R Rameshshanker

PTH-049 Clinical outcomes of endoscopic submucosal dissectionfor colorectal neoplasms: a single UK referral centre experience

Introduction There is limited experience of endoscopic submucosal dissection (ESD) for resection of colorectal lesions in the West and outcome data tends to be worse than that reported from Japanese centres. We report the outcomes of ESD in a single, tertiary UK referral centre. Methods A prospective database was analysed including 165 consecutive patients (mean age: 64.6±12.6 years, 62.4% males) with 173 colorectal neoplasms resected by ESD between 3/2012 and 12/2017. Two experienced colonoscopists performed all procedures. Results The median (IQR) lesion size was 3.5 cm (2–5), and 140 (80.9%) were located in the rectum. Overall, 49.7% were granular-type laterally spreading tumours (LST), 19.7% were non-granular LST, and 30.6% were polypoid lesions. In 29 (16.7%) cases a flexible endosurgical platform was used to assist ESD of complex rectal polyps [median(IQR) size: 6 cm (5–8)] by dynamic trans-anal retraction (Trans-Anal Submucosal Endoscopic Resection; TASER). Histology showed low-grade adenoma/dysplasia in 83 (47.9%), high-grade adenoma/dysplasia in 52 (30%), T1 cancer (<1000 µm) in 17 (9.8%), and T1 cancer (<1000 µm) in 17 (9.8%) lesions. The en bloc, histological complete and curative (R0) resection rates were 97.7%, 80.3% and 76.3% respectively. Three (1.7%) cases of delayed bleeding occurred, with one case requiring transfusion. Perforation occurred in 2 (1.2%) cases: one was recognised and treated intraoperatively with endoclips; the other one was followed up and managed conservatively. Sixty (34.7%) patients were electively admitted to hospital post procedure, for a median duration of 1 day (range 1–5). Twenty patients (12.1%), at risk of lymph node metastasis, underwent additional radical surgery. Eighty-nine (51.4%) ESD cases had endoscopic follow-up data over a median duration of 12 months (range 3.4–51.3). The local recurrence rate was 4/89 (4.5%); all recurrent cases were managed endoscopically. The recurrence rate was lower in cases with en bloc compared with piecemeal resection (3.4% vs 50%, p=0.08), histologic complete compared with histologic incomplete resection (2.5% vs 22.2%, p=0.05), and R0 compared with non-R0 resection (2.5% vs 20%, p=0.06). After a median follow up of 14.6 months (range: 3–55.8), the overall and disease-specific survival in the study population was 98.8% and 100%, respectively. Conclusions The current study demonstrates favourable clinical outcomes of selected colorectal ESD in a Western endoscopy setting. Further studies addressing the cost-effectiveness of ESD and comparing its long-term outcome with endoscopic mucosal resection in the West are needed.

Resection of large sessile serrated polyps by cold piecemeal endoscopic mucosal resection: Serrated COld Piecemeal Endoscopic mucosal resection (SCOPE)

Sessile serrated adenomas/polyps (SSA/ Ps) are frequently found in the proximal colon, where the wall is thinner and easily damaged by diathermy during polypectomy, which also carries a risk of delayed bleeding, perforation, and post-polypectomy syndrome. SSA/Ps are often flat with subtle, irregular edges making endoscopic assessment of their extent difficult [1]. This can lead to incomplete resection and risk of post-colonoscopy cancer [2]. Currently, cold snare resection (CSR) is considered the preferred technique to resect small polyps. It is safe, time efficient, and user friendly [3]. Recently, case series have highlighted the safety and efficiency of CSR for larger adenoE-Videos

PTH-039 Prevalence of sessile serrated adenomas/polyps in distal colon during screening colonoscopy/flexible sigmoidoscopy: a single bowel cancer screening experience from uk

Introduction Sessile Serrated Adenomas/Polyps (SSA/P) are responsible for nearly 20% of colo rectal cancer (CRC). Despite the utility of novel image enhancing techniques including narrow band imaging it is difficult to differentiate hyperplastic (HP) polyps from SSA/Ps. Vast proportion of endoscopists leave the diminutive and possibly small HP polyps in situ in the recto sigmoid area (diagnose and disregard approach). Hence there is a possibility of leaving SSA/P in the recto sigmoid region which could potentially lead to CRC later in life. Aim To estimate the prevalence of SSA/P in recto sigmoid colon at screening colonoscopy and flexible sigmoidoscopy (FS). Method Patients aged >55 years underwent a screening colonoscopy (n=500) or a flexible sigmoidoscopy (n=500) at our institution between August 2014 and April 2015 were included. Data collected from 500 consecutive patients who underwent a colonoscopy or a FS. Demographic, procedural and polyp data were retrieved from our endoscopy database. Abstract PTH-039 Figure 1 Results 99.6% of (498/500) colonoscopy and 97.6% of flexible sigmoidoscopy procedures were completed. Screening colonoscopy detected 1006 polyps and FS detected 249 polyps. Polyp size ranged between 1–80 mm (colonoscopy mean size 6 mm, SD 7.2 mm; FS mean 3.4 mm, SD 3.9 mm). While colonoscopy detected 43 SSA/Ps (4.3%), FS detected only 6 SSA/Ps (2.4%) which equates to an overall prevalence of 3.9% (49/1255). Image 1 summarises the SSA/Ps prevalence by colonic segment. In recto sigmoid there were 21 SSA/Ps detected and resected which equals to a 3.9% of all recto sigmoid polyps. All SSA/Ps detected in this segment were less than 10 mm in size (range 2–10 mm). Only one of the SSA/P had dysplasia (4.7%). Prevalence of SSA/Ps in proximal colon was 4.8%. Conclusion Our cohort showed a slightly higher prevalence of SSA/Ps in rectum and sigmoid colon. Therefore, it becomes clinically relevant to differentiate SSA/Ps from HP polyps in recto sigmoid before adapting a diagnose and disregard approach for small (<9 mm) hyperplastic looking polyps in this location. Disclosure of Interest None Declared

PWE-032 Advanced neoplasia yield in patients undergoing colonoscopy after screening flexible sigmoidoscopy: are the current referral criteria correct?

Introduction Currently patients undergoing a “Bowel Scope” (BS)screening are referred for colonoscopy if the following criteria are met: polyps>1 cm, villous histology, high grade dysplasia 3 or more adenomas, >20 hyperplastic polyps and patient related factors causing an incomplete examination ( discomfort or poor access). Objective To assess the proportion of patients who had a significant polyp (advanced adenoma=adenoma >1 cm, villous or high grade dysplasia on histology) in the proximal colon when referred for a screening colonoscopy after a Bowel Scope examination. Method A retrospective cross sectional study of 9960 patients who underwent BS screening between July 2013 -July 2016 at our Bowel Cancer Screening Centre was performed. Epidemiology, procedural and polyp data were retrieved from the endoscopy data base. Results Number of patients Proximal AA Proximal SSA/P Proximal Advanced SSA/P Adenoma>1 cm 153 14.4% 8.5% 2.6% Villous 189 14.3% 3.2% 0.5% High grade dysplasia 09 36.4% 8.3% 0% Others 169 5.3% 5.8% 1.6% 520 (5.2%) patients had a screening colonoscopy as per the BCS protocol. Median age was 55 years with male: female 2:1. The clear majority of BS examinations reached as far as the descending colon (82%). 351/520 (68%) patients had at least one advanced adenoma (AA) in the distal colon. Overall prevalence of distal AA was 3.2% (351/9960). Caecal intubation was achieved in 98% (510/520) of screening colonoscopies. At least one adenoma or a sessile serrated adenoma/polyp (SSA/P) was detected, proximal to the extent of BS examination in 45% (232/520) of patients, when they had a colonoscopy. Table 1 summarises the prevalence of synchronous proximal colonic pathology. The majority (68%, 351/520) of the colonoscopies were performed due to the presence of AA in the distal colon. Of these 351 patients, 52 (14.8%) had a synchronous proximal colonic AA and 20 had a synchronous SSA/P (5.7%). Only 5 patients had an advanced SSA/P (polyp >1 cm or with dysplasia) in the proximal colon (1.4%). Presence of distal AA was significantly associated with proximal colonic AA (p=0.0006). However, there were no associations between distal AA and proximal SSA/P (p=0.47) or advanced SSA/P (p=NS) Conclusion Distal colonic AA are a marker of synchronous proximal colonic adenomas and SSA/Ps. When colonoscopies were performed for other indications (non-adenomatous polyp >1 cm, multiple distal HP polyps) the yield in the proximal colon was significantly smaller. These “soft” indications for colonoscopy accounted for a significant additional workload that appears unjustified. Disclosure of Interest None Declared

PTU-030 Number of Significant Polyps Detected Per Six Minutes of Withdrawal Time at Colonoscopy (SP6): A New Measure of Colonoscopy Efficiency and Quality

Introduction There is an increasing focus on quality, safety and efficiency of colonoscopy procedures. Colonoscopic efficiency could be defined as the ability to detect clinically relevant pathologies with a minimum expenditure of time and effort without compromising the safety of the procedure. Adenoma Detection Rate (ADR) is considered as a surrogate marker for quality of colonoscopic examination. However, ADR does not take into account sessile serrated polyps/adenomas (SSP/A) or the efficiency of detection. We therefore propose a new measure of colonoscopy efficiency the SP6 that can be used to evaluate both individual endoscopist’s performance and to compare different detection interventions. Our objective was to assess the SP6 for an individual colonoscopist during standard and Endocuff –assisted colonoscopy (EAC) Methods A prospective service evaluation of screening colonoscopies was performed by an experienced endoscopist between October 2014 and September 2015. For consecutive colonoscopies, patient demographics and procedural data were collected. Results 96 patients had screening colonoscopy during this period. The median age was 65 years (55–74 years). A distal disposable attachment such as Endocuff VisionTM was used at the endoscopists’ discretion. 49 patients had Endocuff Vision-assisted colonoscopy and the remainder had standard colonoscopy. Figure 1 summarises the main findings. There was no significant difference in caecal intubation time and withdrawal time between the two groups. Both ADR and SP6 were significantly improved and SP6 demonstrated that EAC appears to significantly improve colonoscopy efficiency with approximately twice as many pre-cancerous lesions detected and removed per 6 minutes of withdrawal time (1.11 vs 0.6, p = 0.004).Abstract PTU-030 Table 1 Endocuff assisted colonoscopy Standard colonoscopy P value No of patients 49 47 Caecal intubation time (mean’± SD) 5.6±3.0 6.2±3.85 0.39 Withdrawal time (mean ± SD) 10.9±4.5 11.3±5.33 0.72 No of polyps 113 62 0.001 No of adenomas 95 51 0.0005 No of SSP/A 04 02 1.0 ADR 83.67% 55.32% 0.004 SP6 (adenomas+SSP/A) 1.11 0.6 0.0004 Conclusion From this preliminary data an SP6 (colonoscopy efficiency metric) appeared significantly higher when Endocuff VisionTM is used. An SP6 >1 can be achieved in the context of bowel cancer screening FOBT positive colonoscopy and may act as a new benchmark to demonstrate high quality examinations. Disclosure of Interest None Declared

OC-085 Lower Gastrointestinal Polypectomy Competencies in the UK: Retrospective Analysis

Introduction The Directly Observed Polypectomy Skills (DOPyS) is a validated tool used to assess polypectomy skills in the UK.1 The overall competency for polypectomy is graded on a scale of 1 to 4 and is used to certify trainees for level 1 polypectomy (size < 1 cm) and level 2 polypectomy (size 0–2 cm). Trainees are certified as competent if they achieve grades 3 or 4 for more than 90% in their last 4 consecutive DOPyS and a caecal intubation rate (CIR) >90% over last 3 months. The aim of the study was to investigate the progress of competency in polypectomy for endoscopy Methods Retrospective data from the e-portfolio from Jan 2009 to Sept 2015 was extracted using pre-determined criteria. 749 DOPyS data from 61 trainees was analysed. 42 trainees had achieved provisional (level 1 polypectomy) certification and 19 trainees in the same cohort subsequently achieved full (level 2 polypectomy) certification. Data collected included time (in days) & number of lower GI procedures to the start of first recorded polypectomy assessment (1 st DOPyS), time in days needed to achieve level 1 & level 2 competency from 1st DOPyS & from the first recorded lower GI procedure, caecal intubation rate (CIR) at time of 1st DOPyS & at last recorded DOPyS before certification. ResultsAbstract OC-085 Table 1 Median n Time to 1 st DOPyS (days) 449 (0–2585) 61 Lower GI endoscopic procedures at 1 st DOPyS 137 (5–508) 61 CIR at 1 st DOPyS (%) 73 (0–100) 61 Time to level 1 competency from 1 st DOPyS (days) 494 (144–1404) 42 Time to level 2 competency from 1 st DOPyS (days) 616 (228–1324) 19 Time from level 1 to level 2 competency (days) 203 (0–734) 19 CIR at last DOPyS before provisional certification (%) 86 (47–94) 42 CIR at last DOPyS before full certification (%) 88 (60–93) 19 Conclusion Trainees in the UK start formative assessment for polypectomy after > 130 lower GI procedures & CIR of >70% Median time for trainees to achieve level 1 & level 2 competencies from 1st DOPyS is < 2 years Median time for trainees to achieve level 1 competency from first recorded lower GI procedure is > 3 years Time to progress to level 2 competency from level 1 competency is > 200 days & may correspond to the rarity of polyps > 1cm in training cases Polypectomy competency in this cohort of UK trainees is achieved after reaching an overall CIR >85% Further studies are needed to analyse the learning curve of polypectomy & to implement changes to improve efficiency of training Reference 1 Gupta S, Bassett P, Man R, Suzuki N, Vance ME, Thomas-Gibson S. Validation of anovel method for assessing competency in polypectomy. Gastrointest Endosc 2012;75(3):568–575.e1. Disclosure of Interest None Declared

OC-014 Extra Wide Angle View Colonoscope (EWAVE) has Superior Polyp Detection Rate When Compared to a Standard Colonoscope (SD): A Randomised Tandem Pre-Clinical Study

Introduction Colonoscopy screening with the removal of adenomas has been the preferred and most effective strategy to prevent colorectal cancer (CRC). However adenomas are often missed during colonoscopic examination, particularly on the proximal sides of folds and at the flexures. The prototype (EWAVE) Extra Wide Angle View colonoscope (Olympus, Tokyo, Japan) has a 147°–235° angle lateral/backward view lens and a standard 140° angle forward view lens. Views from both lenses are constructed and displayed as a single image. By improving visualisation behind the folds and flexures this new scope could increase the polyp detection rate (PDR). Objective is to compare the polyp detection rate between EWAVE and a standard colonoscope in a colonic model with simulated polyps. Methods Two colorectal (Koken, Japan) rubber colon models were prepared with 18 and 20 polyps of different size (520 mm) at various locations. Seventeen endoscopists, 14 gastroenterology trainees and 3 nurse endoscopists with varying levels of experience performed back to back examinations with the standard colonoscope and EWAVE scope. The order which they performed the procedure (i.e. EWAVE or SD first) was randomised using concealed envelopes. In order to minimise type 2 error, on the 2nd model the endoscopists performed the procedure in reverse order. Results There was no significant difference in mean insertion time (p = 0.8) or withdrawal time (p = 0.29) between EWAVE and standard colonoscope (Figure 1). Mean simulated PDR was significantly higher with EWAVE examination when compared to standard colonoscopic examination in both models (p = 0.026 and <0.0001). Mean simulated PDR was significantly higher with EWAVE in comparison to the standard colonoscope for polyps in the mid transverse colon (79.4% vs 32.3%, p = 0.0002) and mid sigmoid colon (82.3% vs 52.9%, p = 0.0186). When the examination was carried out with the standard colonoscope followed by EWAVE, PDR was significantly higher in both models (p = 0.045 for model 1 and p < 0.0001 for model 2). More significantly no difference was observed when the procedure was performed in the reverse order (p = 0.28 for model 1 and p = 0.08 for model’2).Abstract OC-014 Table 1 Model IStandard Model IEWAVE P value Model IIStandard Model IIEWAVE P value Insertion time (mean+/- SD) 3.7+/-1.8 3.74+/-1.4 0.89 3.05+/-1.7 2.89+/-1.7 0.80 Withdrawal time (mean+/- SD) 4.88+/-1.8 4.96+/-2.1 0.91 4.81+/-3.0 3.85+/-1.6 0.29 PDR (mean+/-SD) 14.5+/-1.8 15.93+/-1.3 0.026 15.8+/-1.2 18.13+/-1.5 <0.0001 Conclusion Our non-clinical study showed significantly higher polyp detection rates with the novel extra wide angle colonoscope when colonoscopy was performed by moderately experienced colonoscopists. Further clinical trials appear warranted. Disclosure of Interest None Declared

PTH-041 Large (<4 cm) and giant (≥4 cm) colorectal polyps: comparison of piecemeal resection outcomes

Introduction Piecemeal Endoscopic Mucosal Resection (p-EMR) is a standard and safe endoscopic technique for resection of large colorectal polyps (>2 cm). Limited data are available regarding p-EMR of giant polyps (>4 cm). Method A prospective study recording short and long-term outcomes after p-EMR for colorectal polyps > 2 cm between Jan 2010 and August 2012 was conducted. We compared two cohorts of patients: group-A with large polyps (2 to <4 cm) vs group-B with giant (≥4 cm) polyps. Chi-square/Fischer’s tests were performed between categorical variables including patient demographics/polyp features/techniques applied {p-EMR with spiral snare and hybrid p-EMR). Our primary outcome was to compare the safety, efficacy and complication rate between the two groups. Results Group-B patients were older than group-A patients (mean 70.6 vs. 67.8 yrs, p = 0.01) and were more likely to have come from a tertiary referral source (p = 0.05). Large polyp referrals were almost twice as frequent as giant polyp referrals (218 vs. 123, p < 0.001). Median polyp size was 2.5cm in group-A and 5cm in group-B. Giant polyps were most commonly found in the recto-sigmoid segment (26% rectum and 28% sigmoid, p < 0.001), whilst large polyps were more evenly distributed throughout the colon. No significant difference in cancer prevalence was recorded between the groups. Endoscopic excision was complete in 89% in large (median time 18min) and in 70% in giant groups (median time 38min). All large polyps were excised in one session, whilst 4% of giant polyps required more than one session. Incomplete submucosal lift (46% vs 63%, p = 0.002) and difficult polyp position (45% vs 63%, p < 0.001) were more common in giant polyps. Spiral snare EMR (6% vs 28%, p < 0.001) and hybrid (0% vs 7%, p < 0.001) techniques were more commonly used in giant than in large polyps. Procedural bleeding occurred more frequently in giant polyps (5% vs 17%, p < 0.001). Delayed bleeding was also significantly higher in giant polyps (15% vs 34%, p < 0.001), but hospitalisation or further intervention did not vary significantly by polyp size. The overall long-term recurrence at 24 months was 17% (11% vs 28%, p = 0.02). The follow up occurrence was more frequent for giant polyps at 3 month (43% vs 72%, p < 0.001) and 9 month (14% vs 26%, p = 0.007) intervals. Benign recurrence requiring surgery and the cancer prevalence did not vary between polyp size group. Conclusion Piecemeal resection is a safe and efficacious modality for the resection of colorectal polyps >4 cm. However, these giant polyps more often require spiral snare or hybrid resection techniques and their higher adenoma recurrence rate post p-EMR may dictate shorter surveillance intervals. Disclosure of interest None Declared.

OC-047 A multi disciplinary team (mdt) approach for complex benign colo rectal polyps: a tertiary referral centre experience

Introduction Multi-disciplinary team (MDT) working is an established part of cancer care. Limited data is available on their impact for benign complex colorectal polyps. Increased numbers of these polyps are referred to our tertiary centre for further management. Method Polyp MDT comprising of gastroenterologists, colorectal surgeons and histopathologists was established in January 2013 to discuss the management of complex polyps (large or recurrent polyps or those where endoscopic access was difficult). Cases that were referred to individual consultants and had a provisional management plan made were then discussed at the MDT and a consensus management plan was agreed. The impact of MDT management plan was then evaluated. Results 96 cases were discussed between January 2013 and October 2014. Of those 75 (78%) were tertiary referrals. The reasons for polyp complexity included large polyps 53 (55%), those with difficult access 52 (54%) and previous failed attempt 35 (36%). Majority of the polyps were in recto sigmoid, 49 (51%) or in caecum, 32 (32%). In 38 cases (40%) provisional management plan was changed after MDT discussion. This plan was then followed in 80/96 (82%) cases. Combined surgical-endoscopic approaches were proposed in 68 cases (65%). 25/96 patients had polypectomy during a single hospital visit. The remaining cases (71/96) needed further assessment before attempted polypectomy. Complete polypectomy was achieved in 85/96 (89%) of patients: endoscopically in 75/96 cases (78%): 38 by endoscopic excision alone and 37 by combined endo-surgical approaches. Ten polyps were resected surgically. Of the remaining 11 patients no polyps were found in 2 of those referred, 2 patients were referred back their local hospital for surgery, 5 were not fit for a polypectomy and are under surveillance, 1 had metastatic colorectal cancer and 1 declined any intervention. Cancer was found in 7/96 polyps and 6/7 had surgical resection (the remaining patient had metastatic disease). Conclusion The polyp MDT consensus management plan led to a change in the proposed management in almost half of the patients. This resulted in complete polypectomy for a large majority of patients referred to our service. Disclosure of interest None Declared.

PTH-042 Spiral snare resection and hybrid endoscopic mucosal ablation: a comparison of outcomes after piecemeal resection/ablation

Introduction Incomplete endoscopic removal of colorectal polyps causes severe submucosal fibrosis, making subsequent endoscopic resection challenging. Two approaches to removal of recurrent polyp over a scarred submucosa or to polyps with inherent submucosal fibrosis such as NG-LST’s are either to use a stiff braided snare which helps capture tissue or to firstly snare as much tissue as possible using a conventional snare and then destroy tissue over the centre of the scar with high power APC preceded by submucosal injection (Endoscopic Mucosal Ablation, EMA). Method A prospective database (Jan 2010–Aug 2012) was used to identify large (>2 cm) colorectal polyps removed in a piecemeal fashion using either hybrid EMR/EMA technique or spiral snare EMR (SS-EMR, Olympus, Keymed, UK) at our tertiary referral centre. Patient/polyp/technique-related details and short/long term endoscopic surveillance data were retrieved and analysed (chi-square/Fischer’s). The aim of this study was to compare the safety, technical success and recurrence between each group (group A – hybrid EMR/EMA, group B – SS-EMR). Results This study enrolled 56 patients in group A and 48 patients in group B. Median polyp size was 3 cm (range 2–8 cm) for group A and 5 cm (2–15 cm) for group B. The majority (64.28%) of polyps in group A had previous failed polypectomy attempts compared to only 27% of polyps in group B. There was no difference in time taken to complete the procedure between the groups (mean time for group A – 36 min vs group B – 39 min). Procedural bleeding (A vs B were 7.1% vs 18.8% p = 0.13) and delayed bleeding (A vs B were 19.6% vs 37.5%, p = 0.05) were more common in group B. There were no peforations in either group. Two (4.2%) patients in SS-EMR group developed post polypectomy syndrome and needed brief hospital admission. Four (7.1%) patients in hybrid EMR/EMA cohort developed delayed bleeding requiring admission for transfusion; all made an uneventful recovery. There was no significant difference in polyp recurrence at 24 months between the groups (A vs B 12.5% vs 8.3%, p = 0.44). No patients have required surgery to date. Conclusion Spiral snare resection and hybrid mucosal resection/ablation modalities are both safe and feasible to eradicate recurrent fibrotic colorectal polyps. Delayed bleeding overall is significantly lower when using the hybrid resection/ablation technique though may be more severe when it does occur. Medium term outcomes appear similar in both groups with acceptable levels of endoscopically manageable recurrence. Disclosure of interest None Declared.