Table 1
Recommendations for target definition according to EORTC, RTOG and ESTRO-ACROP
| Contouring approach | Dose prescription | GTV | CTV |
|---|---|---|---|
| EORTC single phase | 30 × 2.0 Gy | Resection cavity + residual T1 enhancement | GTV + 2 cm |
| RTOG two phases | 23 × 2.0 Gy | GTV1: Resection cavity + residual T1 enhancement + FLAIR abnormality (oedema) | CTV1 = GTV1 + 2 cm (the margin is 2.5 cm in cases where no oedema is presented) |
| + 7 × 2.0 Gy | GTV2: Resection cavity + residual T1 enhancement | GTV2 + 2 cm | |
| ESTRO-ACROP | 30 × 2.0 Gy | Resection cavity + residual T1 enhancement + FLAIR abnormality (oedema) for secondary glioblasomas | GTV + 2 cm |
[i] Abbreviations: EORTC = European Organisation for Research and Treatment of Cancer; ESTRO-ACROP = European Society for Radiotherapy & Oncology - Advisory Committee on Radiation Oncology Practice; CTV = clinical target volume; FLAIR = Fluid-attenuated Inversion Recovery. GTV = gross tumor volume; RTOG = Radiation Therapy Oncology Group
Figure 1
An example of an RT treatment plan (color wash display of isodoses with a minimal dose of 57 Gy, that is 95% of the prescribed dose of 60 Gy) in three planes. A RT plan for the same patient was prepared using a simultaneous integrated boost (left) and sequential boost (right). Target volumes are shown in blue contour (yellow labeled arrows). Dose assignment to the “PTV2-boost” target volume is the same in boost cases, 30 × 2.0 Gy. With sequential boost, overtreatment (red arrows) is observed in the area where a lower dose was prescribed.