01Role and principlesWho benefits and the main preventive aims.
Colorectal polyps arise through several biological pathways. Conventional adenomas are tubular, tubulovillous or villous neoplasms and are graded for dysplasia. Serrated lesions include hyperplastic polyps, sessile serrated lesions and traditional serrated adenomas; size, proximal site and dysplasia influence risk. The endoscopist describes location, diameter against a calibrated reference, Paris morphology, surface and vascular features, lifting characteristics and whether removal was en bloc or piecemeal. Pathology then reports type, dysplasia, invasive cancer if present and margin confidence where evaluable. A rounded label such as ‘benign polyp’ loses the details that determine surveillance and whether cancer resection was adequate.
Polypectomy aims for complete excision with the safest effective technique. Diminutive lesions may be removed by cold snare, while larger lesions require planned endoscopic mucosal resection, endoscopic submucosal dissection, full-thickness resection or surgery according to morphology, invasion risk and expertise. Tattoo placement helps later localisation but must be positioned so it does not create submucosal fibrosis beneath a lesion awaiting advanced resection. Suspected deep invasion, non-lifting without prior manipulation, ulceration or an adverse optical pattern should trigger expert discussion, because piecemeal removal destroys pathological staging and may seed fibrosis that makes definitive treatment harder. Pedunculated lesions require assessment of head and stalk, bleeding risk and margin.
Surveillance is risk-based rather than annual by default. BSG, ACPGBI and PHE define a high-risk group after complete removal: two or more premalignant polyps including at least one advanced colorectal polyp, or five or more premalignant polyps. They receive a one-off surveillance colonoscopy at three years; people outside those criteria generally return to the appropriate national screening or symptomatic route. Local recurrence after piecemeal EMR is a different question from metachronous-cancer surveillance, so a lesion at least 20 mm needs focused early site checks before the broader interval is calculated. Always account for baseline colonoscopy quality, pathology reconciliation, hereditary phenotype, IBD, previous colorectal cancer, age, frailty and life expectancy. The best interval is useless if no one owns the booking and histology action.
Key points
- A polyp is a morphological finding, not a final diagnosis. Management depends on size, site, morphology, optical pattern, histology, number and confidence of complete removal.
- Premalignant colorectal polyps include conventional adenomas and serrated lesions; small distal hyperplastic polyps generally carry different risk from proximal dysplastic serrated disease.
- Suspected deep submucosal invasion should be photographed, described, biopsied selectively and referred for colorectal multidisciplinary planning rather than fragmented piecemeal removal.
- A large non-pedunculated lesion without clear deep invasion should be assessed by an endoscopist skilled in advanced resection before surgery is assumed necessary.
- The BSG high-risk criteria are either at least two premalignant polyps with one advanced polyp, or at least five premalignant polyps; this group receives a one-off colonoscopy at three years.
- An advanced polyp for these criteria is a serrated polyp at least 10 mm or with any dysplasia, or an adenoma at least 10 mm or with high-grade dysplasia.
- Piecemeal endoscopic mucosal resection of a lesion at least 20 mm needs an early site check, usually at two to six months, and a further check around eighteen months under BSG guidance.
- Surveillance recommendations assume a high-quality complete baseline colonoscopy and credible excision; poor preparation, an incomplete examination or uncertain margins first requires completion or site assessment.
02Assessment and patient selectionRisk features, eligibility and important cautions.
A tubular, tubulovillous or villous lesion with low- or high-grade dysplasia enters premalignant-polyp counting; size and high-grade dysplasia determine whether it is advanced for surveillance criteria.
A subtle flat proximal lesion with mucus cap and indistinct margins can be missed. Size at least 10 mm or any dysplasia makes it advanced in the BSG surveillance definition.
Ulceration, induration, convergence, depressed morphology, disrupted vascular pattern or convincing non-lifting raises submucosal cancer and should prevent casual piecemeal resection.
Five or more premalignant polyps, or at least two with one advanced lesion, meets the BSG high-risk post-polypectomy threshold after complete clearance and high-quality examination.
Ten or more cumulative adenomas, numerous serrated lesions or young-age multiplicity should prompt hereditary-risk assessment rather than repeated use of the average-risk surveillance algorithm.
Immediate or delayed bleeding, escalating abdominal pain, fever, tachycardia or peritonism after resection raises haemorrhage, perforation or electrocoagulation syndrome and needs acute reassessment.
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-quality colonoscopyFirst step - Why
- Detect synchronous lesions, document caecal completion and bowel preparation, and permit complete optical characterisation and resection.
- Interpretation and limitations
- Surveillance intervals assume a complete adequately prepared examination. An incomplete or poorly prepared colon first needs timely completion rather than automatic assignment to a three-year schedule.
- 02
Histopathology - Why
- Determine adenomatous or serrated type, dysplasia, invasive cancer and evaluable resection margins.
- Interpretation and limitations
- Reconcile every specimen with site and size. Invasive cancer, uncertain deep margin, lymphovascular invasion or other adverse features triggers colorectal MDT review rather than routine polyp surveillance.
- 03
Optical invasion assessment - Why
- Estimate superficial versus deep submucosal invasion before choosing en-bloc, piecemeal or surgical treatment.
- Interpretation and limitations
- A regular surface pattern may support endoscopic resection by an appropriately skilled operator; clear deep-invasion features warrant documentation, tattoo strategy and multidisciplinary treatment planning.
- 04
Early EMR site-check colonoscopy - Why
- Detect residual or recurrent tissue after piecemeal removal of a lesion at least 20 mm.
- Interpretation and limitations
- Perform the first site check at about two to six months under BSG guidance and a further check around eighteen months; treat recurrence using expert technique and document scar assessment.
- 05
Full blood count and iron studies - Why
- Assess chronic occult loss or post-procedural bleeding when anaemia, symptoms or a large lesion makes it relevant.
- Interpretation and limitations
- Iron deficiency requires complete gastrointestinal and cancer assessment appropriate to context; correction does not remove the need to establish and treat the source.
- 06
Hereditary-risk assessment - Why
- Identify multiplicity, young age and family patterns that qualify for genomic or specialist surveillance pathways.
- Interpretation and limitations
- Count cumulative adenomas and serrated lesions across procedures, verify relatives and refer using current NHS Genomic Test Directory and BSG criteria rather than ordering uncontextualised panels.
04InterventionsLifestyle, treatment and escalation options.
01At colonoscopyDescribe before removingFirst stepA colorectal polyp is identified during screening or symptomatic investigation.+
- 1Record exact segment, calibrated size, morphology and optical pattern, photograph the lesion and inspect for synchronous disease before choosing treatment.
- 2Remove a lesion with an evidence-based technique within competence, retrieving tissue and documenting en-bloc versus piecemeal excision and confidence of completeness.
- 3For a large non-pedunculated lesion or possible superficial cancer, seek advanced endoscopy review; for likely deep invasion, avoid destructive fragmentation and refer to colorectal MDT.
- 4Place a tattoo only when useful for later localisation and at an appropriate distance and orientation, recording it precisely so it does not compromise subsequent resection.
02Histology meetingReconcile lesion and pathologyThe pathology report returns after polypectomy.+
- 1Match each specimen to the colonoscopy map, checking type, size, dysplasia, invasion, margin and whether cautery or fragmentation limits interpretation.
- 2EscalationEscalate unexpected invasive cancer or adverse pathological features to the colorectal cancer MDT and arrange staging rather than placing the patient on a routine polyp list.
- 3Confirm complete clearance and baseline quality, then count all premalignant polyps and identify any advanced lesion using BSG definitions.
- 4Communicate the result, cancer significance, site-check need and surveillance or screening plan to the patient and primary care with a named booking owner.
03SurveillanceApply risk and quality togetherAll lesions have been removed and histology is reconciled without an immediate cancer pathway.+
- 1Assign a one-off three-year surveillance colonoscopy if there are at least five premalignant polyps, or at least two including one advanced lesion.
- 2Return those outside high-risk criteria to the national screening or symptom-led pathway appropriate to age and jurisdiction, rather than creating unnecessary annual colonoscopy.
- 3Manage piecemeal resection of a lesion at least 20 mm with focused site checks at two to six months and around eighteen months before applying broader risk surveillance.
- 4Individualise or stop surveillance when age, frailty or life expectancy makes procedural burden exceed plausible prevention benefit, documenting shared decision-making.
05Medicines and treatment safetyRegimens, contraindications and review points.
Bowel-cleansing preparation
Use the locally selected split-dose regimen with timing matched to the procedure, adjusting formulation and fluid advice for kidney, cardiac and electrolyte risk.Check obstruction, frailty, swallowing and aspiration risk, renal function and interacting medicines. Inadequate preparation invalidates surveillance assumptions and usually requires planned early repeat rather than reassurance.
Antithrombotic interruption plan
Alter aspirin, P2Y12 inhibitor, warfarin or direct oral anticoagulant only using the current BSG and local procedure-risk schedule for the individual's thrombotic indication.Do not give generic stop dates without renal function and indication review. High-thrombotic-risk cases need specialist ownership, and every interruption requires an explicit restart plan after haemostasis.
06Targets, monitoring and follow-upResponse, safety and longer-term review.
- Audit caecal intubation, bowel-preparation quality, withdrawal inspection, polyp retrieval and complete-resection documentation because interval advice assumes procedural quality.
- Track histology to a named clinician, reconciling specimen number, site, size, dysplasia and margins against the endoscopy report.
- After polypectomy, safety-net delayed bleeding, fever and increasing abdominal pain and document the emergency contact route.
- For piecemeal EMR, maintain a scar-specific register for the two-to-six-month and later site check, including recurrence treatment and final clearance.
- At surveillance review, recalculate cumulative polyp count, hereditary criteria, age, comorbidity and life expectancy rather than copying the previous interval.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Risk begins with quality
A three-year interval after an incomplete or poorly prepared colonoscopy is false precision. First secure complete mucosal assessment and credible lesion clearance.
Scar and colon differ
An early EMR site check asks whether local tissue remains; post-polypectomy surveillance asks whether future lesions arise elsewhere. They use different timing and should not be conflated.
Piecemeal loses staging
Fragmentation prevents reliable measurement of invasion depth and margins. When cancer is plausible, en-bloc expert resection or surgical planning protects pathological decision-making.
Serrated lesions count
Flat serrated lesions may be visually subtle but are premalignant. Their size and dysplasia contribute to the same high-risk algorithm rather than being dismissed as harmless hyperplastic polyps.
Surveillance can cause harm
Preparation, sedation, bleeding and perforation burdens rise with frailty. Prevention benefit requires sufficient life expectancy and should be reconsidered rather than renewed automatically.
08Common pitfallsFrequent interpretation and management errors.
- 01
Assigning surveillance from the word adenoma without counting number, size, dysplasia and serrated lesions.
- 02
Fragmenting a lesion with deep-invasion features and destroying accurate cancer staging.
- 03
Placing tattoo ink immediately beneath a lesion that needs later advanced endoscopic resection.
- 04
Starting a three-year clock after poor preparation or incomplete caecal intubation.
- 05
Forgetting focused site checks after piecemeal resection of a large lesion.
- 06
Continuing surveillance indefinitely in severe frailty without revisiting benefit, burden and patient preference.