Evidence-based radiation therapy for primary brain tumors

Radiation therapy for five primary brain tumors is discussed based on the results of prospective trials. Many randomized studies have revealed the usefulness of radiation and radiochemotherapy for treating malignant gliomas, and the ineffectiveness of many new treatments modalities. However, novel treatments should be tested further against this tumor. In low-grade gliomas, the usefulness of radiotherapy was shown but a dose-effect relationship was not observed in recent randomized studies. In medulloblastoma, the difficulty in reducing the dose to the cerebrospinal axis has been shown even in low-stage patients. On the other hand, reliable randomized studies are still lacking for germinoma and primary central nervous system lymphoma, and the usefulness of combination chemotherapy remains uncertain. In the future, more prospective studies are needed for primary brain tumors other than glioma. Establishment of IMRT and controlled studies to prove its efficacy are important in the field of neuro-oncology.