Childhood Central Nervous System Embryonal Tumors Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Treatment Options for Newly Diagnosed Childhood Medulloblastoma
Children with medulloblastoma are stratified into average-risk and poor-risk subsets. Owing to concerns about the long-term neurocognitive sequelae of whole-brainradiation therapy on the developing brain, radiation therapy for younger children has often been delayed or eliminated. Children younger than 3 years and sometimes as old as 5 years have not received the same treatment as older patients.
In all subgroups of patients, surgery is the initial means of therapy, and maximal tumor resection is the goal of treatment. Postsurgical treatment has diverged, to some degree, on the basis of risk stratification and age of the patient.
Treatment Options for Stages I and II
Hepatoblastoma of pure fetal histology: For tumors of pure fetal histology, complete surgical resection followed by watchful waiting or single-agent doxorubicin.In the Children's Oncology Group (COG) study COG-P9645, stage I pure fetal histology hepatoblastomas with two or fewer mitoses per 10 high power fields were not treated with chemotherapy. Completely excised tumor of purely fetal and favorable histology may be carefully followed without...
The traditional postsurgical treatment for patients with average-risk medulloblastoma has been 54 Gy to 55 Gy of radiation therapy to the posterior fossa and 36 Gy to the entire neuraxis (i.e., the whole brain and spine).[1,2,3,4] With radiation therapy alone, 5-year event-free survival (EFS) ranges between 50% and 65% in those with nondisseminated disease.[2,3] While the standard boost in medulloblastoma is the entire posterior fossa, patterns of failure data suggest that radiation therapy to the tumor bed instead of the entire posterior fossa would be equally effective and possibly associated with reduced toxicity.[5,6] The minimal dose of craniospinal radiation needed for disease control is unknown. Attempts to lower the dose of craniospinal radiation therapy to 23.4 Gy without chemotherapy have resulted in an increased incidence of isolated leptomeningeal relapse.
Chemotherapy is now a standard component of the treatment of children with average-risk medulloblastoma; a variety of chemotherapeutic regimens have been successfully used, including the combination of cisplatin, lomustine, and vincristine or the combination of cisplatin, cyclophosphamide, and vincristine.[1,2,7] Radiation therapy and chemotherapy given during and after radiation therapy has demonstrated 5-year EFS rates of 70% to 85%.[1,2,3]; [Level of evidence: 2A] A lower radiation dose of 23.4 Gy to the neuraxis when coupled with chemotherapy has been shown to result in disease control in up to 85% of patients and may decrease the severity of long-term neurocognitive sequelae.[7,9,10,11]
Long-term survivors who were prepubertal at the time of diagnosis are at high risk for growth failure due to radiation-related hypothalamic failure as well as effects of radiation on spinal growth. Lower doses of craniospinal radiation therapy may decrease the incidence of hypothalamic dysfunction, but this has not yet been proven. Growth hormone replacement therapy has not been shown to increase the likelihood of disease relapse.
Treatment options under clinical evaluation
The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI Web site.
COG-ACNS0331 (Comparison of Radiation Therapy Regimens in Combination With Chemotherapy in Treating Young Patients With Newly Diagnosed Standard-Risk Medulloblastoma): This Children's Oncology Group (COG) phase III trial is randomly assigning children between the ages of 3 years and 8 years to receive either 18 Gy or 24 Gy of craniospinal radiation and randomly assigning children between the ages of 3 years and 21 years to receive either conformal tumor site radiation therapy or posterior fossa radiation therapy. Patients with anaplastic medulloblastoma are not eligible. In this study, children receive weekly vincristine during radiation therapy and lomustine, vincristine, cisplatinum, etoposide, and cyclophosphamide after radiation therapy for a period of about 1 year.