A 60-year-old male undergoes low anterior resection for a T3N1M0 mid-rectal carcinoma. Post-operatively, histology shows positive circumferential resection margin (CRM+). Which of the following statements about CRM positivity is MOST accurate?

• A CRM positivity is defined as tumour ≤5 mm from the resection margin and mainly predicts distant metastasis
• B CRM positivity occurs only when surgical technique violates the mesorectal plane
• C CRM positivity has no impact on prognosis if adjuvant chemotherapy is administered
• D CRM positivity is defined as tumour ≤1 mm from the mesorectal fascia on pathological examination and is the strongest predictor of local recurrence ✓

Explanation

Pathological CRM positivity is defined as tumour cells within 1 mm of the mesorectal resection margin. It is the single most important pathological predictor of local recurrence in rectal cancer; a CRM+ is associated with local recurrence rates of 20–25% compared to 5–8% for CRM-negative disease. It can result from poor surgical technique (incomplete TME) or inherently advanced tumour extending to the mesorectal fascia. Adjuvant chemotherapy does not fully abrogate the adverse impact of CRM+.

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.