Top Line: The push for reduced treatment margins for glioblastoma multiforme (GBM) continues.
The Study: On the heels of robust patterns of failure data suggesting ESTRO endorses much too liberal treatment volumes for what most GBMs really need, updated ESTRO contouring guidelines are hot off the press. The gross tumor volume is, as always, the resection cavity plus any residual enhancing tumor. The clinical target volume, the real on of controversy, has been reduced ever so slightly from 2 cm to 1.5 cm—still shying away from the 1 cm or even 0.5 cm margins used by many centers—to include T2 FLAIR changes and exclude areas beyond anatomic barriers of spread (note: this does not include corpus callosum or cerebellar peduncles which are notorious offenders). The planning target volume margin is now officially 0.3 cm when using a 6DoF couch and daily 3D-imaging alignment. The guidelines also include options for using interesting novel techniques such as fusion of amino acid PET scans with auto-contouring of areas above a certain SUV threshold. Finally, recommended fractionation schemes and even dose constraints are included for completeness.
TBL: Table 3 summarizes all of the updated adaptations in the current ESTRO contouring guidelines for GBM. | Niyazi, Radiother Oncol 2023
The Study: On the heels of robust patterns of failure data suggesting ESTRO endorses much too liberal treatment volumes for what most GBMs really need, updated ESTRO contouring guidelines are hot off the press. The gross tumor volume is, as always, the resection cavity plus any residual enhancing tumor. The clinical target volume, the real on of controversy, has been reduced ever so slightly from 2 cm to 1.5 cm—still shying away from the 1 cm or even 0.5 cm margins used by many centers—to include T2 FLAIR changes and exclude areas beyond anatomic barriers of spread (note: this does not include corpus callosum or cerebellar peduncles which are notorious offenders). The planning target volume margin is now officially 0.3 cm when using a 6DoF couch and daily 3D-imaging alignment. The guidelines also include options for using interesting novel techniques such as fusion of amino acid PET scans with auto-contouring of areas above a certain SUV threshold. Finally, recommended fractionation schemes and even dose constraints are included for completeness.
TBL: Table 3 summarizes all of the updated adaptations in the current ESTRO contouring guidelines for GBM. | Niyazi, Radiother Oncol 2023