Site-Specific Factor 6

Circumferential Resection Margin (CRM)


**Note 1:** Tumor involvement of the circumferential resection margin (CRM) appears to be a strong prognostic factor for local or systemic recurrences and survival after surgery. **Note 2:** The CRM may also be referred to as the circumferential radial margin or mesenteric margin. **Note 3:** According to AJCC 7th Edition Cancer Staging Manual, "The CRM is the surgically dissected nonperitonealized surface of the specimen. It corresponds to any aspect of the colorectum that is not covered by a serosal layer of mesothelial cells and must be dissected from the retroperitoneum or subperitoneum in order to remove the viscus. In contradistinction, serosalized surfaces of the colorectum are not dissected; they are naturally occurring anatomic structures and are not pathologic surgical margins. The circumferential surface of surgical resection specimens of ascending colon, descending colon, or upper rectum is only partially peritonealized, and the demarcation between the peritonealized surface and the nonperitonealized surface (corresponding to the CRM) of such specimens is not always easily appreciated on pathologic examination." (1) **Note 4:** Record to the nearest tenth in millimeters (mm) the distance between the leading edge of the tumor and the nearest edge of surgically dissected margin as recorded in the pathology report. * For example, if the CRM is 2 mm, code 020 * If the margin is involved (positive), use code 000 * If the margin is described as less than 1 mm with no more specific measurement, use code 000; margins of 0-1 mm are recorded by the pathologist as involved **Note 5:** Codes 001-980 record exact measurements. Codes 992-996 are used for margin descriptions lacking specific measurements. **Note 6:** Use code 999 (CRM not mentioned) if the pathology report describes only distal and proximal margins, or margins, NOS. Only specific statements about the CRM are collected in this data item.




NAACCR #2930


Code Description
000 Margin IS involved with tumor
Circumferential resection margin (CRM) positive
Described as "less than 1 millimeter (mm)"
001-980 0.1- 98.0 millimeter (mm)
(Exact size to nearest tenth of millimeter)
981 98.1 mm or greater
988 Not applicable: Information not collected for this case
990 No residual tumor identified on specimen
991 Margins clear, distance from tumor not stated
CRM negative, NOS
992 Described as "less than 2 mm," or "greater than 1 mm," or "between 1 mm and 2 mm"
993 Described as "less than 3 mm," or "greater than 2 mm," or "between 2 mm and 3 mm"
994 Described as "less than 4 mm," or "greater than 3 mm," or "between 3 mm and 4 mm"
995 Described as "less than 5 mm," or "greater than 4 mm," or "between 4 mm and 5 mm"
996 Described as "greater than 5 mm"
998 No resection of primary site
Surgical procedure did not remove enough tissue to measure the CRM
(Examples include: polypectomy only, excision of tumor only or excisional biopsy only)
999 Unknown or no information
CRM not mentioned
Not documented in patient record
(1) American Joint Committee on Cancer., & Edge, S.B. (2010) *AJCC Cancer Staging Manual (7th ed.)*. New York; London: Springer, pg. 152