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Purpose: To present the effect of radiotherapy doses to different volumes of normal structures on neurocognitive outcomes in young patients with benign and low-grade brain tumors treated prospectively with stereotactic conformal radiotherapy (SCRT)., Methods and Materials: Twenty-eight patients (median age, 13 years) with residual/progressive brain tumors (10 craniopharyngioma, 8 cerebellar astrocytoma, 6 optic pathway glioma and 4 cerebral low-grade glioma) were treated with SCRT to a dose of 54 Gy in 30 fractions over 6 weeks. Prospective neuropsychological assessments were done at baseline before RT and at subsequent follow-up examinations. The change in intelligence quotient (IQ) scores was correlated with various factors, including dose-volume to normal structures., Results: Although the overall mean full-scale IQ (FSIQ) at baseline before RT remained unchanged at 2-year follow-up after SCRT, one third of patients did show a >10% decline in FSIQ as compared with baseline. Logistic regression analysis demonstrated that patients aged <15 years had a significantly higher chance of developing a >10% drop in FSIQ than older patients (53% vs. 10%, p = 0.03). Dosimetric comparison in patients showing a >10% decline vs. patients showing a <10% decline in IQ revealed that patients receiving >43.2 Gy to >13% of volume of the left temporal lobe were the ones to show a significant drop in FSIQ (p = 0.048). Radiotherapy doses to other normal structures, including supratentorial brain, right temporal lobe, and frontal lobes, did not reveal any significant correlation., Conclusion: Our prospectively collected dosimetric data show younger age and radiotherapy doses to left temporal lobe to be predictors of neurocognitive decline, and may well be used as possible dose constraints for high-precision radiotherapy planning., (Copyright 2010 Elsevier Inc. All rights reserved.)

Standard treatment of optic pathways gliomas consists of radiotherapy and surgery when feasible. Owing to the toxicity of irradiation, chemotherapy has emerged as an interesting therapeutic option, especially in young children. This study describes the neuropsychological profile of 27 children (aged between 1.5 and 15.7 years) with optic pathways gliomas treated with chemotherapy as first-line treatment. Eight of them also received radiotherapy as salvage treatment. Eight had neurofibromatosis type 1 (NF1). Intellectual outcome was preserved in children treated with chemotherapy only (mean=107+/-17) compared to children also receiving radiotherapy (mean IQ=88+/-24) or children having NF1 and treated with chemotherapy (mean IQ=80+/-13). Scores for abstract reasoning, mental arithmetic, chessboard/coding, perception, judgement of line orientation were lower in children irradiated than in those treated only by chemotherapy. Children with Nf1 showed subnormal IQ scores with marked impairment of short- and long-term memory. With respect to long-term neuropsychological outcome, our study shows that a chemotherapy-first strategy can preserve the intellectual outcome of these patients either by avoiding the need of radiotherapy or by delaying its use as much as possible.

Background: For more than 60 years, radiation therapy has been an integral part in the management of childhood low-grade glioma. As this tumor carries an excellent long-term prognosis, the risk of late effects is of particular clinical importance and impinges upon radiotherapeutic treatment strategies., Material and Methods: Studies on the use of radiation therapy in children with low-grade glioma were systematically reviewed for data on radiotherapy-induced side effects on brain parenchyma, endocrine dysfunction, growth retardation, neurocognitive dysfunction, vasculopathy, and secondary neoplasms., Results: Data on late effects are scarce and heterogeneous. Past reports included only retrospective series from the 1930s to present days, a time during which treatment policies and radiation techniques widely varied and considerably changed in recent years. Often, considerable uncertainty existed regarding pretreatment health status and radiotherapy-related factors (e.g., total dose, dose per fraction, treatment fields). In spite of these shortcomings and often conflicting observations, it appears that especially younger children and children with neurofibromatosis (NF) are at risk of endocrinopathies in terms of growth retardation and developmental abnormalities, as well as neurocognitive dysfunction expressed as problems in the psychosocial environment such as in education and occupation. However, both observations may be attributed to the higher proportion of NF in the very young who frequently develop large tumors spreading along the entire supratentorial midline. The risk of radiation-induced disturbances in visual function is low (no case reported). Young children with NF appear to have an increased risk of vasculopathies. 33 cases of moyamoya disease were found (preferably in the very young), 18 of whom were NF-positive. Other cerebrovascular accidents (24 cases, of whom 14 were NF-positive) and secondary neoplasms (15 cases, of whom only five occurred in field--four were high-grade astrocytomas) are a rare condition. The latter cannot be distinguished from late relapses with malignant transformation. Modern treatment techniques appear to reduce the risk of radiation-induced late effects., Conclusions: More studies and clear definitions of clinical endpoints such as neurocognitive and endocrinological outcome are needed in order to clarify the impact of radiation therapy on the risk of late sequelae. Presently, the strategy to postpone radiotherapy in the younger children, especially with NF, is justified to reduce the risk of late effects. These information and the contribution of tumor, surgery and chemotherapy will help to define the role of radiation therapy in the future management of childhood low-grade glioma and whether the use of highly sophisticated and expensive treatment techniques is justifiable. The recently initiated prospective study of the APRO (Pediatric Radiooncology Working Party) on documentation of dose prescription to organs at risk and the network of the GPOH to explore late effects as well as the forthcoming prospective SIOP/GPOH (International Society of Pediatric Oncology/German Society of Pediatric Oncology and Hematology) LGG 2003 trial are addressing these issues.