Leukemias and lymphomas: treatment and prophylaxis of the central nervous system

Evaluation of standardized triple intrathecal therapy toxicity in oncohematological pediatric patients

Background The administration of triple intrathecal therapy with methotrexate, cytarabine and a corticosteroid for the prophylaxis and treatment of neoplastic cell infiltration in the central nervous system in hematological malignancies is a widespread practice. There is limited information available about its toxicity profile. Several factors related to intrathecal preparation can affect toxicity. Thus, it was decided to standardize intrathecal chemotherapy, trying to obtain the best toxicity profile. Objective To assess the toxicity of a standardized triple intrathecal chemotherapy in oncohematological pediatric patients and to establish risk factors of toxicity. Setting Oncohematological pediatric unit from a tertiary hospital in Spain. Methods Prospective, descriptive and observational study in which all the administrations of standardized triple intrathecal chemotherapy in pediatric patients were registered. Main outcome measure Toxicity of the intrathecal therapy was recorded and possible risk factors were assessed. Results A total of 269 administrations of triple intrathecal chemotherapy were registered in 41 patients (mean age = 6.6 ± 3.9 years). In 16.7% of the procedures, an adverse event was reported (total number of adverse events = 61). 47.5% were grade 1, 47.5% grade 2 and 4.9% grade 3. The administration of intrathecal chemotherapy inpatient and patient age ≥3 years were risk factors of toxicity in the multivariate analysis. Conclusions The administration of standardized triple intrathecal chemotherapy is related to a low frequency of toxicity and most of the adverse events registered were mild/moderate. The detection of adverse effects was significantly greater in children with age greater than or equal to three years and in hospitalized patients.

Central nervous system prophylaxis in patients with aggressive diffuse large B cell lymphoma: an analysis of 3,258 patients in a single center

Central nervous system (CNS) relapse continues to be a frequent and usually fatal complication in patients with diffuse large B cell lymphoma (DLBCL). Multiple factors identify the possibility of relapse and justify neurological prophylaxis; however, most of these have not been confirmed. Thus, the use of prophylaxis has not been defined. From 1988 to 2008, 3,258 patients with DLBCL with higher clinical risks and multiple extranodal involvement that have been treated with standard anthracycline-based chemotherapy: CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) or CHOP-R (CHOP plus rituximab) and that achieve complete response were retrospectively analyzed to assess the efficacy of CNS prophylaxis. One thousand five patients received different schedules for CNS prophylaxis, and 2,253 patients did not receive CNS prophylaxis. CNS relapse was similar in patients who receive prophylaxis (6 %) compared to patients who did not receive prophylaxis (5.9 %). Overall survival of patients who either receive or did not receive prophylaxis was not statistically significant: 49 % versus 53 % (p = 0.802). Thus, it seems that CNS prophylaxis did not improve outcome in this special setting of patients, and no prognostic factors to predict the presence of CNS relapse were identified. It is evident that multicentric studies are necessary to define the role of prophylaxis in order to prevent CNS relapse and that the therapeutic procedure will be carefully revised.

Cognitive Sparing during the Administration of Whole Brain Radiotherapy and Prophylactic Cranial Irradiation: Current Concepts and Approaches

Whole brain radiotherapy (WBRT) for the palliation of metastases, or as prophylaxis to prevent intracranial metastases, can be associated with subacute and late decline in memory and other cognitive functions. Moreover, these changes are often increased in both frequency and severity when cranial irradiation is combined with the use of systemic or intrathecal chemotherapy. Approaches to preventing or reducing this toxicity include the use of stereotactic radiosurgery (SRS) instead of WBRT; dose reduction for PCI; exclusion of the limbic circuit, hippocampal formation, and/or neural stem cell regions of the brain during radiotherapy; avoidance of intrathecal and/or systemic chemotherapy during radiotherapy; the use of high-dose, systemic chemotherapy in lieu of WBRT. This review discusses these concepts in detail as well as providing both neuroanatomic and radiobiologic background relevant to these issues.

Effect of methotrexate administration on status of some essential trace elements and antioxidant enzymes in pregnant rats in late gestation

OBJECTIVE

Folate antagonists are widely used in the treatment of various cancerous states. Paucity of data on effect of administration of one such widely used drug, methotrexate (MTX), on the status of essential trace elements and antioxidant enzymes in pregnant women or in pregnant animals prompted us to undertake this study.

METHODS

MTX at a concentration of 5 mg/kg body weight was administered intraperitoneally as single dose to pregnant Sprague-Dawley rats for three consequitive days from day 17 of pregnancy. Control group of pregnant rats received single dose of saline instead of the anti-cancer drug on all the 3 days. After receiving the third dose of drug, the treated rats and control group rats were sacrificed, 1 h after intraperitoneal injection of a cocktail of essential trace elements namely, Cu, Se and Zn administered as a single bolus dose. Blood samples were collected 30 min of trace element cocktail injection, after decapitation and concentrations of trace elements in serum samples were determined by atomic absorption spectrophotometry. Concentrations of antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase and total antioxidant status were determined by specific analytical kits, using spectrophotometry.

RESULTS

In control group(n = 6), serum concentrations of Cu, Se and Zn averaged 2330.5, 614.8 and 2773.2 microg/l, while in study group (n = 6) the concentrations of trace elements averaged 2294, 596 and 2713 microg/l, respectively. Student's t-test did not show any statistical significance (p > 0.05) between various trace element concentrations in control and treated groups. Cu:Zn ratios of control and treated group of rats did not vary significantly as well. Concentrations of superoxide dismutase, glutathione peroxidase in whole blood samples in control rats averaged 165 and 43,260 U/ml, respectively, while in MTX-treated group of animals the corresponding antioxidant enzymes averaged 330.6 and 67,101 U/ml respectively. SOD and GPX values were significantly higher in drug-treated animals compared to controls (Student's t-test, p < 0.05) However, total antioxidant activity was shown to be significantly lower (Student's t-test; p < 0.05) in the drug-treated group compared to control.

CONCLUSIONS

We report for the first time that effect of MTX administration in pregnancy is not associated with significant alteration in disposition of essential trace elements. However, the effect of drug administration on antioxidant enzyme status in pregnant women cannot be excluded while using the drug in clinical states.

Maternal–fetal transport kinetics of methotrexate in perfused human placenta:In vitrostudy

OBJECTIVE

Folate antagonists are widely used in the treatment of diverse cancerous states. A paucity of data on transport characteristics of one such widely used drug, methotrexate, in the human placenta, prompted us to study its permeation characteristics in vitro.

METHODS

Placentas from normal pregnancies were collected post-partum. Methotrexate, along with antipyrine as reference marker were injected as a single bolus (100 microL) into the maternal arterial circulation of isolated perfused placental lobules; perfusate samples were collected from both maternal and fetal circulations over a study period of five minutes. National Culture and Tissue Collection medium, diluted with Earle's buffered salt solution was used as the perfusate. The concentration of methotrexate in various samples was determined by high performance liquid chromatography, while antipyrine concentration was assayed by spectrophotometry. Transport and pharmacokinetic data of study and reference substances were computed using standard parameters.

RESULTS

Differential transport rate of methotrexate for 10, 25, 50, 75 and 90% efflux fractions in fetal venous effluent averaged 0.52, 1.30, 2.37, 3.57 and 4.43 minutes in 12 perfusions, representing 1.01 + 0.08, 1.03 + 0.06, 0.95 + 0.03, 0.93 + 0.03, 0.93 + 0.03 respectively times antipyrine reference value. Student's t-test showed varying differences between the control and study group data. Transport Fraction (TF) of methotrexate, expressed as fraction of the drug appearing in fetal vein, during study period of 5 minutes averaged 24.00 + 2.50% of bolus dose while antipyrine TF averaged 68.73 + 2.01% of injected bolus dose, representing 24.00 percent of reference marker value. Student's t-test showed methotrexate and reference marker TF values to be significantly different (p < 0.05). Pharmacokinetic parameters such as area under the curve, clearance, time for maximum response, absorption and elimination rates of study and reference substances showed varying differences.

CONCLUSIONS

We report for the first time that the transport of methotrexate from maternal to fetal circulation is not negligible in human placenta at term. It is reasonable to assume that a direct risk for the fetus from methotrexate use in pregnancy cannot be excluded, and caution is warranted when it is used in emergency clinical situations.

New challenges and opportunities in the management of brain metastases in patients with ErbB2-positive metastatic breast cancer

The introduction of trastuzumab for the treatment of tumors that overexpress ErbB2 (also known as HER2) has contributed significantly to recent improvements in systemic therapy for advanced breast cancer. The advances in systemic therapy have highlighted an increasing prevalence of central nervous system involvement in patients with ErbB2-positive breast cancer and a consequent need for new treatment options for brain metastases. Just as ErbB2-targeted systemic therapy has given rise to this challenge, so too could targeted therapy represent an opportunity to meet it. This Review considers the potential for targeted therapy to facilitate effective management of brain metastases in patients with ErbB2-positive breast cancer, and discusses in particular the data currently available in this setting for lapatinib, an orally available small-molecule tyrosine kinase inhibitor of ErbB1 and ErbB2.