Predicting disease progression in childhood cerebellar astrocytoma

Abstract

Pediatric cerebellar astrocytomas are frequently curable by complete surgical resection. However, even incompletely resected tumors may lie dormant indefinitely or spontaneously involute, and tumors thought to be completely excised have reappeared in the same location several years later. Because of the unpredictable nature of some cerebellar astrocytomas, this study was designed to analyze several variables for their potential value in predicting disease progression. The charts of 78 children treated at a children's hospital between 1966 and 1993 were reviewed; 62 tumors were pilocytic, 13 were fibrillary, and 3 were mixed oligoastrocytomas. Four children had the additional diagnosis of neurofibromatosis type 1, and those children were considered separately. Of the remaining 74 children, 48 underwent postoperative contrast-enhanced computerized tomography or magnetic resonance imaging. Of those 48 children, 17 had residual disease, and in 15 cases the tumor volume could be measured. Frequently the surgeon's report conflicted with the postoperative scan regarding the presence of residual disease. However, the surgeon's report of brainstem infiltration correlated highly with residual disease on postoperative imaging. On univariate Cox analysis, sex, age, tumor location, and tumor morphology did not show prognostic significance. In spite of their differences, the surgeon's report of residual tumor and the presence of residual disease on postoperative imaging were similar in their correlation with disease progression. However, on multivariate analysis, the volume of residual tumor was most closely linked with disease progression. Only the presence of fibrillary histology significantly complemented the volume of residual tumor as a negative prognostic indicator.