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Management of Serrated Polyps of Colorectum. Eric YF Cheung Department of Surgery, NDH. Three messages. Serrated polyp-adenocarcinoma sequence Malignant risk of serrated polyps of colorectum Management and Surveillance: New guidelines needed. Serrated polyps—An overview.
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Management of Serrated Polyps of Colorectum Eric YF Cheung Department of Surgery, NDH
Three messages • Serrated polyp-adenocarcinoma sequence • Malignant risk of serrated polyps of colorectum • Management and Surveillance: New guidelines needed
Colorectal polyps • Adenoma • Tubular adenoma • Tubulovillous adenoma • Villous adenoma • Hyperplastic polyp/Serrated polyp • Harmatoma • Juvenile polyp • Peutz-Jeghers polyps • Inflammatory polyp • Lymphoid aggregates Traditionally viewed as innocuous
Serrated polyps (WHO) • Hyperplastic polyp (HP): Small distal • Microvesicular (MVHP) • Globet-cell rich (GCHP) • Mucin-poor • Traditional serrated adenoma (TSA) • Distal • Sessile serrated adenoma/polyp (SSA) • Proximal, large • Sessile serrated adenoma/polyp with dysplasia (SSA w/ dysplasia) Am J Gastroenterol 2012; 107:1315–1329
Three pathways to CRC • Adenoma • Adenoma-carcinoma sequence: Chromosomal instability • Sessile Serrated Adenoma (SSA) • Serrated polyp-carcinoma sequence(20% CRC) • Traditional Serrated Adenoma (TSA) • Alternative/ fusion pathway • Less well characterized Am J Gastroenterol 2012; 107:1315–1329 BJS 2011; 98: 1685-1694 Gastroenterol Clin N Am 2008; 37:25-46
Serrated polyp-Carcinoma sequence Hypermethylation of promotor silencing of DNA mismatch repair gene MLH-1 Microsatellite instability Initiation Am J Gastroenterol 2012; 107:1315–1329
Serrated Polyps and CRC • Genetic and pathological study ~ 20% CRC from serrated pathway • Large and proximal serrated polyps more synchronous advanced neoplasia/CRC • Sessile serrated adenomas high metachronous CRC rate
METHOD • 3121 asymptomatic patients (aged 50–75 years)who had screening colonoscopies; 1371 had subsequentsurveillance. • RESULTS • Patient with proximal ND-SP were more likely to have advanced neoplasia(17.3% vs 10.0%; OR, 1.90; 95% CI, 1.33-2.70). • Patients with large ND-SP were also more likely to have synchronous advancedneoplasia (OR, 3.37; 95% CI, 1.7-6.65). • During surveillance, • patients with baseline proximal ND-SP and noneoplasia were more likely to have neoplasia comparedwith subjects who did not have polyps (OR, 3.14; 95% CI,1.59-6.20). • Among patients with advanced neoplasia atbaseline, those with proximal ND-SP were morelikely to have advanced neoplasia during surveillance(OR, 2.17; 95% CI, 1.03-4.59).
Serrated polyps and metachronous tumour Am J Surg Pathol 2010;34:927–934 • The incidence of subsequent CRCs was significantly higher in SSA patients than in control patients with HP (12.5% vs. 1.8%) and AP (12.5% vs. 1.8%). All of the subsequent CRCs or APs with HGD developed in the proximal colon. Four of the 5 CRCs demonstrated a high microsatellite instability phenotype. • We conclude that SSAs are high-risk lesions, with 15% of the SSA patients developing subsequent CRCs or APs with HGD. • support close endoscopic follow-up in patients harboring SSA
TreatmentAm J Gastroenterol 2012; 107:1315–1329 • Complete removal of all serrated lesions • Except diminutive sigmoid/rectal lesions • Multiple diminutive (<5mm) serrated appear lesion should be randomly Bx • Piecemeal resection/ possible incomplete removal surveillance colonoscopy 3-6 months • Surgical resection: not endoscopically ressectable, numerous large serrated lesion of proximal colon, Serrated polyposis syndrome
Current Surveillance strategies • Guidelines based on observational studies that link baseline CLN findings to risk of advanced adenoma at FU • For serrated lesions • US • After removal of HP 10 years interval • No recommendation for SSA/TSA • Europe • HP: 10 years • SSA/TSA consider as adenoma
Why we need updated guidelines? • Endoscopic detection is operator dependent and variable • SSA is hard to detect and easy to miss • Serrated adenoma are likely to grow faster then adenoma • Serrated adenomas are responsible for a large portion of interval CRC
Interval Colon Cancer RESULT MSI was found in 30.4% of interval cancerscompared with 10.3% of noninterval cancers (P = .003). Afteradjusting for age, interval cancers were 3.7 times more likely toshow MSI than noninterval cancers (95% CI,1.5–9.1).
Conceptual framework Am J Gastroenterol 2012; 107:1315–1329
Take home messages • Some serrated polyps have malignant potential e.g. SSA/TSA • Grows quicker then traditional adenomas • All should be removed except diminutive HP in rectosigmoid region • Current surveillance recommends treating SSA/TSA as adenoma • Modify according to size, site and numbers
The End Q&A
References • Rex DK, Ahnen DJ, Baron JA et. al. Serrated lesions of the colorectum: Review and recommendations from an expert panel. Am J Gastroenterol 2012;107:1315-1329 • Leonard DF, Dozois EJ, Smyrk TC, Suwanthanma W. et. al. Endoscopic and surical management of serrated colonic polyps. BJS 2011;98:1685-1694 • East JE, Saunders BP, Jass JR. Sporadic and syndromic hyperplastic polyps and serrated adenoma of the colon: classification, molecular genetics, natural history and clinical management. Gastroenterol Clin N Am 2008;37:25-46 • Bauer VP, Papaconstantinou HT. Management of serrated adenomas and hyperplastic polyps. Clin Colon Rectal Surg 2008;21L273-279 • Groff RJ, Nash R, Ahnen DJ. Significance of serrated polyps of the colon. Current Gastroenterology Reports 2008;10:490-498 • Liang JJ, Alrawi S, Tan D. Nomenclature, molecular genetics and clinic significance of the precursor lesions in the serrated polyp pathway of colorectal carcinoma. Int J Exp Pathol 2008;1:317-324 • Snover DC, Jass JR, Fenoglio-Presiser CF, Batts KP. Serrated polyps of the large intestine. Am J Clin Pathol 2005;124:380-391 • O’Brien MJ. Hyperplastic and serrated polyps of the colorectum. Gastroenterol Clin N Am 2007;36:947-968 • O’Brien MJ, Yang S, Mack C et. al. Comparison of microsatellite instability, CpG island methylation phenotype, BRAF and KRAS status in serrated polyps and traditional adenomas indicates separate pathways to distint colorectal carcinoma endpoints. Am J Surg Pathol 2006;30:1491-1501 • Lu F, Niekerk DW, Owen D et. al. Longitudinal outcome study of sessile serrated adenoma of the colorectum: An increased risk of subsequent right-sided colorectal carcinoma. Am J Surg Pathol 2010;34:927–934)
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