P Basford

OC-068 Blue light imaging for barrett’s neoplasia classification (blinc): the development and validation of a new endoscopic classification system to identify barrett’s neoplasia

Introduction Neoplasia in Barrett’s can be subtle and difficult to identify. Blue light imaging (BLI) by Fujifilm is a novel advanced endoscopic technology that provides high intensity contrast imaging for superior visualisation of mucosal surface and vessel patterns. This can improve the identification of Barrett’s neoplasia. To date there is no formal classification system that enables the characterisation of neoplastic and non-neoplastic Barrett’s for BLI. The aim of our study was to develop and validate a classification to identify Barrett’s neoplasia using BLI. Method 3 expert endoscopists formed a working group to identify criteria characterising neoplastic and non-neoplastic Barrett’s on BLI using a modified Delphi method. A simple classification system utilising pit, vessel pattern and colour was developed using a database of 40 images. 6 experienced endoscopists then assessed a library containing 45 images of neoplastic and non-neoplastic Barrett’s using the proposed criteria. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated to assess its performance. The same parameters were then evaluated for each component criteria. Results The BLINC criteria are as follows: Non Neoplastic Neoplastic Pit pattern Circular, tubular or branching with normal density Irregular, crowded with increased density Vessel Pattern Regular, pericryptal, non dilated vessels with normal density Irregular, non cryptal, dilated vessels with increased density Colour Pale Focal darkness The table below shows the overall sensitivity, specificity, PPV and NPV of the classification in the identification of Barrett’s neoplasia. Sensitivity (95%u2009CI) 96.7 (92.4–98.9)% Specificity (95%u2009CI) 96.7 (91.2–99.1)% PPV (95%u2009CI) 97.3 (93.3–99.0)% NPV (95%u2009CI) 95.9 (90.7–98.2)% When each category in the classification was analysed separately the predictive values of pit and vessel pattern in neoplasia characterisation were high compared to colour. Sensitivity (95%u2009CI) Specificity (95%u2009CI) PPV (95%u2009CI) NPV (95%u2009CI) Pit Pattern 96.0 (91.5–98.5)% 98.3 (94.1–99.8)% 98.6 (94.8–99.7)% 95.2 (89.9–97.7)% Vessel Pattern 94.7 (89.8–97.7)% 93.3 (87.3–97.1)% 94.7 (90.1–97.2)% 95.2 (89.9–97.7)% Colour 86.7 (80.2–91.7)% 78.3 (69.9–85.3)% 83.3 (78.0–87.6)% 82.5 (75.6–87.7)% Conclusion We have developed the first internally validated simple classification system for the diagnosis of Barrett’s neoplasia using BLI. The classification criteria demonstrated high sensitivity and specifity. We aim to use the proposed classification in future studies for real time optical diagnosis of Barrett’s neoplasia. Disclosure of Interest S. Subramaniam: None Declared, K. Kandiah: None Declared, F. Chedgy: None Declared, R. Bhattacharyya: None Declared, P. Basford: None Declared, G. Longcroft-Wheaton: None Declared, P. Bhandari Conflict with: Receives educational grants from Fujifilm, Olympus, Pentax

OC-045 High Definition White Light Endoscopy and I-Scan for small Colonic Polyp Evaluation : Results of the Hiscope Study

Introduction Standard definition white light endoscopy is inadequate for in-vivo characterisation of small colonic polyps. The ASGE has identified prediction of polyp surveillance intervals and negative predictive value for adenomatous histology of diminutive recto-sigmoid polyps as key targets for new technologies. High definition white light endoscopy is now available but there is little data on it’s use. Methods We aimed to examine the in-vivo characterisation accuracy of high definition white light endoscopy (HDWL) plus a novel electronic imaging modality – i-Scan (Pentax, Japan). Patients undergoing colonoscopy through the UK Bowel Cancer Screening Programme were prospectively recruited. All colonoscopies were performed by a single expert endoscopist with extensive experience in in-vivo diagnosis. Procedures were performed with Pentax EC-3890Li 1.2 Megapixel HD+ colonoscopes and EPKi processor. An initial classification & validation exercise was carried out to determine the optimum i-Scan settings for in-vivo diagnosis, and to develop a novel in-vivo diagnosis assessment tool. All polyps < 10mm in size were assessed sequentially with HDWL and i-Scan. Optical magnification was not used. Predicted histology (non-neoplastic, adenoma, cancer) was recorded for both modalities and compared to the final histopathological diagnosis as reported by an expert gastrointestinal pathologist. Predictions were rated as high or low confidence assessments. Results were analysed for sensitivity and specificity for neoplasia, overall accuracy, and negative predictive value for rectosigmoid polyps ≤5 mm as recommended by the ASGE PIVI statement. Results 84 patients were recruited, in whom 209 polyps < 10 mm were included. Mean polyp diameter was 4.3mm, median 4mm. 134 polyps were neoplastic and 75 non-neoplastic. There were no significant differences in sensitivity (95.5% vs 97.0%) and specificity (89.3% vs 90.7%) for neoplasia and overall diagnostic accuracy (93.3% vs 94.7%) between HDWL and i-Scan. Negative predictive value for adenomatous histology of rectosigmoid polyps ≤5 mm was 100% with both modalities. Polyp surveillance intervals using in-vivo assessment of diminutive polyps were correct in 95% and 97% of patients with HDWL and i-Scan respectively. Abstract OC-045 Table 1 HDWL i-Scan HDWL vs i-Scanp value Sensitivity % 95.5 97.0 0.5 Specificity % 89.3 90.7 1.0 Accuracy % 93.3 94.7 1.0 Conclusion Excellent in vivo diagnostic accuracy, in excess of 90% can be achieved with HDWL alone. No significant gains in accuracy over HDWL were noted with i-Scan when used with a 1.2Megapixel HD colonoscope Both HDWL and i-Scan fulfil the ASGE criteria for ‘resect and discard’ and ‘do not resect’ strategies for diminutive polyps Disclosure of Interest None Declared

PWE-101 High definition endoscopy increases the number of adenomas detected in the UK bowel cancer screening population

Introduction Adenoma detection and removal is one of the main goals of colonoscopy. Improved adenoma detection has been shown to reduce future risk of colorectal cancer. High definition colonoscopy allows better visualisation of the colonic mucosa and may improve detection of polyps. Previous studies have shown variable results when comparing polyp and adenoma detection between standard definition (SD) and high definition (HD) colonoscopy. The UK bowel cancer screening programme offers colonoscopy to all citizens aged 60–75u2005years who test positive for faecal occult blood (FOB). We aimed to compare polyp and adenoma detection rates between those patients undergoing SD Colonoscopy and HD colonoscopy in the screening population. Methods Endoscopy, histopathology and screening database reports were analysed for all BCSP in our institution for the period September 2009 to October 2011. 1020 colonoscopies were performed of which 68 were excluded from further analysis (Incomplete procedure/polyposis syndrome/colitis/unknown definition of endoscope/previous colonic resection). Procedures were divided according to the definition of endoscope used: SD (500u2008000 pixels) n=421, HD (>500u2008000 pixels) n=531. Reports were analysed for demographic data, bowel preparation, withdrawal time, and the number, size, morphology, site and histology of all lesions removed. Results There were no significant differences between the SD and HD groups respectively in percentage male subjects (57% vs 60.0%, p=0.229), mean age (66.47 vs 66.54, p=0.24), percentage with good or adequate bowel preparation (96.1% vs 96.2%, p>0.5), mean withdrawal time (10.9u2005min vs 10.6u2005min, p=0.06). In total 1553 lesions were detected: 49 cancers, 1149 adenomas and 335 non-neoplastic polyps. There was no significant difference between the SD and HD in overall polyp detection rate (SD 0.63 vs HD 0.65, p=0.401) and adenoma detection rate (SD 0.59 vs HD 0.59, p=0.516). However a significantly greater number of adenomas per patient (APP) were detected in the HD group (SD 1.20 vs HD 1.34, p=0.016). HD endoscopy detected significantly more diminutive adenomas (1–5u2005mm) than SD endoscopy (0.87 per pt vs 0.72 per pt, p=0.02), but there was no difference in the rate of detection adenomas >5u2005mm. More adenomas were detected in the proximal colon in the HD group (0.59 vs 0.44, p=0.03) but there was no significant difference in the distal colon (HD 0.79 vs SD 0.77). Conclusion Overall adenoma detection rate in this study population was excellent with 59% of patients having one or more adenomas detected. HD endoscopy appears to improve the total number of adenomas detected in the screening population. The main gain of HD endoscopy is in detection of diminutive polyps in the proximal colon. Competing interests None declared.

PTU-046 Prospective comparison of emr vs esd in barrett’s neoplasia: are we too afraid of knives in the oesophagus?

Introduction Use of ESD in the Western setting is limited to a few centres with limited numbers of cases, due to concerns regarding complication rates and no established training pathway. The risks of ESD in the oesophagus are perceived to be high and the consequences disastrous. For this reason, endoscopic mucosal resection (EMR) is the most common technique used to resect early Barrett’s cancer. The drawback of EMR is piecemeal resection and poor interpretation of histology. Method We report our experience of oesophageal ESD in 51 cases and compare our data for EMR (140 cases) over the same period. Results 51 ESD resections for Barrett’s neoplasia were performed between 2006 and 2014. 140 EMR’s were performed in the same period. Mean age 71 years for ESD group and 75 for EMR group. All procedures were undertaken by a single expert endoscopist (PB). Table 1shows patient characteristics and lesion characteristics.Abstract PTU-046 Table 1 Patient and lesion characteristics Mean follow Up (Yrs) Paris IIa (nodular) LGD/HGD Early cancer Perforation (%) Bleeding (%) Stricturing (%) ESD group n = 5 n = 51 4.2 92% 16% 84% 2 0 0 EMR group n = 1 n = 140 5.8 10% 41% 59% 0 3 2 The endoscopic cure rate in the ESD group was 83% and the EMR group was 82%. It took a mean of 1.2 procedures in the ESD group and 1.4 procedures in the EMR group. In the ESD group there was a recurrence rate of 3%, in the EMR group 16%. Additional radiofrequency ablation was required in 17% of patients in the ESD group and 34% of patients in the EMR group. There was one perforation in the ESD group which was successfully managed conservatively with endoclips, not requiring surgery. There were 4 cases of bleeding and 3 cases of stricturing managed endoscopically in the EMR group. Conclusion ESD for Barrett’s neoplasia is feasible, safe and effective in Western hands. Our lesion selection data shows that ESD is being used mainly for nodular lesions and cancerous lesions as compared to EMR for flat and non-cancerous lesions. Neoplasia recurrence is higher in EMR vs ESD. This calls for a randomised controlled trial comparing EMR vs ESD for the resection of nodular lesions in Barrett’s neoplasia. Disclosure of interest None Declared.

PTU-047 Acetic acid guided focal endoscopic resection without rfa remains an effective treatment for barrett’s neoplasia: time to reassess the role of rfa?

Introduction Endoscopic resection (ER) is an established effective treatment for Barrett’s neoplasia. ER can lead to recurrence due to residual neoplasia left behind, so it is suggested that all patients should undergo radiofrequency ablation (RFA) after ER. Acetic acid chromoendoscopy has been shown to be an effective method of localising and delineating dysplastic areas of Barrett’s oesophagus and we aim to review the outcome of Acetic Acid guided focal ER without RFA in our patients. Method All ER procedures between January 2005 and November 2014 were recorded in a prospective database which was analysed. Acetic acid guided focal ER was the treatment strategy with the aim of removing all neoplasia visible with acetic acid chromoendoscopy. RFA was not used in this group. Results 112 patients were treated for dysplastic Barrett’s oesophagus or early Barrett’s cancer by ER. The mean age at first procedure was 68 years and 82% of the patients were male. Mean initial Barrett’s length was 5.1 cm. 35 of 112 patients had advanced histological features on the initial ER specimen and were referred for radical cure. The remaining 77 cases showed; intramucosal cancer (IMC) in 46, high grade dysplasia (HGD) in 28 and low grade dysplasia in 3. All 77 cases have follow-up data with a mean duration of 5.4 years. 67 of 77 cases (87%) have sustained eradication of HGIN/IMC after focal ER. 10 patients (13%) developed further neoplasia during follow up. 5/10 patients (6.5%) developed invasive cancer in the residual Barrett’s, all were diagnosed endoscopically and successfully managed with radical curative treatment. Focal ER was successful in a mean of 1.3 procedures per patient (range 1–3). Complication rate was 4% (4 bleeds, 2 strictures). No additional RFA was performed in this patient group. Table 1compares our outcomes with UK HALO registry outcomes where all patients receive RFA.Abstract PTU-047 Table 1 AA guided EMR UK RFA Data1 Clearance of neoplasia 87% 77% Progression to Cancer 6.5% 6.7% Mean Follow up 5.4 Years 2.6 Years Stricturing 2.6% 9.4% Mean number of therapeutic procedures 1.3 ER + 2.6 RFA Conclusion Acetic acid guided ER is an effective and safe treatment for dysplastic Barrett’s oesophagus. Progression to cancer after acetic acid guided ER is equivalent to the reported rate of progression after EMR+RFA.1Equal rates of sustained eradication of HGIN/IMC are achieved. An acetic acid+ER strategy is potentially much cheaper than an ER+RFA strategy. This data calls for a better stratification of patients who require RFA after ER. Disclosure of interest None Declared. Reference Haidry, et al. Gastroenterology2013;145:87–95

PTH-011 Defining the optimal i-scan settings for small colonic polyp characterisation – results from a large prospective series

Introduction Characterisation of small colonic polyps has been identified as a key goal for advanced imaging modalities by the ASGE and ESGE. Pentax i-Scan is an endoscopic digital contrast technology shown to be an accurate tool for characterising small colonic polyps in-vivo. I-Scan combines features which accentuate dark-light borders (surface and contrast enhancement, SE/CE) and suppression of red light whist enhancing blue/green light (tone enhancement, TE). The optimal settings for use of i-Scan in the colon have yet to be determined. Method High quality digital images of 100 small colonic polyps were recorded as part of a prospective study (NCT 01761279). Images of each polyp were recorded in 3 i-Scan modes: i-Scan 1 (SE/CE), i-Scan 2 (TE) and i-Scan 3 (SE/CE/TE). Randomised images were viewed by 2 blinded endoscopists who rated visibility of diagnostic features and predicted polyp histology (neoplastic vs non-neoplastic). Results The proportion of adenomas rated as having visible pericryptal vessels were 59%, 81% and 82% for i-Scan 1, 2 and 3 respectively. The differences between i-Scan 1 and 2 (P = 0.001) and i-Scan 1 and 3 (P < 0.001) were statistically significant. The difference in proportion of adenomas with no visible surface pattern between i-Scan 1 and 2 was statistically significant (26% vs 8%, P = 0.001), as was the difference between i-Scan 1 and 3 (26% vs 9%, P = 0.003). There was no significant difference between i-Scan 2 and 3 (8% vs 9%, P = 1.00). Mean sensitivity for adenomatous histology between the two endoscopists was 69% for polyps viewed with i-Scan 1. Compared to i-Scan 1 assessments sensitivity was significantly higher with i-Scan 2 (86%, P = 0.006 for comparison), and with i-Scan 3 (87%, P = 0.003 for comparison). There was no significant difference in sensitivity between i-Scan 2 and i-Scan 3 assessments (86% vs 87%, P = 1.000). No significant differences in specificity were found between the 3 i-Scan modes (i-Scan 1 vs i-Scan 2 P = 0.828, i-Scan 1 vs i-Scan 3 P = 1.000, i-Scan 1 vs i-Scan 3 P = 1.000). Overall accuracy increased from 79% with i-Scan 1 to 86.5% with i-Scan 2 and 87.5% with i-Scan 3. There was no significant difference in overall accuracy between i-Scan 1 and i-Scan 2 (P = 0.063) or i-Scan 2 and i-Scan 3 (P = 0.882). However there was a significant difference between i-Scan 1 and i-Scan 3 assessments (P = 0.032).Abstract PTH-011 Table 1 Diagnostic Accuracy i-Scan 1 (SE+CE) i-Scan 2 (TE) i-Scan 3 (SE+CE+TE) Sensitivity 69/100 (69%) 86/100 (86%) 87/100 (87%) Specificity 89/100 (89%) 87/100 (87%) 88/100 (88%) Accuracy 158/200 (79%) 173/200 (86.5%) 175/200 (87.5%) Conclusion Tone enhancement appears to be the most effective component of the i-Scan system for accurate small colonic polyp characterisation, with no additional benefit from the addition of surface/contrast enhancement. Disclosure of interest None Declared.

OC-010 Large Cohort Study Evaluating the Role of Hybrid ESD (H-ESD) and Conventional Piecemeal EMR Technique in the Resection of Large and Challenging Colonic Polyps Demonstrates no Outcome Benefit of H-ESD over EMR

Introduction The learning curve for ESD in the west is very long, so a hybrid technique has been proposed. The impact of Hybrid ESD (H-ESD) technique on clinical outcome is unclear. We aim to compare the outcome benefits of Multi-piece EMR and H-ESD in the resection of challenging colonic polyps. Methods A Prospective cohort study of endoscopic resection of difficult colonic polyps. Patients were tertiary referrals from experienced endoscopists. EMR was defined as submucosal injection followed by piecemeal snare resection. H-ESD involved submucosal injection before mucosal incision with an ESD knife followed by snare resection of the lesion. Endoscopic follow up was performed. Multiple linear regression analysis was performed using SPSS. Results 347 flat/sessile polyps > 20 mm were resected between 2007–12. Mean follow-up was 1004 days. H-ESD Cohort N = 110/347(32%). Mean size was 45mm(range 10–170). 25/110(23%) were salvage procedures for scarred lesions due to failed EMR attempts by other endoscopists. Endoscopic clearance was achieved in 95.5% of procedures. Need for surgery (n = 4): 1 for perforation and 3 for unexpected cancer. 98.6% showed no evidence of recurrence at endoscopic follow up. EMR cohort N = 237/347(68%). Mean size was 42mm(range 20–150). 11/237(4.6%) were salvage procedures for polyps with scarring. Endoscopic clearance was achieved in 93% of cases. Need for surgery (n = 21): 1 patient for incomplete resection & 20 for suspicion of cancer in EMR specimen. At endoscopic follow up 98% of cases had achieved complete clearance. Abstract OC-010 Table SIZE TECHNIQUE PREV EMR SITE COMPLICATIONS(25) ≤50mm15/271 (5.5%) > 50mm8/76(10.5%) ESD11/110 (10%) EMR12/237 (5%) Yes3/36 (8%) No20/311(6%) LC20/250 (8%) RC3/97 (3%) P = 0.016 P = 0.11 P = 0.521 P = 0.201 RECURRENCE (35) ≤50mm19/271(7%) > 50mm16/76(21%) ESD12/110 (11%) EMR23/237 (10%) Yes10/36 (28%) No25/311 (8%) LC31/250 (12%) RC4/97 (4%) P = 0.0001 P = 0.156 P = 0.0001 P = 0.105 Risk of recurrence was associated with lesion size > 50 mm & scarring due to previous EMR attempts. This was unaffected by technique (EMR or H-ESD). Perforation/microperforation was more likely in the H-ESD Cohort, but the overall complication rates were similar for H-ESD and EMR cohort. Conclusion Both techniques achieved an excellent overall cure rate for large & challenging polyps. This is the first large series comparing the two techniques and demonstrates that polyp cure rate was equally good with both techniques. H-ESD technique was used more commonly for polyps with significant scarring & was associated with slightly higher perforation rates. Our data does not demonstrate any significant outcome benefit of H-ESD technique over the conventional EMR technique. Disclosure of Interest None Declared

PTH-015 Prospective Comparison of Fice and I-Scan for In-Vivo Characterisation of Small Colonic Polyps: Abstract PTH-015 Table 1

Introduction In-vivo characterisation of small colonic polyps has been reported using several technologies but with few prospective comparisons between them. We aimed to compare the accuracy of Flexible Spectral Imaging Colour Enhancement (FICE) and i-Scan in the assessment of polyps < 10mm. In addition the relationship between accuracy of white light assessment (WL) and resolution of endoscope was assessed. Methods Patients undergoing screening colonoscopy through the UK BCSP were prospectively recruited. All procedures were performed by a single endoscopist with extensive experience in in-vivo diagnosis. For the FICE group Fujinon 410,000 pixel CCD and 650,000 pixel CCD colonoscopes were used with an EPX 4400 processor. For the i-Scan group Pentax 1.2 Megapixel colonoscopes were used with an EPKi processor. All polyps < 10mm were assessed sequentially using white light endoscopy (WL) and either FICE or i-Scan before resection. Predicted histology was recorded with both modalities and compared to the final histopathological diagnosis. In-vivo characterisation accuracy was analysed based on the resolution of the endoscopes used; standard definition - SD (410K pixel), high definition – HD (650K pixel) and HD+ (1.2M pixel). Results In the FICE group 293 polyps of mean size 4.7mm were assessed in 170 patients. In the i-Scan group 209 polyps of mean size 4.3mm were assessed in 84 patients. There was no significant difference in WL accuracy between SD and HD endoscopes (70% vs 72.7%, p = 0.606), however accuracy was significantly higher with the HD+ 1.2megapixel CCD endoscopes (93.3%) compared to both the SD (70.0%, p = 0.0001) and HD (72.7%, p = 0.0001) endoscopes. Sensitivity was significantly greater with FICE using an HD endoscope compared to an SD endoscope (92.6% vs 83.3%, p = 0.048). Overall accuracy was significantly greater with HD+ i-Scan (94.7%) than SD FICE (82.7%, p = 0.0003) and HD FICE (88.8%, p = 0.0439). The use of FICE improved accuracy from 70.0% with WL to 82.7% (p = 0.014) and from 72.7% with WL to 88.8% (p < 0.001) for SD and HD endoscopes respectively. Only a minor gain over WL was seen with addition of iScan (93.3% to 94.7%, p = 0.68). Abstract PTH-015 Table 1 Sensitivity % Specificity % Accuracy % SD WL 76.0 59.3 70.0 HD WL 75.8 66.7 72.7 HD+ WL 95.5 89.3 93.3 SD FICE 83.3 81.5 82.7 HD FICE 92.6 81.3 88.8 HD+ i-Scan 97.0 90.7 94.7 Conclusion Only a small, non-significant gain in WL accuracy is seen between a 410K pixel SD endoscope and a 650K pixel HD endoscope. However diagnostic accuracy with WL improves significantly with a 1.2 megapixel endoscope. FICE significantly improves accuracy when used with an SD or HD endoscope but the very high WL accuracy of a 1.2 megapixel endoscope allows no significant additional improvement with i-Scan. Disclosure of Interest None Declared.

PTU-164 Cost Effectiveness of an ER Dominant Approach in the Management of High Grade Intraepithelial Neoplasia and Mucosal Cancer in Barrett’S Oesophagus

Introduction Endoscopic resection (ER) is an established effective treatment for high grade intraepithelial neoplasia (HGIN) and intramucosal cancer (IMC) arising in Barrett’s oesophagus. ER can lead to recurrence so it is suggested that all patients should undergo radiofrequency ablation (RFA) after ER as a complimentary treatment strategy. However no comparative study to support this concept has been performed. We aimed to compare the cost-effectiveness of an EMR-dominant approach vs an EMR-RFA approach for the treatment of HGIN and IMC in Barrett’s oesophagus. Methods All ER procedures between 2005 and 2012 were recorded in a prospective database which was analysed. Demographic data, histology, procedure success, long-term outcome and complications were assessed. Costs were calculated using NHS HRG codes plus equipment costs for ER and RFA. Results 92 patients were treated for dysplastic Barrett’s oesophagus or early Barrett’s cancer by ER. The mean age at first procedure was 69 years and 87% of the patients were male. 21 of 92 patients had advanced histological features on the initial ER specimen and were referred for surgical or oncological treatment. Of the remaining 71 cases, 63 have follow-up data with a mean duration of 4.3 years. 59 of 63 cases (94%) had successful eradication of HGIN/IMC by ER. The remaining 4 patients were referred for surgery for advanced disease (3) or extensive bulky disease not amenable to ER (1). ER was successful in a mean of 1.46 procedures per patient (range 1–3). Complication rate was 5.2% (4 bleeds, 1 microperforation, 2 strictures). Additional RFA was used in 11 cases. 12 (20%) of patients developed recurrence of HGIN/IMC during follow-up requiring further endoscopic therapy. 2 (3.4%) patients developed more advanced Barrett’s neoplasia during follow-up. The calculated cost per patient of an ER-dominant approach is £4125 compared to £8868 per patient for an RFA dominant approach. Conclusion ER acted as an accurate and safe staging procedure in up to 23% of cases found to have advanced histology. ER is an effective and safe treatment for HGIN/IMC within Barrett’s oesophagus without the need for routine RFA and can be performed successfully in a UK centre. However the recurrence of HGIN/IMC is not uncommon and therefore close follow-up is required to identify and treat it at an early stage. An ER-dominant approach may offer significant cost-savings compared to an RFA-dominant approach without compromising overall outcomes. Disclosure of Interest None Declared

OC-046 Acetic Acid Chromoscopy Significantly Improves Neoplasia Detection Rates as compared to Cleveland Clinic Protocol during Barrett’S Surveillance

Introduction Cost effectiveness of Barrett’s surveillance has recently being questioned due to the low neoplasia detection rate. Acetic acid chromoscopy (AAC) has been shown to improve neoplasia detection in Barrett’s oesophagus but not in surveillance population. The aim of this study is to compare the effectiveness of AAC with Cleveland clinic protocol (2 cm quadrantic) guided biopsies at detecting high risk neoplasia during Barrett’s surveillance. Methods Prospective Cohort study comparing two different Barrett’s surveillance strategies. All patients who underwent Barrett’s surveillance between 2008–12 were recorded on a Barrett’s database. All neoplasias were independently reviewed by two GI Pathologists. Barrett’s surveillance patients were randomly allocated to acetic acid chromoscopy lists (cohort B) or protocol guided biopsy (Cohort A) lists. AAC involved targeted biopsy of area of concern & 3 additional biopsies from lower, middle & top end of Barrett’s. Protocol guided were taken as quadrantic biopsies every 2 cm & any visible abnormality. Fisher’s exact test was used for statistical analysis. Results N = 982 Barrett’s surveillance gastroscopy between 2008–12. Median age was 66 years & Median Barrett’s length was 4.5 cm (range: 1–20). Male: Female = 3.3:1. Protocol guided Cohort A N = 655/982(66.7%). 7/655 (1%) patients were found to have high grade dysplasia (HGD) & 3/655(0.4%) had T-1 cancers with an overall high risk neoplasia detection rate of 10/655(1.5%). Acetic acid Cohort B N = 327/982(33.2%). 18/327(5.5%) patients were found to have HGD & 14/327(4.2%) had T-1 cancers with an overall high risk neoplasia detection rate of 32/327(9.7%). This shows a statistically significant 6.5 fold (p = 0.0001) increased detection of high risk neoplasia with acetic acid guided biopsies as compared to protocol guided biopsies in Barrett’s surveillance. Abstract OC-046 Table 1 Protocol biopsies cohort(Cohort A) AAC cohort(Cohort B) N=655 N=327 Gain p value HGD 7/655(1.0%) 18/327 (5.5%) 5.5 fold 0.0001 T1 Cancers 3/655 (0.4%) 14/327 (4.2%) 10 fold 0.0001 Total 10/655 (1.5%) 32/327 (9.7%) 6.5 fold 0.0001 Conclusion This is the first report from a large exclusively Barrett’s surveillance population. Our data demonstrates that acetic acid chromoscopy significantly (6.5 fold) improves the detection of high risk neoplasia in Barrett’s surveillance as compared to the current standard of 2 cm quadrantic biopsies. AAC also results in significantly less number of biopsies taken so overall it will be very cost-effective. This questions the validity of the current standard of non targeted protocol guided biopsies during Barrett’s surveillance. Disclosure of Interest None Declared