Table 2.

Reported feedback and recommendations

Institution no	Recommendation
1	Large iGTV compared to other institutions
2	Some CT slices with tight borders iGTV in ventral direction Conformal technique (3D conformal); advised to use a more sophisticated technique to lower the dose to the spinal cord
3	Tight borders iGTV in medial, lateral and ventral direction
4	Tight borders iGTV in all directions; smallest iGTV of all the institutions. Not all fiducials incorporated in iGTV
5	Tight borders iGTV in ventral and medial direction
6	No recommendations for delineation
7	Tight borders iGTV in ventral direction (only central part of the tumour) Used IMRT technique (6 MV), advised to use 10 MV energy
8	Tight borders iGTV in ventral directions
9	Tight borders iGTV in ventral and dorsal direction
10	Tight borders GTV in dorsal direction GTV expansion for ten respiratory phases after adding 5 mm margin for CTV
11	Tight borders iGTV in ventral direction

iGTV internal gross tumour volume, CTV clinical target volume, IMRT intensity-modulated radiation therapy, VMAT volumetric modulated arc therapy