What is the watch and wait approach in rectal cancer management?

Watch and Wait Approach in Rectal Cancer Management

The watch and wait approach is a safe strategy for selected rectal cancer patients who achieve a complete clinical response after neoadjuvant chemoradiotherapy, allowing organ preservation with comparable oncological outcomes to surgery while maintaining better functional outcomes and quality of life. 1

Definition and Concept

The watch and wait (W&W) approach, also known as nonoperative management (NOM), is an organ preservation strategy for rectal cancer patients who achieve a complete clinical response (cCR) after neoadjuvant therapy, typically chemoradiotherapy. Instead of proceeding with radical surgery, patients are closely monitored with a rigorous surveillance protocol.

Key Components of Watch and Wait:

• Deferral of surgery in patients with cCR after neoadjuvant therapy
• Implementation of strict surveillance protocols
• Prompt salvage surgery if tumor regrowth is detected
• Preservation of rectal function and avoidance of surgical morbidity

Patient Selection Criteria

Complete Clinical Response (cCR) Definition 1:

• Digital rectal examination (DRE): No palpable tumor material
• Rectoscopy: No residual tumor or only a small residual erythematous ulcer/scar
• MRI: Substantial downsizing with no observable residual tumor or only residual fibrosis with limited signal on diffusion-weighted imaging; no suspicious lymph nodes

Ideal Candidates:

• Patients with documented cCR after neoadjuvant therapy
• Frail elderly patients with low-rectal tumors 1
• Patients with technical challenges for anal sphincter preservation who strongly desire organ preservation 1
• Patients willing to comply with intensive surveillance protocols

Oncological Outcomes

The watch and wait approach has demonstrated promising oncological outcomes:

• Local regrowth rates: Approximately 15-30% of patients experience local regrowth, with most occurring within the first 2-3 years 2, 3
• Salvage surgery: Over 95% of patients with local regrowth can undergo successful salvage surgery 2
• Disease-free survival: Comparable to patients undergoing immediate surgery with pathological complete response 4
• Overall survival: No significant difference compared to patients who undergo surgery 2

A systematic review and meta-analysis found no significant difference between W&W patients and those with pathological complete response identified at resection in terms of non-regrowth recurrence (RR 1.46,95% CI 0.70-3.05) or cancer-specific mortality (RR 0.87,95% CI 0.38-1.99) 2.

Surveillance Protocol

The NCCN Guidelines recommend a rigorous surveillance schedule 1:

• First 2 years:

  • Digital rectal examination, flexible sigmoidoscopy, and CEA every 4 months
  • MRI every 6 months
  • Annual CT chest/abdomen/pelvis
  • Colonoscopy at year 1

• Years 3-5:

  • Digital rectal examination, flexible sigmoidoscopy, and CEA every 6 months
  • MRI every 12 months
  • Annual CT chest/abdomen/pelvis
  • Colonoscopy at year 5

Benefits of Watch and Wait

1. Avoidance of surgical morbidity: No risk of anastomotic leakage, permanent stoma, sexual dysfunction, or urinary dysfunction
2. Improved functional outcomes: Better bowel function, less incontinence, and avoidance of low anterior resection syndrome (LARS) 1
3. Preservation of quality of life: Maintenance of normal bowel function and avoidance of stoma
4. Comparable oncological outcomes: Similar overall survival to surgical approaches when proper surveillance is maintained 2, 4

Potential Risks and Limitations

1. Risk of local regrowth: 15-30% of patients may experience local regrowth 2, 3
2. Need for intensive surveillance: Requires strict adherence to follow-up protocols
3. Limited long-term data: More prospective studies with longer follow-up are needed
4. Requires expertise: Should be implemented at centers with experienced multidisciplinary teams 1

Implementation Considerations

• Multidisciplinary approach: Requires collaboration between gastroenterology, medical oncology, surgical oncology, radiation oncology, pathology, and radiology 1
• Patient counseling: Thorough discussion about potential risks, benefits, and surveillance requirements
• Institutional experience: Best implemented at centers with expertise in rectal cancer management and advanced imaging capabilities
• Standardized assessment: Consistent criteria for evaluating cCR and detecting regrowth

Conclusion for Clinical Practice

The watch and wait approach represents a paradigm shift in rectal cancer management, offering selected patients the opportunity to avoid surgery while maintaining oncological safety. For patients who achieve a complete clinical response after neoadjuvant therapy, particularly frail elderly patients and those with low rectal tumors, this approach provides comparable cancer outcomes with better functional results compared to radical surgery. However, implementation requires experienced multidisciplinary teams, rigorous surveillance protocols, and careful patient selection.