Colorectal Cancer Surgery Medical Slides

Present the TME quality assessment framework: Quirke grading — Grade 3 (complete TME): intact mesorectum, smooth surface, no defects to muscularis propria; Grade 2 (nearly complete): minor irregularities, no visible muscularis propria; Grade 1 (incomplete): major defects, visible muscularis propria. Key metrics: circumferential resection margin (CRM) >1 mm is critical — positive CRM increases local recurrence from 6% to 22%. Adequate lymph node harvest ≥12 nodes for accurate staging. TME should follow the "holy plane" between visceral and parietal pelvic fascia, preserving autonomic nerves (hypogastric, pelvic splanchnic) to prevent urinary and sexual dysfunction. Mercury II trial demonstrated MRI-guided TME surgery achieves CRM negativity in >90%.

Present the two landmark TNT trials: RAPIDO (2021): short-course radiotherapy (5×5 Gy) followed by 6 cycles CAPOX before surgery vs standard long-course chemoradiation. TNT arm: higher pathologic complete response (pCR 28% vs 14%), lower 3-year disease-related treatment failure. PRODIGE 23 (2022): induction FOLFIRINOX × 6 cycles → chemoradiation → surgery. TNT arm: pCR 25% vs 12%, improved 3-year disease-free survival. Both trials establish TNT as new standard for locally advanced rectal cancer (cT3-4 or N+). Teaching message: TNT delivers all chemotherapy before surgery when compliance is highest and tumor biology can be assessed by pathologic response.

Present the organ preservation paradigm: after TNT, 15-30% of rectal cancer patients achieve complete clinical response (cCR). International Watch & Wait Database (IWWD, 880 patients): 5-year overall survival 85%, 5-year local regrowth rate 25%, 88% of regrowths were salvageable with surgery, disease-specific survival not compromised. Assessment of cCR requires: digital rectal exam (no palpable abnormality), MRI (no residual tumor signal, only fibrosis), endoscopy with biopsies (no visible tumor, flat scar). Surveillance protocol: DRE + endoscopy + MRI every 3-4 months for 2 years, then every 6 months. Emphasize: this remains an evolving approach requiring rigorous patient selection and surveillance infrastructure.