumors which generally respond to radiotherapy. Experience is limited in managing the refractory patient. We report a patient whose suprasellar dysgerminoma responded completely to 5,000 rad. Seven years later, disease recurrence was refractory to an additional 4,000 rad. Theorizing that the "blood-brain barrier" was no longer intact after extensive radiotherapy and tumor involvement of the ventricular system, the patient was treated with systemic bleomycin, cisplatin, and vinblastine. Pharmacokinetic studies revealed that the bleomycin and cisplatin entered the cerebrospinal fluid. Serial CT scans and CSF levels of beta-HCG confirmed the clinical impression of a partial remission. Subsequent tumor progression was refractory to therapy with intraventricular bleomycin. It is concluded that systemic chemotherapy may be beneficial in certain cases of CNS germ cell neoplasms.     

Central nervous system involvement at the time of presentation in acute promyelocytic leukemia

Central nervous system (CNS) involvement is rarely observed in acute promyelocytic leukemia (APML). Most cases of CNS involvement occur at relapse rather than at presentation. Because of the extremely low incidence of CNS disease, diagnostic lumbar puncture is not routinely required and prophylactic intrathecal chemotherapy is not routinely administered. Here, we describe a teenage patient with newly diagnosed APML, chloromas, and symptomatic CNS involvement confirmed by MRI and cerebrospinal fluid (CSF) findings. Pediatr Blood Cancer © 2009 Wiley‐Liss, Inc.     

Meningeal Neuroblastoma After Completing Therapy

Neuroblastoma is a common childhood malignant tumor having a very poor prognosis because of its very invasive characteristics. However, the central nervous system (CNS) is usually not affected, with the exception of the disseminating stage. A case with a mediastinal neuroblastoma having a solitary relapse in the CNS after completing therapy is reported here. A lumbar puncture revealed neuroblastoma cell clumps in the cerebrospinal fluid (CSF). This is a rare condition referred to as “meningeal neuroblastoma,” and aggressive therapy, including the intrathecal administration of nimustine (ACNU), was effective in removing the clump from the CSF.     

Central nervous system involvement in the erythrophagocytic disorders of infancy: the role of cerebrospinal fluid neopterins in their differential diagnosis and clinical management

In two children with familial erythrophagocytic lymphohistiocytosis accompanied by neurologic symptoms, total neopterin concentrations in cerebrospinal fluid were 200 times higher than in controls and 10 to 20 times higher than in five children with presumed neurologic disease due to primary viral infections (human immunodeficiency virus, herpes simplex, measles) of the CNS. In one child with familial erythrophagocytic lymphohistiocytosis, clinical remission was accompanied by a fall in neopterin concentrations to normal; in a second child, who died, total neopterin concentrations remained high. In two other children with a diagnosis of infection-associated hemophagocytic syndrome without any neurologic disturbance, neopterin concentrations were also elevated but only to 10 times the concentrations in controls. Total neopterin concentrations in cerebrospinal fluid provide a measure of the severity of macrophage infiltration and activation within the CNS, and are useful in assessing the need for intensive chemotherapy and monitoring the response to treatment.     

Changes of CSF-protein pattern in children with acute lymphoblastic leukemia during prophylactic cns therapy (Berlin protocol)

The cerebral spinal fluid (CSF)-protein profiles of ten children with previously untreated acute lymphoblastic leukemia (ALL) were investigated by agarose gel electrophoresis. The profiles were determined at diagnosis and during the fifth to eighth week of treatment when preventive therapy for central nervous system (CNS) leukemia (skull) irradiation, intrathecal methotrexate (ithMTX) was administered. The profiles were compared with those obtained from a control group of 67 children and those from 42 patients with acute aseptic meningitis. The data from the latter group demonstrated the CSF-protein pattern of partial blood-CSF barrier (B-CSF-B) breakdown. The children with ALL showed no or only minor signs of a B-CSF-B impairment at diagnosis and after four weeks of systemic treatment. However, CSF changes indicative of a lesion of the B-CSF-B increased in all children continuously during CNS prophylaxis. The protein profile at the end of combined chemotherapy and radiotherapy was very similar to that in patients with acute aseptic meningitis. These observations point to neurotoxic side effects on the CNS barrier system with the combination of cranial radiation and ithMTX. A striking finding was restricted heterogeneity of γ-globulin, observed in the CSF of nine out of the ten children with ALL before or during treatment. The significance of this abnormality is unknown.     

Acute ascending motoric paraplegia following intrathecal chemotherapy for treatment of acute lymphoblastic leukemia in children: case reports and review of the literature

Severe side effects of chemotherapy in pediatric patients with acute lymphoblastic leukemia are rare, but well-known. We present two pediatric patients who developed ascending motoric paraplegia (AMP) following intrathecal chemotherapy. Both patients suffered from progressive weakness of their lower extremities, neurogenic bladder dysfunction, autonomous neural dysregulation and minor sensory deficits. Despite an initially similar clinical picture, progression and outcome were fairly different. There is convincing evidence that AMP is caused by spinal cord toxicity of intrathecally applied toxic agents such as cytarabin and/or methotrexate leading to spinal demyelinisation as demonstrated by elevated myelin basic protein in cerebrospinal fluid.     

Sudden neurologic death after intrathecal methotrexate

Methotrexate leukoencephalopathy is a chronic syndrome of ataxia and confusion which may progress to seizures, coma, and death. We report a fatal case of this syndrome in a patient who displayed no evidence of the typical prodrome of neurologic symptoms or signs. This patient suffered brain death after receiving 11 doses of intrathecal methotrexate for leukemic meningitis. Since leukoencephalopathy was not clinically suspected, this case underscores the need for a test that would reliably monitor central nervous system toxicity due to intrathecal therapy.     

Intracerebral hematoma as a complication of intrathecal methotrexate administration

Neurotoxicity of methotrexate is a well-documented issue, but development of an intracerebral hematoma following administration of intrathecal methotrexate is an extremely rare entity. A 6-year-old male with the diagnosis of non-Hodgkin lymphoma was put on a treatment regimen, including intrathecal methotrexate. Six days following the last intrathecal methotrexate administration, the patient developed a deteriorating state of consciousness. There was no history of trauma. Coagulation studies and platelet count were normal. Magnetic resonance imaging of the brain demonstrated a large left frontoparietal hematoma. Intracerebral hematoma may be a very rare, but serious, complication of intrathecal methotrexate administration.     

Pure methotrexate encephalopathy presenting with seizures: CT and MRI features

With the advent of chemotherapy, mortality rates in acute lymphoblastic leukaemia (ALL) have decreased, but complications in the central nervous system have appeared. These include direct involvement of the brain itself and the development of chemotherapy-related encephalopathy as a delayed reaction. In most reported cases, this encephalopathy is believed to be due to necrotising angiitis arising from the combination of chemotherapy with adjuvant radiotherapy. We report the cases of four children with ALL who had been treated with high-dose intravenous and intrathecal chemotherapy but no radiation therapy, and who were admitted to hospital because of seizures. CT of the brain revealed the presence of diffuse periventricular white matter hypodensities in all cases and subcortical hyperdense foci in three cases. MRI showed diffuse hyperintense white matter lesions on T2-weighted images in all four patients; hypointense changes were observed on susceptibility-sensitive FLASH sequences in the hyperdense foci seen on CT as well as changes that were hyperintense on T1-weighted images. It was, therefore, concluded that the lesions corresponded to a leukoencephalopathy with calcific deposits. These findings are of a pure form of methotrexate encephalopathy causing seizures. Received: 23 June 1997 Accepted: 8 September 1997     

Elevation of cerebrospinal fluid sialic acid concentration in children with central nervous system leukemia

We studied sialic acid in the cerebrospinal fluid (CSF) of 52 children with leukemia and 51 children with non-leukemic diseases. The CSF sialic acid concentration in the children with central nervous system (CNS) leukemia was significantly higher than that in the children with acute lymphoblastic leukemia without CNS involvement, acute non-lymphocytic leukemia without CNS involvement, non-hemopoietic diseases, non-suppurative meningitis, epilepsy, and other neurologic diseases. Serial determinations revealed a rapid decline in the CSF sialic acid concentrations in the patients with CNS leukemia who responded well to the therapy and who were free from relapse of CNS leukemia. The simultaneously determined CSF beta 2 microglobulin concentration did not show any significant changes. These results suggest that the CSF sialic acid may be a good indicator of CNS leukemia.     

Medulloblastoma as a secondary malignancy after radiotherapy-free treatment for acute lymphoblastic leukemia

Malignant brain tumors have been reported to occur in survivors of childhood acute lymphoblastic leukemia (ALL) more frequently than in the noncancer control population. The strongest risk factor seems to be cranial radiotherapy, used as central nervous system (CNS) prophylaxis. We report the case of a 9-year-old girl affected with metastatic medulloblastoma that developed 6 years after a diagnosis of acute lymphoblastic leukemia. CNS prophylaxis for ALL consisted of intrathecal methotrexate plus cytarabine (20 administrations) and 4 courses of high-dose methotrexate (5g/m2). No prophylactic cranial radiotherapy was administered. The child, in first complete remission, was well until the occurrence of a second tumor. She was treated for medulloblastoma with craniospinal radiotherapy and chemotherapy. At present, she is alive but with disease. As the unusual association of these 2 malignancies in this patient, the p53 status was investigated using FISH analysis by specific DNA probe; no p53 mutation was detected.     

Unusual presentation of central nervous system relapse with oculomotor nerve palsy in a case of CD56-positive acute myeloid leukemia following allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-SCT) plays an important role in the treatment of infants and children with acute myelogenous leukemia (AML). Leukemic relapse after allo-SCT is responsible for a high rate of treatment failure. Extra-medullary relapse (EMR), without involvement of bone marrow, is rare compared to medullary relapse. CD56, the neural cell adhesion molecule, may contribute to the higher frequency of CNS relapse in CD56-positive AML. We observed an isolated EMR on the oculomotor nerve of a 17-month-old girl 12 weeks after cord blood transplantation (CBT), who was transplanted because of CD56-positive AML. Diagnosis of relapse was suspected clinically and confirmed by magnetic resonance imaging (MRI), and fluorescence-activated cell sorter (FACS) and chimerism analysis of cerebrospinal fluid (CSF). Therapy consisted of intra-thecal chemotherapy, CNS irradiation, and systemic immunomodulation by cyclosporin A (CsA) and basiliximab withdrawal. Twenty-one months after relapse, the patient shows full remission of symptoms and previously described oculomotor nerve infiltration.     

Intellectual function in long-term survivors of childhood acute lymphoblastic leukemia: protective effect of pre-irradiation methotrexate? A Childrens Cancer Study Group study

Having demonstrated in a laboratory model that the neurotoxicity of CNS irradiation can be ameliorated with pre-irradiation methotrexate, we retrospectively compared two methods of CNS prophylaxis in childhood acute lymphoblastic leukemia which differed only in the timing of intrathecal methotrexate and radiotherapy. The results of standard IQ tests conducted 2-11 years after 24 Gy of cranial radiotherapy were obtained in 72 patients, of whom 27 had pre-irradiation methotrexate and 45 did not (control group). The two groups were otherwise comparable. In girls, the full-, performance-, and verbal-scale IQ scores were consistently higher in the pre-irradiation methotrexate group than in the corresponding control group (P less than 0.025). Among girls less than 5 years of age when irradiated, the mean IQ scores were 25-29 points higher after pre-irradiation methotrexate than after the control treatment (P less than 0.0007). These results suggest that pre-irradiation methotrexate may help prevent CNS radiotoxicity in children, and that the benefit is dependent on patient age and gender.     

Elevation of Cerebrospinal Fluid Sialic Acid Concentration in Children with Central Nervous System Leukemia

ABSTRACT. We studied sialic acid in the cerebrospinal fluid (CSF) of 52 children with leukemia and 51 children with non-leukemic diseases. The CSF sialic acid concentration in the children with central nervous system (CNS) leukemia was significantly higher than that in the children with acute lymphoblastic leukemia without CNS involvement, acute non-lymphocytic leukemia without CNS involvement, non-hemopoietic diseases, non-suppurative meningitis, epilepsy, and other neurologic diseases. Serial determinations revealed a rapid decline in the CSF sialic acid concentrations in the patients with CNS leukemia who responded well to the therapy and who were free from relapse of CNS leukemia. The simultaneously determined CSF β2 microglobulin concentration did not show any significant changes. These results suggest that the CSF sialic acid may be a good indicator of CNS leukemia.     

CT scans of long-term survivors of various childhood malignancies

Forty-two children with various systemic malignancies in continuous remission for 1 to 3 years after the completion of chemotherapy had CT scans with normal ventricular dimensions, similar to a noncancer “control” population. Seventeen of these patients had acute lymphocytic leukemia (ALL) treated either with prophylactic cranial irradiation and intrathecal methotrexate [7] or intrathecal methotrexate alone [10] and the remaining 25 patients had soft tissue sarcomas. Sixteen other patients with sarcomatous meningitis had enlarged ventricles while on chemotherapy. Nine had ALL. Seven had soft tissue sarcomas, none of whom received any prior CNS irradiation or intrathecal chemotherapy. In this retrospective study no evidence of hydrocephalus or significant white matter hypodensity was detected in long-term survivors of childhood cancer, regardless of whether prophylactic intrathecal chemotherapy and/or cranial irradiation was given. Direct involvement of the CNS with meningeal cancer was the most important association with ventriculomegaly.