A 65-year-old man undergoes resection for rectal cancer. The pathology report shows T3N1M0 with a circumferential resection margin (CRM) of 0.8mm. According to current guidelines, what does this CRM finding indicate?
- A CRM is clear and no adjuvant treatment is needed
- B CRM is borderline and does not affect prognosis
- C CRM is involved (positive), predicting higher risk of local recurrence ✓
- D CRM measurement is only relevant in colon cancer, not rectal cancer
Correct answer: C. CRM is involved (positive), predicting higher risk of local recurrence
Explanation
The circumferential resection margin (CRM) is defined as positive (involved) when tumor cells are within 1mm of the radial cut surface. A CRM of 0.8mm is therefore positive and is the most important predictor of local recurrence in rectal cancer, increasing the risk approximately three-fold compared to a clear CRM (>1mm). CRM positivity also correlates with poorer overall survival. Quality of total mesorectal excision (TME) is directly reflected in the CRM, making it a key quality indicator for rectal cancer surgery.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.