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Myerson RJ, Garofalo MC, El Naqa I, et al. Int J Radiat Oncol Biol Phys. 2009
CTVA: internal iliac, pre-sacral, peri-rectal
Cranial:
• Bifurcation of the common iliac vessels into external/internal iliacs
(bony landmark: sacral promontory)
• Recto-sigmoid junction
Anterior:
• 1 cm anterior to the sacrum
• Perirectal fascia
• 1 cm into the bladder
• Pelvic organs
Lateral and posterior:
• Pelvic side-wall muscles or bones
Caudal:
Anal canal + 2 cm around, the anal verge
Anal skin involved + 2 cm beyond
sup
inf