LOW-GRADE GLIOMAS OF THE CEREBRAL HEMISPHERES IN CHILDREN - AN ANALYSIS OF 71 CASES

Low-grade gliomas constitute the largest group of cerebral hemispheric tumors in the pediatric population. Although complete tumor resection is generally the goal in the management of these lesions, this can pr ove difficult to achieve because tumor margins may blend into the surr ounding brain. This raises several important questions on the long-ter m behavior of the residual tumor and the role of adjuvant therapy in t he management of these lesions. To examine these issues, the authors r eviewed their experience in 71 children with low-grade cerebral hemisp heric gliomas who were treated at their institution between 1956 and 1 991 and assessed the relationship between clinical, radiographic, path ological, and treatment-related factors and outcome. Only seven patien ts in the series died, one from perioperative complications, five from progressive disease, and one (a child with neurofibromatosis) from a second neoplasm. For the 70 patients who survived the perioperative pe riod, overall actuarial survivals at 5, 10, and 20 years were 95%, 93% , and 85%, respectively; progression-free status was maintained in 88% , 79%, and 76%, respectively. On univariate analysis, the factor that was most strongly associated with both overall and progression-free su rvival was the extent of tumor resection (p = 0.013 and p = 0.015, res pectively). A relationship between extent of resection and progression -free survival was present both in patients with pilocytic astrocytoma s (p = 0.041) and those with nonpilocytic tumors (p = 0.037). Histopat hological diagnosis was also associated with overall survival on univa riate analysis; poorer results were seen in the patients with nonpiloc ytic astrocytoma compared to those with other low-grade gliomas, such as pilocytic astrocytoma, mixed glioma, and oligodendroglioma (p = 0.0 21). The use of radiotherapy was not associated with a significant imp rovement in overall survival (p = 0.6). All three patients who ultimat ely developed histologically confirmed anaplastic changes in the vicin ity of the original tumor had received prior radiotherapy, 20, 46, and 137 months, respectively, before the detection of malignant progressi on. In addition, children who received radiotherapy had a significantl y higher incidence of late cognitive and endocrine dysfunction than th e nonirradiated patients (p < 0.01 and 0.05, respectively). The author s conclude that children with low-grade gliomas of the cerebral hemisp heres have an excellent overall prognosis. Complete tumor resection pr ovides the best opportunity for long-term progression-free survival. H owever, even with incomplete tumor excision: long-term progression-fre e survival is common. The findings in this study do not support the ro utine use of postoperative radiotherapy after an initial incomplete tu mor resection: although irradiation appears to increase the likelihood of long-term progression-free survival, overall survival is not impro ved significantly, and long-term morbidity may be increased.