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Early Tumours
GTV_A
= Primary Tumour
GTV_N
= Involved Nodes
CTV_A
= GTV_A + 5mm
CTV_N
= GTV_N + 5mm
CTV_ALL
= CTV_A + CTV_N + CTV_E
PTV_Anal
PTV_Nodes
PTV_ELEC
*
These margins are appropriate for patients treated with daily online imaging. We recommend centres
audit their local set up regularly.
= GTV_A + 10mm*
= GTV_N + 5mm*
= CTV_ALL + 5 mm