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

Evaluation of the late effects of CNS prophylactic treatment in childhood acute lymphoblastic leukemia (ALL) using magnetic resonance spectroscopy

PURPOSE

The aim of the study was to evaluate the late changes seen in Magnetic Resonance Spectroscopy (MRS) of the brain in Acute Lymphoblastic Leukemia (ALL) survivors to assess neurotoxicity following prophylactic treatment with cranial irradiation (CRT) and/or intrathecal (ITMTX) and systemic MTX.

MATERIALS AND METHODS

The study was performed on two groups of patients. The first group consisted of 30 children who received CRT and ITMTX, and the second group was comprised of 15 children treated only with ITMTX. All patients were ALL survivors treated between 1994 and 2002. Radiotherapy was performed using two opposite fields for a total dose of 18 Gy. The children were examined from 6 to 12 years after treatment. All children underwent a physical and neurological examination and MRI/MRS studies. (1)H-MR spectra were acquired from frontal and occipital regions of the brain. Mean values and standard deviations were calculated for following metabolite ratios: NAA/Cr, Cho/Cr, Cho/NAA, and mI/Cr.

RESULTS

Three of the 45 children (11%) presented with white matter changes upon MRI examination. All children with MRI abnormalities received CRT. In 13 (31%) children, changes in (1)H-MRS metabolite ratios were seen. We observed decreased NAA/Cr and Cho/Cr ratios. MR spectroscopy showed a significant reduction (P < .05) of the mean NAA/Cr ratio in children given CRT.

CONCLUSION

MRS is a sensitive detector of late metabolic changes after prophylactic treatment for ALL in childhood. It is able to detect metabolic effects of treatment in patients even when no morphologic changes are visible upon MRI.

Neurodevelopmental sequelae of pediatric acute lymphoblastic leukemia and its treatment

This review will describe the neurocognitive outcomes associated with pediatric acute lymphoblastic leukemia (ALL) and its treatment. The literature is reviewed with the aim of addressing methodological issues, treatment factors, risks and moderators, special populations, relationship to neuroimaging findings, and directions for future research. It is concluded that neurocognitive outcomes for the majority of children with standard-risk ALL treated according to current chemotherapy protocols is relatively good, but subgroups of children are more significantly compromised. As medical treatments advance and survival rates continue to improve, neurocognitive outcomes and other quality of life indicators will become increasingly important. Preventing or ameliorating treatment-related neuropsychological sequelae represents the next major challenge in pediatric ALL.

Preventing neurocognitive late effects in childhood cancer survivors

Neurocognitive late effects are common sequelae of cancer in children, especially in those who have undergone treatment for brain tumors or in those receiving prophylactic cranial radiation therapy to treat leukemia. Neurocognitive morbidity in attention, executive functioning, processing speed, working memory, and memory frequently occurs and contributes to declines in intellectual and academic abilities. Oncologists are faced with the challenge of using the most effective, often the most intense, therapy to achieve the primary goal of medical success, balanced with the desire to prevent adverse late effects. Not all children with similar diagnoses and treatment have identical neurocognitive outcomes; some do very poorly and some do well. Attention now turns to the reliable prediction of risk for poor outcomes and then, using risk-adapted therapy, to preserve neurocognitive function. Prevention of late effects through rehabilitative strategies, continuation of school, and pharmacotherapy will be explored.

Neuropsychological outcomes from a randomized trial of triple intrathecal chemotherapy compared with 18 Gy cranial radiation as CNS treatment in acute lymphoblastic leukemia: findings from Dana-Farber Cancer Institute ALL Consortium Protocol 95-01

PURPOSE

We evaluated late neuropsychological toxicity in children treated for standard-risk acute lymphoblastic leukemia (ALL) who were randomly assigned to receive either cranial radiation therapy (CRT) with double intrathecal (IT) chemotherapy or intensive triple IT chemotherapy (no CRT) as CNS-directed therapy.

PATIENTS AND METHODS

Between 1996 and 2000, 164 children with standard-risk ALL treated on Dana-Farber Cancer Institute Consortium Protocol 95-01 were randomly assigned to receive either 18 Gy CRT delivered in twice daily fractions (0.9 [DOSAGE ERROR CORRECTED] Gy) with double IT therapy (methotrexate and cytarabine) or intensive triple IT drug (methotrexate, cytarabine and hydrocortisone) without CRT. Neuropsychological testing was completed at a median 6 years postdiagnosis for 79 children (CRT, n = 39; triple IT, n = 40), all of whom were in continuous complete remission.

RESULTS

Cognitive function for both groups was solidly in the average range, with no consistent group differences in basic cognitive skills. Children treated on the CRT plus double IT arm did, however, exhibit less fluent output and were less effective at modulating their behavior by parent report.

CONCLUSION

This randomized trial revealed only subtle differences 6 years after diagnosis between children who received CNS therapy as CRT plus double IT drug or as intensive triple IT drug. In most situations where comparable therapeutic efficacy can be achieved without CRT, it is preferable to do so. Where therapeutically necessary, however, CRT at lower doses may not add risk for significant neurotoxicity.

Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia

INTRODUCTION

Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively.

METHOD AND RESULTS

Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment.

CONCLUSION

In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia.

Age and high-dose methotrexate are associated to clinical acute encephalopathy in FRALLE 93 trial for acute lymphoblastic leukemia in children

The objective of the study was to assess acute neurotoxicity associated with triple intrathecal therapy (TIT)+/-high-dose methotrexate (HD MTX) in children with acute lymphoblastic leukemia (ALL). 1395 children were enrolled on FRALLE 93 protocol from 1993 to 1999. Lower-risk group (LR, n=182) were randomized to weekly low-dose MTX at 25 mg/m(2)/week (LD MTX, n=81) or HD MTX at 1.5 g/m(2)/2 weeks x 6 (n=77). Intermediate-risk group (IR, n=672) were randomized to LD MTX (n=290) or HD MTX at 8 g/m(2)/2 weeks x 4 (n=316). Higher-risk group (HR, n=541) prednisone-responder patients received LD MTX and cranial radiotherapy. HR group steroid resistant cases were grafted (autologous or allogenic). TIT (MTX, cytarabine and methylprednisolone) was given every 2 weeks during 16-18 weeks and every 3 months during maintenance therapy in LR and IR patients. 52 patients (3.7%) developed neurotoxicity. Isolated seizures: n=15 (1.1%), peripheral and spinal neuropathy: n=17 (1.2%) and encephalopathy: n=20 (1.4%). Age >10 years was significantly associated with neurotoxicity (P=0.01) and use of HD MTX is associated with encephalopathy (P=0.03). Sequels are reported respectively in 60 and 33% of spinal neuropathy and encephalopathy cases. Current strategies tailoring risk of neurological sequels has to be defined.

Visual attention in long-term survivors of leukemia receiving cranial radiation therapy

The effect of cranial radiation therapy (CRT) on visual attention was examined in long-term survivors of childhood acute lymphoblastic leukemia (ALL) compared to peers with no history of ALL (n = 24) using a cued orienting task and a global-local task. ALL participants treated with CRT (n = 13) demonstrated an increased cost in response time with invalid spatial orienting cues and inefficient shifts of attention across hierarchical levels. ALL participants treated only with chemotherapy (n = 8) showed performance similar to the non-ALL comparison group. Participants with exposure to CRT early in life appeared to largely account for the attention deficits, and showed particular difficulties with shifting attention from the local level of stimuli to the global level. The data are consistent with prior reports emphasizing attention deficits following CRT, and suggest that attention shifting may be particularly affected by CRT early in life.

Quantitative MRI assessment of leukoencephalopathy

Quantitative MRI assessment of leukoencephalopathy is difficult because the MRI properties of leukoencephalopathy significantly overlap those of normal tissue. This report describes the use of an automated procedure for longitudinal measurement of tissue volume and relaxation times to quantify leukoencephalopathy. Images derived by using this procedure in patients undergoing therapy for acute lymphoblastic leukemia (ALL) are presented. Five examinations from each of five volunteers (25 examinations) were used to test the reproducibility of quantitated baseline and subsequent, normal-appearing images; the coefficients of variation were less than 2% for gray and white matter. Regions of leukoencephalopathy in patients were assessed by comparison with manual segmentation. Two radiologists manually segmented images from 15 randomly chosen MRI examinations that exhibited leukoencephalopathy. Kappa analyses showed that the two radiologists' interpretations were concordant (kappa = 0.70) and that each radiologist's interpretations agreed with the results of the automated procedure (kappa = 0.57 and 0.55). The clinical application of this method was illustrated by analysis of images from sequential MR examinations of two patients who developed leukoencephalopathy during treatment for ALL. The ultimate goal is to use these quantitative MR imaging measures to better understand therapy-induced neurotoxicity, which can be limited or even reversed with some combination of therapy adjustments and pharmacological and neurobehavioral interventions.

Methotrexate leukoencephalopathy presenting as Klüver-Bucy syndrome and uncinate seizures

Methotrexate causes several biochemical changes that impact the nervous system. The neurotoxicity usually affects the cerebral white matter, causing a leukoencephalopathy that can be chronic and progressive with cognitive decline. A 15-year-old male developed olfactory seizures and behavioral abnormalities (hypersexuality, placidity, and memory disturbances) compatible with partial Klüver-Bucy syndrome after treatment for central nervous system leukemia with intraventricular methotrexate. A magnetic resonance imaging study revealed evidence of white matter disease affecting both temporal lobes. A brain biopsy revealed a necrotizing encephalopathy compatible with methotrexate-related white matter injury. It may be prudent to verify normal cerebrospinal fluid dynamics before the administration of intraventricular methotrexate in children with a history of central nervous system leukemia.

Hypofractionated moderate dose radiation, intrathecal chemotherapy, and repetitive reinduction/reconsolidation systemic therapy for central nervous system relapse of acute lymphoblastic leukemia in children

BACKGROUND

We assessed efficacy and morbidity of chemotherapy and 1, 800 cGy of hypofractionated craniospinal irradiation (CSI) in children with central nervous system (CNS) relapse following first remisssion of acute lymphoblastic leukemia (ALL).

PROCEDURE

Nineteen patients with isolated CNS relapse and 4 with combined CNS/marrow or CNS/testicular relapse received treatment according to Children's Hospital of Philadelphia (CHOP) protocols CHP-449 and CHP-497. CNS treatment included intrathecal methotrexate, cytarabine, and hydrocortisone and 1,800 cGy CSI in 16 fractions over 12 months. Systemic therapy consisted of reinductions with vincristine, prednisone, and daunorubicin and reconsolidations with cytarabine, etoposide, and L-asparaginase every 56 days for 2 years. Outcome measures were event-free survival (EFS), survival, growth, and neuropsychologic assessment or school performance.

RESULTS

Follow-up of survivors from first relapse ranges from 52 to 133 months(median 91 months). Actuarial survival and EFSat 10 years are 58% (CI95 = 38-78%) and 54% (CI95 = 32-76%). Events include 2 second CNS, 4 marrow, 1 testicular, and 2 testicular/marrow relapses and 1 secondary leukemia. EFS is 100% (CI95 = 93-100%) in 9 patients with recurrence more than 26 months from diagnosis. Three patients have significant treatment-related reduction in stature. Median full-scale IQs of 6 patients tested were 112 pretreatment and 111 posttreatment among surviving patients. All 17 survivors attend regular school, but 2 receive supplementary special services.

CONCLUSIONS

Lower dose, hypofractionated CSI, intrathecal chemotherapy, and moderately intensive systemic chemotherapy provide excellent disease control for patients with late isolated CNS or combined marrow and CNS relapse. Children with brief first remissions remain at substantial risk of subsequent relapse with this therapy, especially in the marrow and testes.

Intellectual, educational, and behavioural sequelae after cranial irradiation and chemotherapy

Cognitive and educational sequelae are inconsistently reported in children treated with cranial irradiation for acute lymphoblastic leukaemia. This study investigated differences in these skills after cranial irradiation, controlling the effects of chemotherapy and psychosocial factors. Three groups were evaluated: 100 children diagnosed with acute lymphoblastic leukaemia and treated with cranial irradiation and chemotherapy; 50 children diagnosed with acute lymphoblastic leukaemia or other cancers and treated with chemotherapy alone; and a healthy control group of 100 children. Children in the clinical groups stopped treatment at least two years before evaluation and had no history of relapse. Children were aged between 7 and 16 at the time of assessment. Evaluation included cognitive, educational, and behavioural measures. Analyses found that children receiving cranial irradiation and chemotherapy performed more poorly than non-irradiated groups on intellectual and educational tests, with verbal and attentional deficits most pronounced. Children receiving chemotherapy alone performed similarly to controls, suggesting such treatment is not associated with adverse neurobehavioural sequelae.