Chemotherapy for medulloblastoma/primitive neuroectodermal tumors of the posterior fossa.
 Chemotherapy has only marginal efficacy in adult malignant brain tumors.
 In contrast, drug therapy is considerably more effective in medulloblastoma/primitive neuroectodermal tumors (MB/PNET) of the posterior fossa, the most common childhood primary central nervous system tumor.
 At the time of disease recurrence, a variety of different single agents and drug combinations result in tumor shrinkage and increased survival.
 The addition of chemotherapy to standard radiotherapy improves the rate and length of disease-free survival for those children with MB/PNET who have the most extensive tumors at diagnosis.
 It remains to be determined which drug or drug combinations are the most effective in MB/PNET, and which patients are most likely to benefit from chemotherapy.
 Chemotherapy may be useful to reduce or, in selected cases, obviate the need for radiotherapy and reduce treatment-related sequelae.
