Colonoscopy surveillance interval
Enter the polyps removed and see the surveillance interval the guideline sets, with the rule and its source.
Canada has no maintained national post-polypectomy guideline; the provinces differ.
Not for intervals after a surveillance colonoscopy.
Tick if any apply.
| Prevalence | Histopathology | Guideline interval |
|---|---|---|
| ~45–60% | Tubular adenoma | Follow-up colonoscopy in 10 years |
| ~20–30% | Hyperplastic | No surveillance required. Resume screening |
| ~5–15% | Tubulovillous / villous | Follow-up colonoscopy in 3 years |
| ~1–8% | Sessile serrated | Follow-up colonoscopy in 10 years |
| <1% | Traditional serrated | Follow-up colonoscopy in 3 years |
How BCGuidelines 2022 sets the colonoscopy surveillance interval
British Columbia's BCGuidelines (2022) sets post-polypectomy intervals from a single grid that pools all precancerous lesions, both adenomas and serrated lesions, by risk and by count rather than tracking adenoma subtypes on their own. One to four low-risk lesions return at 10 years, while 5 or more low-risk lesions or any high-risk lesion return at 3 years, and a normal exam or only small hyperplastic polyps goes back to fecal immunochemical test (FIT) screening. High risk here means an advanced adenoma: villous features, high-grade dysplasia, a lesion 10 mm or larger, or one of the higher-risk serrated types.
| Finding at the baseline colonoscopy | Surveillance interval |
|---|---|
| No polyps, or only hyperplastic polyps under 10 mm | No surveillance; return to FIT screening |
| 1 to 4 low-risk precancerous lesions (tubular adenomas under 10 mm with low-grade dysplasia only, or sessile serrated lesions (SSLs) without dysplasia) | Colonoscopy in 10 years |
| 5 or more low-risk precancerous lesions (tubular adenomas under 10 mm with low-grade dysplasia only, or SSLs without dysplasia) | Colonoscopy in 3 years |
| 1 or more high-risk lesions (advanced adenoma): villous features, high-grade dysplasia, an adenoma or SSL 10 mm or larger, an SSL with cytologic dysplasia, a traditional serrated adenoma (TSA), or a hyperplastic polyp 10 mm or larger | Colonoscopy in 3 years |
| Large precancerous lesion removed piecemeal | Repeat colonoscopy at 6 months to check the resection site; later intervals at the endoscopist's discretion |
| 10 or more precancerous lesions removed over a lifetime | No set colonoscopy interval; referral to the Hereditary Cancer Program |
BC keeps 1 to 4 low-risk lesions on a 10-year colonoscopy, longer than the US, which surveils 3 to 4 such lesions at 3 to 5 years, and unlike Ontario, which returns 1 to 2 low-risk adenomas to FIT screening in 5 years.
Source: BCGuidelines.ca — Colorectal Cancer Part 2: Follow-up of Colorectal Cancer and Precancerous Lesions (Polyps), 2022 ↗. This is the baseline colonoscopy table; enter specific findings in the calculator above for the rule and its exact wording.
For common questions and the source behind each rule across all the guidelines, see the colonoscopy surveillance guideline reference.
Reference tool for health professionals. Not medical advice, not a medical device, and does not make or replace a clinical decision. The calculation runs in your browser; the findings you enter are not transmitted or stored. The Aescia clinical team reviews this tool periodically against the source guidelines and updates it when they change, but guidelines are revised without notice; verify against the current version before acting. If you notice an error, tell us at contact@aesciahealth.com.
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