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was treated with craniospinal irradiation and a boost to the posterior fossa, only 20% of patients had an IQ greater than 90 at 5 years, and the proportion decreased to 10% at 10 years. In a separate publication, a review of multiple studies compared the IQ of pediatric patients treated postopera- tively with craniospinal irradiation, focal irradiation of the primary site, or no irradiation. 35 Patients who received craniospinal irradiation had significantly lower IQs than those who did not receive such treatment; however, those treated with focal irradiation had IQ values comparable to those who received no irradiation. These results support efforts to reduce the volume of irradiation. Much of the fear instilled in those who treat young children with brain tu- mors may be derived from reports about children with medulloblastoma for whom a persistent and early decline in intellectual outcome is anticipated after craniospinal irradi- ation. 36 Perhaps the most direct comparison of the present neurocognitive outcomes can be made with the results from the study of Grill et al, 37 who reported a mean IQ of 85.3 (standard deviation, 13.6) for 12 long-term survivors of ependymoma treated with conventional posterior fossa ir- radiation at age 5 years. Spiegler et al 38 recently reported on four patients with ependymoma and 30 with medullo- blastoma in a study that was meant to show change over time and the onset of stability for IQ measured after radia- tion therapy. Because of the small number of serial evalua- tions, their modeling was limited to 17 patients evaluated within 6 months from diagnosis and followed for a median of 3.3 years. They found that patients evaluated early in their treatment course experienced a steep decline with eventual leveling in the pattern of a quadratic function. Our study is unique because it includes children younger than 3 years at the time of irradiation. The age of 3 years has been used to define those who are at greatest risk of the effects of irradiation and for whom trials have been designed in an effort to delay or avoid irradiation. Age at the time of diagnosis has also been described as an important prognostic factor. In the present study, 13 of the 48 patients younger than 3 years experienced disease progression. Chil- dren in this age group in earlier studies had a worse prog- nosis than older patients, possibly because of more aggressive tumor biology, reluctance to give postoperative radiation therapy, or use of lower doses of radiation. 29,39, 40 The first infant study by the Pediatric Oncology Group attempted to delay radiation therapy by using postoperative chemotherapy and showed a significant difference in out- come based on age. 3,41 The 5-year PFS estimate was 12.7% 8% for the 31 patients between the ages of 0 and 23 months treated with chemotherapy for 2 years, whereas the 17 patients who were 24 to 36 months old treated with chemotherapy for 1 year had an estimate of 54.8% 15%. The age-related differences remained even when the analy- sis was limited to those without metastases who had under- gone gross-total resection: the 5-year PFS estimates were

Fig 4. Mean Vineland Adaptive Behavior Scale scores before and after conformal radiation therapy.

failure changed as a result of the high rate of local tumor control and gross-total resection. 30 The improved rate of disease control in this study may be attributable to factors that include the high proportion of cases in which gross-total resection was done, systematic targeting with three-dimensional imaging, and the rela- tively high prescribed total dose. Gross-total resection was performed in 84% of cases, near-total resection in 7%, and subtotal resection in 9%; the average volume of residual disease was only 1.2 cm 3 . The percentage of cases in which gross-total resection was conducted in this study was higher than the national average, which has ranged from 40% to 60%. 32,33 We evaluated CNS effects in a rigorous, consistent manner, using widely accepted tests to identify the effects of radiation on cognitive, endocrine, and neurologic function. The most encouraging finding from this study was the level of function and lack of treatment-related effects in a young and vulnerable group of children treated with high-dose irradiation. Only a limited comparison of neurocognitive effects can be made between patients from this study and those treated conventionally, because prospective data from a similarly well-characterized group of pediatric patients with ependymoma are not available. After correcting for other factors responsible for neurocognitive function in pediatric patients with CNS tumors, other investigators found that the dose and volume of irradiation seem to play a role in altering neurocognitive status or intellectual out- come. In a study that included 59 pediatric patients with medulloblastoma and 37 with posterior fossa ependymoma (including 14 patients younger than 3 years at the time ependymoma was diagnosed), 90% of those with ependy- moma, which was treated with irradiation to the posterior fossa, maintained an IQ greater than 90 at 5 to 10 years after treatment. 34 In the group with medulloblastoma, which

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