Cerebellar medulloblastoma: results of a new method of radiation treatment

Nine patients with medulloblastoma were referred to the Radiation Oncology Section at the University of Chicago from 1966 to 1976. In all patients, the tumor was situated in the posterior cranial fossa, projecting from the cerebellum into the fourth ventricle. After partial tumor resection and histological diagnosis, radiation treatment was instituted: a localized dose of 1000 rad to the posterior fossa through lateral opposing ports and a total dose of 4000-5000 rad through the "hockey-stick" port to the entire CNS. With this treatment, 9 patients yielded actuarial 3- and 5-year survival rates of 88% and 73%, respectively. Five of the patients possessed no history of neurologic or spinal growth deficits after treatment. Two patients had a slight retardation of spinal growth. The remaining patients had presented symptoms of a tumor mass in the posterior fossa for a period of over 8 months prior to treatment. They were found at craniectomy to have diffuse intracranial tumor involvement, and their survival times deteriorated rapidly. The "hockey-stick" port provided a uniform distribution of radiation exposure to the entire brain and spine. It was simple to use and posed little inconvenience to patients in the pediatric age group.