Management of children with primitive neuroectodermal tumors of the posterior fossa/medulloblastoma.
Primitive neuroectodermal tumors of the posterior fossa/medulloblastoma (PNET-MB) are the most common malignant primary central nervous system tumors of childhood. Current approaches to therapy for children with PNET-MB are illustrative of both the advances which have been made in management of childhood brain tumors and the areas where increased understanding is needed. With the optimal use of surgery and radiotherapy, the majority of children with PNET-MB can be expected to be alive and free of disease 5 years after diagnosis. Based on various factors, including the age of patient, the extent of the disease at the time of diagnosis and histological parameters, it is possible to stratify patients with PNET-MB into 'risk' groups. It is unclear whether preoperative or postoperative factors are most predictive of outcome. Patients with factors predictive of a higher likelihood of disease relapse seem to benefit from treatment with chemotherapy. The amount of radiotherapy and the type and amount of chemotherapy which is most efficacious in controlling the disease has yet to be determined. Children surviving PNET-MB are at high risk for endocrinologic and neuropsychologic sequelae. Multiple prospective treatment protocols are now underway, attempting to determine which therapy is best at controlling disease without causing severe long-term damage. A multidisciplinary approach is needed for the treatment of children with PNET-MB.