Su1432I-SCAN Detects More Polyps in Lynch Syndrome (HNPCC)Patients: A Prospective Controlled Randomized Back-to-BackStudyRaf Bisschops*1, Sabine Tejpar1, Hilde Willekens1, Gert De Hertogh2,Eric Van Cutsem1

1Gastroenterology/Endoscopy, University Hospital UZ Leuven, Leuven,Belgium; 2Pathology, University Hospital UZ Leuven, Leuven, BelgiumBackground: Narrow-band imaging and chromo-endoscopy have been reportedto detect more polyps in comparison to (high definition) white light endoscopy(HDWL) in hereditary non-polyposis colonic cancer (HNPCC) patients in a back-to-back study. However, no randomisation for the order of imaging method wasapplied. I-scan with tone enhancement (TE) is a new form of digital chromo-endoscopy. We aimed to assess the additional value of the i-scan TE system inpolyp detection in HNPCC. Method: 49 HNPCC patients underwent a back-to-back colonoscopy (Pentax EC3890Fi) with two imaging modalities and wererandomized in 2 groups. Group 1 underwent HDWL first followed by i-scan,group 2 i-scan first followed by HDWL. For HDWL, standard settings and for iscan, the i-scan 2 preset (surface enhancement �4, TE c-modus) were used on aPentax Hi-line processor. Patients with clinical diagnosis or proven geneabnormality for HNPCC were included in the study. Patients with knownneoplasia or colectomy with � 50cm remaining colon were excluded. Bowelpreparation after PEG solution was assessed using the Bristol Bowel preparationscale (BBPS). Patients with a BBPS�6 were excluded. Total inspection time wascalculated after subtracting the time needed for polypectomy. Lesion detectionrate (total number of lesions for each method/total procedures) and the miss rate(� number of lesions/adenomas detected during second inspection/total numberof lesions/adenomas in that group) were assessed. Results: 25 and 24 patientswere included in group 1 and 2 respectively (mean age 45.3 � 1.69, 25 male).There was no difference in age or BBPS. The lesion detection rate was 0.73 �019 for i-scan and 0.36 � 0.12 for HDWL (p�0.095). In group 1, 14 lesions weredetected with HDWL first and 15 with subsequent i-scan. In group 2, 21 lesionswere detected with i-scan first and 4 with subsequent HDWL. The miss rate forendoscopic lesions was 52% and 16 % respectively and was significantly differentin favor of i-scan (p�0.01 95% CI 0.38 to 0.87). Similarly, 5 adenomas weredetected with HDWL vs 7 with i-scan in group 1. In group 2, i-scan detected 13of the 15 adenomas, resulting in a miss rate of 58% and 13% respectively(p�0.05 95% CI 0.24 to 0.96). The higher miss rate in group 1 was not due to ashorter inspection time. On the contrary, in general the second inspection timewas significantly shorter than the first one (407 � 19 vs 503 � 24 sec, p�0.01)and inspection time during the second pass was not significantly differentbetween group 1 and 2 (427 � 24 vs 384 � 32 sec resp p�0.27). Conclusion: Inpatients with HNPCC the miss rate for polyps is significantly reduced duringcolonoscopy performed with i-scan in comparison to HDWL, independently frominspection time. These findings add to the evidence that HNPCC may be a goodindication for (virtual) chromoendoscopy.

Su1433Evaluating the Process of Colonoscopy Using Systems andHuman Factors Engineering TechniquesMark E. Benson*1, Pascale Carayon2, Patrick Pfau1, Ian C. Grimes1,Kerstin E. Austin1, Mark Reichelderfer11University of Wisconsin Medical School, Madison, WI; 2University ofWisconsin Department of Engineering, Madison, WIIntroduction: Human Factors Engineering provides methods for thoroughlyevaluating the interaction between people and their environment to determinethe work system factors that influence and contribute to performance. This pilotproject was a collaboration between the University of Wisconsin Center forQuality and Productivity Improvement and its Systems Engineering Initiative forPatient Safety (CQPI/SEIPS) and the Dept of Medicine, Division ofGastroenterology and Hepatology, funded by grant 1UL1RR025011 from theClinical and Translational Science Award program of the National Center forResearch Resources, National Institutes of Health. The aim was to utilize theSEIPS model and human factors engineering tools to examine the process ofscreening colonoscopy and identify system factors that influence healthcarequality outcomes. Methods: We examined the process of screening colonoscopyusing a computer-based valid and reliable tablet PC observation tool designed bythe CQPI/SEIPS researchers. The interactive tablet PC observation tool recordedand tabulated 20 system factors involved in the process of screeningcolonoscopies including procedural outcomes, patient and physiciancharacteristics. Results: We prospectively evaluated the screening colonoscopyprocess of 52 average risk consenting patients. Of the 20 factors studied, therewas a statistically significant relationship between the endoscopist’s perceivedlevel of stress and the number of polyps detected [not stressed�0.5 polyps/patient screened vs stressed� 1.4 polyps/patient screened (P�0.03)]. Therelationships between the number of polyps detected and the other systemfactors were found not to be statistically significant. These factors included theactual busyness of the endoscopist’s schedule [easy�1.3 polyps/patient screenedvs hard�1.0 polyps/patient screened (P �0.45)], patient discomfort

[uncomfortable during the procedure�1.8 polyps/patient screened vscomfortable during the procedure�1.1 polyps/patient screened (P � 0.79)], thenumber of the procedure of the day (r �0.05 P�0.70), and the amount of non-procedure or procedure related conversation (r �0.18 P�0.28; r �0.13 P�0.37respectively). Conclusion: Human Factors Engineering methods can be used toaccurately evaluate the process of screening colonoscopy to identify systemfactors contributing to procedure and healthcare outcomes as shown in thisfunded pilot project. Interestingly, more polyps were detected when theendoscopists perceived a higher stress level. The other factors, expected toimpact procedural outcomes, were not statistically significant.

Su1434Nativity, Race-Ethnicity and the Prevalence of ColorectalNeoplasiaNneoma O. Okoronkwo*1, Chukwuma Umunakwe2, Alan Tieu1,John Kwagyan5, Hassan Brim3, Hassan Ashktorab4, Edward L. Lee3,Adeyinka O. Laiyemo2

1Howard University College of Medicine, Washington, DC; 2HowardUniversity Cancer Center, Washington, DC; 3Department of Pathology,Howard University College of Medicine, Washington, DC; 4Departmentof Medicine, Howard University College of Medicine, Washington, DC;5Center of Clinical and Translational Science, Howard UniversityCollege of Medicine, Washington, DCBackground: Colorectal cancer disproportionately affects blacks in the UnitedStates whereas the burden of colorectal cancer is low in Africa, their ancestralorigin. No previous study has evaluated the prevalence of precursors ofcolorectal cancer by place of birth. Aim: To compare the prevalence of colorectalneoplasia at colonoscopy among black and non-black patients who were foreignborn versus those born in the United States. Methods: We reviewed thecolonoscopy reports of patients who underwent colonoscopy at HowardUniversity Hospital in Washington DC from January 2009 to September 2010 andidentified 897 patients who indicated their place of birth as part of their baselineinformation. We manually abstracted the data in standard fashion. We usedlogistic regression models to evaluate the association of nativity and race-ethnicity with colorectal neoplasia and calculated odds ratios (OR) and 95%confidence intervals (CI). Results: There were 632 (70.5%) patients who wereborn in the US (mean age � 60.1 years; 59.0% female; 92.6% black) and 265(29.5%) patients who were foreign born (mean age � 59.5 years; 64.5% female;46.8% black). There was no difference in the prevalence of polyps betweenthose born in or outside the US (26.4% versus 23.8%, P � 0.41) and betweenblacks and non-blacks (26.2% versus 23.4%, P � 0.43). There was also nodifference in the prevalence of adenoma between those born in or outside theUS (11.9% versus 13.2%, P � 0.577) and between blacks and non-blacks (12.3%versus 12.2%, P � 0.989). After adjusting for age, sex, body mass index and useof non steroidal anti-inflammatory drugs, there was no difference in theprevalence of adenoma by place of birth whether patients were black or not.Conclusion: We did not find any association between place of birth and theprevalence colorectal neoplasia regardless of race-ethnicity. This suggests anenvironmental etiology for the increased susceptibility to colorectal cancer thatoccurs with migration.

Association of colorectal adenoma by place of birth and race-ethnicity

Among blacks Among non-blacks

Place ofbirth

% withadenoma OR (95% CI)

% withadenoma OR (95% CI)

Foreign-born 14.5 Ref 12.1 RefUS-born 11.8 0.78 (0.44–1.36) 12.8 0.58

(0.19–1.79)

Adjusted for age, sex, body mass index and use of non steroidal anti-inflammatorydrugs.

Su1435Predictors of Incomplete Endoscopic Resection (EMR) of theLarge (2cm or More) Colon Polyps: Analysis of LargeProspectively Collected EMR DatabaseMihir K. Patel*, Bashar Qumseya, Cynthia Rizk, Ernest P. Bouras,Massimo Raimondo, Michael B. Wallace, Timothy A. WoodwardGastroenterology and Hepatology, Mayo Clinic, Jacksonville, FLIntroduction: Endoscopic technically challenging procedure to remove largecolon polyp or superficial colon mass. Predictors of the incomplete EMR(endomucosal resection) have not been well studied in large (2cm or more)colon polyps. Aim: To determine the various predictors of incomplete removal oflarge colon polyp during EMR. Method: We reviewed our large prospectively

Abstracts

www.giejournal.org Volume 75, No. 4S : 2012 GASTROINTESTINAL ENDOSCOPY AB330