serrated polyps/aenoma of the colon and rectum
DESCRIPTION
1. Colon and rectal cancers –molecular pathways 2. Colon and rectum polyps 3. Colon and rectum Serrated polyps/adenomas 4. Colon and rectal Serrated polyps/adenomas ManagementTRANSCRIPT
SERRATED POLYPS/AENOMA OF THE COLON AND RECTUM
: 1. Colon and rectal cancers molecular pathways
2. Colon and rectum polyps 3. Colon and rectum Serrated
polyps/adenomas 4. Colon and rectal Serrated polyps/adenomas
Management Over the last 20 years it has become clear that
colorectal cancer (CRC) evolves through multiple pathways. REVIEW
Classification of colorectal cancer based on correlation of
clinical, morphological and molecular features Histopathology 2007,
50, 113130. DOI: /j x colorectal cancer (CRC) evolves through
multiple pathwaysAdvanced colorectal polyps with the molecular and
morphological features of serrated polyps and adenomas: concept of
a fusion pathway to colorectal cancer 2006 The Authors. Journal
compilation 2006 Blackwell Publishing Ltd, Histopathology, 49,
121131. Adenoma-Carcinoma Sequence APC gene Serrated polyp-cancer
pathway. BRAF (gene) Concept of fusion pathways to CRC These
pathways may be defined on the basis of two molecular features:
Histopathology 2007, 50, 113130. DOI: /j x (i) DNA microsatellite
instability (MSI) status stratified asMSI-high (MSI-H),
MSI-low(MSI-L) and MSstable (MSS), and (ii) CpG island methylator
phenotype (CIMP) stratified as CIMPhigh,CIMP low and CIMP-negative
(CIMPneg). This approach to the classification of CRC should
accelerate understanding of causation and will impact on clinical
management in the areas of both prevention and treatment. Serrated
polyps are the precursors
In this review the morphological correlates of five molecular
subtypes are outlined:REVIEW Classification of colorectal cancer
based on correlation of clinical, morphological and molecular
featuresHistopathology 2007, 50, 113130. Serrated polyps are the
precursors Type 1 (CIMP-high MSI-H BRAF mutation), (12%). Type 2
(CIMP-high MSI-L or MSS BRAF mutation), (8%). Either: Type 3
(CIMP-low MSS or MSI-L KRAS mutation), (20%). adenomacarcinoma
sequence. Type 4 (CIMP-neg MSS) (57% ). and Type 5 or Lynch
syndrome (CIMP-neg MSI-H) 3%. This approach to the classification
of CRC should accelerate understanding of causation and will impact
on clinical management in the areas of both prevention and
treatment. Histopathology 2007, 50, 113130. DOI: /j x Colorectal
polyps neoplastic or non-neoplastic.
can be classified as neoplastic or non-neoplastic. Neoplastic
polyps are subclassified into the following types: Adenomas (most
common, with a risk of progression to carcinoma) Polypoid
adenocarcinomas Lipomas, leiomyomas, and lymphomatous polyps (the
less-common carcinoid tumours). Non-neoplastic polyps
are subclassified into the following types: Hyperplastic polyps
(always benign) Inflammatory polyps (usually in ulcerative colitis
and occasionally in Crohn's disease) Lymphoid polyps or hamartomas
(a benign overgrowth of tissues normally found at the site; e.g.,
Peutz-Jeghers syndrome). Neoplastic (adenomas) Describe the current
general classification of colon polyps. Which features of an
adenomatous polyp correlate with greater malignant potential? Clin
Med Res. Jul 2003; 1(3): 261262 Tubular adenomas (0-25% villous
tissue) Tubulovillous adenomas (25-75% villous tissue) Villous
adenoma (75-100% villous tissue) All types of adenomas are
dysplastic and pre-malignant, although adenomas with a significant
villous component are more likely to become malignant. Malignant
potential is associated with 1.degree of dysplasia
When does a polyp become a problem?From Wikipedia, the free
encyclopedia Malignant potential is associated with 1.degree of
dysplasia 2. Type of polyp (e.g. villous adenoma): Tubular Adenoma:
5% risk of cancer Tubulovillous adenoma: 20% risk of cancer Villous
adenoma: 40% risk of cancer 3.Size of polyp: > MPHP Sessile
serrated adenoma/polyp(SSA/P)
5-25% of all serrated polyps In one prospective study, 9% of all
patients undergoing screening colonoscopy Precursor to sporadic
carcinomas with microsatellite instability (MSI) Probably the
precursor for CpG island-methylated microsatellite-stable
carcinomas Histology of SSA/P Serration may be very prominent and
is often seen at the base of the crypts The crypts are often
dilated with abnormal shapes including L-shaped and inverted
T-shaped Goblet-cell or gastric-foveolar differentiation at the
base of the crypts Some areas of SSA/P may have straight crypts
similar to those of MVHP Cytological dysplasia in SSA/P
Cytological dysplasia is not present in uncomplicated SSA/P Present
while progression toward carcinoma Dysplasia resemble that of
conventional adenomas "mixed SSA/P-tubular adenomas" (or mixed
HP-TA) in the older literature "SSA/P with cytological dysplasia"
is preferred SSA/P with cytological dysplasia
Often in conjunction with methylation of the MLH1 gene and with the
development of MSI Biologically the cytologically, dysplastic part
of these lesions is not the same as conventional adenoma The
behaviour of these lesions may be more aggressive than that of
conventional adenoma. Traditional serrated adenoma (TSA)
Uncommon, < 1 % of all polyps Complex and villiform growth
pattern TSA is generally not associated with carcinoma with high
MSI but may be associated with low MSI Cells showing cytological
features different from the dysplasia of conventional adenomas or
of SSA/P with cytological dysplasia Histology of TSA Narrow
pencillate nucleus and eosinophilic cytoplasm
"ectopic" crypts : crypts lost their anchoring to the underlying
muscularis mucosae Conventional dysplasia can occur in TSA,
reflecting progression toward carcinoma Serrated polyp,
unclassified
Distinction of HP from SSA/P and TSA is based mainly on
architectural criteria Not all serrated lesions are easily
classified, often because of sampling issues or poor orientation of
the specimen. "serrated polyp, unclassified may be used Serrated
adenoma? "serrated adenoma" was initially coined for any lesion
showing serration and cytological dysplasia TSA SSA/P with
cytological dysplasia Conventional adenomas with serrated
architecture Because of this potentially confusing ambiguity, it is
recommended that the term "serrated adenoma" never be used without
a qualifier Serrated polyps at VGHKS
Hyperplastic polyp: 6970 (95.6%) Serrated adenoma: 319 (4.4%) SSA:
56 (17.5%) TSA: 66 (20.7%) Without qualifier: 197 (61.8%)
Terminology for Reporting Serrated Polyps of the Large Intestine Am
J Clin Pathol 2005;124:380-391
1. Hyperplastic polyp Microvesicular type (optional) Goblet
cellrich type (optional) Mucin-poor type (optional) 2. Sessile
serrated adenoma 3. Traditional serrated adenoma 4. Mixed serrated
polyp (list individual components in parentheses, eg, mixed sessile
serrated adenomatubular adenoma) 5. Sessile serrated polyp (with a
comment that this is an equivocal diagnosis that includes both
hyperplastic polyp and sessile serrated adenoma; one should try to
favor 1 or the other in the comment, based on the location and size
of the lesion, eg, large right-sided lesions favor SSA, small
left-sided lesions favor HPP) HYPERPLASTIC POLYP ,The benign
hyperplastic polyp
Management of Serrated Adenomas and Hyperplastic Polyps Clin Colon
Rectal Surg. Nov 2008; 21(4): 273279. doi: /s HYPERPLASTIC POLYP
,The benign hyperplastic polyp accounts for 80 to 90% of serrated
polyps. SESSILE SERRATED ADENOMA , SSA is recognized as the most
common of the serrated adenomas accounting for 15 to 20% serrated
polyps TRADITIONAL SERRATED ADENOMA, The TSA is very
rare,constituting less than 1% of all colorectal polyps. MIXED
POLYP The mixed polyp variant displays features of hyperplastic
polyp and SSA, and a dysplastic component resembling conventional
adenoma Serrated Polyps of the Large Intestine A Morphologic and
Molecular Review of an Evolving ConceptAm J Clin Pathol 2005;124:
Serrated polyps of the large intestine, including traditional
hyperplastic polyps, traditional serrated adenomas, and more
recently described sessile serrated adenomas, have gained increased
recognition in recent years because of growing evidence that one of
these lesions, the sessile serrated adenoma, might be the precursor
lesion for some cases of microsatellite unstable colorectal
carcinoma. PrevalenceThe clinical importance of serrated lesions of
the colorectum Rev. gastroenterol. Perv.33n.2Limaabr./jun.2013 In
one large study of over 7000 screening colonoscopies done by 13
endoscopists, the prevalence of adenomas was 22%, HP 12% and SSP
0.6% (18). Another study in over 3000 screening colonoscopies from
66 endoscopists demonstrated the SSP detection rate was 2% Risk to
the individual with SSA The clinical importance of serrated lesions
of the colorectum Rev. gastroenterol. Perv.33n.2Limaabr./jun.2013
Individuals who harbor serrated neoplasms are at in increased risk
of synchronous serrated lesions as well as AN (21-25) (advanced
conventional neoplasia ). Li et al found that both right and left
sided, large serrated polyps are associated with a 3 fold risk of
synchronous AN (22) Patients with either a proximal or large HP or
SSP were found to be at increased risk of synchronous AN versus
those without those lesions Risk to the individual with SSA The
clinical importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 Vu et al : The data
demonstrated that individuals who co-express SSP and conventional
adenomas have significantly more numerous, larger, SSPs and
conventional adenomas and more pathologically advanced conventional
adenomas than individuals with only SSA or conventional adenomas.
Synchronous CRCs were found exclusively in the cohorts with SSA. In
another study which identified polyps from pathology archives and
assessed the clinical follow up found the incidence of CRC was
higher in the SSP patients (12.5%) than in patients with HP (2%) or
adenomatous polyps (2%) (33). Risk to the individual with
SSAvsscreening and surveillance colonoscopyThe clinical importance
of serrated lesions of the colorectum Rev. gastroenterol.
Perv.33n.2Limaabr./jun.2013 The current target of screening and
surveillance colonoscopy is the detection and prevention of
metachronous advanced conventional neoplasia (AN) (tubular,
tubulovillous [TVA], and villous [VA]). Advanced neoplasms are
adenomas that are one centimeter or greater in size, harbor any
villous component (TVA or VA), high grade dysplasia or invasive
adenocarcinoma. Little is known about the risk of metachronous
lesions in individuals with serrated colon polyps. colonoscopy on
CRC incidence and mortality
1. COLONOSCOPIC EXAMINATIONAS SYMPTOMS / SIGNS. 2. REGULAR
FOLLOW-UP EXAMINATION. 3. PHYSICAL CHECK-UP EXAMINATION. variable
protection from the use of colonoscopy on CRC incidence and
mortalityThe clinical importance of serrated lesions of the
colorectum Rev. gastroenterol. Perv.33n.2Limaabr./jun.2013 a
reduction of CRC mortality by up to 53% (6). variable protection
from the use of colonoscopy on CRC incidence and mortality a
decrease in overall and left sided CRC mortality, a lesser benefit
of colonoscopy in the reduction of CRC mortality in the proximal
colon. Interval cancers have been shown to occur in up to 9% of
individuals with CRC who have undergone colonoscopy in the
preceding 3 years the variable protection from colonoscopy and
interval cancer The clinical importance of serrated lesions of the
colorectum Rev. gastroenterol. Perv.33n.2Limaabr./jun.2013 Factors
directly associated with the endoscopist : The specialty of the
provider: 1. in particular procedures done by a non-
gastroenterologist, or 2. by an endoscopist with low rates of
adenoma detection,polypectomy or cecal intubation (10,12). Other
factors include 1. the technical limitations of the exam, 2missed
or insufficient resection of lesions, 3inadequatebowel preparation,
and 4. the varying biologic behavior of lesions. Interval cancer
The clinical importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 Interval cancers, which
are cancers which develop after a colonoscopy and before the next
recommended interval, are of increasing recognition and concern.(or
within 5 yrs) The factors most likely to becontributing to interval
cancer is 1. the variability in the detection of SSP by the
endoscopist and 2. inadequate resection of those lesions. 95
95 3.5 Variability in recognition and diagnosis of SSP (2-1) The
clinical importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 Recent data shows a
significant variability in the ability of an endoscopist to detect
an SSP. Kahi et al. found a 3 fold difference in adenoma detection
rate and 18 fold variability in the detection of at least one
proximal serrated polyp (26). Data from Hetzel et al. showed a 7
fold difference in SSP detection rate while the variability in
adenoma detection was less than a 3 fold difference (18).
Variability in recognition and diagnosis of SSP (2-2) The clinical
importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 They also showed that
SSP detection rates increased over time; being 0.6% in 2006 and
increasing to 1.1% of exams in 2008. This may be due to an
increasing awareness of the clinical importance of SSP by the
endoscopist or even increasing ability to diagnose these lesions by
the pathologist. Polyp Size Location Dysplasia Malignant Mutation
Potential
Table 1 Histologic and Genetic Characteristics of Serrated Polyps
Management of Serrated Adenomas and Hyperplastic Polyps CLINICS IN
COLON AND RECTAL SURGERY/VOLUME 21, NUMBER Polyp Size Location
Dysplasia Malignant Mutation Potential Hyperplastic polyp 5
mmProximalYes Yes KRAS Traditional serrated >5 mm Distal Yes Yes
KRAS Sessile serrated >5 mm Proximal No Yes BRAF BRAF, v-raf
murine sarcoma viral oncogene homolog B1; KRAS, v-Ki-ras2 Kirsten
rat sarcoma viral oncogene homolog. Endoscopic characteristics of
serrated polyps/adenoma of the colonorectum Hyperplastic
polypEndoscopic characteristicsManagement of Serrated Adenomas and
Hyperplastic Polyps Clin Colon Rectal Surg. Nov 2008; 21(4):
273279. doi: /s favor a small (< 3 to 5 mm) sessile lesion that
is pale, often multiple, and located predominantly in the left
colon at the rectosigmoid area, usually in older patients.1 It is
the most common polyp encountered on flexible sigmoidoscopy.
Figure1 Linear and regularly patterned colonic mucosa surrounding a
polyp. On endoscopic removal, pathology revealed a hyperplastic
colon polyp. A: Before spraying with acetic acid a sessile polyp is
seen; B: After spraying with acetic acid the colonic mucosa
surrounding the polyp has a linear and regular pattern World J
Gastroenterol March 28; 14(12): Figure 2 Nodular and irregularly
patterned colonic mucosa surrounding a polyp. On endoscopic
removal, pathology revealed a hyperplastic colon polyp. A: Before
spraying with acetic acid a sessile polyp is seen; B: After
spraying with acetic acid the colonic mucosa surrounding the polyp
has a nodular and irregular pattern.World J Gastroenterol March 28;
14(12): Rectal hyperplastic polyps without any clinical
significance Gastrointestinal HD Endoscopy Images: Rectal Diseases
Endoscopic appearance of SSAManagement of Serrated Adenomas and
Hyperplastic Polyps Clin Colon Rectal Surg. Nov 2008; 21(4):
273279. doi: /s is typically a pale, large, sessile lesion that
rests on the crest of the mucosal folds. A SSA is predominantly
found in the proximal colon of middle-aged women and grows to
larger sizes than other serrated adenomas. SSA/P resection also
poses challenges
Identification and Resection of Sessile Serrated Adenomas/Polyps
during Routine Colonoscopy 2013 Elsevier GmbH. Sessile serrated
colon polyps (SSA/Ps) are precursors to colorectal cancer. In
comparison to adenomatous polyps, SSA/P can be challenging to
detect during colonoscopy; they are often minimally elevated, pale,
and concealed behind mucus, a colonic fold, or intraluminal debris.
Because they are typically flat, located in the right side of the
colon, the same color as the background mucosa, and have indistinct
borders, SSA/P resection also poses challenges BURKE, Carol. The
clinical importance of serrated lesions of the colorectum. Rev.
gastroenterol. Per [online]. 2013, vol.33, n.2, pp ISSN Photo of of
flat serrated polyp ( Dr. Wong Kee Song, Mayo Clinic) eFigure
15112. Small Flat Polyp: During screening colonoscopy, a small (6
mm) flat polyp was seen, the outlines of which are well
demonstrated by application of a dye (indigo carmine).
Histopathology confirmed a sessile serrated adenoma.(Used with
permission from Kenneth McQuaid, MD.) CURRENT Medical Diagnosis
& Treatment 2014 > Chapter 15. Gastrointestinal Disorders
The endoscopic appearance of an SSP is subtle
The endoscopic appearance of an SSP is subtle. The clinical
importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 They are often the same
color as the surrounding mucosa, can be covered with a layer of
mucus and have a tendency to look like a prominent fold. One study
assessing 7 endoscopic features of SSP found that nearly 50% of SSP
express a mean of 2.4 features (20). The prevalence of the
characteristic features in the study included a mucus cap (64%), a
rim of debris or bubbles (52%), a nodular surface or abnormal fold
contour (30-37%), and obscuration of surface blood vessels (32%)
(Figura 3). SSPs are usually bigger than adenomas and multiple
studies confirm that 50% are > 10 mm Cecum, 1.1 x 0.7 x 0.3
cm.--- Sessile serrated adenoma/polyp with low grade dysplasia
VGHKS Traditional serrated adenoma Gross appearance Management of
Serrated Adenomas and Hyperplastic Polyps Clin Colon Rectal Surg.
Nov 2008; 21(4): 273279. doi: /s favors a pedunculated lesion on
the left side of the colon that is easily identified on
colonoscopy. Variations in gross appearance may overlap with those
of adenomatous polyps Traditional serrated adenoma Traditional
serrated adenoma appendix VGHKS Traditional serrated adenomaThe
clinical importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 Less is known of the
rare lesion, the TSA, which is usually left sided, more polyploidy
in appearance and comprises < 0.5% of all polyps. Mixed polyp
Management of Serrated Adenomas and Hyperplastic Polyps Clin Colon
Rectal Surg. Nov 2008; 21(4): 273279. doi: /s These polyps tend to
occur in the right side of the colon, are smaller in size, and show
a predominance of BRAF mutation with MSI-H and CIMP-H profile.
Endoscopic discriminationManagement of Serrated Adenomas and
Hyperplastic Polyps Clin Colon Rectal Surg. Nov 2008; 21(4):
273279. doi: /s Endoscopic discrimination between nondysplastic HP
and SSA versus dysplastic SSA, TSA, and mixed polyp may be improved
using adjuncts to visualization of pit and capillary pattern
differences. High-definition colonoscopy with the use of indigo
carmine and narrow band imaging can help differentiate between the
starlike pit pattern and honeycomb capillary pattern of HP versus
the irregularly organized pits and elongated and dilated capillary
pattern seen in adenoma. pit pattern of SSAs Editorial: sessile
serrated adenomas and their pit patterns: we must first see the
forest through the trees. Burke CA1, Snover DC. Am J Gastroenterol
Mar;107(3): doi: /ajg A novel pit pattern, Type II-O, has been
demonstrated to have a high specificity for SSAs. Unfortunately,
the sensitivity is too low to utilize a Type II-O pit pattern to
determine which serrated lesion is neoplastic and needs resection.
Moreover, there is significant endoscopist-related variability in
the detection of serrated lesions of the colon. Efforts to improve
the detection of serrated neoplasms are warranted. pit pattern of
SSAs A Novel Pit Pattern Identifies the Precursor of Colorectal
Cancer Derived From Sessile Serrated Adenoma Am J
Gastroenterol.2012;107(3): Through retrospective analysis of a
training set (n=145), we identified a novel surface microstructure,
the Type II open-shape pit pattern (Type II-O), which was specific
to SSAs with BRAF mutation and CIMP. Subsequent prospective
analysis of an independent validation set (n=116) confirmed that
the Type II-O pattern is highly predictive of SSAs (sensitivity,
65.5%; specificity, 97.3%). A small flat hyperplastic polyp as seen
after spraying with indigo carmine SESSILE SERRATED ADNOMA Sessile
serrated adenoma/polypSSA/P NBI Sessile serrated adenoma/polypSSA/P
Indigocarmine Identification of the Type II open-shape (Type II-O)
pit pattern in sessile serrated adenomas (SSAs). (a) Colonoscopic
view of a representative SSA with (right) and without indigo
carmine dye (left). (b) Magnified views of the SSA areas indicated
by the red and yellow boxes in panel a. Left panel: the majority of
the pits are Type II-O. Right panel: the upper region is covered by
Type II-O pits, whereas the lower region is covered by conventional
Type II pits. Schematic diagrams of Type II and Type II-O pits are
shown below. (c) Histological appearance of the SSA with Type II-O
pits.Am J Gastroenterol.2012;107(3): Tomoaki Kimura MD etc.
progression of sessile serrated adenomas (SSAs) with Type II
open-shape (Type II-O pits). (a) Schematic diagram of serrated
lesions with mixed pit patterns.Am J Gastroenterol.2012;107(3):
Tomoaki Kimura MD etc. Traditional serrated adenoma, NBI Therefore,
the diagnosis of SSA/P is suggested to be performed using a
combination of endoscopic diagnosis, as well as the assessment of
tumor location and endoscopic morphology Management of Serrated
AdenomaCLINICS IN COLON AND RECTAL SURGERY/VOLUME 21, NUMBER 4
2008
A similar way to patients with conventional adenomas: lack of
evidence-based data the natural history of serrated adenoma is not
well defined. the recurrence rate and rate of progression to
carcinoma remain unknown it is clear that serrated adenomas are a
precursor to adenocarcinoma of the colon and rectum. TREATMENT OF
S.S.A. From Wikipedia, the free encyclopedia
Complete removal of a SSA is considered curative. Several SSAs
confer a higher risk of subsequently finding colorectal cancer and
warrant more frequent surveillance. The surveillance guidelines are
the same as for other colonic adenomas. The surveillance interval
is dependent on (1) the number of adenomas, (2) the size of the
adenomas, and (3) the presence of high-grade microscopic
features.[5] Recommendations for Treatment Am J Clin Pathol
2005;124:380-391
The interval from diagnosis of SSA to diagnosis of carcinoma was
greater than 3 years in 90% of cases and greater than 5 years in
55%. Given these facts and uncertainties, we recommend the
following management: Right-sided SSAs without cytologic dysplasia
(adenomatous change): RESECTABLE: ENDOSCOPIC REMOVE. NOT COMPLETELY
RESECTABLE AND CYTOLOGIC DYAPLASIA: SURGICAL EXCISION, Left-sided
lesions OF SSA
Left-sided lesions OF SSA. Recommendations for Treatment Am J Clin
Pathol 2005;124: 1. are more problematic. 2. most left-sided SSAs
are small lesions and generally are removed at biopsy. 3. For
lesions that are not completely excised, repeated endoscopy and
complete excision would b recommended. It would be hard to
recommend left-sided colectomy or an abdominoperineal resection for
such a SSA, even if it could not be resected totally,
Recommendations for Treatment Am J Clin Pathol
2005;124:380-391
It is unclear: 1. how rapidly SSA may progress to cancer and 2.what
the recurrence rate of SSA is if incompletely resected. These are
factors vital to determining 1. the appropriate treatment for
unresectable lesions and 2.the appropriate rescreening interval for
individuals who have had one or more of these lesions completely
removed. Unfortunately, hard follow-up data are lacking The
interval to repeated endoscopy Recommendations for Treatment Am J
Clin Pathol 2005;124:380-391 The clinical importance of serrated
lesions of the colorectum Rev
The clinical importance of serrated lesions of the colorectum Rev.
gastroenterol. Perv.33n.2Limaabr./jun.2013 Identification and
Resection of Sessile Serrated Adenomas/Polyps during Routine
ColonoscopyVideo Journal and Encyclopedia of GI Endoscopy Volume 1,
Issue 2, October 2013, Pages 372374 DOI: /S (13)70164-X
Retrospective Prospective Or both Quality Measures for Colonoscopy
Philip Schoenfeld, MD March 16, 2012 Note: The recommendations
assume that the baseline colonoscopy was complete and adequate and
that all visible Baseline Colonoscopy: Most Advanced Finding(s)
Recommended Surveillance Interval (years) Quality of Evidence
Supporting the Recommendation New Evidence Stronger than 2006 No
polyps 10 Moderate Yes Small (