Circumferential resection margin (CRM) is a term used to denote the standard plane of excision of total mesorectal excision, used for resection of rectal cancers. The anatomic correlate is the mesorectal fascia. The distance between tumor tissue or satellite tumor deposits and the mesorectal fascia, as judged at staging MRI, is predictive of involvement of the CRM and likelihood of incomplete resection at surgery, and hence has long term prognostic implications. Note that the mesorectal fascia is only considered the CRM for the non-peritonealised portion of the rectum.
Pathologic evaluation of the resection margin on the excised rectum has been considered important for determining the risk of local recurrence. A margin of ≤1 mm is considered by some to be a negative prognostic factor for local recurrence 2.
The prognostic value of the circumferential resection margin has been called into question in some recent studies 3.
- 1. Nagtegaal ID, Quirke P. What is the role for the circumferential margin in the modern treatment of rectal cancer?. J. Clin. Oncol. 2008;26 (2): 303-12. doi:10.1200/JCO.2007.12.7027 - Pubmed citation
- 2. Park JS, Huh JW, Park YA et-al. A circumferential resection margin of 1 mm is a negative prognostic factor in rectal cancer patients with and without neoadjuvant chemoradiotherapy. Dis. Colon Rectum. 2014;57 (8): 933-40. doi:10.1097/DCR.0000000000000171 - Pubmed citation
- 3. Nikberg M, Kindler C, Chabok A et-al. Circumferential resection margin as a prognostic marker in the modern multidisciplinary management of rectal cancer. Dis. Colon Rectum. 2015;58 (3): 275-82. doi:10.1097/DCR.0000000000000250 - Pubmed citation