Historically, medulloblastoma treatment has been determined by the amount of leftover disease present after surgery, also known as clinical risk (standard vs. high risk). Recent studies have shown that medulloblastoma is made up of distinct molecular subgroups which respond differently to treatment. This suggests that clinical risk alone is not adequate to identify actual risk of recurrence. In order to address this, we will stratify medulloblastoma treatment in this phase II clinical trial based on both clinical risk (low, standard, intermediate, or high risk) and molecular subtype (WNT, SHH, or Non-WNT Non-SHH). This stratified clinical and molecular treatment approach will be used to evaluate the following: