Overview.
A colonoscopy report can be confusing — full of medical terminology about polyps, biopsies, and inflammation. This guide explains what each finding means, which polyp types are concerning, how surveillance intervals are determined, and when your results require follow-up versus simple reassurance. Understanding your results helps you ask better questions and take appropriate next steps.
Context: Colorectal cancer is the third most common cancer and the second leading cause of cancer death, yet it is one of the most preventable through screening and polyp removal. Colonoscopy both detects and prevents cancer by removing precancerous polyps before they transform. Your follow-up interval depends on what was found — getting it right means neither over-screening (unnecessary risk and cost) nor under-screening (missed progression).
Key takeaways.
- A normal colonoscopy with good bowel prep: next screening in 10 years (average risk)
- Hyperplastic polyps (rectum/sigmoid, <10mm): not precancerous — next in 10 years
- 1-2 tubular adenomas <10mm: low risk — next colonoscopy in 7-10 years
- 3-4 tubular adenomas, or any ≥10mm, or villous/tubulovillous: next in 3 years
- ≥10 adenomas: next in 1 year and consider genetic testing
- Sessile serrated lesions ≥10mm or with dysplasia: next in 3 years
- Biopsy results matter more than what the polyp looked like during the procedure
Normal Colonoscopy.
A completely normal colonoscopy with adequate bowel preparation (rated 'good' or 'excellent') and withdrawal time ≥6 minutes is the best possible result. It means no polyps, masses, or significant inflammation were found.
- Average risk, normal result
- Repeat colonoscopy in 10 years. No additional testing needed between screens.
- Adequate bowel prep
- Your bowel was clean enough to visualise all surfaces. If prep was 'poor' or 'inadequate', you may need a repeat sooner (within 1 year) because polyps could have been missed.
- Family history of CRC in first-degree relative
- Even with a normal result, repeat in 5 years (or sooner if the relative was diagnosed before age 60).
Polyp Types — What the Biopsy Shows.
Polyps are growths on the inner lining of the colon. They are extremely common (found in 25-40% of screening colonoscopies in adults >50). The biopsy pathology determines the risk and surveillance interval, not the appearance during the procedure.
- Hyperplastic Polyps
- Not precancerous. Very common, especially in the rectum and sigmoid colon. Small hyperplastic polyps (<10mm) in the distal colon carry no increased cancer risk. Surveillance: 10 years (same as normal).
- Tubular Adenomas
- The most common precancerous polyp. 'Adenoma' means glandular growth with dysplasia. Tubular adenomas grow in tube-like patterns. Risk depends on size and number: 1-2 small (<10mm) = low risk; 3+ or ≥10mm = higher risk.
- Villous or Tubulovillous Adenomas
- Adenomas with a finger-like (villous) growth pattern. Higher malignant potential than tubular adenomas, especially when >10mm. Always prompt a shorter surveillance interval (3 years).
- Sessile Serrated Lesions (SSL)
- Flat, subtle polyps that follow the 'serrated pathway' to cancer (different from the adenoma-carcinoma sequence). Harder to detect because they're flat and pale. SSLs ≥10mm or with dysplasia require 3-year surveillance.
- Traditional Serrated Adenomas (TSA)
- Rare serrated polyps with a distinct protruding shape. Considered precancerous. Surveillance: 3 years.
- High-Grade Dysplasia (HGD)
- Cells within the polyp that are significantly abnormal but have not yet invaded through the muscularis mucosae (not yet cancer). Complete removal is curative. Surveillance: 1-3 years depending on completeness of removal.
- Adenocarcinoma in a polyp
- Cancer found within a removed polyp. If the cancer is confined to the polyp and margins are clear (complete excision), endoscopic removal may be curative. Surgical resection is needed if margins are involved or there is lymphovascular invasion.
Surveillance Intervals (USMSTF 2020 Guidelines).
The US Multi-Society Task Force on Colorectal Cancer (USMSTF) provides evidence-based surveillance intervals. These assume adequate bowel preparation and complete polyp removal.
- Normal colonoscopy
- 10 years.
- 1-2 tubular adenomas <10mm
- 7-10 years.
- 3-4 tubular adenomas <10mm
- 3-5 years.
- 5-10 adenomas
- 3 years.
- Any adenoma ≥10mm
- 3 years.
- Any adenoma with villous histology or HGD
- 3 years.
- >10 adenomas
- 1 year. Consider genetic testing for familial polyposis.
- SSL <10mm without dysplasia
- 5-10 years.
- SSL ≥10mm or with dysplasia
- 3 years.
- Piecemeal resection of large polyp
- 6 months to verify complete removal, then per histology.
Other Findings.
Colonoscopy can reveal findings beyond polyps that may appear in your report.
- Diverticulosis
- Small pouches (diverticula) in the colon wall. Extremely common after age 50. Not precancerous. No change in surveillance interval. Only requires attention if complicated by diverticulitis (inflammation/infection).
- Haemorrhoids (internal)
- Swollen blood vessels at the rectum. Very common. Noted but rarely require treatment unless symptomatic. Not precancerous.
- Colitis / Inflammation
- If biopsied, may indicate IBD (Crohn's or UC), microscopic colitis, infectious colitis, or ischaemic colitis. Biopsy pathology determines the diagnosis and next steps.
- Mass or stricture
- A suspicious mass always requires biopsy. Strictures (narrowing) may be from prior surgery, IBD, diverticular disease, or malignancy. These findings always require gastroenterologist follow-up.
When to Follow Up vs Relax.
Use this guide to understand the urgency of your findings:
- Reassurance (routine follow-up)
- Normal colonoscopy, small hyperplastic polyps in the rectum/sigmoid, diverticulosis without complications, small internal haemorrhoids.
- Moderate follow-up (shorter surveillance)
- Adenomatous polyps (any type), sessile serrated lesions, multiple polyps. Ensure your gastroenterologist has set a specific follow-up date.
- Prompt follow-up needed
- High-grade dysplasia, cancer in a polyp, incomplete removal of a large polyp, suspicious mass, significant colitis. Your gastroenterologist should contact you directly about these results.
FAQs.
I had polyps removed — does that mean I had cancer?
Almost certainly not. Polyps are extremely common and most are benign or precancerous (not yet cancer). Removing adenomatous polyps prevents them from becoming cancer — that's the whole point of screening. Only if the biopsy shows adenocarcinoma within the polyp is cancer confirmed, and even then, complete removal may be curative.
Why is my follow-up interval different from my friend's?
Surveillance intervals are personalised based on what was found: the number, size, and type of polyps. One person with 2 small tubular adenomas gets 7-10 years; someone with a large villous adenoma gets 3 years. Both had 'polyps' but the risk profiles are completely different.
My bowel prep was rated 'fair' — does that matter?
Yes. Inadequate prep means parts of the colon weren't well visualised and polyps may have been missed. If prep was 'poor', a repeat colonoscopy within 1 year is typically recommended. 'Fair' may or may not require earlier repeat — discuss with your gastroenterologist.
Should I start screening at 45 or 50?
Current USMSTF and ACS guidelines recommend starting at age 45 for average-risk adults (lowered from 50 in 2021). If you have a first-degree relative with CRC, screening should begin 10 years before their age at diagnosis, or at age 40, whichever is earlier.