T1883

Detection of High-Grade Dysplasia and Esophageal Adenocarcinoma UsingEndoscopic Mucosal Resection in Combination with Fluorescence in SituHybridizationWytske Westra, Ganapathy A. Prasad, Kevin C. Halling, Shannon M. Brankley, Emily BarrFritcher, Trynda N. Oberg, Jesse S. Voss, Michael B. Campion, Navtej Buttar, Louis-Michel Wong Kee Song, Lori S. Lutzke, Kelly T. Dunagan, Lynn S. Borkenhagen,Agnieszka M. Rygiel, Kausilia K. Krishnadath, Kenneth K. Wang

BACKGROUND: Barrett's esophagus (BE) is a premalignant condition of the distal esophagusthat predisposes to esophageal adenocarcinoma (EAC). Progression of BE to cancer is aprocess that is characterized by increasing dysplasia grade and accumulation of severalgenetic abnormalities. Surveillance endoscopy with biopsies is recommended but this is timeconsuming and not cost-efficient. More importantly, focal areas with HGD still can bemissed. Our hypothesis is that histological assessment of visible lesions in combination withfluorescence in situ hybridization (FISH) cytology is superior to the current strategy ofrandom biopsies AIM: The aim of this study was to determine if endoscopic mucosal resection(EMR) of visible lesions and FISH for assessment of genetic abnormalities is a more sensitiveapproach to detect HGD/EAC then random biopsies alone. METHODS: A prospective cohortstudy was done in which EMR and FISH were initially performed, followed by 4-quadrantbiopsies every centimetre. Multi-color FISH using a panel of 12 DNA probes for p16, CEP9, hTERT, APC, CEP Y, Her2Neu, CEP 17, p53, 20q, c-myc, CEP 7 and EGFR was appliedto assess cytogenetic abnormalities (gains and losses) in BE brush cytology specimens. FISHwas considered positive if ≥ 1 marker was abnormal according to previously establishedcut-off values. RESULTS: A total of 90 cases with a previous diagnosis of HGD were assessed.EMR and biopsies showed EAC/HGD in 60/90 (67 %) and 41/90 (46 %) respectively.Targeted EMR and biopsies agreed on EAC/HGD versus low-grade dysplasia /intestinalmetaplasia/squamous in 61/90 (68%) of EMRs. Thus, EMR and biopsy results were discordantin 29/90 (32%) of cases. EMR classified 30/90 (33 %) cases as LGD/IM/squamous, comparedto 49/90 (54 %) by biopsies. In 24 of the discordant cases, EAC/HGD was detected by EMRbut missed by biopsies. Only five cases with HGD/EAC by biopsy were misclassified byEMR and all were positive by FISH with gain of at least seven probes. Interestingly, FISHwas also positive in 10 cases that were not positive by EMR or biopsy. Three of these casesdeveloped HGD/EAC on follow up, two had 9p loss, one had CEP Y loss as their onlyabnormality. CONCLUSION: This study shows that a combination of targeted EMR andFISH on brush cytology is superior in diagnosing EAC/HGD compared to biopsies per Seattleprotocol alone. It also indicates that a positive FISH, especially in the light of a previousdiagnosis of HGD has predictive value and cannot be discarded as a false positive resultwithout further follow-up. Further investigation is needed to confirm the results of thisstudy and to determine long term outcome.

T1884

Temporal Trends in Patients Newly Diagnosed with Barrett's Esophagus in aSingle-Center Cohort, 1997-2007Patrick S. Yachimski, Rebecca A. Lee, Angela Tramontano, Norman S. Nishioka, ChinHur

Introduction: It is not known whether there have been recent changes in demographicor clinical characteristics among patients newly diagnosed with Barrett's esophagus (BE).Characteristics such as age at diagnosis or body mass index (BMI) could have implicationsfor surveillance and management strategies. The aim of this study was to determine whetherthere has been a change in age at diagnosis of BE, or shift in other demographic andendoscopic characteristics over the past decade. Methods: The study was performed at atertiary medical center. An endoscopy database was used to identify all EGDs performedbetween 1997 and 2007. The cohort was restricted to patients with newly diagnosed BE.Patients with a prior diagnosis of BE, including those referred for staging or therapy of BE,were excluded. For patients who underwent multiple EGDs, only the index EGD wasincluded. Pathology records were reviewed to confirm biopsy findings of intestinal metaplasia(IM). Further data were obtained from the medical record. Results: BE was reported as afinding in 1349 EGDs in the period 1997-2007. Excluding cases of multiple EGDs, caseswith prior diagnosis of BE, and cases without biopsy confirmation of IM, the final cohortconsisted of 379 subjects. 79% of subjects were male, and 92% were Caucasian. Mean ageat diagnosis of BE was 60.6 ± 14.1 yrs, with mean BMI of 27.4 ± 5.2 and mean BE lengthof 4.7 ± 3.7 cm at diagnosis. Between 1997 and 2007 there was no significant change inmean age at diagnosis (P=0.88 by ANOVA), BMI (P=0.24 by ANOVA), length BE (P=0.57by ANOVA), or in proportion of men vs women newly diagnosed (P=0.45 by Chi square).Rates of prevalent pathology were as follows: 86% (327/379) had IM alone, 7% (26/379)had biopsies indefinite for dysplasia, 2% (9/379) had low grade dysplasia, 1% (4/379) hadhigh grade dysplasia, 1% (4/379) had intramucosal carcinoma, and 2% (9/379) had invasiveadenocarcinoma. In comparing men and women, there was no difference in age at diagnosis(59.9 vs 62.2 yrs, P=0.14), BMI (27.4 vs 27.5, P=0.90), or length of BE (4.8 vs 4.4 cm, P=0.39), although rates of prevalent dysplasia/cancer were higher in men than women (6% vs1%, P=0.03). Conclusions: Despite an increase in the number of EGDs performed in anopen access endoscopy unit from 1997 - 2007, there was no appreciable change in age atdiagnosis of BE. BMI among newly diagnosed patients also remained stable over this timeperiod. Rates of prevalent dysplasia/cancer at diagnosis of BE were low, and particularlyuncommon among women. The results of this study may be used to further tailor screeningstrategies for BE.

A-593 AGA Abstracts

T1885

Interobserver Variability in the Diagnosis of Crypt Dysplasia in Barrett'sEsophagusDominique Coco, John R. Goldblum, Jason L. Hornick, Gregory Y. Lauwers, Elizabeth A.Montgomery, Amitabh Srivastava, Helen H. Wang, Robert D. Odze

Background: Recent clinic and DNA content (by image cytometry) studies suggest thatdysplasia developing in Barrett's esophagus (BE) begins in the crypt bases [”crypt dysplasia”(CD)] and extends to the surface epithelium with progression. In some patients, CD isidentified in biopsy specimens prior to the development of traditional low or high-gradedysplasia. To date, the diagnostic reproducibility of CD, which is an important step if futurebiology and natural history studies are to be performed accurately, has not been evaluated.The aim of this study was to evaluate the interobserver reproducibility of diagnosing CDamong gastrointestinal pathologists with research interest in BE. Design: Glass slides of 40routinely processed H&E stained mucosal biopsies of BE and related neoplasms [10 BEwithout dysplasia, 9 CD, 10 low-grade dysplasia (LGD), 9 high-grade dysplasia (HGD), and2 intramucosal adenocarcinoma (IMCa) diagnosed by the index pathologist] were selectedby two of the investigators (DPC, RDO), and sent to 5 other GI pathologists for a blindedevaluation of the grade of neoplasia. Prior to the slide review, investigators were providedwith diagnostic criteria for CD, LGD, and HGD. Analysis was performed by Kappa statistics.Results: The overall Kappa value for interobserver agreement in the entire case cohort wasmoderate (K=0.44). The degree of agreement was highest for IMCa (K=0.65) and BE withoutdysplasia (K=0.57) and lowest for LGD (K=0.31). Notably, no significant differences wereobserved in the degree of reproducibility in the diagnosis of CD (K=0.44) compared to LGD(K=0.31) or HGD (K=0.46). Of the 9 cases of CD, all 6 observers agreed in 22% of thecases with at least 5 observers agreeing in 33% and at least 4 observers agreeing in 78% ofthe cases. In general, when there was a disagreement with the index pathologist regardinga diagnosis of CD (n=17/45 readings), the majority diagnosed either LGD or HGD ratherthan BE without dysplasia. Conclusions: The level of agreement for a diagnosis of CD wasmoderate and similar to that observed for other grades of dysplasia, both in this study andin previous interobserver reproducibility studies in BE. Thus, similar to LGD and HGD,there is sufficient interobserver agreement to perform further biology and natural historystudies to elucidate the role of CD in the pathogenesis of cancer in BE.

T1886

Effect of Barryx Halo Radiofrequency Ablation Treatment On mRNA GeneExpression in Barrett's Esophagus with DysplasiaReginald V. N. Lord, Araluen Freeman, Natalia K. Botelho, Antony R. Wettstein, Naser El-Hammuri, Angelique Levert-Mignon, Sarah J. Lord

Background: The neosquamous mucosa that replaces Barrett's esophagus (BE) mucosa afterendoscopic radiofrequency ablation (RFA) is endoscopically and microscopically similar tonormal squamous epithelium, but whether it has a similar gene expression profile has not beenreported. Methods: We compared mRNA expression of 40 genes shown to be differentiallyexpressed in BE in 10 consecutive patients with dysplastic BE (9 LGD, 1 HGD) before andafter RFA and in 5 controls individuals without GERD. mRNA expression was measuredfrom formalin-fixed, paraffin embedded endoscopic biopsy tissues from the distal oesophagususing a multiplex tandem PCR method. Post-treatment biopsies were from the neosquamousmucosa replacing BE or from residual BE. Results: Seven of 10 patients had no evidence ofBE after RFA with normal squamous esophagus or mild inflammation on biopsy. Islands ofIM (2 patients) or LGD (1 patient) remained in the other patients. Expression levels variedwidely between subjects for some genes. Expression levels in the neosquamous mucosa werenot significantly different to normal esophagus from control patients for any gene (Mann-Whitney test). A mean five-fold or greater decrease after RFA was detected in TERT (telomer-ase), MMP1, TSPAN 1 and 8 and GDF15 - genes known to have increased expression inBE; and a mean five-fold or greater increase was detected in expression of RAR-gamma,SERPINB2, GSTP1 - genes known to be downregulated in BE. Of these, TERT, GDF15, andMMP1were significantly differentially expressed pre- versus post-treatment (Wilcoxon pairedtest). The gene expression profile in pre-RFA BE and post-RFA residual BE was not signific-antly different for any gene. Conclusions: The neosquamous mucosa after RFA treatmenthas a gene expression profile that is significantly different to pre-treatment BE and is moresimilar to that found in normal squamous mucosa from control individuals without GERD.The residual BE after RFA treatment still has a Barrett's-like expression profile, indicatingthat all the BE segment should ideally be eradicated. These conclusions are limited by thesmall patient numbers and wide between-patient variability in expression changes, andpatients should remain in surveillance after ablation.

T1887

Development of Biomarkers for Non-Endoscopic Screening for Barrett'sEsophagusSudarshan R. Kadri, Madhumita Das, Pierre Lao-Sirieix, Maria O'Donovan, IreneDebiram, Rebecca C. Fitzgerald

INTRODUCTION: Screening for Barrett's esophagus (BE) may be key to reducing thenumber of patients presenting de novo with incurable oesophageal adenocarcinoma. Wehave developed a non-endoscopic screening test whereby the esophagus is sampled usinga sponge contained within a gelatine capsule and the specimen is stained for immunohistoch-emical markers since cytology alone is insufficient to discriminate columnar cells from thegastric cardia and BE. AIMS & METHODS: The aim of the study was to validate a panelof biomarkers to identify the optimal combination for diagnosis of BE. The biomarkers usedwere alcian blue as a marker of intestinal metaplasia, trefoil factor 3 (TFF3) (Lao-Sirieix,2008a) and minichromosome maintenance proteins (Mcm) (Lao-Sirieix, 2008b) which hadpreviously been shown to be useful. We compared a number of Mcm antibodies: ProExC(toposisomerase 2 and Mcm2, Tripath, BD Diagnostic), Mcm2 and 7 (Tripath) and an inhouse Mcm2). Patients with known BE (n=26) and endoscopy confirmed BE negative patients(n=25) were recruited to the study. The samples from patients who swallowed the capsule

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