Radiation Therapy

Radiation therapy is appropriate for patients who have not previously been irradiated. Radiation doses and volumes are similar to those used for newly diagnosed patients. Generally, this is limited to young children initially treated with radiation-avoiding strategies.

For previously irradiated patients with non–brain stem pediatric-type high-grade gliomas, reirradiation has been used, although the data demonstrating benefit are sparse. Stereotactic radiosurgery (SRS) or stereotactic radiation therapy (SRT) techniques using either hypofractionated radiation therapy or standard fraction sizes may be considered. For small volume distinct lesions, SRS allows for maximum sparing of normal tissues. For more infiltrative lesions, fractionated radiation therapy may better spare normal tissues.[1]

For patients with DIPG, reirradiation has been shown to prolong survival and can be considered at progression in children who have had an initial response to radiation therapy.[2,3] In a phase I/II study of 12 patients treated at three dose levels (24 Gy/12 fractions, 26.5 Gy/12 fractions, or 30.8 Gy/14 fractions), almost all patients improved. Clinical utility analysis showed that the 24-Gy regimen was preferable.[4] A recent survey confirms the effective use of even lower doses (e.g., 12 Gy fractionated). These doses are beneficial, and they allow for additional radiation therapy courses.[5]