2. • 54 y/o, male, Constipation and bloody stool for one month
• Digital rectal exam: cauliflower mass at posterior rectum wall, 3 cm
from anal verge.
• Biopsy: adenocarcinoma.
• MRI Pelvis:
–
–
–
–
Abnormal thickening and enhancing wall
Increased fatty stranding in the perirectal space.
Multiple enlarged lymph node in the perirectal space.
No evidence of para-aortic lymphadenopathy
• Whole Body PET:
– intense hypermetabolic lesion at rectum
– Mild to moderate hypermetabolic spots at right perirectal and bilateral
external iliac nodes
• Rectal adenocarcinoma cT3N1M0
7. Mesorectal lymph nodes (MLN) :
46% of all patients
87% of patients with positive lymph nodes
Risks for Lymph node involvement
in N+ patients:
Mesorectal : 87%
Lateral : 27%
External iliac : 9%
Inguinal : 1%
Posterior pelvic subsite (PPS) recurrence :
22% of all patients
Inferior pelvic subsite (IPS) recurrence:
4% of all patients
8% in tumors < 6 cm from anal verge
8. Rectal Cancer Radiotherapy Contouring
Guideline for clinical target volumes (CTV) for neoadjuvant
chemoradiotherapy in locally advanced rectal cancer: gross tumor, peri-rectal,
pre-sacral, internal iliac and external iliac.
NTUH practice:
• GTV: main tumor mass + involved lymph nodes
• CTV:
– GTV with 15 mm expansion
– Distal 20 mm margin to GTV for CTV
– Vessels with 7 mm expansion
– Contour CTV to include mesorectum and pre-sacrum
– Avoid bone and small bowel
Int J Radiat Oncol Biol Phys. 2009 Jul 1;74(3):824-30. doi: 10.1016/j.ijrobp.2008.08.070.
15. Summary
• Pre-op CCRT is the standard treatment for
locally advanced rectal cancer
• Contouring guideline
– GTV: main tumor mass + involved lymph nodes
– CTV:
•
•
•
•
•
GTV with 15 mm expansion
Distal 20 mm margin to GTV for CTV
Vessels with 7 mm expansion
Contour CTV to include mesorectum and pre-sacrum
Avoid bone and small bowel
