A patient with T2N0M0 rectal cancer (4 cm from anal verge) achieves a clinical complete response after long-course chemoradiation. The watch-and-wait (non-operative management) approach is most appropriate when which criterion is met?

• A MRI shows T2 signal with minimal residual tumour; no clinical or endoscopic evidence of disease
• B CEA normalises to <2.5 ng/mL and CT shows no pelvic nodal disease
• C Biopsy of the rectal scar shows no residual malignant cells on random sampling
• D Clinical complete response defined as absence of ulceration on digital rectal examination, normal mucosa on endoscopy, and MRI showing complete response (mrTRG 1-2) with no residual tumour signal ✓

Explanation

Clinical complete response (cCR) for watch-and-wait strategy requires all three components: absence of palpable tumour on DRE, endoscopic mucosal normalization (no ulceration, flat or minor mucosal irregularity only), and MRI showing mrTRG grade 1-2 (complete or near-complete regression with fibrosis only). The Habr-Gama group pioneered this approach; the OPRA and OnCoRe registries show that approximately 80-90% of patients with true cCR at 2 years achieve organ preservation, though local regrowth occurs in ~30% and is usually salvageable.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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