Treatment Option Overview
PFS for patients with Group C and D tumors ranged between 32% and 63%. Other studies have confirmed the excellent prognosis of children with WNT tumors and poor prognosis of those with tumors with MYC amplification.[4,5] If this type of molecular and immunohistochemical separation can be confirmed in a homogeneously treated population of patients, preferably studied prospectively, it will dramatically alter disease stratification and likely therapy offered.
Surgery is usually the initial treatment for children with medulloblastoma, both to confirm diagnosis and to remove as much tumor as is safely possible. Evidence suggests that more extensive surgical resections are related to an improved rate of survival, primarily in children with nondisseminated disease at the time of diagnosis.[7,8] One study in high-risk patients utilized presurgical chemotherapy (after tumor biopsy) to reduce tumor bulk and make subsequent resection of the tumor easier. This small study did not demonstrate a high rate of survival, and postchemotherapy surgery did not seem easier and was not related to a reduced incidence of postoperative complications.
Postoperatively, children may have significant neurologic deficits caused by preoperative tumor-related brain injury, hydrocephalus, or surgery-related brain injury.[Level of evidence: 3iC] In addition, a significant number of patients with medulloblastoma will develop delayed onset of mutism, suprabulbar palsies, ataxia, hypotonia, and emotional lability. This constellation of findings has been termed the cerebellar mutism syndrome, and its etiology remains unclear, although cerebellar vermian damage has been postulated as a possible cause for the mutism.[11,12]; [Level of evidence: 3iC] In two Children's Cancer Group studies evaluating children with both average-risk and poor-risk medulloblastoma, the syndrome has been identified in nearly 25% of patients.[12,13,14]; [Level of evidence: 3iiiC] Many patients with this syndrome may manifest neurologic and neurocognitive sequelae posttreatment.[13,15]
Radiation therapy is usually initiated after surgery with or without concomitant chemotherapy.[16,17,18] To date, the best survival results for children with medulloblastoma have been obtained when radiation therapy is begun within 4 to 6 weeks postsurgery.[16,17,18,19]; [Level of evidence: 1iA]