Recent studies using a combination of chemotherapy and radiation therapy to treat children with standard risk medulloblastoma have been 70 and 80% effective in curing this disease. However, many children experience long-term side effects from radiation therapy to the brain and spine.

This study will look at what will happen if a smaller amount of radiation therapy is given to the brain and spinal cord of children with medulloblastoma. Some patients on this study will be given a standard dose of radiation and others will receive a reduced dose.

In addition this study will look at what will happen if the volume of radiation that is given during the “boost dose” of radiation is reduced.  A “boost dose” is extra radiation delivered to the tumor area. Some patients on this study will be given a standard-volume boost, which means that the radiation is targeted at the entire posterior fossa. Other patients will be given a smaller volume boost, which means that they will be given radiation targeted more directly to the tumor bed.

All patients on this study will be treated with chemotherapy during and after radiation therapy.