What is the appropriate volume to re-irradiate in a recurrent GBM?

If a patient has increasing FLAIR and T1 enhancing activity, should both be included in the treatment volume? What factors to you consider in making your decision (such as PFS since prior CRT, KPS, etc)?

1 Answer

Mednet MemberInvited Expert

Radiation Oncology · Thomas Jefferson University Hospital

Answered on

We need to recognize there is no standard dose fractionation regimen for re-irradiation in recurrent GBM. The volume and CTV/PTV margin are heavily depended on the dose/fraction you pick for your patients, and radiation techniques. The most commonly accepted regimen is probably 35 Gy in 10 fractions. Such regimen has been proven safe based a large single institution series (Fogh, JCO, 2010). It is also used in the RTOG 1205 trial. As a result, the volume and margin guideline from the protocol should be adopted. The protocol has a tumor/cavity size limit of 6 cm. And the target volume is recurrent tumor (enhancing tumor) and/or resection cavity. FLAIR changes were not used for radiation volume definition. And a minimum CTV margin of < 5mm, a...

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