Circumferential Resection Margin
The circumferential resection margin is the distance from rectal tumour to the resection plane (mesorectal fascia) when viewed in a transverse section through the rectum. A complete resection of rectal cancer is defined as a CRM of >2 mm. The CRM can be predicted preoperatively on MRI. In this way, radiologist can predict a narrow margin and indicate at which location a wider excision is needed for radical resection.