Background
Retrospective cohort analysis (MSKCC). 1,009 patients with rectal cancer receiving preoperative CRT at MSKCC evaluated for outcomes of clinical complete response (cCR). 113 patients (11.2%) achieved cCR and were managed with either watch-and-wait or radical resection. Compared outcomes between management strategies.
Interventions and follow up
Arm A: Watch-and-wait: stringent MRI + endoscopy-defined cCR, surveillance every 3–4 month
Arm B: Radical surgery (TME) despite cCR
Primary endpoint: OS, local regrowth, distant recurrence
mFollow up: 43 month
Arm B: Radical surgery (TME) despite cCR
Primary endpoint: OS, local regrowth, distant recurrence
mFollow up: 43 month
Results
3-yr local regrowth (W&W): 21.4% vs 0% (surgery), P<.001
3-yr distant recurrence: 8.7% (W&W) vs 17.9% (surgery), P=.08
3-yr OS: 95.6% (W&W) vs 93.2% (surgery), P=.67 — no difference
Salvage surgery success: 96% of regrowths salvaged
3-yr distant recurrence: 8.7% (W&W) vs 17.9% (surgery), P=.08
3-yr OS: 95.6% (W&W) vs 93.2% (surgery), P=.67 — no difference
Salvage surgery success: 96% of regrowths salvaged
Adverse events
Main adverse events: W&W avoids stoma and surgical morbidity. Salvage surgery for regrowths successfully performed in 96% (all R0). Colostomy rate: 0% in W&W group vs 36% in surgery group.
Conclusions
Watch-and-wait achieves comparable 3-year OS (95.6% vs 93.2%) to radical resection despite 21.4% local regrowth rate. Near-universal salvageability (96%) of regrowths with R0 resection, combined with dramatically lower colostomy rates, supports W&W as oncologically safe. W&W substantially improves quality of life via organ preservation and avoidance of stoma.
Key Limitations
Key Limitations: Retrospective, non-randomized — patients choosing W&W vs surgery differed in multiple characteristics. Small W&W cohort (n=46). Median follow-up was insufficient to detect long-term OS differences (cancer-specific mortality is a late event in rectal cancer). Selection bias inherent in W&W vs surgery decision. MSKCC institutional expertise in cCR assessment and surveillance may not generalize.
Clinical Context
MSKCC Retrospective (Smith 2019) is a key contemporary series supporting W&W at a high-volume center with stringent cCR criteria (MRI + endoscopy). The demonstrated 0% colostomy rate vs 36% in the surgical arm powerfully illustrates the quality-of-life benefit. Combined with IWWD data, this series contributed to NCCN and ESMO endorsing W&W for stringently defined cCR in rectal cancer.
References
References: Smith JJ et al, JAMA Oncol 2019 (MSKCC W&W)