Background
Systematic review and meta-analysis (Renehan). Identified 23 studies (n=867 patients) evaluating watch-and-wait (W&W) or organ-preserving approaches in rectal cancer patients with clinical complete response (cCR) after preoperative CRT. Evaluated outcomes of non-operative management compared to surgical management after cCR.
Interventions and follow up
Arm A: Watch-and-wait with close surveillance after cCR (n=436)
Arm B: Surgical resection after cCR (n=431)
Primary endpoint: OS, DFS, local regrowth rate
mFollow up: Varied by study
Arm B: Surgical resection after cCR (n=431)
Primary endpoint: OS, DFS, local regrowth rate
mFollow up: Varied by study
Results
5-yr OS (W&W): ~88% pooled
Local regrowth rate: ~15–25% in first 2 years
Salvageable after regrowth: ~85% with radical surgery
5-yr DFS (W&W vs surgery): Comparable (pooled analyses)
Local regrowth rate: ~15–25% in first 2 years
Salvageable after regrowth: ~85% with radical surgery
5-yr DFS (W&W vs surgery): Comparable (pooled analyses)
Adverse events
Main adverse events: W&W avoids surgical morbidity, sphincter loss, stoma, and bowel dysfunction. Local regrowth requires salvage surgery (radical in most cases).
Conclusions
Non-operative watch-and-wait management in rectal cancer patients achieving cCR after preoperative CRT is oncologically safe, with 5-year OS ~88% and a local regrowth rate of ~15–25%. The majority of local regrowths are salvageable with radical surgery. W&W avoids surgical morbidity and preserves sphincter function in patients maintaining cCR.
Key Limitations
Key Limitations: Meta-analysis of heterogeneous, mostly retrospective studies with varying definitions of cCR, surveillance protocols, and follow-up durations. Selection bias — patients achieving cCR represent a favorable subgroup. Definition of cCR not standardized (clinical exam, MRI, endoscopy, biopsy) — disagreement between institutional criteria affects generalizability. Systematic meta-analysis provides pooled estimates, not randomized comparisons with radical surgery.
Clinical Context
Renehan's meta-analysis and the International Watch and Wait Database (IWWD, van der Valk 2018) together established W&W as the preferred management for cCR after preoperative CRT. This approach is endorsed by ESMO and NCCN in selected patients (cCR by MRI + endoscopy + biopsy, adherent to surveillance). The OPRA trial (Garcia-Aguilar) further compared TNT regimens for optimizing organ preservation.
References