01Role and principlesWho benefits and the main preventive aims.
Chronic colonic inflammation increases colorectal neoplasia risk, but the risk is uneven. Duration and extent of colitis, cumulative inflammatory activity, primary sclerosing cholangitis, a stricture, previous dysplasia, post-inflammatory polyps and family history all contribute. The current BSG model therefore begins with a baseline colonoscopy at eight years after symptom onset and then selects annual, three-year or population-risk follow-up rather than giving every patient the same interval.
BSG suggests annual surveillance after optimised therapy when moderate endoscopic or histological inflammation persists, or when dysplasia, PSC or a colonic stricture is present; a validated calculator can also place someone in a moderate five-year advanced-neoplasia risk category. Mild persistent inflammation, extensive UC proximal to the splenic flexure, Crohn disease involving more than half the colon or at least three colonic segments, and post-inflammatory polyps support three-year surveillance. A first-degree family history of colorectal cancer also supports three-year surveillance. Severe persistent inflammation should trigger a colectomy discussion rather than simply shortening serial colonoscopy.
Detection quality matters because flat or subtle dysplasia can be missed. The procedure should be performed when disease is as quiescent as feasible, with adequate preparation and a high-definition colonoscope. Dye-spray chromoendoscopy is suggested because it adds a small benefit over high-definition white-light examination. Target visible abnormalities and describe morphology, borders, ulceration, lifting and relation to inflamed mucosa. In higher-risk situations such as PSC or previous dysplasia, segmental non-targeted biopsies can supplement targeted sampling; they do not replace careful inspection.
Dysplasia is a management finding, not an automatic synonym for colectomy. Expert pathology confirmation and an IBD dysplasia MDT are central. A clearly delineated lesion that can be completely removed is usually resected endoscopically, ideally in one piece so margins can be assessed. Surgery is reserved for invasive cancer, lesions that cannot be removed endoscopically, high-risk multifocal or invisible dysplasia, adverse combined risk, or a colon that cannot be surveyed effectively. The patient should hear the trade-offs between cancer prevention, repeated procedures and the functional consequences of colectomy or pouch surgery.
Key points
- Offer baseline colonoscopic risk assessment around 8 years after symptom onset for colonic IBD, but do not place repeatedly confirmed isolated proctitis into an IBD surveillance programme; PSC instead triggers annual surveillance from diagnosis.
- Current BSG risk strata use annual surveillance for moderate active inflammation, dysplasia, PSC or a colonic stricture, and every 3 years for mild activity, extensive colitis or post-inflammatory polyps.
- People whose risk remains close to the general population enter population colorectal screening and receive colonoscopic risk reassessment every 10 years rather than automatic 1–3-year IBD surveillance.
- Use a high-definition colonoscope; dye-based chromoendoscopy gives a small dysplasia-detection benefit over high-definition white light, while the guideline makes no recommendation for virtual chromoendoscopy.
- Surveillance quality depends on controlled inflammation, adequate bowel preparation, complete intubation, careful withdrawal and clear segmental documentation; an inadequate examination must be repeated rather than counted as reassurance.
- All dysplasia arising within a colitis-affected segment should be reviewed by an IBD dysplasia MDT. Most visible resectable lesions are removed endoscopically, ideally en bloc.
- Surgery is considered for endoscopically unresectable dysplasia, high-risk multifocal or invisible dysplasia, colorectal cancer, dysplasia plus adverse risk factors, or when effective surveillance is impossible.
02Assessment and patient selectionRisk features, eligibility and important cautions.
The baseline risk-assessment clock begins at symptom onset rather than the date on which the diagnosis was finally coded, because diagnostic delay can otherwise postpone surveillance.
Concurrent primary sclerosing cholangitis places a patient in annual surveillance; a new PSC diagnosis after years of colitis requires immediate interval review rather than waiting for the previous plan.
Persistent endoscopic or histological activity matters even when symptoms are mild, so surveillance decisions use objective inflammatory history rather than stool frequency alone.
Repeatedly confirmed isolated proctitis is not offered IBD colorectal surveillance and may not need colonoscopic risk stratification around year 8. Extension into the colon changes eligibility, so new symptoms or altered extent must be reassessed.
A new colonic stricture may conceal cancer and can prevent complete surveillance, requiring biopsy, cross-sectional staging and early colorectal discussion.
Visible and completely resectable, visible but unresectable, unifocal invisible and multifocal invisible dysplasia carry different management consequences and must not be collapsed into one label.
03Baseline assessmentMeasurements that guide the plan and track progress.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
High-definition surveillance colonoscopyFirst step - Why
- Inspect the entire colitis-affected colon, update disease extent and inflammatory activity and detect visible dysplasia.
- Interpretation and limitations
- A complete, well-prepared examination can set the next risk interval; an incomplete or poorly prepared procedure cannot exclude dysplasia and needs an explicit repeat plan.
- 02
Dye-based chromoendoscopy - Why
- Enhance mucosal contrast during high-definition withdrawal to detect subtle colitis-associated dysplasia.
- Interpretation and limitations
- BSG suggests dye chromoendoscopy for a small detection benefit over high-definition white light; it still requires deliberate inspection and targeted sampling.
- 03
Targeted biopsy or en-bloc resection of a visible lesion - Why
- Establish grade and invasion while preserving architecture and assess whether endoscopic treatment is complete.
- Interpretation and limitations
- Clear lateral and deep margins without invasive cancer can support surveillance after MDT review; incomplete, non-lifting or invasive disease prompts further endoscopic or surgical treatment.
- 04
Segmental non-targeted biopsies in selected high-risk surveillance - Why
- Sample apparently normal mucosa in people such as those with PSC or previous dysplasia while also targeting visible abnormalities.
- Interpretation and limitations
- Invisible dysplasia requires expert pathology confirmation and usually a repeat high-quality expert examination to exclude a missed visible lesion.
- 05
Histological activity assessment - Why
- Measure inflammatory burden and separate active inflammatory atypia from established dysplasia.
- Interpretation and limitations
- Moderate activity despite optimised therapy supports annual surveillance; severe persistent activity prompts a colectomy discussion and may make dysplasia interpretation difficult.
- 06
Contrast CT and cancer staging when invasion or obstruction is suspected - Why
- Define a stricture, mass, nodal or distant disease and acute obstruction outside routine surveillance.
- Interpretation and limitations
- A cancer or obstructing lesion moves the patient into diagnostic cancer and surgical pathways rather than another elective surveillance interval.
04InterventionsLifestyle, treatment and escalation options.
01Worked case: new PSC during long-standing colitisReset surveillance to the current high-risk intervalFirst stepA 49-year-old has had extensive ulcerative colitis symptoms for 12 years. The last high-definition surveillance colonoscopy 20 months ago showed no dysplasia. Magnetic-resonance cholangiography now supports a new diagnosis of primary sclerosing cholangitis.+
- 1Confirm the colitis history, prior histology, extent, preparation quality, family history and the new PSC diagnosis. Do not use the previously planned three-year interval because PSC now confers an annual-surveillance indication.
- 2Arrange high-definition surveillance colonoscopy now with experienced IBD surveillance practice and dye-based chromoendoscopy. Optimise current inflammation and bowel preparation without delaying for years.
- 3The caecum is reached with adequate preparation. Dye-spray inspection finds no visible lesion; targeted samples of two subtle areas and segmental non-targeted biopsies show quiescent chronic colitis without dysplasia.
- 4Record an annual surveillance plan from this high-quality examination. Continue objective inflammation control and PSC care, and give safety-net advice for bleeding change, anaemia, weight loss or obstruction between scheduled procedures.
- 5At 12 months a second complete examination again finds no dysplasia. Verification requires the endoscopy quality record, segmental pathology and booked next annual date, not only a clinic statement that surveillance is current.
02Confirmed isolated proctitis after extent reassessmentUse population screening rather than an IBD surveillance intervalA 37-year-old has ten years of ulcerative proctitis. Diagnostic and year-eight examinations with segmental biopsies repeatedly confirmed inflammation confined to the rectum, with no PSC, dysplasia, stricture, post-inflammatory polyps or first-degree colorectal-cancer history.+
- 1Verify that the year-eight examination was complete and high quality and that histology as well as endoscopy confirms rectum-only disease; do not infer isolated proctitis from symptoms alone.
- 2Explain that current BSG guidance does not offer an IBD surveillance programme to confirmed isolated proctitis, so neither annual, three-year nor automatic ten-year IBD colonoscopy is booked.
- 3Ensure access to age-appropriate population colorectal screening and continue ordinary review of proctitis activity and treatment.
- 4Reassess sooner if the symptom pattern changes, anaemia or weight loss develops, colitis extends proximally, PSC is diagnosed or another colorectal risk factor appears; document the exception and safety net explicitly.
03A visible lesion within a colitis segmentResect when feasible and use pathology plus MDT to set follow-upDuring annual surveillance for previous dysplasia, a 58-year-old has a clearly demarcated 12 mm non-ulcerated polypoid lesion in previously inflamed sigmoid colon. There is no endoscopic sign of deep invasion.+
- 1DefinitivePhotograph and describe the lesion, its borders and background inflammation, inspect the remainder of the colon carefully and avoid piecemeal sampling that could compromise definitive resection.
- 2An expert endoscopist removes it en bloc. Pathology, reviewed by a gastrointestinal pathologist, reports low-grade dysplasia, no invasive cancer and clear lateral and deep margins.
- 3Present the lesion, resection images, whole-colon findings and pathology at the IBD dysplasia MDT. The absence of invasion and complete resection supports continued endoscopic surveillance rather than automatic colectomy.
- 4Book annual surveillance for five years if there is no recurrence, while controlling mucosal inflammation and retaining individual background-risk assessment. Recurrence, multifocality, unresectability or cancer reopens surgical discussion.
- 5At one year, high-definition dye-spray examination finds a normal resection scar and no metachronous lesion; scar biopsies and targeted samples show no dysplasia, verifying the chosen strategy.
04Invisible multifocal dysplasiaConfirm the finding and discuss cancer-prevention surgeryNon-targeted biopsies from two separate colonic segments are reported as low-grade dysplasia in a patient with long-standing extensive Crohn colitis, but the index examination showed no visible lesion.+
- 1Obtain review by a second gastrointestinal pathologist and confirm the segments and specimen identity; active inflammation and interpretive disagreement must be resolved.
- 2Repeat a well-prepared high-definition dye-based chromoendoscopy with an expert IBD endoscopist to seek a previously missed visible lesion and remap the colon.
- 3If repeat targeted and segmental samples confirm multifocal invisible dysplasia, take the case to the IBD dysplasia MDT and colorectal surgeon.
- 4Discuss colectomy because high-risk multifocal invisible dysplasia may not be controllable by focal endoscopic resection. Explain operative options, stoma or pouch consequences and the residual risk of continued surveillance.
- 5DefinitiveDocument the shared decision and a time-bound interim plan; vague routine recall is unsafe while definitive cancer-prevention treatment is being considered.
05Targets, monitoring and follow-upResponse, safety and longer-term review.
- Maintain a surveillance register recording symptom-onset date, current and greatest colitis extent, PSC, family history, strictures, post-inflammatory polyps, dysplasia and objective inflammation.
- Audit each procedure for preparation adequacy, caecal intubation, withdrawal and inspection quality, chromoendoscopy use, lesion photography, resection completeness and pathology concordance.
- After every colonoscopy, state the risk factor that sets the next interval and book the actual date. Annual and three-year surveillance, ten-year reassessment for colonic IBD close to population risk, and no IBD surveillance for confirmed isolated proctitis are distinct pathways.
- Review surveillance benefit and burden after repeated inflammation-free procedures, major comorbidity or around age 75 through shared decision-making rather than an automatic age cut-off.
- Track every dysplasia result to expert pathology review and an IBD MDT outcome, including visible/invisible status, focality, margin status, surgery discussion and the agreed follow-up.
- Monitor inflammatory control between procedures because cumulative activity raises neoplasia risk and poor control can obscure subtle dysplasia.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Eight years is a risk-assessment point
It initiates a high-quality baseline procedure; the findings and risk factors then determine whether follow-up is annual, three-yearly or population-based.
PSC overrides a previous interval
A new PSC diagnosis changes risk now, so a patient cannot safely wait for a previously scheduled lower-risk colonoscopy.
Quality and timing interact
A nominally annual colonoscopy with poor preparation and active severe inflammation may be less protective than a prompt repeated high-quality examination.
Visible dysplasia is often treatable
Complete en-bloc endoscopic resection can preserve the colon when pathology, background mucosa and MDT review support surveillance.
Surveillance must be effective
A non-traversable stricture, repeatedly inadequate preparation or extensive pseudopolyposis can make endoscopic risk control impossible and support surgery.
07Common pitfallsFrequent interpretation and management errors.
- 01
Starting the surveillance clock at diagnosis instead of symptom onset can delay the baseline procedure in people with a long diagnostic interval.
- 02
Keeping a three-year appointment after PSC is diagnosed ignores the new annual indication.
- 03
Calling high-definition virtual colour enhancement equivalent to dye-spray exceeds the current BSG guideline, which could not recommend virtual chromoendoscopy.
- 04
Treating any dysplasia as automatic colectomy denies appropriate expert endoscopic resection for many visible, completely resectable lesions.
- 05
Accepting an inadequate or incomplete colonoscopy as a reassuring surveillance examination creates false protection.
- 06
Allowing an invisible dysplasia report to trigger irreversible treatment without expert pathology and repeat expert examination risks acting on inflammatory atypia or a missed visible lesion.