Download Management of Serrated Polyps of Colorectum

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
Colorectal polyps

Adenoma

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
Tubular adenoma
Tubulovillous adenoma
Villous adenoma
Hyperplastic polyp/Serrated polyp
 Harmatoma
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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
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Traditional serrated adenoma (TSA)
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Sessile serrated adenoma/polyp (SSA)
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Distal
Proximal, large
Sessile serrated adenoma/polyp with
J Gastroenterol
2012; 107:1315–1329
dysplasia (SSAAmw/
dysplasia)
Incidence of Colorectal Polyps
Serrated polyp-Adenocarcinoma
sequence
Three pathways to CRC

Adenoma
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Sessile Serrated Adenoma (SSA)
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Adenoma-carcinoma sequence: Chromosomal
instability
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
Initiation
Hypermethylation of promotor silencing
of DNA mismatch repair gene MLH-1
Microsatellite instability
Am J Gastroenterol 2012; 107:1315–1329
Malignant Risk of Serrate Polyps
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 subsequent surveillance.
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 advanced
neoplasia (OR, 3.37; 95% CI, 1.7-6.65).
During surveillance,
•patients with baseline proximal ND-SP and no neoplasia were more likely to have
neoplasia compared with subjects who did not have polyps (OR, 3.14; 95% CI,1.596.20).
•Among patients with advanced neoplasia at baseline, those with proximal ND-SP
were more likely 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
Management and Surveillance
Treatment
Am J Gastroenterol 2012; 107:1315–1329
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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 cancers
compared with 10.3% of noninterval cancers (P
= .003). After adjusting for age, interval
cancers were 3.7 times more likely to show 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
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