Reirradiation for pediatric brain tumor: practices and challenges

Abstract

Reirradiation to the brain has traditionally been considered contraindicated, but in recent years, it has become relatively accepted owing to the progress of radiotherapy modalities and their techniques. Because of the risk of radiation necrosis, the indication for reirradiation should be carefully decided depending on the type of disease and the condition of patients. Since there is no other efficacious treatment for diffuse intrinsic pontine glioma (DIPG) after its progression, reirradiation should be considered because of its high efficacy. However, further investigation is required for the optimum timing and dosage of reirradiation. For ependymoma, the effectiveness of reirradiation, including craniospinal irradiation (CSI) after the first recurrence, has been reported in recent years. However, the late effect should be fully taken into consideration when reirradiation is planned, since ependymoma patients are expected to have a relatively long-term survival even after recurrence. In the setting of local reirradiation for ependymoma, a strict irradiation plan that fully considers the previous irradiation plan is required because of the extremely high cumulative dosage. Reirradiation for relapsed medulloblastoma potentially has a relatively high risk of radiation necrosis because standard therapy for medulloblastoma includes CSI. Nevertheless, reirradiation has been shown to prolong overall survival after medulloblastoma relapse. Note that the dose and fields of reirradiation differ depending on the previous irradiation plan and/or the site of relapse. Bevacizumab is an effective treatment for radiation necrosis, and its efficacy in children has recently been shown.