Medulloblastoma and other primary malignant neuroectodermal tumors of the CNS

Abstract

✓ Studies to evaluate the extent of their disease were performed on 30 children with newly diagnosed malignant neuroectodermal tumors of the central nervous system, including 25 children with medulloblastomas. The studies consisted of postoperative computerized tomography scanning, cerebrospinal fluid (CSF) cytology, myelography, and bone marrow aspiration. In 11 patients (36%) one or more of these studies was positive, indicating disease dissemination (Group 1), and in 19 (64%) all four studies were negative (Group 2). The CSF cytology was positive for malignant cells in all 11 Group 1 patients; myelograms indicated subclinical filling defects in nine, and the bone marrow aspirate from two patients revealed extrinsic cells. All patients received a conventional course of neuraxis radiation therapy as tolerated, and some also received chemotherapy. Patients with abnormal myelograms received additional radiation to areas of identifiable subarachnoid disease. The median survival time in Group 1 was 12 months, with five patients still surviving. The prognosis for Group 2 patients was considerably more favorable; only three of the 19 had died at the time of this report. Four of the six deaths in Group 1 were related to disease dissemination, the other two to chemotherapy toxicity. All three deaths in Group 2 were related to local tumor recurrence. The mean age of Group 1 patients was 3.9 years compared to 11 years for Group 2. Of the 14 patients aged 5 years and under in both groups, nine presented with widely disseminated disease (Group 1), six of whom had a relatively short survival time. The performance of a postoperative extent-of-disease evaluation is especially important in young children with medulloblastoma. Knowledge of disease dissemination at diagnosis not only helps determine prognosis, but also assists in planning treatment. Aggressive multimodal therapy appears warranted in younger patients who present with widely disseminated disease.