What is the 2‑year risk of colorectal cancer in an average‑risk adult after a complete colonoscopy 2 years ago that removed a solitary 4 mm tubular adenoma with low‑grade dysplasia, and what surveillance interval is recommended?

Risk of Colorectal Cancer After Removal of Single Small Tubular Adenoma

Your 2-year risk of colorectal cancer is extremely low—essentially equivalent to the general population—and you do not need surveillance colonoscopy for another 5-8 years (total of 7-10 years from your original procedure). 1, 2

Why Your Risk is So Low

You fall into the lowest risk category for post-polypectomy surveillance. Your single 4mm tubular adenoma with low-grade dysplasia meets all criteria for "low-risk" findings: 3

• Only 1-2 adenomas (you had just one) 1
• Small size (<10 mm; yours was only 4mm) 1, 2
• Tubular histology (not tubulovillous or villous) 3, 1
• Low-grade dysplasia (not high-grade) 1, 2

Evidence Supporting Your Low Cancer Risk

Multiple high-quality studies demonstrate no increased long-term cancer risk in patients like you:

• Patients with only small (<1 cm) tubular adenomas removed showed no increased risk of developing colon cancer long-term compared to the general population 3
• In a landmark study of 776 patients with only small tubular adenomas, colon cancer developed in only 4 patients, yielding a standardized incidence ratio of 0.5 (meaning lower risk than the general population) 4
• The cumulative detection rate of advanced adenomas or cancer was only 3% over three years in surveillance studies 3

Your Recommended Surveillance Schedule

Next colonoscopy: 7-10 years from your original procedure (meaning 5-8 years from now). 1, 2

This extended interval is based on:

• The 2020 US Multi-Society Task Force guidelines that specifically address patients with 1-2 small tubular adenomas 1, 2
• Evidence showing patients with your findings have metachronous advanced neoplasia risk of only 4.9%, similar to those with completely normal colonoscopy 2
• European guidelines that recommend returning patients with your findings directly to routine screening rather than intensive surveillance 5

Important Caveats

This recommendation assumes your baseline colonoscopy was high-quality: 1, 2

• Complete examination to the cecum with photo documentation 1
• Adequate bowel preparation to detect lesions >5 mm 1, 2
• Minimum withdrawal time of 6 minutes 1, 2
• Complete removal of the polyp (not piecemeal) 1, 2

If your 4mm polyp was removed piecemeal (in fragments rather than whole), you would have needed a 2-6 month follow-up colonoscopy to verify complete removal before establishing the standard 7-10 year interval 1, 6

What Happens at Your Next Surveillance

If your next colonoscopy (at 7-10 years) shows:

• Normal findings or 1-2 small tubular adenomas: Extend to another 5-10 years 1, 2
• High-risk features (adenoma ≥10mm, high-grade dysplasia, or 5+ adenomas): Shorten to 3-year surveillance 1, 2

Common Pitfalls to Avoid

Do not undergo fecal occult blood testing for surveillance—this is not recommended for post-polypectomy patients 1

Do not continue 3-year surveillance indefinitely if subsequent exams are normal—this represents overuse without evidence-based benefit 1

Colonoscopy miss rates exist: Even expert colonoscopists miss approximately 25% of small polyps, which is why quality metrics (withdrawal time, adequate preparation) are critical 3

Age Considerations

Surveillance is generally not recommended after age 75 years, as remaining life expectancy is typically less than the time required for new adenomas to become malignant 1