Abstracts

tertiary care center. Subjects with a biopsy proven diagnosis of SCCa or AC of therectum or anal canal were included for analysis. EUS staging of depth of invasion andnodal status were compared to CT and to surgical specimen when available. Results:204 patients were identified in sequential fashion, of which 172 were forstaging of a new lesion. 9 (4.4%) and 133 (65.2%) of those patients wereconfirmed by pathology to have SCC and AC, respectively. The mean age fordiagnosis of SCC was 58.7�11.5 and 57.0�14.7, with mean distance of thelesion from the anal verge of 4.9�7.9cm and 5.6�4.1, respectively. Lower EUSidentified anal sphincter involvement in 44.4% of these lesions. [Table 1] Therewere no adverse events associated with EUS. Data were analyzed for inter-procedural agreement regarding the detection of suspicious lymph nodes be-tween EUS and CT utilizing kappa statistic; for those with SCC kZ0.73 (pZ0.02), and those with AC kZ0.18 (pZ0.22). Conclusion: This study supports therole of EUS in the staging of anal SCC, where the depth of invasion of an endo-phytic lesion and nodal involvement are paramount in determining treatment andprognosis. Similarly, this study has confirmed the ability of EUS to identify inva-sion of the anal sphincter. Whereas this study showed only slight agreement innodal evaluation in rectal AC, it demonstrates substantial agreement in detectingsuspicious lymph nodes by EUS and CT for the staging of SCC of the anal canal.Further study is required; as surgical interventions become more precise, use ofEUS in anorectal SCC may ultimately alter surgical approach improve operativeoutcomes.

Summary of descriptive data

Characteristic

AB298 GASTROINTESTINAL ENDOSCO

SCC (%)

PY Volume 79, No.

AC (%)

Male Gender

55.6 63.3 Anal Sphincter Involvement 44.4 12.2 Prostate Involvement 11.1 2.0 Suspicious LN on EUS 22.2 50.0 Suspicious LN on CT 33.3 40.0 LN Sampled 66.7 34.5 Radial utilized 100 87.5 CLA (Linear) utilized 50 31.3 Probe utilized 0 2.1 CT 100 100 PET 77.8 63.3 T stage (0) 0 6.1 T stage (1) 11.1 10.2 T stage (2) 33.3 8.2 T stage (3) 33.3 73.5 T stage (4) 22.2 2.0

Mo1354Low Mechanical Index Contrast-EnhancedEndoscopic Ultrasound for Quantitative Assessmentof Tumour Perfusion in Colorectal Cancer Patients:Preliminary StudyTatiana Cartana*1, Lene Brink2, Costin T. Streba1, Daniel Pirici3,Dan Ionut Gheonea1, Irina F. Cherciu1, John G. Karstensen2,Adrian Saftoiu1,2, Peter Vilmann2, Gabriel Gruionu1,41Research Center of Gastroenterology and Hepatology, University ofMedicine and Pharmacy of Craiova, Craiova, Romania;2Gastrointestinal Unit, Copenhagen University Hospital Herlev,Copenhagen, Denmark; 3Department of Histology, University ofMedicine and Pharmacy of Craiova, Craiova, Romania; 4SteeleLaboratory of Tumor Biology, Massachusetts General Hospital, HarvardMedical School, Boston, MAIntroduction: Contrast enhanced ultrasound is an already established and valuableimaging technique with increasing clinical applications. Furthermore contrastenhanced endoscopic ultrasound (CE-EUS) benefits from a higher imaging reso-lution that enables minimally invasive assessment of tumour perfusion. Despiterecent technology advancements, the use of CE-EUS in the evaluation of colo-rectal cancer (CRC) has not been previously reported. Aim & Methods: Thereforethe aim of our study was to evaluate tumour vascularity in CRC by using CE-EUSand to describe time intensity curve parameters for these tumors in relation todifferent clinical and pathological features. We prospectively included 40 patientswith CRC that were examined by low mechanical index (0.2) CE-EUS prior to anytherapy, using as a contrast agent 4.8 ml of Sonovue (Bracco, Italy) administeredin bolus injection. Offline analysis of the recorded video sequences was per-formed with specific software (VueBox�, Bracco) and several parameters weredetermined based on time intensity curves (TIC), including peak enhancement(PE), rise time (RT), mean transit time (mTT), time to peak (TTP) and area underthe curve (AUC). Results: CE-EUS examination showed that most of the tumourswere well vascularized, with either homogenous uptake of the contrast agent orinhomogeneous enhancement resulting from stronger peripheral uptake and

5S : 2014

avascular areas towards the intestinal lumen, with the latter pattern mostfrequently seen in advanced tumors (T3, T4). Only 6 (15%) of the colorectal tu-mors were hypoenhancing. The mean values (� SE) for TIC parameters were:51.93 � 20.46 a.u. for PE, 7.49 � 1.18 s for RT, 76.52 � 22.39 s for mTT, 9.76 �1.30 s for TTP and 889.39 � 466.94 a.u.*s for the area under the curve (AUC).Conclusion: The assessment of intratumoral perfusion in colorectal cancer ispossible with low mechanical index CE-EUS examination and TIC analysis. Inthe future this imaging method could be used to predict the response to targetedantiangiogenic therapies or to follow-up intratumoral drug distribution, based onfurther investigation and validation on larger groups of patients which willimprove the examination technique and define its actual role in the evaluation ofCRC patients.

Mo1355Prognostic Multigene Mutation Profile of EUSFNA Cytology Specimens by Next- GenerationSequencing in Locally Advanced Rectal CancerFerga C. Gleeson*1, Benjamin R. Kipp2, Jesse S. Voss2,Michael B. Campion2, Michael Henry2, Andrew P. Sciallis2,Rondell Graham2, Konstantinos Lazaridis1, George Vasmatzis2,Michael J. Levy11Division of Gastroenterology and Hepatology, Mayo Clinic Foundation,Rochester, MN; 2Department of Anatomic Pathology, Mayo Clinic,Rochester, MNBackground: Patient and tumor specific molecular profiling of cancers is activelybeing addressed to enhance prognostic and predictive applications. Thispersonalized approach to patient care is soon anticipated to become standardclinical practice. Rather than performing laborious, time intensive, and expen-sive sequential single gene testing, multiplexed genotyping is being developedto optimize patient management. Aims: To assess the clinical, pathological, andmulti-gene mutation profile associated with progression free survival (PFS) inpatients with locally advanced rectal cancer. Methods: The Ion AmpliSeq� V2Cancer Hotspot NGS Cancer Panel and MiSeq sequencers were used to simulta-neously sequence and assess for R 2,500 possible mutations in 50 oncogene andtumor suppressor genes from 102 archived (2002-2010) EUS FNA malignantlymph node (LN) cytology specimens. Results: Patient age, gender, CEA (R 5ng/ml at diagnosis), tumor location, concurrent malignant iliac LN or R uT3were not associated with PFS. One or more driver mutations were identified in91 (89.2%) patients. KRAS, FBXW7, PIK3CA and BRAF mutations were presentin 31%, 9.8%, 7% and 5%, respectively. Disease progression was more commonin patients with an elevated CEA (pZ0.031) and GNAS mutation (pZ0.0389).In a KRAS wild-type population (nZ70), disease progression was morefrequent in patients with an elevated CEA (pZ0.0001) and an EUS FNA ma-lignant iliac LN (pZ0.0407). The presence of KRAS, PIK3CA, or BRAF mutationsdid not confer a shorter PFS than wild-type patients (HR 0.76, 95% CI 0.46-1.25). The FBXW7 mutation was associated with greater PFS than wild-typepatients [9.1 years (95% CI 7.5-11.4)] vs. [7.5 years (95% CI 7.1-8.3)], HR 2.2;95% CI 1.2-3.9; pZ 0.0342. Conclusion: Multiplexed genotype testing of archivedEUS FNA cytological material from malignant LNs identified GNAS mutations thatwere associated with disease progression versus the FBXW7 mutation that wasassociated with greater PFS, respectively. The findings offer real promise for pa-tients by enhancing prognostic determination as a key to offering tumor specific,personalized patient care.

Mo1356A Single Tertiary Care Center’s Ten Year StagingExperience With Rectal Endoscopic Ultrasound inEarly Rectal CancerAndrew J. Walker*1, Charles P. Heise2, Gregory D. Kennedy2,Mark E. Benson1, Eric Johnson1, Patrick R. Pfau1, Deepak V. Gopal11Internal Medicine, Division of Gastroenterology and Hepatology,University of Wisconsin Hospital and Clinics, Madison, WI; 2Departmentof Surgery, University of Wisconsin Hospital and Clinics, Madison, WIBackground: Rectal endoscopic ultrasound (RUS) has become an essential tool inthe management of rectal adenocarcinoma because of the ability to accuratelystage lesions. Accurate RUS staging is critical in directing the proper preoperativemanagement of rectal adenocarcinoma. The aim of our study was to identify thestaging agreement of early RUS-staged rectal adenocarcinoma with surgical resectedpathology and ultimately determine how this impacts the management of earlyrectal cancer (T1-T2). Methods: Patients were identified through an IRB approvedendoscopic database that included all individuals undergoing RUS from November2002 to January 2013 at a single institution. Retrospective chart review was per-formed through November 2013 to identify procedure indication, RUS staging data,surgical management, and post-operative surgical pathology data. Results: Therewere a total of 598 RUS exams available for review. 275 of these were performed fora new diagnosis of rectal adenocarcinoma. 33 T1 NO lesions were identified by RUS;

www.giejournal.org

Abstracts

however surgical and histologic data was available only in 21 of these patients (66%).There was staging agreement between RUS and surgical pathology in 18 out of 21(85%) RUS-staged T1 cases. There were 15 RUS-staged T2 NO lesions; howeversurgical and histologic data was available in only 9 of these patients (60%). There wasstaging agreement between RUS and surgical pathology in 2 out of 9 (22%) RUS-staged T2 cases. There was significantly better staging agreement for RUS-staged T1lesions compared to RUS-staged T2 lesions (P Z 0.002). All instances of T2 stagingdisagreement were due to overstaging by RUS of the actual surgically resectedpathologic T1 lesions. 16 of the 21 RUS-staged T1 NO patients were referred fortransanal excision. Among the RUS-staged T2 N0 group of patients, three underwenttransanal excision and the remaining six underwent low anterior resection (LAR).Conclusions: Our study, one of the larger clinical experiences in RUS, for unclearreasons, identified only a small number of T1-T2 adenocarcinomas. There wasgood staging agreement between RUS and surgical pathology among RUS-staged T1lesions while poor among RUS-staged T2 lesions. While transanal excision is largelyindicated by the staging of a T1 lesion, this approach may be less appropriate for T2lesions due to high reported local recurrence.

Mo1357Utility of EUS Following Endoscopic Polypectomyof High Risk Rectosigmoid LesionsLeticia P. Luz*1,2, Gregory a. Cote2, Mohammad a. AL-Haddad2,Lee Mchenry2, Julia K. Leblanc2, Stuart Sherman2, Daniel Moreira3,Ihab El Hajj2, Kathleen a. Mcgreevy2, John M. Dewitt21Medicine/Gastroenterology, Roudebush VA Medical Center,Indianapolis, IN; 2Medicine/Gastroenterology, Indiana University,Indianapolis, IN; 3North Shore- LIJ Health System, New Hyde Park, NYIntroduction: Utility of EUS compared to standard white light endoscopy (WLE)following recent polypectomy of high risk rectosigmoid polyps is unknown.Objective: To assess the incremental yield of EUS after endoscopic polypectomyof a high risk rectosigmoid lesion. Methods: In a retrospective, single centercohort study, we identified consecutive patients referred for EUS between 10/2002- 10/2009 following attempted endoscopic resection of a high risk recto-sigmoid neoplasm, defined as a carcinoid, tubulovillous adenoma, tubular ad-enoma with high grade dysplasia/carcinoma-in-situ, or adenocarcinoma.Evaluation included: sigmoidoscopy +/- mucosal biopsy and EUS +/- FNA toevaluate for: residual polyp/tumor in the rectal wall and peritumoral adenop-athy (LN). Outcomes assessed: 1) sensitivity and specificity for WLE+/- biopsy(WLE/BX) and EUS+/-FNA for detection of residual neoplasia in patients withcancer (CA group) or benign disease (non-CA group) and; 2) incremental yieldof EUS, defined as detection of: a) residual intramural neoplasia not present onWLE � BX and; b) peritumoral LN. Results: 70 patients (mean age 64 � 11years, 61% male) with a final CA (nZ38) or non-CA (nZ32) diagnosis under-went follow-up sigmoidoscopy/EUS a mean 35 � 24 days after endoscopicresection. Resection margins were positive in 17(24%), negative in 16 (23%)but unknown in 37 (53%). Follow-up was available in 48/70 (68%) patients.There was no difference between the sensitivity and specificity of WLE (65%and 84%), WLE/BX (71% and 95%), and EUS (59% and 84%), for detection ofresidual neoplasia (pO0.05 for all; Table 1). EUS identified 3 masses missed byWLE, all in the CA group. Malignant (nZ2) or benign-appearing (nZ3) LNwere identified in 5 (13%) CA patients; EUS-FNA (performed in 2) confirmed 1malignant and 1 reactive LN. No LN were identified in the non-CA group.Conclusion: Following endoscopic polypectomy of high risk rectosigmoidneoplasia, the incremental yield of EUS compared to WLE/BX for evaluation ofresidual disease appears limited, especially in patients with benign disease. EUStherefore is recommended for short-term follow-up only after resection ofmalignancy.

Table 1. Sensitivity, Specificity, Positive and Negative Predictive Valuesof WLE, WLE /BX and EUS for the Detection of Residual High RiskNeoplasia after Polypectomy

All PatientsN[48

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WLE N[48

al.org

P**

WLE/BX N[33* P*** EUS N[48 P****

SensitivitySpecificityPPV NPV

65% 84% 69%81%

0.29

71% 95% 91%84%

0.29

59% 84% 67%79%

0.85

CA Group NZ26SensitivitySpecificityPPV NPV

NZ26 45%93% 83% 70%

0.41

NZ18* 67%89% 86% 73%

0.51

NZ26 55%80% 67% 71%

0.22

Non-CA groupNZ22SensitivitySpecificityPPV NPV

NZ22 100%75% 60% 100%

0.14

NZ15 * 80%100% 100% 91%

0.37

NZ22 67%88% 67% 88%

0.14

* No BX done in 15 patients (CA group: 8 patients, non-CA group: 7 patients) ** WLE vs WLE/BX ***WLE/BX vs EUS ****WLE vs EUS

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Mo1358Efficacy of Endoscopic Ultrasound-Guided Fine-Needle Aspirationfor Rectal and Colonic Subepithelial LesionsKo Watanabe*1, Takuto Hikichi2, Tadayuki Takagi1, Masaki Sato1,Rei Suzuki1, Jun Nakamura1, Mitsuru Sugimoto1, Yuichi Waragai1,Hitomi Kikuchi1, Naoki Konno1, Mika Takasumi1, Atsushi Irisawa3,Katsutoshi Obara2, Hiromasa Ohira11Department of Gastroenterology and Rheumatology, FukushimaMedical University, Fukushima, Japan; 2Department of Endoscopy,Fukushima Medical University Hospital, Fukushima, Japan;3Department of Gastroenterology, Fukushima Medical University AizuMedical Center, Aizuwakamatu, JapanAim: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is widely usedfor pancreatic masses and subepithelial lesions (SELs) of the gastrointestinal tract.We previously reported EUS-FNA via the rectum as a safe and useful method fordiagnosing recurrent rectal carcinoma and peri-rectal malignant tumors (DDW in2004). Since then, we have performed EUS-FNA for various rectal and colonic SELs.The present study evaluates the efficacy and the problem related to EUS-FNA forrectal and colonic SELs. Methods: Twenty-one patients (12 men, 6 women; mean age63.0 years) with 22 rectal and colonic SELs who underwent EUS-FNA between July2001 and May 2013 were enrolled in this study. EUS-FNA was performed usingconvex echoendoscopes and 22-gauge needles. Antibiotics were administered viainfusion on the day of EUS-FNA, and orally for 2 days thereafter. Patient character-istics, diagnostic accuracy, and complications were examined. Results: The locationsof SELs were 20 in the rectum, 1 in the sigmoid colon, and 1 in the ascending colon.The mean tumor diameter was 20.9 mm (10-35 mm). The mean puncture countswere 3.8 (range 2-7) and the sample collection rate was 91.0% (20/22). The accuracywas 86.7% (19/22). Final diagnoses were 12 cases (54.5%) of neoplasms: 3 postop-erative recurrence of colon cancer in the anastomotic region, 3 neuroendocrinetumors, 2 rectal infiltration by bladder cancer, 2 GIST, 1 rectal cancer, and 1 ma-lignant lymphoma. Non-neoplasm lesions were 10 (45.5%) cases: 5 benign strictureor swelling post-operation of rectal cancer in the anastomotic region, 2 abscess, 2lymphoid hyperplasia, and 1 intestinal endometriosis. Only one case was misdiag-nosed as rectal GIST by EUS-FNA, which was identified as intestinal endometriosisafter surgery. Misdiagnosis occurred because the sample obtained by EUS-FNA wastoo small. Two cases did not yield adequate samples for diagnosis by EUS-FNA. Onehad only mucus by EUS-FNA. It was diagnosed as mucinous carcinoid according tosurgery data. The other yielded no sample because swelling post-operation of rectalcancer in the anastomotic region was extremely hard. No procedural complication,especially infection, occurred. Conclusion: Final diagnosis of EUS-FNA for rectal andcolonic SELs showed various alternatives. Therefore, EUS-FNA for them is useful toselect treatments. However, particular care must be taken for cases with inadequatesamples for diagnosis.

Mo1359High Frequency Mini-Probe Endoscopic Ultrasonography HelpsDifferentiate Colonic Crohn’s Disease From IntestinalTuberculosisJin Yan*1, Qin Ouyang1, Gandi LI2, Chengwei Tang1, Yina Yang1,Yu-Fang Wang1, Libin Huang1, Chuncheng Wu1, Xiao LI11Gastroenterology, West China Hospital, Sichuan Universtiy, Chengdu,China; 2Pathology, West China Hospital, Sichuan Universtiy, Chengdu,ChinaBackground: It is difficult but crucial to differentiate colonic Crohn’s disease(CD) from intestinal tuberculosis (ITB). Colonoscopy is an indispensablediagnostic modality for the two similar entities. However, it is unclear whetherhigh frequency ultrasonic mini-probe introduced through the forceps channelof the colonoscope and applied directly to the lesion is useful or not inimproving the efficacy of differential diagnosis. Methods: Images from colo-noscopy and ultrasonic scan in 15 Patients with ITB (nZ7) and CD (nZ8) wereretrospectively reviewed. The diagnoses were made based on clinical data, dis-cussion between gastroenterologists and pathologists, result of at least 3-6 monthstargeted treatment and clinical follow-up with endoscopic reexamination. Patientswho had typical clinical manifestations and mimic EUS features with CD or ITB,but failed to fit the criteria of pathology or follow-up feedback are excluded. A 12MHz radial ultrasonic probe was utilized to scan the wall of colon or ileumtransversely when notable inflamed mucosa was revealed by endoscopy. The le-sions including strictures, nodules, cobblestones and ulcers were detected byendoscopic ultrasound (EUS). Results: There was no difference of demographiccharacteristics including sex and age between the two groups. Lesions of CD andITB were polymorphic in both endoscopic and ultrasonographic exam. The dif-ferences of extent and segmentation of lesions in two groups showed no statisticalsignificance difference (PZ0.343). Typical longitudinal ulcers in CD (3 out of 8)and transverse semi circumferential ulcers in ITB (2 out of 7) had specific diag-nostic value. Two EUS features, including asymmetry (CD: 87.5% versus ITB:28.6%, PZ0.041) and transmural defect of layers (CD: 75.0% versus ITB: 14.3%,PZ0.041) were significantly different between two groups. The thickening oflayers showed different characteristic in CD and ITB, which is notable in the third

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