Abstracts

alternate pathway to malignancy, a significant number of SSPs are still misclassifiedas benign HPs. This occurs more commonly in the right colon than in the left colonand often leads to inappropriate surveillance recommendations. Accurate identifi-cation of SSPs is a critical element of an effective colon cancer screening program,and this study highlights the need for improved recognition of the histologicappearance of SSPs.

Tu1413Increased Risk of Advanced Serrated Polyps and Colorectal Cancerin Patients With Serrated Polyposis: an Observational Case-Control StudyEstanislao J. GóMez*1, Lisandro Pereyra1, Raquel GonzáLez1,Carolina Fischer1, José M. Mella1, Mariana Omodeo1,Guillermo N. Panigadi1, Marcelo F. Amante2, Gabriel Casas2,Silvia C. Pedreira1, Daniel G. Cimmino1, Luis a. Boerr11Gastroenterology and Endoscopy Unit, Hospital Alemán, Buenos Aires,Argentina; 2Pathology, Hospital Alemán, Buenos Aires, ArgentinaIntroduction: Serrated polyposis syndrome (SPS) is a rare disease characterized bythe presence of multiple serrated polyps in the colon. Small case series have sug-gested a high prevalence of colorectal cancer (CRC). The risk of colorectal neoplasiain these patients compared with those with sporadic sessile serrated adenomas(SSA) has not well evaluated. Aim: To compare the risk of advanced serrated polyps(ASP) and CRC in patients with SPS and SSA. Methods: Clinical records of patientswho met the WHO diagnostic criteria for SPS between Aug 2007 and Oct 2013 wereretrospectively analyzed. In order to perform a case-control study, patients withsporadic SSA were randomly selected during the same period. Patients with SPSwere regarded as "cases" and patients with sporadic SSA as "controls". The risk ofconventional adenomas, advanced neoplastic lesions (ANL: villous component R75%, size R 10 mm, or high grade dysplasia), ASP (cytological high grade dysplasiaor size R 10 mm) and CRC was assessed. Univariate analysis was performed usingFisher’s test for dichotomous variables. We considered results to be significant if theP value was! 0.05. Results: 120 patients were analyzed: 30 with SPS (cases) and 90with sporadic SSA (controls). There were no significant differences regarding to: ageat diagnosis [SPS (59.9 years; SD+10; range 36-78) vs. SSA (61 years; SD +12; range30-89); P: 0.66)], female [SPS (63%) vs. SSA (54%); P: 0.42)] or BMIO25 [SPS (53%)vs. SSA (55%); P: 0.8)]. Smoking status [SPS (50%) vs. SSA (28%); P: 0.04, OR 2,6 CI1,02-6,64], and first-grade CRC family history [SPS (23%) vs. SSA (8%); P: 0.04, OR3,6 CI 1,01-13,04] were more frequent in patients with SPS. The presence of hy-perplastic polyps (53% vs. 25%; P: 0.007, OR 3,2 CI 1,3-8,6) on index colonoscopywas also more frequent in patients with SPS, but we found no difference withrespect to the presence of at least a traditional serrated adenoma (13% vs. 3%; P:0.06), conventional adenoma (43% vs. 38%; P: 0.6) or ANL (17% vs. 9%; P: 0.3). Therisk of SSA R 10 mm (73% vs. 19%; P: 0.000, OR 11,81 CI 4,1-35,1), SSA withcytological high grade dysplasia (13% vs. 2%; P: 0.03, OR 6,77 CI Inf-56,96), ASP (7%vs. 22%; P: 0.000, OR 9,62 CI 3,41-28) and CRC (10% vs. 1.1%; P: 0.048, OR 9,89 CIInf-258) was higher in patients with SPS than in sporadic SSA subjects. Colectomywas also more frequently performed in patients with SPS (23% Vs. 3%; P: 0.002, OR8,83 CI 1,84-47,4). Conclusion: We found a higher risk of advanced serrated polypsand CRC in patients with SPS. Our data suggest the need for better detection ofserrated lesions and awareness of SPS in screening programs.

Tu1414High Prevalence of Serrated Polyps At Screening ColonoscopyIndicates Their Potential Use As Quality IndicatorPhilipp Steininger*, Viktoria Winna, David Allerstorfer, Michael HaefnerKH St. Elisabeth Vienna, Vienna, AustriaIntroduction: Colonoscopy has a central role in detection and prevention of colo-rectal carcinoma (CRC). Recent studies have raised concerns, that screening colo-noscopy may not decrease CRC prevalence and mortality in the proximal colon inthe same extent as in the distal colon [1-5]. Serrated polyps as a precursor lesion tocolorectal carcinoma are especially in the proximal colon a diagnostic challenge.Including hyperplastic polyps, sessile serrated adenomas and traditional serratedadenomas, serrated polyps may play an important role in right sided carcinomadevelopment [7-8]. In european quality standards for colonoscopy there are nocertain recommendations concerning proximal serrated polyps, as adenoma detec-tion rate or cecal intubation rate are at the moment [6]. Methods: In our study weanalyzed all screening colonoscopies from three experienced gastroenterologists atour hospital for the prevalence and localisation of serrated polyps. In addition weregistered the polyp- and adenoma detection rate and the cecal intubation rate.Results: In the period of January 2011 until April 2012 862 colonoscopies were per-formed. Mean patient age was 65,49 years. In more than 95% of the investigationscecal intubation succeded. The mean polyp detection rate was 58,54% (SD �4%),the mean adenoma detection rate was 45,72% (SD �7,5%). In 36,27% (SD �6,94%)of all colonoscopies a polyp and in 12,72% (SD �3,87%) a serrated polyp has beendetected proximal to the splenic flexure. 45% of all serrated polyps were locatedproximal and 55% distal to the splenic flexure. Discussion: Due to recent studies35% of detected CRC colon carcinoma is linked to the serrated pathway [7-8]. As

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from other authors recently reported, serrated polyps have a higher prevalence asusually suspected [6]. Due to our findings a recommendation for detection rate ofserrated polyps in european colonoscopy quality control should be discussed as it iswith adenoma detection rate or cecal intubation rate. Looking at our results, aserrated polyp detection rate of 5% can be realistic.

Tu1415Comparison of Complication Risk for Endoscopic Removal ofSerrated Polyps and Adenomas; an Observational AnalysisJoep E. Ijspeert*, Yark Hazewinkel, Barbara a. Bastiaansen,Sascha C. Van Doorn, Kristien M. Tytgat, Paul Fockens, Evelien Dekkergastroenterology and hepatology, Academical Medical Centre,Amsterdam, NetherlandsBackground: Apart from the adenoma-carcinoma pathway, evidence for an alterna-tive serrated pathway, in which serrated polyps (SPs) develop into colorectal can-cer, has accumulated. For this reason international guidelines now support removalof large (R5mm) and/or right-sided SPs. Most SPs have a flat or sessile morphologyand are located in the right-sided colon. Therefore the complication risk for poly-pectomy of SPs might be relatively high, raising concerns about aggressive removalof SPs. Aim: To evaluate the complication risk and risk factors in endoscopic removalof SPs compared to adenomas (ADs). Methods: Patient and polyp characteristicswere gathered from two colonoscopy databases: 1) colonoscopies performed since2007 in a prospective follow-up cohort of patients with serrated polyposis syndrome(SPS) in an academic hospital and 2) colonoscopies performed since 2011 in pa-tients referred for symptoms or surveillance in a private colonoscopy centre. Allcolonoscopies were performed by gastroenterologists or senior fellows under su-pervision. Data were linked to a national database for prospective registration of 30-day post-colonoscopy complications. The occurrence of complications was verifiedby use of a post-colonoscopy telephone consult. A complication was defined as aperforation or post-procedure bleeding resulting in additional patient-care, hospitaladmission, blood transfusion or re-colonoscopy. Primary endpoint was the risk ofcomplications after the removal of SPs compared to ADs. Secondary endpoint wasevaluation of potential risk factors for complications: proximal colonic location,polyp size and morphology, removal technique and polypectomy in patients withSPS. Results: 1725 ADs and 2536 SPs were removed during 1277 colonoscopies, in92 SPS patients and 960 patients with various referral indications. Equal proportionsof ADs and SPs were R10mm. ADs were more often located in the proximal colonthan SPs, but for polyps R10mm the opposite applies (Figure 1). In total 7 com-plications were observed. The overall (per polyp) complication incidence was0.002%. The complication incidence for polyps R10mm was 0.02%. All complica-tions were post-polypectomy bleedings. 3 patients were conservatively treated at theoutpatient clinic and 4 patients were admitted for one day. In one patient a re-co-lonoscopy was performed. No blood transfusions were given. No perforationsoccurred. Chi-square analysis showed no difference in complication risk betweenpolypectomy of SPs or ADs. Size R10mm was correlated with an increased risk forcomplications (Figure 2). Conclusion: In a mixed patient population, the polypec-tomy complication incidence of both SPs and ADs was low and comparable. Endo-scopic removal of SPs is safe and should not be an obstacle in pursuing guidelines.

Table 1. Characteristics of all polyps in the study

ume 79, No. 5S : 2014

SPs (%)

GASTROI

ADs (%)

NTESTINA

P-value

L ENDO

RR

SCOPY

95% CI

Polyp number

2536 1725 Proximal colon location 1220 (48.1) 1022 (59.2) !0.001 0.81 0.77-0.86 Size R10mm 241 (9.5) 152 (8.8) 0.44 1.08 0.89-1.31 Proximal colon location

of polyps R10mm

201 (83.4) 68 (44.7) !0.001 1.86 1.55-2.24

AB423

Abstracts

AB424 GASTROINTESTI

SPs (%)

NAL ENDO

ADs (%)

SCOPY V

P-value

olume

RR

79, No.

95% CI

Morphology PedunculatedSessile Flat

29 (2.0)1262(80.6)274(17.4)

214(14.2)1210(80.5)79 (5.3)

!0.0010.93

!0.001

0.111.00 3.33

0.07-0.170.97-1.042.62-4.23

Removaltechnique Snare polypectomyLift and snare Forceps

505(23.9)693(32.8)

918 (43.3)

680 (40.9)351 (21.2)630 (37.9)

!0.001!0.0010.001

0.131.551.14

0.09-0.191.39-1.731.06-1.24

Table 2. Risk analysis for polypectomy complications per polyp

RR

95% CI P-value

Histology (SP vs. AD)

0.41 0.10-1.71 0.22 Colon location (proximal vs. distal) 1.50 0.36-6.27 0.58 Size (R10mm vs.!10mm) 16.40 3.93-68.38 !0.001 Morphology (non- vs. pedunculated) 0.60 0.07-4.90 0.64 Removal technique (snare vs. forceps) 0.93 0.21-4.14 0.92 SPS vs. non-SPS patients 1.05 0.26-4.20 0.94

Tu1416Sessile Serrated Polyp Detection Rate in a Large CommunityPractice As a Potential Quality Indicator for ColonscopyCarson Keck*1, Mudit Chowdhary1, Matthew N. Varn1, Minh Hang1,Ali Keshavarzian2, Shahriar Sedghi11Mercer University School of Medicine, Macon, GA; 2Rush UniversityMedical Center, Chicago, ILBackground: Adenoma detection rate is currently being used as one of the qualitymeasures in colonoscopy performance. However, this criterion may be flawedbecause a high initial detection rate may subsequently lead to a lower detection rateduring follow-up surveillance. We propose that sessile serrated polyp detection rate(SSPDR) may be a better quality measure as these polyps are harder to detect, have ahigher potential risk for malignancy, and may recur more rapidly. Furthermore, forthe same reason, SSPDR may be better in comparing detection sensitivity betweencolonoscopy and emerging technologies such as virtual colonoscopy and capsuletechnology. Surprisingly, there is scant information regarding SSPDR and thesestudies show a variable detection rate, which may be due to inconsistent patho-logical diagnostic criteria. Objective: The aim of our study was to compare theSSPDR with the adenoma detection rate (ADR) in approximately 13,000 patients at alarge outpatient center with multiple physicians over a 2-year period. Additionally,the colon withdrawal time in minutes was compared to SSPDR and ADR. Methods:This was a comparative, retrospective study in which 277 patients had an SSP de-tected during colonoscopy over a 2-year span. The ADR and the SSPDR werecalculated for each physician and for the practice as a whole. A Pearson’s correlationcoefficient was then calculated between the SSPDR and the ADR. The averagewithdrawal time for each doctor was calculated and a Pearson’s correlation coeffi-cient was computed between the withdrawal times and both the sessile serratedpolyp and adenoma detection rates. Results: The mean adenoma detection rate was25.64 and the mean sessile serrated polyp rate was 1.95. The mean withdrawal timewas recorded as 9.73 minutes (See Table 1). The Pearson’s correlation coefficientbetween the ADR and SSPDR was RZ 0.756. Analysis of the SSPDR and withdrawaltime revealed an R value of -0.141. An R value of 0.024 was calculated reflecting thecorrelation between ADR and withdrawal time. Conclusion: Statistical analysis re-vealed a positive correlation between ADP and SSPDR. A slight negative correlationwas identified between the SSR detection rate and withdrawal time. This may reflectoverall physician experience rather than withdrawal time alone. The low variance forSSPDR in our study may signify that detection of sessile serrated polyps may proveto be a more consistent quality measure than ADR. However, we recommendfurther studies to classify SSPDR as a quality measure as opposed to or in addition toADR. If SSP detection is a more accurate quality measure, further studies would beneeded to assess this in follow up surveillance colonoscopies. It would also bebeneficial to compare sensitivity of SSPDR via colonoscopy and virtual colonoscopyand other emerging technologies.

Table 1

SSP Detection Rate

Adenoma

Detection Rate

Withdrawal

Time (minutes)

Mean

1.95 25.64 9.73 Variance 0.33 7.15 2.70 Standard Deviation 0.57 2.67 1.64 Standard Error 0.21 1.02 0.62

5S : 2014

Tu1417Prevalence of Serrated Adenomas: Experience in a Large VolumeCentre in ArgentinaEugenia Del Cantare*1, Ricardo F. Figueredo1, Sandra Canseco1,Mauricio Fuster1, Patricio Sheridan1, Jorge E. Bosch1, Alejandra Avagnina3,Boris Elsner4, Santiago De Elizalde2, Carolina Bolino1, Luis E. Caro1,Cecilio L. Cerisoli11Gedyt, Buenos Aires, Argentina; 2Laboratorio de Anatomia Patologica,Buenos Aires, Argentina; 3Centro de Patologia Dr. Elsner, Buenos Aires,Argentina; 4CEMIC, Buenos Aires, ArgentinaIntroduction: Serrated adenomas (SA) evolve to Colorectal Cancer (CRC) in15-20% through the serrated pathway. The prevalence is variable (0.8 to13%) because some lesions are unseen even in case of experienced endo-scopists. Objectives: 1. To estimate the prevalence of SA. 2. To describe theirendoscopic and histological characteristics. Materials and methods: AdultsR 18years who performed videocolonoscopy (VCC) were included consecutively.Anticoagulation, incomplete studies, insufficient colon cleaning (Boston scale!6), high risk for CRC except for Inflammatory Bowel Disease were exclu-sion criteria. The study was conducted in an outpatient gastroenterologyclinic between November, 2012 and April, 2013. Design: descriptive, pro-spective and cross sectional study. The VCC were performed under sedationwith Olympus equipment and by trained operators. Colon cleansing was donewith polyethylene glycol or phosphates, with / without bisacodyl. The lesionswere resected according to current practice. Histological evaluation wasperformed according to the World Health Organization criteria includingSessile Serrated Adenomas (P / SSA), the P / SSA with dysplasia and Tradi-tional Serrated Adenomas (TSA). Age, gender and risk factors for CRC wereevaluated as confounding variables. Ethics: The protocol was approved by thelocal IRB. Statistical analysis: VCCstat 2.0. package, 95%CI; Chi square test.Results: We reviewed 3052 VCC; 316 were excluded and 2736 were analyzed.58% (1584/2736) were female, mean age: 56 � 12.6 years (range 20-93).According to CRC risk, 4 groups were established: No risk: 18.45%, average:58.9%, moderate: 21.8%, and high: 0.85%. 73% had no lesions. 100 polypswere recorded in 75 patients. No differences were observed between R50and!50 years and between genders (p Z ns). A higher prevalence of SA wasobserved in patients with moderate risk (p Z 0.0048) and there was a ten-dency that these lesions were more prevalent at average risk group (p Z0.0684) 1. The prevalence of SA was 2.7% (95%CI 2.2-3.4). 2. Most prevalentendoscopic features are detailed in the table. P/SSA were prevalent in 87%(95%CI 78-92) followed by P/SSA with dysplasia 13% (95%CI 7-21); all theselatter lesions had Low Grade Dysplasia. Conclusions: In this sample, theprevalence of SA was low and SSA without dysplasia were predominant. Mostof these lesions, regardless the dysplasia, were similar in size andmorphology but differed in the location; P/SSA were more prevalent in rectosigmoid, followed by proximal colon and transverse, and P/SSA with dysplasiawere more prevalent in transverse followed by proximal colon and rectosig-moid. This data should warn endoscopists to emphasize the importance ofcolonic cleansing and rigorous evaluation of right and transverse colon.

Predominant endoscopic and histologic features of SA

Histological andendoscopic features

P/SSA (n:87)

www

P/SSA withdysplasia(n:13)

n

% 95CI n % 95CI

Size (mm)

6-9 50 57,5 (46-67) 9

.giejo

69,2 (38-90)

Morphology Is 50 57,5 (46-67) 8 61,5 (31-86) Location Transverse - - 6 46,2 (19-74)

Recto sigmoid

32 36,8 (27-48) - -

Tu1418Risk Factors for Dysplasia in Sessile Serrated Adenomas/ PolypsLeonardo C. Duraes*, David Liska, Matthew F. Kalady, James M. ChurchColorectal Surgery, Cleveland Clinic Foundation, Cleveland, OHPurpose: Serrated lesions of the colorectum are the precursors of about one-third of colorectal cancers. The World Health Organization (WHO) classifi-cation of serrated colorectal polyps includes hyperplastic polyps, sessileserrated adenomas / polyps (SSA/P) with or without dysplasia, and traditionalserrated adenomas (TSA). Among these lesions, SSA/P with dysplasia is themain precursor of carcinoma. The development of dysplasia in SSA/P hasbeen linked to promoter methylation of MLH and microsatellite instability.Unfortunately, little is known about clinical factors that may predict dysplasiain SSA/P, and thus identifying patients at risk is difficult. The aim of thisstudy was to identify factors that may predict dysplasia in SSA/P. Methods: Asingle colonoscopist database was queried to identify patients with

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