Medulloblastomas and central nervous system primitive neuroectodermal tumors.

Abstract

Significant advances in the treatment of medulloblastoma and primitive neuroectodermal tumors have been made in the past three decades. Maximal surgical resection is a mainstay of therapy. However, unlike many other central nervous system neoplasms, medulloblastoma and primitive neuroectodermal tumors are radiation and chemotherapy responsive. Despite this response, the prognosis for patients with these tumors remains variable and is relatively poor in infants and patients with metastatic disease. These tumors most commonly arise in children, thus most clinical trials emphasize the reduction of long-term sequelae, in addition to improving survival. All newly diagnosed patients who are eligible should be offered participation in a clinical trial. If a patient is ineligible or declines consent/assent for a clinical trial, the best current treatment approach is surgical resection, followed by radiation therapy (except for children younger than 3 years) with weekly vincristine. For high-risk patients, 36 Gy of craniospinal irradiation should be delivered plus a boost of 19.8 Gy to the posterior fossa/primary tumor bed and sites of bulk metastatic disease. For average-risk patients, the craniospinal irradiation dose may be lowered to 23.4 Gy plus 32.4 Gy to the posterior fossa/tumor bed. After radiation therapy, intensive multimodal chemotherapy should be used for all patients.