- Note: clinical stage of the primary tumor and nodes may be determined locally by endoscopic ultrasound or abdominal/pelvic MRI (MRI is preferred); CT scan with IV contrast is acceptable provided there is evidence of T4 and/or N2 disease; clinical nodal or "cN" status for eligibility includes the total number of nodes (N2 = 4 or more) in the mesorectal and superior rectal stations measuring >= 1.0 cm in any axis on cross sectional or endoscopic imaging