Meningeal Dissemination of Cerebellar Medulloblastoma

Abstract

Thirty-four patients with medulloblastoma treated between 1967 and 1983 are reviewed. There were 28 infants and children, and 6 adults. Four patients died within 6 weeks after surgery, and the operative mortality rate was 12%. In infants and children the overall survival rate from the time of tumor resection was 39% at 3 years, and unchanged at 5 years. In adults it was 67% and 50%, respectively. There was no difference in survival rates between male and female patients. Eighteen cases showed recurrence. The types of recurrence were as follows: meningeal dissemination, 72%; local regrowth, 22%; bone metastasis, 6%. Seventy-four percent of the patients with meningeal dissemination died within one year after the appearance of clinical manifestations. There was no relationship between the dissemination and the presence of posterior fossa tumor. Posterior fossa tumors were considerably controlled by a radiation dose of 50 Gy. Therefore it was considered that initial whole central nervous system irradiation was one of the most important prognostic factors. Before 1980 radiation doses to the whole spine were 26.7 Gy on the average. Patients were in a supine position during whole brain and posterior fossa irradiation and in prone position only during whole spinal radiation. After 1980 patients were fixed in prone position during the whole irradiation course, and an increased radiation dose to the whole spine (average 31.4 Gy) was applied. Furthermore, the whole brain and spinal cord were irradiated simultaneously for a few days to prevent the migration of tumor cells. Nine children with medulloblastoma were treated after 1980 and none of them showed meningeal dissemination. Among those nine cases there were two recurrences. Local regrowth developed in spite of radical removal of the tumor in one case and systemic bone metastasis in the other. These are problems which remain in treatment of medulloblastoma. Therapy for meningeal dissemination is usually difficult because of the late appearance of clinical manifestations. The role of cerebrospinal fluid polyamines in the early detection of dissemination is briefly discussed.