Table 1.
Current GBM contouring guidelines by the European Organization for Research and Treatment of Cancer (EORTC), the Radiation Therapy Oncology Group (RTOG), and the Adult Brain Tumor Consortium (ABTC).
| EORTC | RTOG | ABTC |
|---|---|---|
| Phase 1: 60 Gy in 30 fractions | Phase 1: 46 Gy in 23 fractions | Phase 1: 46 Gy in 23 fractions |
| GTV: resection cavity + residual T1 postcontrast enhancement | GTV1: resection cavity + residual T1 post-contrast enhancement + surrounding edema (FLAIR) | GTV1: T1 enhancing and non-enhancing tumor volume (T2 or FLAIR) |
| CTV: GTV + 2 cm | CTV1: GTV1 + 2 cm | CTV1: GTV1 + 5 mm |
| PTV: CTV + 3–5 mm | PTV1: CTV1 + 3–5 mm | PTV1: CTV1 + 3–5 mm |
| Phase 2: 14 Gy in 7 fractions | Phase 2: 14 Gy in 7 fractions | |
| GTV2: resection cavity + residual T1 post-contrast enhancement | GTV2: T1 enhancing tumor volume | |
| CTV2: GTV2 + 2 cm | CTV2: GTV2 + 5 mm | |
| PTV2: CTV2 + 3–5 mm | PTV2: CTV2 + 3–5 mm |