A 58-year-old man with rectal cancer at 7 cm from anal verge undergoes staging MRI. Tumor is staged mrT3c N1 (extramural invasion 6 mm, CRM negative). According to current MERCURY study-based criteria, the optimal neoadjuvant strategy is:
- A Short course radiotherapy (5×5 Gy) followed by immediate surgery
- B Long course chemoradiotherapy (45-50 Gy with capecitabine) over 5 weeks ✓
- C Total neoadjuvant therapy (TNT): FOLFOX then long-course chemoradiotherapy
- D Upfront surgery without neoadjuvant treatment
Explanation
The MERCURY trial demonstrated that MRI-defined CRM involvement or threat (CRM ≤1 mm) predicts local recurrence and guides neoadjuvant treatment. For mrT3c with 6 mm extramural invasion but negative predicted CRM, long-course chemoradiotherapy is the standard approach to achieve tumor downstaging and negative margins before TME. Short-course RT (5×5 Gy) is preferred for resectable T3 with clear predicted CRM. TNT (total neoadjuvant therapy combining systemic chemotherapy with RT) is increasingly used for T4 or very high-risk tumors (RAPIDO, PRODIGE-23 trials). Upfront surgery is inappropriate for mrT3c with significant extramural invasion.
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.