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Inferior pelvic subsite
(anal sphincter and ischiorectal fossae)
–
IPS
has a risk of
LR: 4%,
– low seated tumors
(<6 cm
from the AV):
8%
– after APR:
11%
Rules for inclusion in the CTV
Anal sphincter:
INCLUDE
when INFILTRATED and when APR is planned
EXCLUDE
when SPHINCTER PRESERVATION is planned
IR fossa:
INCLUDE
only in case of direct infiltration
Roels et al IJROBP 2006
Joye I and Haustermas K et al IJROBP 2014