Surveillance for Low-Risk Colon Cancer
For patients with low-risk colon cancer (resected colorectal cancer), perform colonoscopy within 1 year after resection, then at 3 years if normal, and subsequently every 5 years thereafter. 1
Post-Resection Surveillance Strategy
The surveillance approach for patients who have undergone curative resection of colorectal cancer follows a structured timeline:
Initial Surveillance Colonoscopy
- Perform colonoscopy within 1 year after surgical resection (assuming a perioperative complete colon examination was done) 1
- If the perioperative colonoscopy was incomplete or not performed due to obstructing lesion, perform colonoscopy within 3-6 months post-resection 1
Subsequent Surveillance Intervals
- If the 1-year colonoscopy is normal, repeat colonoscopy at 3 years 1
- If the 3-year colonoscopy remains normal, continue surveillance every 5 years 1
Important Distinction: This is NOT Polyp Surveillance
The question asks about "low-risk colon cancer," which refers to resected colorectal cancer, not low-risk adenomatous polyps. These are distinct clinical scenarios with different surveillance protocols:
For Comparison: Low-Risk Adenomatous Polyps
If the question were about low-risk adenomatous polyps (1-2 small tubular adenomas <1 cm), the recommendation would be:
- Repeat colonoscopy in 5-10 years 1
- Low-risk polyps are defined as 1-2 tubular adenomas <1 cm in size 1
Key Implementation Points
Quality Colonoscopy Requirements
- Cecal intubation rates must exceed 90% in screening populations 2, 3
- Withdrawal time should be at least 6 minutes 2, 3
- Adenoma detection rates should be ≥25% in men and ≥15% in women over 50 2, 3
Common Pitfalls to Avoid
- Do not use flexible sigmoidoscopy or other partial colon examinations for post-cancer surveillance—complete colonoscopy is required 1
- Inadequate bowel preparation reduces effectiveness and should trigger repeat examination 4, 3
- Shorter intervals may be necessary if there was uncertainty about completeness of polyp removal or suboptimal preparation 1
Lynch Syndrome Screening Requirement
All patients diagnosed with colorectal cancer should undergo Lynch syndrome screening at the time of diagnosis using either:
- Microsatellite instability (MSI) testing, and/or
- Immunohistochemistry (IHC) for the 4 mismatch repair proteins (MLH1, MSH2, MSH6, PMS2) 1
If Lynch syndrome is identified, surveillance intervals and strategies change significantly, requiring more intensive monitoring 1