Colorectal polyps: recognition, characterisation and management

Management of colon polyps

1. Colorectal polyps: recognition, characterisation and management Wits reg symposium: 20/3/2024 Presenter: Dr Madsen Moderator: Dr McRoberts

2. Overview Introduction Anatomy of colonic wall Characteristics and types of polyps General management and surveillance Screening and diagnostic modalities Therapeutic techniques Conclusion

3. Introduction Definition: A protrusion of tissue into the lumen above the surrounding mucosa Usually mucosa Usually sporadic or as part of a syndrome Usually asymptomatic May bleed or cause obstructive symptoms if large Majority identified on screening Some are precursors for colorectal cancer (CRC) >95% of CRC arise from pre-existing adenomas or sessile serrated lesions

4. Anatomy

5. Characterisation

6. Histological classification and general management

7. Inflammatory polyps

8. Inflammatory polyps Consisting of stromal and epithelial components and inflammatory cells Non-neoplastic Inflammatory pseudopolyps : Chronic inflammation Prolapsed type inflammatory polyps Mechanical trauma

9. Inflammatory pseudopolyps Irregularly islands of residual intact mucosa resulting from mucosal ulceration and regeneration in response to inflammation e.g. IBD Pedunculated or sessile Treat underlying cause

10. Prolapsed type inflammatory polyps Traction, distortion, and twisting of mucosa caused by peristalsis-induced trauma results in localized ischemia and lamina propria fibrosis Ulceration or bleeding Excision if symptomatic or for diagnosis Treat underlying cause e.g. rectal prolapse

11. Hamartomatous polyps

12. Hamartomatous polyps Disorganised mucosal masses of normal tissue elements No intrinsic malignant potential Juvenile polyps Overgrowth of lamina propria Peutz-Jeghers polyps Overgrowth of muscularis mucosa

13. Juvenile polyps Sporadic: Solitary Occurs in 2% of children < 10 years of age Resection if bleeding, prolapsing or intussusception Juvenile polyposis syndrome: AD condition. Multiple throughout the GI tract >5 juvenile polyps Increased risk of CRC (40%) and gastric cancer Surveillance, polypectomy +/- surgery

14. Peutz-Jeghers Polyps Usually benign May grow progressively and produce symptoms Requires resection Usually associated with Peutz-Jeghers syndrome AD condition Gastrointestinal polyposis Mucocutaneous pigmented macules Cancer predisposition Gastrointestinal (CRC 40%) and non-gastrointestinal cancers Surveillance, polypectomy +/- surgery of affected area

15. Sessile serrated lesions

16. Sessile serrated lesions A heterogenous group of serrated polyps Variable malignant potential Responsible for +/- 30% of CRC Hyperplastic polyps Traditional serrated adenomas (TSA) Sessile serrated polyps (SSP) Saw’s teeth appearance on histology

17. Hyperplastic polyps Small sessile polypoid lesions No dysplasia Most common non-neoplastic polyp Mostly recto-sigmoid Very low malignant potential Natural history of larger, right sided not well understood Polypectomy for diff dx Surveillance: Number, site, size and society

18. Sessile serrated lesions with malignant potential Traditional serrated adenomas (TSA) Sessile or pedunculated Diffuse but often mild dysplasia Mostly recto-sigmoid Complete excision Surveillance: Every 3 years Sessile serrated polyps (SSP) Sessile and flat and may be covered by mucus Often dysplasia Mostly proximal colon Precursor to sporadic microsatellite instability high (MSI-H) colon cancer Complete excision Surveillance: size and number dependent 3-10 years

19. TSA HP SSP

20. Adenomatous polyps

21. Adenomatous polyps Always dysplastic Most common neoplastic polyp 2/3 of all colonic polyps Precursor to most CRC At diagnosis: Majority <10 mm 30-50% synchronous adenomas 3-5% invasive carcinoma 27-36% flat More difficult to detects and more histologically advanced for their size 1% are depressed Often high grade-dysplasia or malignant

22. Hereditary cancer syndromes Usually sporadic but can be part of a syndrome

23. Aetiology and Epidemiology Risk factors for development: Age: 20-30: 1-4% 50 years: 25-30% 70 years: 50% BMI and abdominal obesity Lack of physical activity Gender: M>F Diet: high fat and low fibre Tobacco and excessive alcohol Family history

24. Histological features Tubular adenoma: 80% Villous adenoma: 5-15% Long glands extending from surface to centre of polyp Tubulovillous adenoma: 5-15%

25. The Paris endoscopic classification

26. Natural history of adenomatous polyps

27. Progression of neoplastic changes

28. Management of adenomatous polyps Always complete excision Polypectomy Piecemeal if necessary Surgical resection Not amenable to polypectomy Biopsy not recommended Likely to miss malignant area

29. Classification of malignant polyps Haggitt Classification Kikuchi Classification

30. Management post resection Piecemeal/incomplete resection: Contributes to interval CRC Repeat C scope in 6 months HG dysplasia or carcinoma in-situ Polypectomy adequate if free margins Surveillance as advanced adenomas Invasive cancer: Early-stage (T1): Polypectomy adequate if no risk factors C scope in 3 months then as advanced adenomas >T1 or risk factors Surgical resection Risk factors for recurrence/nodal mets Margins <2 mm Poorly differentiated Submucosal invasion depth > 1 mm Haggitt 4 with Kikuchi Sm2 and Sm3 LVI or PNI Tumour budding

31. Surveillance post resection

32. Advanced adenoma

33. European Society of Gastrointestinal Endoscopy (ESGE)

34. Screening for CRC

35. Diagnostic modalities

36. Faecal immunochemical testing (FIT) for haemoglobin Likely to miss colonic polyps: Asymptomatic patients: Randomised , controlled trial, of asymptomatic screened adults (50-69 years) comparing one-time colonoscopy in 26 703 patients with FIT every 2 years in 26 599 patients (Quintero, N Engl J Med, 2016) Higher detection of adenomas in colonoscopy group than FIT group Advanced adenomas: 1.9% vs 0.9% (Odd ratio 2.3) and non-advanced adenomas: 4.2% vs 0.4% (Odds ratio 9.80) Symptomatic patients: Mul ticentre prospective cohort study from the UK including 3496 patients (above 16 years) referred with symptoms suggestive of CRC (excluded 97 patients diagnosed with cancer and included 553 with neo-plastic polyps (Bath, BJS Open 2023) Sensitivity of FIT in detecting neoplastic polyps compared to C scope: 34.9% for all polyps and 46.8% for high-risk polyps

37. Colonoscopy Gold standard Polyp miss rate of 22% Factors for improving detection rate: Adequate bowel preparation Cleaning and suctioning Adequate distension +/- Buscopan Position change Examination of proximal side of flexures, folds and valves Rectal retroflexion +/- caecal retroflexion Distal scope attachments: Cuffs, caps and rings Withdrawal time: 6-10min Detection of any neoplasm: 28.3% (>6min) vs 11.8% (<6 min), P<0.001

38. New techniques in endoscopic mucosal visualisation

39. New techniques in endoscopic mucosal visualisation Optical enhancement (electronic chromoendoscopy) Optical filters narrowing bandwidth of white light (narrow-band imaging, NBI) Spectral emission processing of white light (I-scan) Enhances visualisation of the capillary network or micro-surface pattern of colonic adenomas

40. New techniques in endoscopic mucosal visualisation High-magnification endoscopy Up to 100 times and HD Combined with chromoendoscopy Differentiate non-adenomatous, adenomatous and cancerous polyps: Kudo pit pattern classification Narrow-band Imaging International Colorectal Endoscopic (NICE) classification

41. New techniques in endoscopic mucosal visualisation Artificial Intelligence Additional eyes or virtual eyes Generates a box when a polyp is detected Shown to increase adenoma detection rate RCT increased adenoma detection rate by 9% without increasing withdrawal time compared to standard withdrawal ( Milluzzo , Clin Endosc . 2021)

42. CT colonography/Virtual colonoscopy Produces 2D and 3D pictures Low dose CT scan of abdomen and pelvis Less-invasive: Requires bowel prep Rectal air insufflation No sedation Sensitivity: Large polyps (>10mm): 90% Cancer: 96%

43. Colon capsule PillCam COLON 2 capsule (Medtronic) Wider field of view than standard SB capsule High specificity for polyps over 10mm Requires expertise in image interpretation Recommended as an option following incomplete colonoscopy or in patients with no alarm systems, by European societies (ESGE, ESGAR)

44. Therapeutic techniques Endoscopic resectability depends on: Morphology: Serrated lesions: difficult due to indistinct edges Sessile and flat polyps: difficult due to need for lifting off submucosa Size: Large sessile polyps extending beyond 50% of bowel circumference Submucosal invasion/scaring Difficulty to lift off submocosa Site: Right sided Extending beyond dentate line Encircling the appendix orifice

45. Polypectomy Simple methods 2mm polyps Forceps 2-10mm sessile polyps Cold snare 10-20mm sessile polyps Hot Snare with Endoscopic Mucosal Resection (EMR) >20mm sessile polyps Piece meal resection with EMR Larger stalked polyps Hot snare +/- prophylactic clip/Adrenaline/ endoloop Endoscopic Mucosal Resection

46. Retrieval of polyp Small polyps Sucked through scope into a polyp trap or gauze Larger polyps Grasped or snared and withdrawn with the scope Multiple pieces of tissue or polyps Retrieval baskets or nets

47. Conclusion Usually sporadic and asymptomatic but may over time become symptomatic Majority are adenomas Slow growth: 5 % will become malignant in 10 years: Higher risk for “Advanced adenomas/High risk adenomas” >10mm, villous components, high grade dysplasia Generally, requires excision: Biopsies rarely representative Polypectomy can prevent progression to CRC

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